People v. Tran

Filed 6/9/20
CERTIFIED FOR PARTIAL PUBLICATION*

COURT OF APPEAL, FOURTH APPELLATE DISTRICT

DIVISION ONE

STATE OF CALIFORNIA

THE PEOPLE, D075280

Plaintiff and Respondent,

v. (Super. Ct. No. SCD270648 )

HUNG TRAN,

Defendant and Appellant.

APPEAL from a judgment of the Superior Court of San Diego County, Michael S.

Groch, Judge. Affirmed.

Spolin Law and Aaron Spolin, for Defendant and Appellant.

Xavier Becerra, Attorney General, Julie L. Garland, Assistant Attorney General,

Eric A. Swenson, and Junichi P. Semitsu, Deputy Attorneys General, for Plaintiff and

Respondent.

A jury convicted Hung Tran of assault by means likely to produce great bodily

injury (Pen. Code,1 § 245, subd. (a)(4); count 1) and mayhem (§ 203; count 2). In regard

* Pursuant to California Rules of Court, rule 8.1110, this opinion is certified for
publication with the exception of parts II, III, IV.
to count 1, the jury found true that Tran personally inflicted great bodily injury upon the

victim (§ 12022.7, subd. (b)).

The court sentenced Tran to prison for four years. In doing so, the court struck the

great bodily injury allegation and stayed the sentence under count 2.

Tran appeals, contending the court erroneously admitted into evidence "doctored"

videos used by the prosecution's expert witness during his testimony; substantial evidence

does not support his conviction under counts 1 and 2; the court erroneously admitted lay

opinion testimony from a prosecution witness; and Tran's trial counsel was prejudicially

ineffective. We determine that none of Tran's claims has merit and affirm.

FACTUAL BACKGROUND

In the summer of 2016, M.C., his cousin, and his friends were experiencing the

nightlife in San Diego's Gaslamp Quarters. Around 1:30 a.m. on Saturday, August 27,

2016, M.C. and his friend A.N. left Fluxx Nightclub and walked to The New Yorker to

grab a slice of pizza. The Gaslamp district was crowded at the time because the bars

were about to close at 2:00 a.m.

Around the same time, two groups of people had been quarreling inside the

Gaslamp Café, which prompted D.M., one of the establishment's bartenders and servers,

to ask them to leave. The two groups exited the restaurant. One of the two groups

consisted of Tran, his girlfriend K.B., his brothers T.T. and D.T., his cousin D.X., and

1 Statutory references are to the Penal Code unless otherwise noted.
2
three friends: D.M., K.N., and S.P., who were all in San Diego to celebrate T.T.'s

birthday. Multiple witnesses described Tran's group as being of Asian ancestry.2

On the other side of the dispute were two unidentified African American men,

although one eyewitness identified them as "a few Hispanics" and another recalled them

being of Asian ancestry as well. None of the individuals involved in the argument were

known to be affiliated with any gang.

Around 2:00 a.m., shortly after leaving the Gaslamp Café, the two groups

remained agitated and congregated in the patio area outside the café where they

continued to yell at each other. While eating their pizza, M.C. and A.N. heard "a lot of

yelling" from the argument outside the nearby Gaslamp Café, as the two groups

splintered into multiple groups of people arguing, escalating the intensity, and eventually

leading to physical altercations.

As dozens of people surrounded or became ensnared in the rapidly escalating

confrontation, bystander D.M. tried to intervene, but without success. Also trying to

defuse the situation, M.C. and A.N. walked toward the center of the conflict and

attempted to break up the fight and prevent further escalation. They both inserted

themselves in between combatants and tried to push them away from each other. A.N.

recalled lifting his hands and pushing on the chests of the men engaged in fisticuffs.

As chaos ensued, the two African American men walked away from the

altercation, but multiple members of Tran's group instead shifted their aggression toward

2 One eyewitness described the men punching the victim as "Hispanic."
3
M.C. and A.N. One of the women in Tran's group told A.N. not to intervene. Moments

later, Tran's brother T.T. moved toward A.N. to ask him, "What's up? What's up?" A.N.

tried to ease the tension, responding, "the cops are coming, and I know nobody wants to

go to jail." But T.T. responded, "Oh, so you want to talk shit?" Just as A.N. signaled for

T.T. to back up, another Asian American man swung at A.N. but missed, while a third

Asian American man from Tran's group landed a punch in A.N.'s ribs. A.N. then

countered by punching the third man in the face, which dislocated one of A.N.'s fingers.

While A.N. tried to defend himself from attacks, M.C.'s interceding efforts were

similarly thwarted once three Asian American men wearing dark colors suddenly started

"punching and kicking" him. While standing, M.C. raised his arms to defend himself

from the blows. M.C. did not fight with any other individuals. His three attackers

collectively pushed M.C. to the ground, toward the back end of a car.

After this first fall to the ground, M.C. was able to stand up "for a second." But

almost immediately after M.C. stood up, he ended up back on the ground again. Tran,

who was standing by M.C.'s side, flipped M.C. over, causing his head to be slammed into

the hard concrete of Fourth Avenue. S.M., the General Manager of the La Puerta Bar,

had a "clear shot" of the moment, witnessing a "shorter, stocky Asian male" perpetrator3–

with a "fuller" face and "spikey" hair, standing five feet eight inches "if that" and 160

3 S.M. was unable to identify Tran as the perpetrator. Over a month after the crime
was committed, S.M. picked another man (not Tran) out of a photograph lineup of six
men as the perpetrator. However, the person in the photograph that S.M. selected was
not at the scene of the crime. At trial, S.M. testified that he had "no doubt" that the
person depicted in the Snapchat video seen punching M.C. was the "short, stocky guy"
that S.M. identified as the perpetrator.

4
pounds4—picking up the victim, flipping him, and then "body-slamm[ing] him, with the

victim's head and the back of the neck hitting the ground, and then he landed his weight

on him and threw a couple of punches." Tran straddled—"almost like sitting on"—M.C.

as he repeatedly punched the victim in the face. A bystander's Snapchat5 video depicted

Tran punching M.C.'s paralyzed body at least five times. And Tran could not be

excluded as a major contributor to the mixture of DNA found on M.C.'s shirt as well as

the bottom of his shoe. Immediately after Tran punched M.C., Tran's girlfriend K.B. then

approached "and threw a couple of punches" at M.C.'s head as well. S.M. described

K.B.'s punch as a "haymaker," meaning a very violent punch with the intent to knock

someone out. S.M. was unsure, however, whether K.B. actually landed a punch. Tran

did not stop punching M.C. until D.M. approached and pulled him off of the victim.

About the same time, Tran's brother T.T. pulled K.B. away from M.C. and gestured that

they should all leave. Tran and his group abandoned M.C. and walked to the nearby

sidewalk where Tran took off his shirt and wiped his face.

After he removed his button-down shirt, Tran was still wearing an undershirt.

Neither Tran nor K.B. appeared to be significantly injured. Tran and his group then

returned to the Hard Rock Hotel, where they were staying that evening.

4 According to Tran's 2015 DMV information, he was five feet five inches tall and
weighed 152 pounds. However, at trial, a witness claimed Tran "appeared to be a little
bit heavier in the surveillance videos" and his face "was a bit fuller" in comparison to his
DMV photograph.
5 "Snapchat is a smartphone application that allows users to send pictures and
videos (not to exceed 10 seconds in length) to friends or followers." (In re M.H. (2016)
1 Cal.App.5th 699, 704.)
5
 When A.N. returned to M.C., he found M.C. lying motionless in the middle of

Fourth Avenue. From that point on, M.C. was unable to move any part of his body below

his neck; as he stated at trial, "[i]mmediately after I hit the ground, I just felt everything

shut down." Z.T., a Gaslamp Café employee, and S.M. both separately called 911 after

witnessing M.C.'s injury.

With the aid of other bystanders, A.N. helped move M.C.'s body from the middle

of the street to the sidewalk and remained with him until an ambulance arrived.

Paramedics transported M.C. to the UC San Diego Hospital, where he underwent

multiple surgeries after sustaining a severely crushed spinal cord and several broken neck

bones.

Neither the victim nor any of the eyewitnesses at trial positively identified Tran—

or anyone else—as the one who slammed M.C. onto the ground and caused his paralysis.

While at least one video captured M.C. and another person falling to the ground at high

velocity behind a car, no camera was positioned to capture Tran flipping M.C. over or

otherwise knocking M.C. down on his head.

At trial, an orthopedic spine surgeon explained that M.C. received "devastating

vertebral column or spine injuries to the bones." He testified that such injuries required

"a very large velocity and force" that typically involves spinal bone fractures and

retropulsion into the spinal cord. He agreed that M.C.'s injuries were consistent with

someone being thrown or dropped on their head. At the time of trial, M.C. remained a

quadriplegic, paralyzed from his shoulders down.

6
 DISCUSSION

I

THE VIDEOS OF THE INCIDENT

A. Tran's Contentions

Tran asserts that the trial court erroneously admitted a "doctored" video6 that was

"compiled by" the prosecution's expert witness Grant Fredericks. As a threshold matter,

we observe the use of the term "doctored" connotes that Fredericks somehow

manipulated or falsified the video.7 Tran provides absolutely no evidence whatsoever to

support such a serious allegation. In the absence of any evidence to support a claim that

the other side fabricated evidence, a party or his or her attorney would be wise to avoid

such inflammatory accusations.

If we look past Tran's hyperbole, it appears Tran challenges Fredericks's testimony

about the videos after he enhanced them, arguing Fredericks "became the [fact finder]

who decided and shaped the facts of the case instead of the jury." Specifically, Tran

argues the videos were improperly enhanced by Fredericks when he adjusted the height

and width ratio on a video, synchronized multiple videos, corrected the blurring of a

video, and used color coded arrows to identify certain individuals on the videos,

6 Although Tran refers to a single video, there were multiple videos admitted into
evidence at trial. Tran does not describe or distinguish the multiple videos in much
detail. Nevertheless, all the videos are in the record, and we will evaluate Tran's
challenges to all of them.
7 Oxford's online dictionary defines "doctored" as: "change the content or
appearance of (a document or picture) in order to deceive; falsify." (Oxford dictionary
[as of June 8, 2020] archived at archived
at .)
7
including Tran. Tran then baldly asserts these enhancements resulted in Fredericks

invading the province of the jury by making key factual determinations.

However, Tran's argument that Fredericks usurped the jury's role is undermined by

later portions of his own brief. For example, Tran admits Fredericks testified that when

and where he could not definitively identify a person in the video, he did not identify that

person with a colored arrow. As Tran notes and one of the videos shows, at the time

when the victim was slammed to the ground head first, there is no color coded arrow

indicating Tran was near the victim at that time. Further, Tran emphasizes that there are

2.7 seconds of the video near when the victim is injured where there is no indication that

Tran is in the video. Based on these alleged shortcomings in that video, Tran insists: "If

Mr. Tran does not appear in any video causing or initiating [the victim's] injury-causing

fall to the ground and if Mr. Tran does not also appear on the video(s) showing the victim

on the ground immediately after the injury-causing fall, then it is quite difficult to convict

him of Counts one and two."

Thus, Tran's complaint regarding the videos and Fredericks's testimony appears to

be that the videos and testimony are not sufficient to convict him on either count. In

other words, the videos are not substantial evidence to support his convictions. Beyond

challenging the admissibility of the videos, Tran does argue that substantial evidence

does not support his convictions, which we address in part II post. However, to the

extent that he is arguing that Fredericks's testimony about the videos someone improperly

made Fredericks the fact finder at trial in place of the jury, we struggle to find any

support in the record for that argument. Tran admits that the videos do not show him

8
body slamming the victim. Fredericks testified at trial that he could not identify Tran in

the video at the time the victim was body slammed; so, there is no color coded arrow

pointing to Tran in the video at that time. Also, Tran does not point to anywhere in

Fredericks's testimony where Fredericks opined that it was Tran who body slammed the

victim or otherwise paralyzed him. As such, we reject Tran's contention that the

admission of the video somehow transformed Fredericks into the ultimate fact finder at

trial.

In almost a throw away fashion, Tran claims the "forensic video enhancement is

not universally accepted and the law is not clear." He then implies that the enhancement

techniques should be evaluated under the Kelley-Frye test.8 However, Tran does not

discuss the Kelley-Frye test or even argue that the video enhancement here does not

qualify for admission under the Kelley-Frye test. Because he failed to provide any

authority or cite to any portion of the record to support his position regarding Kelley-

Frye, we conclude Tran has waived any such argument here. (See Nelson v. Avondale

Homeowners Assn. (2009) 172 Cal.App.4th 857, 862; In re Marriage of Falcone & Fyke

(2008) 164 Cal.App.4th 814, 830.)

Although we find Tran's challenges to the videos wanting, as the People note,

there is no published California case addressing the admissibility of videos like those

admitted at trial below. In addition, Tran's briefing on this issue did not provide any

necessary background to describe the careful and thoughtful approach of the trial court in

8 The Kelly-Frye test is derived from two cases: People v. Kelly (1976) 17 Cal.3d
24, 30 (Kelly); Frye v. United States (D.C. Cir. 1923) 293 F. 1013, 1014 (Frye).
9
admitting the videos and Fredericks's detailed testimony about the videos. In contrast,

the People describe with great specificity the steps taken by the trial court and Fredericks

below. Because of the novelty and importance of this issue, we will address the court's

admission of the videos and Fredericks's related testimony.

B. Background

Video surveillance from nearby businesses and bystanders' cell phone videos

captured the melee from multiple angles. To help analyze and sequence these videos, the

prosecution sought to call certified forensic video analyst Fredericks as an expert witness

and admit his demonstrative work.

The prosecution filed a pleading entitled "People's Trial Brief and Motions In

Limine" that included a motion to admit Fredericks's expert testimony regarding

"forensic analysis of surveillance videos." The motion noted that Fredericks would

"clarify" the footage, explain "how he was able to assemble the multiple videos into a

chronological sequence," and demonstrate "how he was able to track various individuals

as they move across each of the videos." In response, Tran's trial counsel opposed the

prosecution's motion "to admit purported expert and lay testimony about the contents of

video that the jury can see for itself," as well as the prosecution's "effort to introduce

substantively altered video that merely reflects law enforcement's inadmissible opinions."

At the Evidence Code section 402 hearing, Fredericks laid out his qualifications,

including summarizing his 30 years of experience as a certified forensic video analyst.

Fredericks obtained a degree in television broadcast communications with an emphasis

on television engineering from Gonzaga University. He worked as a television news

10
reporter and producer for five years before joining the Vancouver Police Department,

where he eventually headed the department's Forensic Video Unit. Since 1991, he has

continually served as a forensic video analyst for Forensic Video Solutions. As the

principal instructor for the Law Enforcement and Emergency Services Video Association

(LEVA), he also has trained video analysts throughout the world. Since 2002, he has

served as an instructor at the FBI National Academy, where he teaches four national

academy sessions each year. In 2012, he became certified in the area of forensic video

analysis by LEVA. Although he has a law enforcement background, his work as an

expert witness has been evenly split between working for the prosecution and the

defense.

After discussing his background, Fredericks explained how he generally processes

videos for criminal investigations. First, he is proficient in performing video

synchronization, image comparison investigations, aspect ratio calibration, color

correction, motion tracking, and image authentication. Therefore, he focuses on

preserving the integrity of a video. Because digital videos employ varying levels of

image refresh rates, prediction levels, and frame rates to compress the size of videos,

Fredericks tries to ensure that the resulting variances do not get misinterpreted by the

viewer. He employs a variety of tools to "interrogate" each video file and analyze

compression levels, frame rates, and pixel matrixes. Among other tools, he utilizes

iNPUT-ACE, a software program that allows forensic investigators to process, enhance,

and analyze videos, including movement management. Fredericks testified that the

11
procedures he described are "currently [used by] several hundred certified analysts and

technicians, all of whom have been trained in this process."

Fredericks next detailed the work he did in this case. He spent "many dozens of

hours" reviewing surveillance videos from the Hard Rock Hotel, the Las Hadas

restaurant, Pacifica Hotel, Sultan Shawarma, and the Reef Bar. He also reviewed a cell

phone video that had been filmed and uploaded to Snapchat. He then used slides 24

through 27 and 34 through 36 of the "Camera Perspective" PDF document, which is part

of the record before us, to visually display how he determined the location and position of

each camera, the area depicted in the footage, and the overlap between the footage.

Fredericks explained in great detail how he synchronized the videos to create

chronological sequences by, for example, using a person's leg movement in multiple

videos to test synchronicity.

Fredericks's synchronized chronological sequences allowed him to track specific

individuals moving across videos through color-coded arrows. By synchronizing minute

details like clothing patterns and the location of one's feet, Fredericks was able to track an

individual through multiple videos, even though that individual's image might have

otherwise been too blurry to identify any person when simply viewing a specific moment

of one video. For example, he explained how he was able to synchronize and track one

individual (later identified as D.M.) across multiple videos:

"The individual with the pink arrow that I'm tracking moves
toward the activity on the ground. And . . . he then turns to his right,
and we can see that same activity in the Las Hadas Video. . . .

12
 "So the feet in the Las Hadas video turns to the right and moves
in just as the individual that I have been tracking in the pink arrow
turns to the right and moves in and down at the same time as in the
Reef Bar video. We see now the full upper body and face of the
individual I was tracking. His face is reflected. He is obviously a
light-skinned male reflected in the light. And he bends down and
over. He is the only person doing this. That's reflected in the
Snapchat video and the Reef Bar video. And he bends down. He
then pulls back up.

"So if I go backwards and forward and move my arrows to do
that, up, he goes backwards and now down. So we can track his
movement. We now know without a doubt, we are tracking the right
person."

Fredericks testified that he only assigned a color arrow to an individual when he

could validate its accuracy with forensic certainty. He acknowledged that "where I have

assigned an arrow, my opinion is it is the same person." Consequently, there are several

moments in a video when Tran or others in his group may appear in the video, but

Fredericks did not include a corresponding arrow because the person was too far away

from the camera or Fredericks could not be certain that the shoes appearing on the street,

for example, belonged to a specific individual.

Fredericks explained that all of his work and conclusions are documented in a way

that another person with similar training and experience could review Fredericks's work

and identify areas where he or she disagreed with any of his conclusions. Specifically, he

noted that with regard to "all of my work product and all of the placement, there is a

record within Photoshop of every position of every hour for every image, and that's

locked into Photoshop," allowing peer review. Fredericks also explained that all his work

13
is "technically peer reviewed before it goes out." While the peer review is handled

"internally," some of his work "gets externally peer reviewed."

Fredericks acknowledged the limits of his expertise and how he would not opine

in various areas that might infringe on the province of the jury. For example, he noted

that he would not be testifying to whether the video shows one person making contact

with another. He explained:

"My general practice in force issues is to describe the X/Y
coordinate of a motion perhaps or these pixels that I would describe
represent the arm of this clothing, and I can track that motion from
this area to this area.

"I'm not a use-of-force expert. I am not going to tell the jury,
'here, you should see this person kicking this person and this person
punching that person.' That's not what I am going to do."

Specifically, Fredericks stated that he "wouldn't be offering any opinion,

statement, comment about the nature of [M.C.'s] fall and what injuries were caused" or

"who caused the motion to the ground." Fredericks then explained why his expertise was

necessary to assist the jury, and how and why the average person who separately views

multiple videos may not appreciate how and when they capture the same scene at the

same time. First, he noted that most laypeople struggle to process how one object or

person in a video is the same object or person in another video. Because of cameras

positioned on different sides and points of the street, "you have individuals not just

moving left to right, moving at the Z axis . . . , which is away from the camera in one

view, but left to right on another view."

14
 Additionally, Fredericks explained that people have difficulty understanding the

significance of blurring in a video, which could represent fast motion. According to

Fredericks, jurors also might fail to appreciate how infrared impacts various colors—and

more specifically, the colors of a person's clothing—causing a person to appear to be

wearing different clothing in different videos of the same event. Fredericks disputed the

notion that he "altered" the videos, emphasizing that "the meaning of all the videos are

maintained." While he acknowledged adding the movement-tracking arrows, he stressed

that the "actual images are completely untouched." He also pointed out that he used a

cubic interpolation process to calibrate the Las Hadas video to the correct aspect ratio.

However, for all other videos, "the tonal values of every single pixel are maintained."

After hearing Fredericks's testimony at the Evidence Code section 402 hearing, the

trial court allowed Fredericks to testify at trial and admitted his "color-tracking" videos

into evidence. The court concluded: "It is clear to me that the testimony of the witness

would assist the trier of fact, and that not only would it assist the trier of fact, I think it is

quite necessary to assist the trier of fact." The court further determined that Fredericks's

testimony "is related to a subject that is sufficiently beyond common experience." Given

that the videos were "busy, full of commotion, hard to follow, active, and even with the

benefit of the colored indicators, . . . are very difficult to track," the court found that

tracking them without Fredericks's assistance would be "impossible . . . and even with his

assistance, very difficult."

The trial court ruled that there was no need to apply the Kelly-Frye test, noting that

"the methods and procedures described by the expert are not a novel, scientific testing

15
method or procedure." The court observed the Ninth Circuit's opinion in United States v.

Cairns (1970) 434 F.2d 643, 644 (Cairns), which allowed an FBI photographic

identification specialist to testify that the bank robber in a bank's surveillance camera

photograph was the same person in a police photograph (of defendant), after enlarging

the head area of the bank photo and comparing the similarities in facial characteristics,

hairlines, chin lines, and ear contours. The trial court noted that Cairns demonstrated

"how long photographic comparisons have been done." Additionally, the court found

that Fredericks's process of "synchronization, which is really the heart of the

value . . . that the witness provides, uses no special method" and rests on common sense.

Also, the court observed that it believed Tran's trial counsel's cross-examination of

Fredericks "was very effective" and commented that "the jurors are going to very easily

not be blinded by any of the science. There really isn't science to this."

After weighing the various Evidence Code section 352 factors, the trial court then

found no prejudice and further concluded that any prejudice was outweighed by the

probative value under the facts and circumstances of this case.9 Dismissing concerns that

Fredericks's testimony or the videos might be based on unreliable or speculative

techniques, the court noted the minimal risk "that the jurors are going to be blinded by

[the expert's] magic and accept a conclusion without any independent analysis." Because

Fredericks's work is "transparent" and subject to replication, the trial court noted that the

9 Evidence Code section 352 provides: "The court in its discretion may exclude
evidence if its probative value is substantially outweighed by the probability that its
admission will (a) necessitate undue consumption of time or (b) create substantial danger
of undue prejudice, of confusing the issues, or of misleading the jury."
16
jury "can track what it is that the witness relied upon" and "make independent

determinations as to the reliability."

At trial, after summarizing his credentials, Fredericks explained to the jury that

"most of what a video analyst does is ensure that the evidence can be played accurately,

and that any errors that might be in the images can be explained and that objects can be

tracked." He stated that "tracking comparison work" is very common and the most

common request he receives. Another "very common request" is synchronizing videos

from multiple sources, which he has done "thousands of times." He also told the jury that

his work in criminal cases is nearly "50/50" between working with prosecutors and

working with the defense.

Fredericks next discussed his work in the instant matter, detailing which videos he

received, and their differences in quality. He used annotated maps of the surrounding

area to show the jury the location and angles of each camera that provided footage. He

also explained any corrections or calibrations he made to account for infrared cameras or

distorted aspect ratios. He then synchronized these videos, and "put them in a format that

would allow them to be understood in court and to assist in tracking the movements of a

number of individuals who appear in a large number of cameras, and then to determine

the relationship, how the individuals interact together, and how then to produce

demonstratives that demonstrate that process."

17
 He then described how he tracked individuals. Specifically, when tracking

Tran,10 he noted how Tran differed in appearance from the others in his group.

Fredericks testified that Tran wore "pointed dress shoes," "a dark crewneck t-shirt," and

"a dark dress shirt" that he later removed and eventually rolled up; he had short, shaved

hair on the side of his head; and he was often "arm in arm" with the woman underneath

the green arrow." Unlike D.X., Tran was not wearing a red hat, he did not have visible

arm tattoos, and he was not wearing casual shoes with white tips and white shoelaces.

Unlike K.N., he was not wearing a pink shirt. Unlike his brother T.T., he was not

wearing a white shirt, a white cap, and white pants Unlike his brother D.T., Tran did not

wear glasses. Fredericks also explained that he tracked individuals who were not part of

Tran's group. The victim, M.C., was tracked with a yellow arrow. M.C.'s friend A.N.

was tracked with a purple or fuchsia arrow. D.M. was tracked with a pink arrow.

Finally, M.M., the bystander who filmed the fight through the Snapchat app on his phone,

was tracked with a peach arrow.

Most significantly, Fredericks opined that M.C. and just one other individual

moved to the ground between frames 50999 and 51114, which immediately preceded the

moment in which M.C. became immobilized. As Fredericks slowly advanced and

"rewinded" these moments for the jury, he noted that the video shows "the movement on

the ground of two individuals." He further explained that 2.7 seconds separated the point

10 Although Fredericks never identified any of the individuals in the videos by name,
it was understood that Tran was indicated in the videos by a blue arrow. Indeed, Tran's
own trial counsel referred to Tran as the blue arrow individual.
18
in which M.C. first goes to the ground in the Reef Bar video and the moment in which the

action "is picked up on the other side by the Snapchat video." He noted that "nobody

goes to those two individuals at this point until [after] we see the movement on the

Snapchat video" when "the green arrow female" (K.B.) and the "red male dressed all in

white" (T.T.) move toward M.C. Fredericks also observed that "nobody moves away

from that area" during this critical portion of the video. While the videos depicted other

individuals who stood watching and filming the fight, Fredericks observed that there was

"still quite some distance between any of the individuals" and M.C.

In the footage before M.C. hit the ground the second time, Fredericks explained

that he placed no blue (or any color) arrow above the individual who hit the ground with

M.C. because he could not track that person in those frames with forensic certainty.

Fredericks stated that he did not use an arrow in those circumstances where he lost

continuity or the individual was too far away or lost in a group. However, Fredericks

cautioned that the lack of an arrow "doesn't mean the person is not there," but rather, "just

means that I can't prove to a certainty that that is the person."

Fredericks showed that the blue arrow appears again around frame 51304 because

the Snapchat video captured Tran's pointed dress shoe, his long, dark pants, and his long-

sleeved dark shirt with cuffs, as he repeatedly punched M.C. Moreover, when D.M.

appeared in the video and pulled Tran off M.C., the video, around frame 51333, provided

a clear view of Tran's tightly cropped or shaved hair on the sides of his head. Fredericks

further noted that "nobody ha[d] that specific ensemble characteristics that I can see" in

the videos. Additionally, other videos tracked Tran moving off with his group as they

19
returned to the Hard Rock Hotel, where cameras depicted him carrying his dress shirt in

his right hand.

C. The Law

The trial court is empowered with broad discretion to determine the relevance of

evidence, including questions regarding its probative value and undue prejudice.

(People v. Rodriguez (1999) 20 Cal.4th 1, 9-10 (Rodriguez).) This broad discretion

applies to the determination of the relevancy of expert evidence as well. (People v.

Richardson (2008) 43 Cal.4th 959, 1008.)

Given the broad discretion accorded to trial courts to determine the relevancy of

evidence, trial judges bear a substantial gatekeeping responsibility to ensure the proper

use of expert testimony. (See Sargon Enterprises, Inc. v. University of Southern

California (2012) 55 Cal.4th 747, 772-773.) "[U]nder Evidence Code sections 801,

subdivision (b) and 802, the trial court acts as a gatekeeper to exclude expert opinion

testimony that is (1) based on matter of a type on which an expert may not reasonably

rely, (2) based on reasons unsupported by the material on which the expert relies, or

(3) speculative." (Id. at pp. 771-772; see People v. Olguin (1994) 31 Cal.App.4th 1355,

1371; Evid. Code, §§ 801-802.)

Evidence Code section 801 provides:

"If a witness is testifying as an expert, his testimony in the form
of an opinion is limited to such an opinion as is:

"(a) Related to a subject that is sufficiently beyond common
experience that the opinion of an expert would assist the trier of fact;
and

20
 "(b) Based on matter (including his special knowledge, skill,
experience, training, and education) perceived by or personally
known to the witness or made known to him at or before the hearing,
whether or not admissible, that is of a type that reasonably may be
relied upon by an expert in forming an opinion upon the subject to
which his testimony relates, unless an expert is precluded by law
from using such matter as a basis for his opinion."

Whether a person qualifies as an expert upon a particular subject depends upon the facts

of that case and the witness's qualifications. (People v. Davis (1965) 62 Cal.2d 791,

801.) "The competency of an expert is relative to the topic and fields of knowledge about

which the person is asked to make a statement. In considering whether a person qualifies

as an expert, the field of expertise must be carefully distinguished and limited."

(People v. King (1968) 266 Cal.App.2d 437, 445.)

" 'Expert opinion testimony is admissible only if it is "[r]elated to a subject that is

sufficiently beyond common experience that the opinion of an expert would assist the

trier of fact." ' " (People v. McDowell (2012) 54 Cal.4th 395, 425-426, quoting People v.

Watson (2008) 43 Cal.4th 652, 692; Evid. Code, § 801, subd. (a).) The pertinent question

in allowing expert testimony and expert opinion is whether, even if the jurors have some

knowledge of the subject matter, the testimony would assist them. (People v. Lindberg

(2008) 45 Cal.4th 1, 45 (Lindberg); accord, People v. Prince (2007) 40 Cal.4th 1179,

1222.)

Although the trial court concluded that the Kelly-Frye test did not need to be

applied to the admission of the videos, and we found that Tran waived any challenge that

such a determination was error, we believe it prudent to briefly describe the subject test to

provide necessary context to our analysis. The Kelly-Frye test consists of three prongs

21
and was adopted by the California Supreme Court to analyze the reliability of expert

testimony based on new or novel scientific methods or techniques. (See People v. Lucas

(2014) 60 Cal.4th 153, 223.) The rule "governs the admissibility of evidence derived

from new scientific techniques." (People v. Jones (2013) 57 Cal.4th 899, 936.) The rule

applies only " 'to that limited class of expert testimony which is based, in whole or part,

on a technique, process, or theory which is new to science and, even more so, the law.'

[Citation.]" (People v. Leahy (1994) 8 Cal.4th 587, 605.)

The purpose underlying the rule is to protect a jury from expert testimony that

conveys a " 'misleading aura of certainty' " about a scientific technique. (Kelly, supra, 17

Cal.3d at pp. 30-32; see People v. Stoll (1989) 49 Cal.3d 1136, 1155.) The Kelly analysis

thus is designed to address "scientific evidence or technology that is so foreign to

everyday experience as to be unusually difficult for laypersons to evaluate." (People v.

Venegas (1998) 18 Cal.4th 47, 80.)

Under the Kelly-Frye test, "the proponent of evidence derived from a new

scientific technique must establish that (1) the reliability of the new technique has gained

general acceptance in the relevant scientific community, (2) the expert testifying to that

effect is qualified to give an opinion on the subject, and (3) the correct scientific

procedures were used." (People v. Doolin (2009) 45 Cal.4th 390, 445.) "Whether a new

scientific technique has gained general acceptance is a mixed question of law and fact."

(Id. at p. 447.) However, "proof of such acceptance is not necessary if a published

appellate opinion affirms a trial court ruling admitting evidence obtained through use of

22
that technique, at least until new evidence is admitted showing the scientific community

has changed its attitude." (People v. Cordova (2015) 62 Cal.4th 104, 127.)

The trial court's discretion to admit any demonstrative evidence is reviewed for

abuse of discretion. (See People v. Caro (2019) 7 Cal.5th 463, 508.) In People v.

Duenas (2012) 55 Cal.4th 1 (Duenas), the California Supreme Court explained that the

admissibility of any evidence altered, generated, or otherwise analyzed by computer

software depends on whether such evidence constitutes a "computer animation" or a

"computer simulation." (Id. at pp. 20-21.) The court explained the difference between

the two:

" 'Animation is merely used to illustrate an expert's testimony
while simulations contain scientific or physical principles requiring
validation. [Citation.] Animations do not draw conclusions; they
attempt to recreate a scene or process, thus they are treated like
demonstrative aids. [Citation.] Computer simulations are created by
entering data into computer models which analyze the data and reach
a conclusion.' [Citations.] In other words, a computer animation is
demonstrative evidence offered to help a jury understand expert
testimony or other substantive evidence . . . ; a computer simulation,
by contrast, is itself substantive evidence." (Id. at p. 20, citations
omitted.)

The court determined that a computer animation is admissible if " ' "it is a fair and

accurate representation of the evidence to which it relates. . . ." ' " (Ibid.) In contrast, a

computer simulation is only admissible if it complies with the Kelly-Frye test. (Duenas,

at pp. 20-21.)

D. Analysis

As a threshold matter, we agree with the trial court that neither Fredericks's

testimony nor the videos were subject to the Kelly-Frye test. Like the animated video in

23
Duenas, Fredericks's work is a form of computer animation analogous to "charts or

diagrams" used in other "classic forms of demonstrative evidence." (Duenas, supra, 55

Cal.4th at p. 20.) Fredericks did not alter the underlying surveillance videos, except to

enhance their quality and correct pixel ratios. In fact, he aimed to preserve the integrity

of the videos. In addition, Fredericks testified that his technique for tracking and

sequencing videos involved both common sense and longstanding tools routinely used for

image comparison. Tran does not point to any contrary testimony in the record. Tran did

not call an expert witness to contradict Fredericks's testimony about the techniques that

he was using. And we have found nothing in the record that Fredericks was using new or

novel techniques to enhance the videos.

Also, unlike computer simulations created by reconstruction experts, the videos

admitted at trial in the instant action were not speculative or imaginative creations that

purported to show what Fredericks (or anyone else) believed might have happened at the

time in question. Rather, Fredericks's expertise was provided as an aid to help others

understand the raw surveillance footage, which the jury was also provided. Moreover,

Fredericks's tracking arrow videos resembled surveillance videos that are routinely

modified so that a specific area of the screen is circled or brightened (or the rest of the

video is darkened) to draw the viewer's attention to a specific area. These arrows

essentially functioned like a witness writing an X on a map or placing a Post-It note with

a name on an enlarged photograph. Indeed, if one of Tran's friends had testified and

identified individuals in the surveillance videos, such testimony would have been

unremarkable, though the effect would have been no different than Fredericks's testimony

24
and demonstrative evidence (the videos). While that hypothetical witness's ability to

identify people would stem from knowing them personally and having been present at the

scene, Fredericks's ability to identify individuals in the videos stems from his study of the

videos as well as his own awareness of each person's physical characteristics on the night

in question. Put differently, the colored arrows identifying individuals that Fredericks

added to the videos were not the product of some new scientific technique that he

developed for the instant matter. Instead, they were based on Fredericks's observations

and were intended to help the jury. The jury was free to disregard the arrows if the

arrows did not comport with the jury's viewing of the videos. Simply put, because

Fredericks's videos did not constitute or seek to replace substantive evidence, there was

no need to apply the Kelly-Frye test. (See Duenas, supra, 55 Cal.4th at p. 20.)

Because we agree with the trial court that the Kelly-Fyre test did not apply to the

admission of the videos, we turn to whether the court abused its discretion in admitting

the subject evidence. (See People v. Wallace (2008) 44 Cal.4th 1032, 1057.)

Based on the record before us, we conclude that the trial court did not abuse its

discretion in admitting the videos or Fredericks's testimony about the videos. The

challenged evidence was relevant, useful, and highly probative of the circumstances that

led to M.C.'s paralysis. Fredericks's testimony helped the jury to identify what portions

of the video evidence required closer examination and to interpret some of the

information conveyed by the video evidence. His expertise was necessary for the jury to

accurately evaluate the videos to appreciate who and what they were watching as well as

the chronology and relationship between each video. As the trial court noted, the

25
individuals in the videos were very difficult to track "even with the benefit of

[Fredericks's] colored indicators," and "impossible" to track without his expert assistance.

Although jurors ordinarily may be capable of watching a surveillance video and

understanding what they see without expert help, the scene captured by the multiple

videos was especially challenging. As such, Fredericks's assistance in this case was

critical because multiple surveillance videos depicted a moving melee, at night, with at

least a dozen bodies interacting on a crowded street. Fredericks's testimony and

sequenced videos were necessary to aid the jury's understanding of how the different

videos captured the same action from different angles, thus minimizing confusion that

can result from contrasting video perspectives, contradictory descriptions, or unreliable

eyewitnesses. Indeed, Fredericks's synchronization demonstratives and tracking videos

were critical for the jury to make sense of the various videos that differed by way of time

stamps, camera angles, dimensions, lighting, resolution, pixel ratios, and quality.

Further, as the crime occurred at night and the lighting of the streets and in the videos

was not uniform, Fredericks's testimony and enhancement of the videos aided the jury in

identifying the various participants in the melee. Of course, if a juror did not agree with

Fredericks's identification of an individual in a video, he or she was free to disregard it.

In fact, the trial court jury instructions buttressed this point as the court informed the jury

that it could disregard Fredericks's opinion and testimony:

"Witnesses allowed to testify as experts and to give opinions. . . .
You must consider the opinions, but you are not required to accept
them as true or correct. . . . The meaning and importance of any
opinion are for you to decide.

26
 "In evaluating the believability of an expert witness, follow the
instructions about the believability of witnesses generally.

"In addition, consider the expert's knowledge, skill, experience,
training, and education, the reasons the expert gave for any opinion,
and the facts or information on which the expert relied in reaching
that opinion. You must decide whether information on which the
expert relied was true and accurate.

"You may disregard any opinion that you find unbelievable,
unreasonable, or unsupported by the evidence.

"An expert witness may be asked a hypothetical question. A
hypothetical question asks the witness to assume certain facts are
true and to give an opinion based on the assumed facts.

"It is up to you to decide whether an assumed fact has been
proved. If you conclude that an assumed fact is not true, consider
the effect of the expert's reliance on that fact in evaluating the
expert's opinion."

Further, the court also instructed the jury that it was the ultimate finder of fact, not

Fredericks: "You must decide what the facts are. It is up to all of you, and you alone, to

decide what happened[.]"

Additionally, Evidence Code section 352 does not change our conclusion. The

highly probative value of Fredericks's videos was not substantially outweighed by the

danger of unfair prejudice. While Fredericks's work may have involved sophisticated

software, technical jargon, and years of experience, there was no risk that the jurors

would be left confused or misled. There was nothing sensational about his testimony or

videos. Fredericks's testimony and enhancement of the videos simply helped the jury

observe what the videos showed. The jurors could easily appreciate that Fredericks

clarified some videos, sequenced and combined videos so that the jury could watch the

27
same events (at the same time from different angles) on one screen, and tracked various

individuals. There was nothing improper about the admission of the videos or

Fredericks's testimony. (Cf. People v. Perry (1976) 60 Cal.App.3d 608, 615 [in allowing

a police officer to identify the perpetrator in blurry surveillance footage, the court noted

"[t]he testimony d[id] not invade the province of the trier of fact, but rather [wa]s

submitted as an aid in the determination of the ultimate question of the identity of the

culprit and the defendant's guilt or innocence"].)

Although there is no published California case addressing the admissibility of

videos that were enhanced as in the instant matter, we observe that our conclusion that

the court did not abuse its discretion in admitting the videos at trial is consistent with how

other jurisdictions have dealt with similar situations. (See, e.g., State v. Almaraz (2013)

154 Idaho 584, 603 [forensic video analyst Grant Fredericks properly qualified to opine

about, and assist the jury to determine, which frame depicted the victim reacting to being

shot]; Stevenson v. State (Tex.Ct.App. 2010) 304 S.W.3d 603, 623 [forensic video analyst

Grant Fredericks's testimony admissible to help the jury clarify the images obtained from

a poor-quality, black-and-white video]; see United States v. Alexander (5th Cir. 1987)

816 F.2d 164, 167 [holding that the trial court should have allowed bank robbery

defendant to present expert testimony challenging the government's assertion that

defendant was the one depicted in surveillance photographs of the robbery]; United

States v. Sellers (4th Cir. 1977) 566 F.2d 884, 886 [expert's testimony admissible to

explain the effects of light, shadow, reflections, distortion from perspective, and other

technical factors on surveillance photograph]; Cairns, supra, 434 F.2d at p. 644

28
[photographic identification specialist's testimony permitted to testify to similarities

between enlarged surveillance photograph and police photograph].) Also, our high court

has "decline[d] to require a greater showing of authentication for the admissibility of

digital images merely because in theory they can be manipulated." (People v. Goldsmith

(2014) 59 Cal.4th 258, 272, citing Owens v. State (2005) 363 Ark. 413, 420 [214 S.W.3d

849], 854 [refusal to impose a higher burden of proof for admissibility of still

photographs taken from a store surveillance camera's videotape merely because digital

images are easier to manipulate].)

Accordingly, we are satisfied that the trial court did not abuse its discretion in

admitting the videos and Fredericks's testimony at trial.

II

SUFFICIENCY OF THE EVIDENCE

A. Tran's Contentions

Tran maintains the evidence was insufficient for the jury to convict him of assault

by means likely to produce great bodily injury and/or mayhem. We disagree.

B. Standard of Review

We review a sufficiency of the evidence claim under the familiar and deferential

substantial evidence standard of review. (See People v. Hicks (1982) 128 Cal.App.3d

423, 429.) Substantial evidence is evidence that is "reasonable, credible, and of solid

value." (Rodriguez, supra, 20 Cal.4th at p. 11.) In reviewing for substantial evidence,

we presume in support of the judgment the existence of every fact the trier could

reasonably deduce from the evidence. (See People v. Lee (2011) 51 Cal.4th 620, 632.)

29
"Conflicts and even testimony which is subject to justifiable suspicion do not justify the

reversal of a judgment, for it is the exclusive province of the trial judge or jury to

determine the credibility of a witness and the truth or falsity of the facts upon which a

determination depends. [Citation.] We resolve neither credibility issues nor evidentiary

conflicts; we look for substantial evidence." (People v. Maury (2003) 30 Cal.4th 342,

403.)

"When a jury's verdict is attacked on the ground that there is no substantial

evidence to sustain it, the power of an appellate court begins and ends with the

determination as to whether, on the entire record, there is any substantial evidence,

contradicted or uncontradicted, which will support it, and when two or more inferences

can reasonably be deduced from the facts, a reviewing court is without power to

substitute its deductions for those of the jury. It is of no consequence that the jury

believing other evidence, or drawing different inferences, might have reached a contrary

conclusion." (People v. Brown (1984) 150 Cal.App.3d 968, 970.) Whether the evidence

presented at trial is direct or circumstantial, the relevant inquiry on appeal remains

whether any reasonable trier of fact could have found the defendant guilty beyond a

reasonable doubt. (See People v. Manibusan (2013) 58 Cal.4th 40, 92.) Moreover,

unless the testimony is physically impossible or inherently improbable, testimony of a

single witness is sufficient to support a conviction. (See People v. Dominguez (2010) 180

Cal.App.4th 1351, 1356.)

30
 C. Analysis

The parties do not dispute the elements of the two offenses the jury convicted Tran

of. At trial in the instant action, the court instructed the jury that to prove that Tran was

guilty of assault with force likely to produce great bodily injury (§ 245, subd. (a)(4)), the

prosecution had to prove that: (1) The defendant did an act that by its nature would

directly and probably result in the application of force to a person; (2) the force used was

likely to produce great bodily injury; (3) the defendant did that act willfully; (4) when the

defendant acted, he was aware of facts that would lead a reasonable person to realize that

his act by its nature would directly and probably result in the application of force to

someone; (5) when the defendant acted, he had the present ability to apply force likely to

produce great bodily injury to a person; and (6) the defendant did not act in self-defense

or in defense of someone else. (See CALCRIM No. 875.)

To conclude that Tran personally inflicted great bodily injury that caused M.C. to

become paralyzed within the meaning of section 12022.7, subdivision (b), the jury had to

find the prosecution proved: (1) the defendant personally inflicted great bodily injury on

M.C. during the commission of the crime; and (2) the defendant's acts caused [M.C.] to

suffer permanent paralysis. (See CALCRIM No. 3161.)

Regarding the crime of mayhem, section 203 defines simple mayhem as follows:

"Every person who unlawfully and maliciously deprives a human being of a member of

his body, or disables, disfigures, or renders it useless, or cuts or disables the tongue, or

puts out an eye, or slits the nose, ear, or lip, is guilty of mayhem." As the jury here was

instructed, the prosecution had to prove that Tran unlawfully and maliciously disabled or

31
made useless a part of someone's body and the disability was more than slight or

temporary, and the defendant was not acting in self-defense. (See CALCRIM No. 801.)

In the instant action, Tran claims the prosecution did not present any evidence that

he committed an act of force on the victim that could have possibly caused serious bodily

injury such as paralysis. To this end, Tran focuses on the fact that there is no video

depicting him slamming the victim to the ground on his head. He also points out that the

eye witnesses to the brawl offered differing testimony and did not testify that they saw

Tran commit any act that would have seriously harmed the victim (like causing

paralysis). However, in making these arguments, we note that Tran all but ignores the

substantial evidence standard. Although he points out all the evidence that he believes is

insufficient, he fails to appreciate that, in a substantial evidence review, we must review

" 'the whole record in the light most favorable to the judgment below to determine

whether it discloses substantial evidence—that is, evidence which is reasonable, credible,

and of solid value–such that a reasonable trier of fact could find the defendant guilty

beyond a reasonable doubt.' " (People v. Wolfe (2018) 20 Cal.App.5th 673, 681, quoting

People v. Johnson (1980) 26 Cal.3d 557, 578.) When we apply the proper standard of

review to the whole record, we conclude that substantial evidence supports Tran's

convictions.

S.M. testified that the person who threw the victim down on his head was the same

person who then began punching the victim's face immediately afterwards. The original

Snapchat video taken at the scene captured Tran straddling M.C. and punching his

immobile body in the face, without any other individuals standing immediately nearby.

32
(See People's Exhibit No. 11.) Indeed, Tran does not dispute that he was the one who

repeatedly punched M.C. several seconds after the act that caused the permanent

paralysis. Nor does he contend that he was acting in self-defense.

Although S.M. incorrectly identified someone else (who was not at the scene of

the crime) in a photographic lineup as the "closest" to who he observed on the night in

question and described the perpetrator as someone with a different colored undershirt, the

jury nonetheless determined that S.M. was credible when he testified about how the

person who body slammed the victim was the same person who was repeatedly punching

the victim's face seconds later. Because S.M.'s testimony was not "physically impossible

or inherently improbable," we are not free to disregard the jury's implicit finding that

S.M.'s testimony was believable. (People v. Elliot (2012) 53 Cal.4th 535, 585.) The

jurors could disregard that portion of S.M.'s testimony that conflicted with its ultimate

finding regarding Tran's guilt. In fact, it seems logical the jury would believe a witness

who observed a terrifying event: a man slamming another man headfirst into the ground

then pummeling the fallen man without mercy.

Additionally, we are not troubled by inconsistencies Tran points out in S.M.'s

testimony. Tran is merely arguing about the weight to give S.M.'s testimony and raising

issues of credibility. Both of those issues are for the jury to decide, not this court. We do

not reweigh evidence or reassess a witness's credibility and we presume the existence of

every fact the trier of fact could reasonably deduce from the evidence. (Lindberg, supra,

45 Cal.4th at p. 27.) Simply put, the jurors were free to disbelieve all of Tran's version of

33
events in favor of other conflicting evidence. (See People v. Silva (2001) 25 Cal.4th 345,

369.)

Further, the video footage supports S.M.'s testimony that Tran was the perpetrator.

Although S.M. misremembered details about Tran's appearance, his general description

of the perpetrator as a "shorter, stocky Asian male" with a "fuller" face and "spikey" hair,

with a height of, at most, five feet eight inches, and a weight of approximately 160

pounds accurately describes Tran. Moreover, S.M.'s testimony of the perpetrator using a

button-down shirt to wipe his face while wearing an undershirt were corroborated by

video footage from the Hard Rock Hotel; while Tran wore a black—and not a white—

undershirt, multiple cameras captured Tran walking with his button-down shirt in his

hands and repeatedly holding it up to an apparent cut on his eye.

Also, surveillance videos reveal that only 2.7 seconds separated the moment that

M.C. is slammed to the ground from the point that the Snapchat footage begins. Yet,

during that intervening period of time, no person is seen next to or moving toward or

away from Tran, aside from multiple bystanders filming the fight with their cell phones.

Thus, it is reasonable and logical for the jury to determine that the video footage

supported S.M.'s testimony that Tran was the perpetrator.

Against this backdrop, we are satisfied that substantial evidence supports the jury's

verdict at trial, specifically that Tran was the person who slammed the victim headfirst to

the ground causing him to be paralyzed.

34
 III

THE TESTIMONY OF MARCO PEREZ

Tran insists the trial court erred in admitting the opinion of Detective Marco Perez.

Specifically, Tran claims the court abused its discretion in allowing Perez "to testify as to

the factual and legal conclusions that he drew from his work with the videos acquired

from the establishments in the Gaslamp district." However, Tran does not cite to any

portion of Perez's trial testimony and explain why that specific portion of the testimony

should not have been admitted. Instead, he cites to portions of Perez's testimony during

the Evidence Code section 402 hearing, which occurred outside the presence of the jury

and was not evidence considered by the jury in rendering its verdict.

Toward the end of that Evidence Code section 402 hearing, Tran's attorney argued

that Perez's testimony constituted inadmissible expert testimony. The trial court

disagreed, finding that Perez "has laid the foundation that he has spent well over 100

hours viewing the different videos," and "has prepared exhibits showing how he reached

his conclusions, one showing the DMV and Facebook and the different videos, thus

allowing the jurors to assess the validity of the reliability of this witness' opinion."

The court concluded that "it is entirely proper and appropriate and helpful, if not

necessary, to the jury to have the testimony of the detective be able to opine who the

individuals are, if he is able to, in different videos that are relevant to the facts the jury

needs to find."

We assume that Tran takes issue with the court allowing Perez to testify at trial,

not at the preliminary hearing. In their respondent's brief, the People point to some of

35
Perez's trial testimony in an attempt to ascertain what portions of Perez's testimony Tran

finds improper. In his reply brief, Tran could have responded to the respondent's brief by

citing to the portions of the record containing Perez's testimony and explaining why each

specific portion was improperly admitted. But he did not do so. Instead, Tran merely

provided us with a general argument. He confirmed that he was challenging "not

only . . . Perez's testimony from the [Evidence Code section] 402 hearing, but also his

identification of people in the surveillance videos at trial." However, he provided no

citations to the record, leaving it for this court to scour the record to support his

argument. That is not the domain of the appellate court.

An appellant has the burden to provide an adequate record and affirmatively show

reversible error. (Denham v. Superior Court (1970) 2 Cal.3d 557, 564; Ballard v. Uribe

(1986) 41 Cal.3d 564, 574.) Further, it is the appellant's duty to support arguments in his

or her briefs by references to the record on appeal, including citations to specific pages in

the record. (Duarte v. Chino Community Hospital (1999) 72 Cal.App.4th 849, 856.)

"Appellate briefs must provide argument and legal authority for the positions taken.

'When an appellant fails to raise a point, or asserts it but fails to support it with reasoned

argument and citations to authority, we treat the point as waived. [Citations.]' "

(Nelson v. Avondale Homeowners Assn., supra, 172 Cal.App.4th at p. 862.) "We are not

bound to develop appellants' argument for them. [Citation.] The absence of cogent legal

argument or citation to authority allows this court to treat the contention as waived." (In

re Marriage of Falcone & Fyke, supra, 164 Cal.App.4th at p. 830.)

36
 Here, Tran has not provided any citation to the record to support his argument that

Perez's testimony was improperly admitted. He does not specifically indicate any

testimony or even point us to Perez's trial testimony whatsoever. As such, we consider

his challenge to Perez's testimony waived. (See Nelson v. Avondale Homeowners Assn.,

supra, 172 Cal.App.4th at p. 862; In re Marriage of Falcone & Fyke, supra, 164

Cal.App.4th at p. 830.)

IV

INEFFECTIVE ASSISTANCE OF COUNSEL

A. Tran's Contentions

Tran asserts that his trial counsel was prejudicially ineffective because he "did not

present any defense or introduce any witnesses to contest the various versions of events."

Tran also takes issue with the fact that his counsel did not call an expert witness at trial.

B. Analysis

To show that trial counsel's performance was constitutionally defective, an

appellant must prove: (1) counsel's performance fell below the standard of

reasonableness, and (2) the "deficient performance prejudiced the defense."

(Strickland v. Washington (1984) 466 U.S. 668, 687 (Strickland).) It is the defendant's

burden to prove the inadequacy of trial counsel, and defendant's burden is difficult to

satisfy on direct appeal. Competency is presumed unless the record affirmatively

excludes a rational basis for trial counsel's choice. (People v. Ray (1996) 13 Cal.4th 313,

349; People v. Musselwhite (1998) 17 Cal.4th 1216, 1260.)

37
 The United States Supreme Court explained that "[j]udicial scrutiny of counsel's

performance must be highly deferential [because i]t is all too tempting for a defendant to

second-guess counsel's assistance after conviction or adverse sentence, and it is all too

easy for a court, examining counsel's defense after it has proved unsuccessful, to

conclude that a particular act or omission of counsel was unreasonable." (Strickland,

supra, 466 U.S. at p. 689.) Thus, the court explained, reviewing courts "must indulge a

strong presumption that counsel's conduct falls within the wide range of reasonable

professional assistance; that is, the defendant must overcome the presumption that, under

the circumstances, the challenged action 'might be considered sound trial strategy.' "

(Ibid.; see People v. Lucas (1995) 12 Cal.4th 415, 437 (Lucas), quoting Strickland, at

p. 689 ["[T]here is a 'strong presumption that counsel's conduct falls within the wide

range of reasonable professional assistance.' "].) We reverse on the ground of inadequate

assistance only if the record affirmatively discloses no rational tactical purpose for

counsel's act or omission. (Lucas, at pp. 436-437.)

Here, the record does not provide us with sufficient information from which we

could determine whether Tran met his burden to show ineffective assistance of counsel.

Essentially, Tran insists that his trial counsel did not put on a defense whatsoever. Our

review of the record does not support such a conclusion.

Tran's trial counsel cross-examined the prosecution's witnesses. For example, he

pointed out several discrepancies in A.N.'s testimony, thus identifying reasons for the

jury to find him not credible. Defense counsel also repeatedly challenged A.N.'s memory

38
and veracity by confronting him with his own contradictory testimony from the

preliminary hearing.

Moreover, during his closing argument, defense counsel focused on A.N.'s and

other witnesses' inconsistencies. Counsel began by emphasizing how the prosecution's

"best witness, Mr. [S.M.] . . . didn't say that Mr. Tran slammed this person. In fact, he

said somebody else did, based on the photo identification." Defense counsel specifically

reminded the jury how A.N. previously testified that he punched an Asian man (who

turned out to be Tran) when the brawl first started, but at trial, only admitted to evading

and parrying others' punches. Counsel also stressed that one of the key witnesses, D.M.,

described the perpetrators as "two Hispanic males, either 6 feet tall or almost 6 feet tall,

190 to 200 pounds."

After summarizing these "conflicting testimonies," defense counsel then argued

that the jury could not convict Tran by "just pick[ing] out a couple of things that happen

to fit into the prosecutor's case and jettison[ing] the rest":

"We have to evaluate how all the evidence fits together. But
that's not the same thing as saying we can kind of cherry pick our
way to a guilty verdict, meaning, you know, disregard that
inconvenient thing about [R.R.]. Disregard [D.M.'s] final 18
seconds. Disregard the white shirt. Disregard all these other things.
That's not the way this works."

The prosecutor apparently believed defense counsel's closing was effective

because he responded directly to defense counsel's argument by noting that eyewitnesses

to a chaotic brawl on a crowded street at 2:00 a.m. are inevitably going to falter in their

recollections.

39
 Although Tran's trial counsel might not have called any witnesses during Tran's

case-in-chief or an expert witness to challenge the prosecution's expert, these strategic

choices are not of the moment. Defense counsel's strategy was to argue the prosecution

failed to prove its case. Generally, we defer to the tactical decisions of trial counsel.

(See People v. Scott (1997) 15 Cal.4th 1188, 1212; People v. Holt (1997) 15 Cal.4th 619,

703; Lucas, supra, 12 Cal.4th at p. 437.) Here, without some indication in the record that

this decision showed that defense's counsel's trial performance fell below the standard of

reasonableness, we will defer to counsel's tactical decision in this case.11 (See Scott, at

p. 1212.)

An appellate court generally cannot fairly evaluate counsel's performance at trial

based on a silent record. (People v. Mendoza Tello (1997) 15 Cal.4th 264, 266-267.) In

many instances, like here, evaluation of a claim of ineffective assistance of counsel will

have to await a petition for writ of habeas corpus, should the defendant believe there is a

viable claim that can be pursued. (Ibid.)

11 Because Tran cannot show his trial counsel's representation at trial fell below an
objectively reasonable standard, we need not evaluate his claim of prejudice.
40
 DISPOSITION

The judgment is affirmed.

HUFFMAN, J.

WE CONCUR:

BENKE, Acting P. J.

HALLER, J.

41