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Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

Version: 1.0 (September 17, 2020)

This document includes a cover page with the SWGDE disclaimer.

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Multimedia Evidence in Court Disclaimer:

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Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

Version: 1.0 (September 17, 2020)

This document includes a cover page with the SWGDE disclaimer.

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Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

Version: 1.0 (September 17, 2020)

This document includes a cover page with the SWGDE disclaimer.

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SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

Table of Contents

1. Purpose................................................................................................................................... 4

2. Scope....................................................................................................................................... 4

3. Limitations ............................................................................................................................. 4

4. Retrieval, Storage of Evidence, and Chain of Custody ..................................................... 4

5. Considerations for Submission of Multimedia Evidence .................................................. 5

5.1 Admission of Evidence .................................................................................................. 6

5.2 Common Challenges/Objections to the Admission of Multimedia Evidence .......... 7

6. Optimizing Playback of Image or Video ............................................................................. 8

7. Optimizing Playback of Audio ........................................................................................... 11

8. SWGDE Framework and Guidance Documents ............................................................. 11

Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

Version: 1.0 (September 17, 2020)

This document includes a cover page with the SWGDE disclaimer.

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1. Purpose

Multimedia evidence is commonly presented in court and is increasingly becoming a prolific

form of evidence in judicial proceedings. Multimedia evidence can have a profound impact on a

proceeding by providing clarity to the trier of fact. This document provides guidance and

practical considerations for participants in court proceedings to ensure that multimedia evidence

is submitted and presented in an optimal manner. For the purposes of this document, multimedia

evidence refers to audio, video, images, and associated metadata, which may be in digital or

analog format.

2. Scope

For the purposes of this document, personnel retrieving and/or examining the multimedia

evidence will be referred to as “practitioners.” This document’s audience also includes attorneys

who introduce multimedia evidence provided by practitioners either as a demonstrative or

evidentiary exhibit, witnesses, judges, and any other participants who will be presenting in a

courtroom setting. This document does not address multimedia that consists of a witness-

prepared digital model, presentation, reenactment, or demonstrative exhibit.

Determining optimal playback of multimedia in court is an often-overlooked component of the

trial process. This document addresses the importance of testing multimedia playback with

existing equipment in the courtroom prior to use at trial and in consultation with court staff and

attorneys. The goal is to optimize playback of multimedia for maximum effectiveness in court

proceedings. As with other forms of evidence, multimedia evidence must comply with any

applicable local, state, or federal laws and policies governing admission.

3. Limitations

This document is not intended to constitute legal advice or replace an organization’s Standard

Operating Procedures (SOPs). Evidence rules in this document refer to the Federal Rules of

Evidence (F.R.E.) and may differ from State Rules. The guidance from this document should be

implemented after consultation with legal personnel versed in the laws and rules applicable to the

practitioner’s particular jurisdiction.

Variations on the principles outlined in this document may be appropriate based upon continuing

changes in technology.

4. Retrieval, Storage of Evidence, and Chain of Custody

Multimedia can originate from many sources, including the following:

• Multimedia generated or recorded by an agency (e.g., interviews, security and surveillance footage, in-car video, body-worn cameras, crime scene video); or

• Multimedia retrieved or provided to an agency from a third party (e.g., social media sources, digital video recorder system footage, mobile devices, drone cameras,

commercial cameras, Internet of Things [IoT] devices).

Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

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The documentation of acquisition, retrieval, and receipt of multimedia evidence is the first step

in multimedia examination (e.g., validate date and time, format, device manufacturer, media, the

hash value of original files, etc.). This should also include documentation of any persons

contacted in relation to the evidence who provided input on the examination. Practitioners should

store evidence in a manner consistent with the organization’s SOPs, ensuring that the chain of

custody is maintained. Practitioners should refer to SWGDE documents referenced in Section 8

for guidance on these procedures.

5. Considerations for Submission of Multimedia Evidence

When providing copies of multimedia evidence for legal purposes, practitioners should consider

taking steps to demonstrate the file integrity (e.g., hash values) to the recipient to enable future

integrity verification. Recipients should verify the integrity of multimedia evidence prior to use.

For additional information on hash algorithms refer to SWGDE Position on the Use of MD5 and

SHA1 Hash Algorithms in Digital and Multimedia Forensics.

During the discovery process, multimedia evidence may be distributed through cloud-based

technology; however, any multimedia shared through the cloud should be downloaded and

submitted on physical media (e.g., write-once optical media, USB flash drive or portable hard

drive) for admission into evidence. The physical media should be maintained after the

completion of court proceedings in the event that it needs to be reviewed (e.g., in appellate or

post-conviction proceedings). The multimedia should generally be displayed from the physical

media on which it is contained. However, if playback performance from that physical media is

an anticipated issue, consider asking permission of the court and opposing counsel to play the

video from a temporary location, so long as that location contains a fair and accurate duplicate of

the physical media (e.g., from a file stored locally on a computer rather than from optical media).

To minimize playback errors, consideration should be given to optimize playback and avoid

dropout.

It is recommended that the practitioners and other witnesses should meet with the attorney or

individual who will be utilizing the multimedia evidence in court prior to the commencement of

the proceedings. The attorney must understand the steps the practitioner took to retrieve the

multimedia, the chain of custody, and also have the ability to address legal challenges based on

technical aspects of multimedia retrieval, playback, storage, and admission. If the multimedia is

going to be submitted in court in a medium that differs from its original format, the contents

should be reviewed by the witness and attorney in order to address possible authentication

objections. This ensures the attorney is prepared to conduct a direct-examination of the

practitioner, make objections, address any issues within cross-examination, and effectively

communicate the process and its reliability to the judge, jury, or other trier of fact. A lack of

understanding of the technology and its attributes can result in the unintended suppression or

misuse of evidence. Likewise, technically deficient evidence may be admitted through a lack of

understanding. If the practitioner should have to meet with opposing counsel, representative

counsel should be present. For a more detailed discussion on the proper recovery of evidence and

Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

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chain of custody, refer to the documents referenced in Section 8 specific to the type of

multimedia being introduced.

5.1 Admission of Evidence

Admission of evidence is determined by the court consistent with Federal Rules of Evidence

(F.R.E.) 104 and other applicable rules and generally requires satisfaction of the following legal

prerequisites:

• Is the proffered evidence relevant? F.R.E. 401, 402.

• Has the proffered evidence been properly authenticated? F.R.E. 901, 902.

• Does the proffered evidence constitute hearsay? F.R.E. 801. If so, is it admissible under a hearsay exception? F.R.E. 803, 804, 807.

• Is the proffered evidence an original or an accurate reproduction of the original? F.R.E. 1002, 1003.

• Is the probative value of the proffered evidence substantially outweighed by the danger of unfair prejudice, confusing the issues, misleading the jury, undue delay, wasting time, or

needlessly presenting cumulative evidence? F.R.E. 403.

• Are any redactions required?

Although the attorney will need to establish that the relevant factors and foundation have been

met prior to the admission of multimedia evidence, the practitioner acquiring the multimedia

evidence may be required to testify to establish authentication of the multimedia evidence and to

establish that it is the “best” evidence. If multimedia evidence cannot be properly authenticated,

it may not be admitted, even if it is otherwise probative and valuable to the trier of fact.

F.R.E. 901(a), and most state counterparts, indicates that “the requirement of authenticating or

identifying an item of evidence” is satisfied when the proponent of the evidence produces

“evidence sufficient to support a finding that the item is what the proponent claims it is.” This

may be accomplished through the testimony of the practitioner who retrieved or processed the

multimedia evidence, perhaps in combination with the testimony of other witnesses. To meet this

standard, the practitioner should be able to identify the procedures followed for retrieving the

multimedia and any associated documentation.

Authentication testimony may include:

• The retrieval method.

• The condition of the original recording device and the accuracy of the resultant multimedia.

• Time offsets and other observations noted during the retrieval.

• Agency evidence and storage protocols.

• Chain of custody documentation.

Pursuant to F.R.E. 902, some digital evidence is self-authenticating and will “require no extrinsic

evidence of authenticity in order to be admitted.” F.R.E. 902(13) describes a process for

Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

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authenticating records “generated by an electronic process or system,” which can include a

printout from a webpage, or a document retrieved from files stored in a personal computer.

F.R.E. 902(14) provides a similar procedure for authenticating data copies from electronic

sources through a certification.

5.2 Common Challenges/Objections to the Admission of Multimedia Evidence

Multimedia evidence admissibility is often challenged when the file type offered into court has

changed from how it was originally recorded on the source device.

Generally, F.R.E. 1002 requires the production of the original “writing, recording, or photograph

in order to prove its content unless” the rules provide otherwise. However, pursuant to F.R.E.

1001(d), for electronically stored information, an original includes “any printout - or other output

readable by sight - if it accurately reflects the information.” Additionally, a “duplicate” which is

“a counterpart produced by a mechanical, photographic, chemical, electronic, or other equivalent

process or technique that accurately reproduces the original” is admissible pursuant to F.R.E.

1001(e). Finally, F.R.E. 1003 authorizes admission of a duplicate “to the same extent as the

original unless a genuine question is raised about the original’s authenticity or the circumstances

make it unfair to admit the duplicate.”

While the Federal Rules of Evidence state that an original piece of evidence is preferred over

duplicates, they also provide for the introduction of a duplicate when the original is no longer

available or impractical for introduction in court (e.g., playback of the original is unavailable).

This is referred to as the “best evidence” rule. In the context of multimedia evidence, a copy of

original recordings is often the first acquired data. Steps should be taken to ensure that the

duplicates are an accurate representation of the original.

Even if not played from its original source or format, multimedia evidence can be admitted.

Therefore, the practitioner acquiring the multimedia evidence may be called to testify that the

multimedia contains information consistent with the original file. This may include explaining all

processing steps taken to demonstrate the processed copy is being used in court without data

alteration, edit, or deletion (e.g., transcoding, conversions, etc.). Additionally, if the multimedia

has been changed in any way to optimize playback, the practitioner should be able to explain

how this does not materially alter the evidence from the original.

Another common challenge/objection to preclude admission of multimedia evidence is that the

exhibit being presented in the court contains only a portion or portions of the information/data

that was actually acquired or received.

F.R.E. 1006 allows the use of “a summary, chart, or calculation to prove the content of

voluminous writings, recordings, or photographs that cannot be conveniently examined in court.”

In this situation the “originals or duplicates [must be made] available for examination or

copying, or both” or produced in court if so ordered.

In some situations, there are challenges to the admission of multimedia, or portions thereof, mid-

trial and the attorney will need to address them.

Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

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The attorney and practitioner should be prepared to deal with the need to conduct redactions

and/or change the format of the multimedia to be consistent with court rulings if required. The

practitioner should ensure the attorney is aware of what limitations may exist in redacting the

recording, as well as its effect on the quality or effectiveness of the video, other information/data,

or audio. This additional analysis or redaction should not be performed while testifying. For

additional information on redaction, see SWGDE Video and Audio Redaction Guidelines.

Note: Care should be given to multimedia exhibits offered to the jury for consideration as they

may contain information not intended to be seen or heard by the jury (e.g., file names, titles,

dates, or other identifying prejudicial information).

6. Optimizing Playback of Image or Video

Once an image or video is deemed admissible, efforts should be made to ensure that all required

equipment and software is available, properly installed, in functioning order, and properly

configured (e.g., aspect ratio, resolution). Any audio should be tested to ensure that it is audible

and intelligible. See Section 7 Optimizing Playback of Audio.

Practitioners should ensure that the attorney admitting the evidence is aware of how these factors

can affect the presentation detail of the image or video, and work with the attorney to address

these issues prior to use in court.

The image or video should be reviewed utilizing the specific equipment that will be used in

court, as well as tested in the courtroom where it will be displayed. If possible, this should be

completed with sufficient time prior to the trial or court proceeding to address any technical

issues, or to allow for the procurement of additional equipment. During this process, parties

should ensure that the playback of the video is optimal to serve its purpose and is clearly visible

to the judge and/or jurors. For example, if there is minute detail that is essential to the

proceeding, effort should be made to optimize settings to minimize loss of detail during

playback. In making this determination, various factors can be considered, including but not

limited to:

• Playback system configuration

• Image quality (e.g., format, resolution, frame rate)

• Audio fidelity (see Section 7)

• Size and quality of display screens

• Projector quality (e.g., amount of lumens, type of signal ports)

• Projector configuration (e.g., color space, white balance, gamma curve, etc.)

• Appropriate audio and video cables, adapters or signal convertors (e.g., HDMI cable, Thunderbolt to HDMI video convertor, etc.)

• Room lighting

• Distance from and angle of screens to viewers

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SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

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Upon identifying any deficiencies or limitations caused by either the multimedia evidence itself

or the equipment being utilized, consideration should be given to the following possibilities:

• Changing the settings

• Finding more suitable equipment

• Moving the jurors or judge to provide them with a better view of the video

• Relocating equipment in the courtroom

• Modifying settings within the multimedia itself to optimize playback

Costs for larger projectors and associated projection screens may be prohibitive for some

jurisdictions. Where cost or storage of monitors is an issue, use of multiple smaller high

definition video monitors (e.g., a computer tablet) may be a more practical alternative to

effectively display video evidence. When employing multiple monitors, consideration should be

given to their display settings and location so as to not impede or obstruct the presentation of

other evidence or the view of the jurors. Additionally, the visual color display of monitors may

vary. When color is of importance (e.g., vehicle color, clothing color), consider color calibration

of monitors. In lieu of purchasing Audio/Video (AV) equipment, equipment rental is an option.

When using a projector or single large display, refer to Figure 1 below for recommended general

viewing distances based upon monitor size and image resolution.

Figure 1. Recommended maximum viewing distances1

Recommended Maximum Viewing Distance based on Screen Size and Resolution

Diagonal Size (inches)

Vertical Resolution

480 720 1080

32 11.5 6.2 4.2 M a x im

u m

V ie

w in

g D

ista n c e (fe

e t)

40 14.3 7.8 5.2

42 15 8.2 5.5

46 16.5 9 6

50 17.9 9.8 6.5

52 18.6 10 6.8

55 19.7 10.7 7.2

58 20.8 11.3 7.5

60 21.5 11.7 7.8

63 22.6 12.3 8.2

65 23.3 12.7 8.5

1 Chart produced by SWGDE with information derived from various sources.

Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

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The following photographs show various examples of monitors or projectors that can be utilized

for optimal viewing.

Example of a courtroom with multiple large monitors

Example of a courtroom with portable smaller monitors

Scientific Working Group on Digital Evidence

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Evidence in Court

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7. Optimizing Playback of Audio

Audio evidence can play a significant role in judicial proceedings and may include

conversational speech or important background sounds. Examples of audio evidence include

wiretap recordings, recorded phone calls, surveillance recordings, and interviews of suspects in

custody. The ability of a jury and other participants to hear audio may be compromised by the

playback system and acoustic environment in a courtroom.

Those responsible for the playback of audio in a courtroom should strive to achieve the best

playback possible. Playback equipment should be selected to support the format of the audio

evidence. If the courtroom lacks the necessary equipment, the attorney should consult with the

practitioner to find an appropriate solution. Ideally, this would include high-quality headphones

for all members of the jury, the judge, and courtroom personnel. If headphones are not available,

high-quality speakers in close proximity to the intended listeners should be used. This often

requires the use of equipment that is in addition to what is typically employed in most

courtrooms. Playback from low-quality equipment such as computer speakers, television

speakers, and “boom boxes” should be avoided. As discussed in section 6, pre-trial testing

should be conducted to minimize any playback challenges.

Courtroom construction (materials and design) often are not conducive to proper presentation of

audio evidence. Hard surfaces and parallel walls are examples of features which compromise

acoustics for speech intelligibility. If possible, consider designing or modifying an environment

adequate for audio presentation.

Limitations of low-quality systems can result in a loss of intelligibility, audio signal quality, and

may also affect translation and transcription services. Attorneys and courtroom technicians

should seek out information on these topics through consultation with acousticians, audio

engineers, SWGDE Best Practices for Forensic Audio, and the references in this document.

8. SWGDE Framework and Guidance Documents

Additional documents from SWGDE can provide the framework and understanding for

courtroom personnel. It is highly recommended that courtroom personnel be familiar with the

documents listed below, in addition to other national and international forensic standards

organizations.

• SWGDE Best Practices for Data Acquisition from Digital Video Recorders

• SWGDE Best Practices for Digital & Multimedia Evidence Video Acquisition from Cloud Storage

• SWGDE Collection of Digital and Multimedia Evidence Myths vs Facts

• SWGDE Best Practices for the Acquisition of Data from Novel Digital Devices

• SWGDE Best Practices for Computer Forensic Acquisitions

• SWGDE Best Practices for Forensic Audio

• SWGDE Core Competencies for Forensic Audio

• SWGDE Technical Overview of Digital Video Files

Scientific Working Group on Digital Evidence

SWGDE Practical Considerations for Submission and Presentation of Multimedia

Evidence in Court

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• SWGDE Best Practices for Mobile Phone Forensics

• SWGDE Core Competencies for Mobile Phone Forensics

• SWGDE Best Practices for Digital Forensic Video Analysis

• SWGDE Requirements for Report Writing in Digital and Multimedia Forensics

SWGDE Practical Considerations for Submission and Presentation of

Multimedia Evidence in Court

History

Revision Issue Date Section History

1.0

DRAFT 2019-06-06 All

Initial draft created and voted by SWGDE

for release as a Draft for Public Comment.

1.0

DRAFT 2019-07-16 All

Formatting and technical edit performed for

release as a Draft for Public Comment.

1.0 2019-09-19 2, 4, 5

Minor edits to address public comments.

SWGDE voted to publish as an Approved

document.

1.0 2019-09-29 -- Formatted for release as Approved version

1.0.

1.0 2020-09-17 Voted for release as final publication