About the Kyle Rittenhouse drone video…

I saw a thread poster by Tim Pool on Twitter today about Kyle Rittenhouse drone video, and I shared a short response in three tweets, here is the first tweet from Tim Pool:

Now, let me first state that I’m not lawyer, I’m a tech enthusiast with around 27 years of experience in all things tech related, and that my native language is Spanish. Having said that, I think that in the legal world, they lack industry standards for file sharing.

Industry standards for file sharing

If you download Ubuntu, and want to verify the integrity of your copy, you use either gpg or sha256, both are command line tools for analyzing a file and generating a hash, checksum or signature that is unique for the contents of a file, here you can read more on that: https://ubuntu.com/tutorials/how-to-verify-ubuntu#1-overview

And here is a video explaining the different tools for generating and verifying checksums:

File handling in a trial

In a trial, every digital evidence should be shared as an identical copy using any checksum tool to generate the first signature/hash/checksum when the evidence is accepted, include the signature with the copy of the file, doing so, would prevent any modification of the files in question, and as far as I know, this wasn’t the case with the Kyle Rittenhouse drone video.

How HandBrake works

I use HandBrake since 2005 when it was a Mac only app, it was originally designed for common users (non tech savvy) to rip DVDs and transcode them to a MP4/M4V file compatible with Apple devices. Because the app was designed for non tech savvy users, it has many automated functions and easy to use presets. One of those automated functions is the auto-crop feature, which removes the horizontal black bars in the case of letterboxing, or the vertical bars in case of pillarboxing. I created a small 5 second video using the following image and then load the video into HandBrake, you can see it auto-crops the video. You can download the test video here and try it by yourself:
https://rodrigopolo.com/wp-content/uploads/2021/11/Letterboxed.mp4

Image to create a letterboxed video.
How HandBrake auto-crops the video.

Of course the user has the possibility to customize the cropping area of the video, clicking on the “Dimensions” tab, and choosing “Custom” instead of “Automatic”:

Automatic crop in HandBrake
Custom crop in HandBrake

Video re-encoding while sharing

File sharing services as Google Docs, Dropbox, iCloud, OneDrive, etc. do NOT re-encode any video file, the same file that is uploaded can be downloaded without any modification, but again, signing files is strongly recommended.

Sharing a video through Twitter, Facebook, YouTube, Vimeo, Rumble, etc. or sending the video through a chat app like WhatsApp, Telegram, Twitter DMs, etc. will result in the re-encoding of the video, and in most cases, the video resolution is shrunk to fit bandwidth and each platform predefined encoding schemes and it switches between resolutions to accommodate the video to the users bandwidth. For instance, one of the latest Tim Pool live videos has 10 different video resolutions, 4 different audio tracks, and two video+audio tracks:

[info] Available formats for 3IRyjNDVv3s:
format code  extension  resolution note
249          webm       audio only tiny   50k , webm_dash container, opus @ 50k (48000Hz), 52.64MiB
250          webm       audio only tiny   58k , webm_dash container, opus @ 58k (48000Hz), 60.79MiB
251          webm       audio only tiny  105k , webm_dash container, opus @105k (48000Hz), 109.83MiB
140          m4a        audio only tiny  129k , m4a_dash container, mp4a.40.2@129k (44100Hz), 135.21MiB
160          mp4        256x144    144p   84k , mp4_dash container, avc1.4d400c@  84k, 30fps, video only, 88.75MiB
278          webm       256x144    144p   86k , webm_dash container, vp9@  86k, 30fps, video only, 90.09MiB
242          webm       426x240    240p  152k , webm_dash container, vp9@ 152k, 30fps, video only, 158.75MiB
133          mp4        426x240    240p  193k , mp4_dash container, avc1.4d4015@ 193k, 30fps, video only, 201.82MiB
243          webm       640x360    360p  282k , webm_dash container, vp9@ 282k, 30fps, video only, 295.27MiB
134          mp4        640x360    360p  372k , mp4_dash container, avc1.4d401e@ 372k, 30fps, video only, 389.18MiB
244          webm       854x480    480p  498k , webm_dash container, vp9@ 498k, 30fps, video only, 520.64MiB
135          mp4        854x480    480p  688k , mp4_dash container, avc1.4d401f@ 688k, 30fps, video only, 718.86MiB
247          webm       1280x720   720p 1038k , webm_dash container, vp9@1038k, 30fps, video only, 1.06GiB
136          mp4        1280x720   720p 1361k , mp4_dash container, avc1.64001f@1361k, 30fps, video only, 1.39GiB
18           mp4        640x360    360p  458k , avc1.42001E, 30fps, mp4a.40.2 (44100Hz), 478.87MiB
22           mp4        1280x720   720p 1489k , avc1.64001F, 30fps, mp4a.40.2 (44100Hz) (best)

In conclusion

  1. In a court case, every digital evidence should have some kind of digital signature and every copy should be identical bit by bit, there is no question about it.
  2. File sharing is quite different from video publishing or video sharing trough some apps, even if you post the same video twice, the resulting videos would NOT have the same file signature.
  3. HandBrake can, and would auto-crop videos if it finds black areas near the edges, and the user has the availability to customize the cropping of the video.

Now, the prosecutor could argue that they didn’t knew that using A or B app or platform reduced the quality of the video, or even that the app would do an auto-crop, they can also argue that they just wanted to help reducing the file size/resolution to make the video easy to share, but again, I strongly believe that in a court case, each party should have an identical copy of any digital evidence, including some digital signature.

I also think that for this evidence to have any value, it should come from the original source, which in this case, is the memory of the drone that recorded the scene, and NOT from a TV broadcast. This are my 2 cents to the discussion.

Some tweets from reference

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