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Comment by ansible | Hacker News Reader

There are some evidence recording systems that are supposed to be tamper-proof. So the video while being recorded is digitally signed, and then the officer's recording system uploads it securely to the police servers when back at the station. This is to maintain a complete chain-of-custody, so that when used as evidence in court, it can't easily be dismissed or disregarded.

This one... is apparently not? What's going on here?

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This has also clearly been cropped to exclude the timecode. As far as I have ever seen from dashcams, the timecode is usually and quite sensibly burnt-in to the actual video to make editing harder.

What do you mean by "burnt-in" exactly? Like a watermark? I don't see any reason why the running timestamp can't be encoded in the file format, invisible to the user. Then tampering would at least require some technical know-how.

Meaning the timestamp is included as pixels in the video frame, it's not metadata. Usually the timestamp also has some alpha, it's not just a black background, so tweaking it would require some skill. This is far from foolproof but it at least raises the bar a little bit.

Some CCTV systems show the time, camera number etc in the video stream, like http://www.cctvcamerapros.com/v/images/color-quad-processor/...

It can be useful because when you're watching a video where nothing is moving, you know the video hasn't frozen; and if you transcode the video to another format (upload to youtube, for example) the data is preserved.

Of course, even better would be if the cops' cameras recorded to a standard format that included accurate timecodes and secure digital signatures - and that same format could be viewed by most video players.

When Texas DPS installed the first camera systems which were VHS tape systems. In those, the officer was responsible for changing their own tapes and turning them in to their supervisor. In rural areas this means that there could be a considerable amount of time that the tape was available for editing. Those systems were an improvement over nothing at all, but there was always the possibility for funny business. The systems main effects were to protect officers from frivolous claims and assist them in report writing. They couldn't stop a dishonest officer from destroying a tape, and therefore didn't always protect people from abuse.

I'd like to think that things (other than the format) have improved in ~25 years, but there is no guarantee of that. Often enough, it takes a significant event like this in order to motivate the right people to do their jobs properly.

I don't think you'd know from the released video whether or not it had been tampered with (in terms of the tech you're talking about); presumably if it had, it wouldn't be admissible in court for precisely that reason. This is PR, not evidence.

Don't worry. The camera was just malfunctioning!

Did you read the parent comment? What does tamper-proof mean to you?

It's digitally signed and then the officer's recording system uploads it securely to the police servers when back at the station. This is all to maintain a complete chain-of-custody, so when used as evidence in court it can't be easily dismissed or disregarded by the criminal's attorney.

It can't be edited because there wouldn't be a digital signature!!!?

Cameras will malfunction but not like you're saying they will.

Relax, he made an joke!

In case someone takes his comment seriously, there's mine. In case someone takes my comment seriously they'd agree with the grandparent so no harm done.

There's the chance someone would agree with the grand/parent ('malfunction...', secure, etc.), read my comment, and think... well that's ridiculous.

Case study for "'/s' considered harmful"; Would-be PhDs take note.

This joke has spawned a large monitor's worth of discussion, none of which is really contributing to the conversation.

Relax. This situation has me riled up too. But s/he was trying to be humorously sarcastic. Not exactly condoned HN comment behavior, and a bit flip given the seriousness of the topic, but not what you thought s/he was saying.

Also the parent says "There are some evidence recording systems..." We don't know if this police department's system is one of those.

I apologise for the misinterpretation. HN is not the best place for my sarcasm.

I appreciated your contribution of sarcasm and I'm sorry if my playing off your sarcasm caused you grief. It's stupid that people downvoted (what's the HN euphemism for this?) your comment. It was appropriate.

Keep commenting. Moderate yourself; Fuck karma... just stay positive, I don't know what happens to the people <0. I heard they burn the bodies for fuel to run the server.

I didn't know you can downvote here...

You need I think around 500 karma to be able to do it. That's what's up with the grey and nearly-invisible comments are--they have been downvoted

...my playing off your sarcasm...

Oh no, you attempted two-level sarcasm? That simply won't work here. b^)

"Gen-Y places a high value on authenticity. Sarcasm can be seen as 'inauthentic' and diminish the immediately perceived value of a piece. Satire, however, is a goodthing. Sarcasm is cheap; Satire is art. ... Sarcasm is more easily absorbed by the digestive tract of Gen-Y due to the short chains it forms. ... Society, long having moved from prechewed, tasteless meat into pre-prechewed, more tasteless meat substitute, the majority of Gen-Y simply can't process more than 140 characters at a time. ... Somewhere in every great satire post-2000 must be sarcasm, how ever much it cheapens the 'experience'."[1]

You'd think I wouldn't be getting killed here. Everything is falling flat. Bah humbug.

1. "The Truth About Satire" -- Faye Weather, 2001, http://thereisnopunchlinehere.com.us/books/weather,faye%20th...

Hmm.

>Sarcasm can be seen as 'inauthentic' and diminish the immediately perceived value of a piece.

I'd rewrite this as such:

"Sarcasm is seen as 'inauthentic' and diminishes the perceived value of the piece."

>the majority of Gen-Y simply can't process more than 140 characters at a time.

I'd strike 'simply'. It's unnecessarily condescending.

>post-2000

Didn't like it when I wrote^H^H^H^H^Hread it and don't like it now. Clumsy. More forced than I'm comfortable with.

It can be edited for public use. And for good propaganda of course. ;-) But when in court, I hope they have the digitally signed version. If that one gets lost somehow, that would be bad.

I haven't read or seen anything to indicate that Tx DPS uses any sort of technology to protect chain-of-custody from tampering by troopers or other parties within DPS. This isn't a problem for state prosecutions because a DPS trooper is a sworn officer and is usually considered a reliable witness.

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