framemd5 / framecrc output format specification?

[Peter B.]

I've tried to find documentation about the output file produced by "-f
framemd5", but couldn't find any. What are the other 3 values before
the checksum?

I tried to look for the specification of framecrc output (assuming it's
the same, but CRC instead of MD5), but to no avail. :(

Could anyone please point me into the right direction?

Thanks,
Peter B.


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[Dave Rice]

On Jan 7, 2011, at 6:02 AM, "Peter B." <[hidden email]> wrote:

> I've tried to find documentation about the output file produced by "-f framemd5", but couldn't find any. What are the other 3 values before the checksum?

1. Stream number
2. PTS
3. Size of frame data
4. Checksum

> I tried to look for the specification of framecrc output (assuming it's the same, but CRC instead of MD5), but to no avail. :(
>
> Could anyone please point me into the right direction?
>
> Thanks,
> Peter B.
>
>
> _______________________________________________
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> [hidden email]
> https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-user

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[Peter B.]

Zitat von Dave Rice <[hidden email]>:

>> What are the other 3 values before the checksum?
>
> 1. Stream number
> 2. PTS
> 3. Size of frame data
> 4. Checksum

Thank you very much!
Wow. Stream number... This means, that I'm also getting e.g. the audio
track checksummed?

Is there any official documentation publicly available about this?

Thanks,
Pb

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[Dave Rice]

On Jan 7, 2011, at 8:00 AM, Peter B. wrote:

> Zitat von Dave Rice <[hidden email]>:
>
>>> What are the other 3 values before the checksum?
>>
>> 1. Stream number
>> 2. PTS
>> 3. Size of frame data
>> 4. Checksum
>
> Thank you very much!
> Wow. Stream number... This means, that I'm also getting e.g. the audio track checksummed?

Yes it will include the default streams like any other ffmpeg transcode that doesn't specify specifics for streams. For instance if you run `ffmpeg -i file.mov anotherfile.avi` without specifying streams then you'll likely get both audio and video in the output. If you want only the video stream in the output, do `ffmpeg -i file.mov -an -f framemd5 somemd5s.txt`

> Is there any official documentation publicly available about this?

you could read libavformat/md5enc.c
dave

> Thanks,
> Pb
>
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[Peter B.]

Zitat von Dave Rice <[hidden email]>:
> Yes it will include the default streams like any other ffmpeg
> transcode that doesn't specify specifics for streams. [...]

Makes perfect sense. :)

>> Is there any official documentation publicly available about this?
>
> you could read libavformat/md5enc.c

I was afraid to hear that. ;)
I'm able to read the code, but my colleagues ain't...

If you wouldn't have mentioned that feature, I wouldn't have found out
that it existed (Ok, I found evidence of it in the SVN logs, but...)

Thanks anyway,
Peter B.

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[Stefano Sabatini]

On date Friday 2011-01-07 15:32:36 +0100, Peter B. encoded:

> Zitat von Dave Rice <[hidden email]>:
> >Yes it will include the default streams like any other ffmpeg
> >transcode that doesn't specify specifics for streams. [...]
>
> Makes perfect sense. :)
>
> >>Is there any official documentation publicly available about this?
> >
> >you could read libavformat/md5enc.c
>
> I was afraid to hear that. ;)
> I'm able to read the code, but my colleagues ain't...
>
> If you wouldn't have mentioned that feature, I wouldn't have found
> out that it existed (Ok, I found evidence of it in the SVN logs,
> but...)

File a feature request for keeping track of, addind documentation for
muxers is on my radar...
--
ffmpeg-user random tip #11
One minute of video silence with ffmpeg:
ffmpeg -t 60 -s qcif -f rawvideo -pix_fmt rgb24 -r 25 -i /dev/zero \
    -y silence.mpeg
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