On 02.03.2017 15:22, James Almer wrote:
On 3/2/2017 6:28 AM, Nicolas George wrote:
Le primidi 11 ventôse, an CCXXV, James Almer a écrit :
Ah, i see there's generic code to read and write CodecPrivate elements
to and from raw extradata for native codecids where no special handling
is required.
In any case, the spec says
"For FFV1 versions 2 or less, Private Data SHOULD NOT be written."
The ffv1 encoder creates extradata for v2 and newer, so the muxer
should have a custom case for ffv1 in order to detect v2 streams and
avoid writing said extradata.
I have not looked myself at the situation, I only read what you wrote
her. According to it, it seems here the FFV1 encoder is violating the
specification and needs to be fixed.
I can't say if the encoder exporting extradata for version 2 is right or
wrong, as muxers or bsfs could still use it for whatever reason, but at
least according to the draft ffv1 spec by Michael, it's to be stored at
the container level *only* on versions 3 and above.
https://tools.ietf.org/html/draft-niedermayer-cellar-ffv1-01#section-4.1
The IETF draft explicitly excludes to specify FFV1 version 2:
https://tools.ietf.org/html/draft-niedermayer-cellar-ffv1-01#section-4.8.1
IIRC there have been some edits to remove references to version 2 in the
IETF draft. In the older document at
http://www.ffmpeg.org/%7Emichael/ffv1.html#configuration-record the
section contains "version >= 2".
Regards,
Tobias
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