[FFmpeg-devel] [PATCH] avformat/oggdec: Add page CRC verification

[Lynne]

Apr 27, 2020, 21:55 by michael at niedermayer.cc:

> On Mon, Apr 27, 2020 at 05:19:49PM +0200, Mattias Wadman wrote:
>
>> Fixes seek issue with ogg files that have segment data that happens to be
>> encoded as a "OggS" page syncword. Very unlikely but seems to happen.
>>
>> Have been observed to happen with ffmpeg+libvorbis and oggenc encoding
>> to 441khz stereo at 160kbps.
>> ---
>>  libavformat/oggdec.c | 96 +++++++++++++++++++++++++++++++++-----------
>>  1 file changed, 73 insertions(+), 23 deletions(-)
>>
>
> breaks chained ogg
>
> ./ffmpeg -threads 1 -i ~/tickets/868/chained_streams.ogg -f null -
>
> frame=  954 fps=0.0 q=-0.0 Lsize=N/A time=00:00:31.79 bitrate=N/A speed= 105x
> vs
> frame=  120 fps=0.0 q=-0.0 Lsize=N/A time=00:00:03.99 bitrate=N/A speed= 289x
>
> stream should be here:
> http://v2v.cc/~j/theora_testsuite/chained_streams.ogg
>
> thx
>

I've sent a patchset which amongst other things, implements this cleanly and does not break that file.
Had this for a long time, wanted to finish Opus chaining, but seeing this made me send it to the list.