[vlc-devel] [PATCH] demux:mkv: detect bogus MPEG-2 framing from MakeMKV

[Steve Lhomme]

Le 18/01/2018 à 14:37, Francois Cartegnie a écrit :
> Le 18/01/2018 à 14:02, Steve Lhomme a écrit :
>> This software doesn't put mpeg-2 frames properly in mkv frames. Without a
>> packetizer we get a lot of decoding issues.
>>
>> Fixes #18916
>> ---
>>   modules/demux/mkv/matroska_segment_parse.cpp | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/modules/demux/mkv/matroska_segment_parse.cpp b/modules/demux/mkv/matroska_segment_parse.cpp
>> index 0b7967d48b..e442d8435f 100644
>> --- a/modules/demux/mkv/matroska_segment_parse.cpp
>> +++ b/modules/demux/mkv/matroska_segment_parse.cpp
>> @@ -1510,6 +1510,8 @@ bool matroska_segment_c::TrackInit( mkv_track_t * p_tk )
>>           }
>>           S_CASE("V_MPEG2") {
>>               vars.p_fmt->i_codec = VLC_CODEC_MPGV;
>> +            if (strstr(vars.obj->psz_muxing_application,"libmakemkv"))
>> +                vars.p_fmt->b_packetized = false;
>>               fill_extra_data( vars.p_tk, 0 );
>>           }
>>           S_CASE("V_THEORA") {
>>
> sample from 18916 behaves now worse with radeon and now crashes my system.
> Unsure if i want to test again with packetizer, but afair, that did only
> remove some artifacts.
>
> That's trying to work around decoders bugs :/

Yes and no. The issue is deeper in avcodec. But nevertheless that 
Matroska muxer is not muxing frames the way it's supposed to. So we 
still need this patch no matter what.