[FFmpeg-devel] [PATCH 1/3] avformat/matroskadec: Add a workaround for missing WavPack extradata

[David Bryant]

On 4/1/20 12:53 AM, Andreas Rheinhardt wrote:
> Andreas Rheinhardt:
>> mkvmerge versions 6.2 to 40.0 had a bug that made it not propagate the
>> WavPack extradata (containing the WavPack version) during remuxing from
>> a Matroska file; currently our demuxer would treat every WavPack block
>> encountered as invalid data (unless the WavPack stream is to be
>> discarded (i.e. the streams discard is >= AVDISCARD_ALL)) and try to
>> resync to the next level 1 element.
>>
>> Luckily, the WavPack version is currently not really important; so we
>> fix this problem by assuming a version. David Bryant, the creator of
>> WavPack, recommended using version 0x410 (the most recent version) for
>> this. And this is what this commit does.
>>
>> A FATE-test for this has been added.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>> ---
>> James has already uploaded the sample. Thanks for this.
>>
>>  libavformat/matroskadec.c                            | 11 ++++++++++-
>>  tests/fate/matroska.mak                              |  5 +++++
>>  tests/ref/fate/matroska-wavpack-missing-codecprivate |  9 +++++++++
>>  3 files changed, 24 insertions(+), 1 deletion(-)
>>  create mode 100644 tests/ref/fate/matroska-wavpack-missing-codecprivate
>>
>> diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
>> index 4d7fdab99f..5b55606b98 100644
>> --- a/libavformat/matroskadec.c
>> +++ b/libavformat/matroskadec.c
>> @@ -2613,6 +2613,14 @@ static int matroska_parse_tracks(AVFormatContext *s)
>>              ret = matroska_parse_flac(s, track, &extradata_offset);
>>              if (ret < 0)
>>                  return ret;
>> +        } else if (codec_id == AV_CODEC_ID_WAVPACK && track->codec_priv.size < 2) {
>> +            av_log(matroska->ctx, AV_LOG_INFO, "Assuming WavPack version 4.10 "
>> +                   "in absence of valid CodecPrivate.\n");
>> +            extradata_size = 2;
>> +            extradata = av_mallocz(2 + AV_INPUT_BUFFER_PADDING_SIZE);
>> +            if (!extradata)
>> +                return AVERROR(ENOMEM);
>> +            AV_WL16(extradata, 0x410);
>>          } else if (codec_id == AV_CODEC_ID_PRORES && track->codec_priv.size == 4) {
>>              fourcc = AV_RL32(track->codec_priv.data);
>>          } else if (codec_id == AV_CODEC_ID_VP9 && track->codec_priv.size) {
>> @@ -3165,9 +3173,10 @@ static int matroska_parse_wavpack(MatroskaTrack *track, uint8_t *src,
>>      uint16_t ver;
>>      int ret, offset = 0;
>>  
>> -    if (srclen < 12 || track->stream->codecpar->extradata_size < 2)
>> +    if (srclen < 12)
>>          return AVERROR_INVALIDDATA;
>>  
>> +    av_assert1(track->stream->codecpar->extradata_size >= 2);
>>      ver = AV_RL16(track->stream->codecpar->extradata);
>>  
>>      samples = AV_RL32(src);
>> diff --git a/tests/fate/matroska.mak b/tests/fate/matroska.mak
>> index b9ed7322fd..93b5bff89a 100644
>> --- a/tests/fate/matroska.mak
>> +++ b/tests/fate/matroska.mak
>> @@ -17,6 +17,11 @@ fate-matroska-remux: REF = 49a60ef91cf7302ab7276f9373f8a429
>>  FATE_MATROSKA-$(call ALLYES, MATROSKA_DEMUXER VORBIS_PARSER) += fate-matroska-xiph-lacing
>>  fate-matroska-xiph-lacing: CMD = framecrc -i $(TARGET_SAMPLES)/mkv/xiph_lacing.mka -c:a copy
>>  
>> +# This tests that the Matroska demuxer correctly demuxes WavPack
>> +# without CodecPrivate; it also tests zlib compressed WavPack.
>> +FATE_MATROSKA-$(call ALLYES, MATROSKA_DEMUXER ZLIB) += fate-matroska-wavpack-missing-codecprivate
>> +fate-matroska-wavpack-missing-codecprivate: CMD = framecrc -i $(TARGET_SAMPLES)/mkv/wavpack_missing_codecprivate.mka -c copy
>> +
>>  # This tests that the matroska demuxer supports decompressing
>>  # zlib compressed tracks (both the CodecPrivate as well as the actual frames).
>>  FATE_MATROSKA-$(call ALLYES, MATROSKA_DEMUXER ZLIB) += fate-matroska-zlib-decompression
>> diff --git a/tests/ref/fate/matroska-wavpack-missing-codecprivate b/tests/ref/fate/matroska-wavpack-missing-codecprivate
>> new file mode 100644
>> index 0000000000..4645a86ff6
>> --- /dev/null
>> +++ b/tests/ref/fate/matroska-wavpack-missing-codecprivate
>> @@ -0,0 +1,9 @@
>> +#extradata 0:        2, 0x00240014
>> +#tb 0: 11337/500000000
>> +#media_type 0: audio
>> +#codec_id 0: wavpack
>> +#sample_rate 0: 44100
>> +#channel_layout 0: 3
>> +#channel_layout_name 0: stereo
>> +0,          0,          0,    22051,    14778, 0x02819286
>> +0,      22051,      22051,    22052,    14756, 0x21976243
>>
> Any comments on this patchset? If not, I'd like to apply it tomorrow.

This looks good to me. Thanks!

-David