When a Matroska Block is only stored in compressed form, the size of the uncompressed block is not explicitly coded and therefore not known before decompressing it. Therefore the demuxer uses a guess for the uncompressed size: The first guess is three times the compressed size and if this is not enough, it is repeatedly incremented by a factor of three. But when this happens with lzo, the decompression is neither resumed nor started again. Instead when av_lzo1x_decode indicates that x bytes of input data could not be decoded, because the output buffer is already full, the first (not the last) x bytes of the input buffer are resent for decoding in the next try; they overwrite already decoded data.
This commit fixes this by instead restarting the decompression anew, just with a bigger buffer. This seems to be a regression since 935ec5a1. A FATE-test for this has been added. Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com> --- libavformat/matroskadec.c | 3 ++- tests/fate/matroska.mak | 4 ++++ tests/ref/fate/matroska-lzo-decompression | 10 ++++++++++ 3 files changed, 16 insertions(+), 1 deletion(-) create mode 100644 tests/ref/fate/matroska-lzo-decompression diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index 72624dc3f1..75f72d330c 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -1599,6 +1599,7 @@ static int matroska_decode_buffer(uint8_t **buf, int *buf_size, #if CONFIG_LZO case MATROSKA_TRACK_ENCODING_COMP_LZO: do { + int insize = isize; olen = pkt_size *= 3; newpktdata = av_realloc(pkt_data, pkt_size + AV_LZO_OUTPUT_PADDING + AV_INPUT_BUFFER_PADDING_SIZE); @@ -1607,7 +1608,7 @@ static int matroska_decode_buffer(uint8_t **buf, int *buf_size, goto failed; } pkt_data = newpktdata; - result = av_lzo1x_decode(pkt_data, &olen, data, &isize); + result = av_lzo1x_decode(pkt_data, &olen, data, &insize); } while (result == AV_LZO_OUTPUT_FULL && pkt_size < 10000000); if (result) { result = AVERROR_INVALIDDATA; diff --git a/tests/fate/matroska.mak b/tests/fate/matroska.mak index 597be7346c..4aca4dc8eb 100644 --- a/tests/fate/matroska.mak +++ b/tests/fate/matroska.mak @@ -22,6 +22,10 @@ fate-matroska-xiph-lacing: CMD = framecrc -i $(TARGET_SAMPLES)/mkv/xiph_lacing.m FATE_MATROSKA-$(call ALLYES, MATROSKA_DEMUXER ZLIB) += fate-matroska-zlib-decompression fate-matroska-zlib-decompression: CMD = framecrc -i $(TARGET_SAMPLES)/mkv/subtitle_zlib.mks -c:s copy +# This tests that the matroska demuxer can decompress lzo compressed tracks. +FATE_MATROSKA-$(call ALLYES, MATROSKA_DEMUXER LZO) += fate-matroska-lzo-decompression +fate-matroska-lzo-decompression: CMD = framecrc -i $(TARGET_SAMPLES)/mkv/lzo.mka -c copy + # This tests that the matroska demuxer correctly propagates # the channel layout contained in vorbis comments in the CodecPrivate # of flac tracks. It also tests header removal compression. diff --git a/tests/ref/fate/matroska-lzo-decompression b/tests/ref/fate/matroska-lzo-decompression new file mode 100644 index 0000000000..241d5adf44 --- /dev/null +++ b/tests/ref/fate/matroska-lzo-decompression @@ -0,0 +1,10 @@ +#tb 0: 11337/500000000 +#media_type 0: audio +#codec_id 0: pcm_s16le +#sample_rate 0: 44100 +#channel_layout 0: 3 +#channel_layout_name 0: stereo +0, 0, 0, 4096, 16384, 0x00000000 +0, 4096, 4096, 4096, 16384, 0xad7eebf4 +0, 8192, 8192, 4096, 16384, 0x1d1ff9d9 +0, 12288, 12288, 4097, 16384, 0xf1d9e2e2 -- 2.20.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".