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avformat/matroskadec: Fix lzo decompression 

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.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2019-12-28 03:40:33 +01:00 committed by James Almer
parent 6c735b96ee
commit 2ff687c17f
3 changed files with 16 additions and 1 deletions
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3
libavformat/matroskadec.c
View File

@ -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;

4
tests/fate/matroska.mak
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@ -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.

10
tests/ref/fate/matroska-lzo-decompression Normal file
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@ -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