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h264: improve parsing of broken AVC SPS

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Parsing the entire NAL as SPS fixes decoding of some AVC bitstreams
with broken escaping. Since the size of the NAL unit is known and
checked against the buffer end we can parse it entirely without buffer
overreads.

Fixes playback of
http://streams.videolan.org/streams/mp4/Mr_MrsSmith-h264_aac.mp4

Signed-off-by: Janne Grunau <janne-libav@jannau.net>
(cherry picked from commit 3aa661ec56)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
This commit is contained in:
Michael Niedermayer
2011-10-01 17:41:28 +02:00
committed by Reinhard Tartler
parent 48f0eeb2e5
commit a81a6d9c80
2 changed files with 12 additions and 2 deletions
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9
libavcodec/h264.c
View File

@@ -3924,7 +3924,14 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size){
break;
case NAL_SPS:
init_get_bits(&s->gb, ptr, bit_length);
ff_h264_decode_seq_parameter_set(h);
if (ff_h264_decode_seq_parameter_set(h) < 0 &&
h->is_avc && (nalsize != consumed) && nalsize) {
av_log(h->s.avctx, AV_LOG_DEBUG, "SPS decoding failure, "
"try parsing the coomplete NAL\n");
init_get_bits(&s->gb, buf + buf_index + 1 - consumed,
8 * (nalsize - 1));
ff_h264_decode_seq_parameter_set(h);
}
if (s->flags& CODEC_FLAG_LOW_DELAY ||
(h->sps.bitstream_restriction_flag && !h->sps.num_reorder_frames))

5
libavcodec/h264_ps.c
View File

@@ -228,7 +228,6 @@ static inline int decode_vui_parameters(H264Context *h, SPS *sps){
get_ue_golomb(&s->gb); /*max_dec_frame_buffering*/
if (get_bits_left(&s->gb) < 0) {
av_log(h->s.avctx, AV_LOG_ERROR, "Overread VUI by %d bits\n", -get_bits_left(&s->gb));
sps->num_reorder_frames=0;
sps->bitstream_restriction_flag= 0;
}
@@ -238,6 +237,10 @@ static inline int decode_vui_parameters(H264Context *h, SPS *sps){
return -1;
}
}
if (get_bits_left(&s->gb) < 0) {
av_log(h->s.avctx, AV_LOG_ERROR, "Overread VUI by %d bits\n", -get_bits_left(&s->gb));
return AVERROR_INVALIDDATA;
}
return 0;
}