From 3aa661ec561d7a20812b84b353b0d7855ac346c8 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Sat, 1 Oct 2011 17:41:28 +0200
Subject: [PATCH] h264: improve parsing of broken AVC SPS
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>
---
libavcodec/h264.c | 9 ++++++++-
libavcodec/h264_ps.c | 5 ++++-
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index 20aed27fd1c..c3ef3f0110e 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -3925,7 +3925,14 @@ 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))
diff --git a/libavcodec/h264_ps.c b/libavcodec/h264_ps.c
index 287702c7c4f..276eb77d1da 100644
--- a/libavcodec/h264_ps.c
+++ b/libavcodec/h264_ps.c
@@ -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;
}
--
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