From d25c945247979a88fac6bb3b7a26370262b96ef1 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Fri, 22 Jun 2018 21:45:59 +0200
Subject: [PATCH] avcodec/h264_parser: Reduce needed history for parsing mb
index
This fixes a bug/regression with very small packets
Fixes: output_file
Regression since: 0782fb6bcb32fe3ab956a99af4cc472ff81da0c2
Reported-by: Thierry Foucu <tfoucu@google.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
libavcodec/h264_parser.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
index 1a9840a62c5..5f9a9c46eff 100644
--- a/libavcodec/h264_parser.c
+++ b/libavcodec/h264_parser.c
@@ -121,20 +121,23 @@ static int h264_find_frame_end(H264ParseContext *p, const uint8_t *buf,
}
state = 7;
} else {
+ unsigned int mb, last_mb = p->parse_last_mb;
+ GetBitContext gb;
p->parse_history[p->parse_history_count++] = buf[i];
- if (p->parse_history_count > 5) {
- unsigned int mb, last_mb = p->parse_last_mb;
- GetBitContext gb;
- init_get_bits(&gb, p->parse_history, 8*p->parse_history_count);
- p->parse_history_count = 0;
- mb= get_ue_golomb_long(&gb);
+ init_get_bits(&gb, p->parse_history, 8*p->parse_history_count);
+ mb= get_ue_golomb_long(&gb);
+ if (get_bits_left(&gb) > 0 || p->parse_history_count > 5) {
p->parse_last_mb = mb;
if (pc->frame_start_found) {
- if (mb <= last_mb)
+ if (mb <= last_mb) {
+ i -= p->parse_history_count - 1;
+ p->parse_history_count = 0;
goto found;
+ }
} else
pc->frame_start_found = 1;
+ p->parse_history_count = 0;
state = 7;
}
}
@@ -149,7 +152,7 @@ found:
pc->frame_start_found = 0;
if (p->is_avc)
return next_avc;
- return i - (state & 5) - 5 * (state > 7);
+ return i - (state & 5);
}
static int scan_mmco_reset(AVCodecParserContext *s, GetBitContext *gb,
--
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