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[FFmpeg-devel] avcodec/h264_parser: Reduce needed history for parsing mb index

Message ID 20180622194559.2263-1-michael@niedermayer.cc
State Accepted
Commit d25c945247979a88fac6bb3b7a26370262b96ef1
Headers show

Commit Message

Michael Niedermayer June 22, 2018, 7:45 p.m. UTC 
This fixes a bug/regression with very small packets
Fixes: output_file

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(-)

Comments

Michael Niedermayer June 25, 2018, 12:09 a.m. UTC | #1 
On Fri, Jun 22, 2018 at 09:45:59PM +0200, Michael Niedermayer wrote:
> This fixes a bug/regression with very small packets
> Fixes: output_file
> 
> 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(-)

will apply


[...]
diff mbox

Patch

diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
index 1a9840a62c..5f9a9c46ef 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,