[FFmpeg-devel] [PATCH] h264 parser: detect new extradata on frame parsing.

[Benoit Fouet]

Try to detect new extradata when parsing frames, and decode it.
Fixes issue #3787
---
 libavcodec/h264_parser.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c
index ea0ab98..c8276a7 100644
--- a/libavcodec/h264_parser.c
+++ b/libavcodec/h264_parser.c
@@ -489,6 +489,40 @@ static int h264_parse(AVCodecParserContext *s,
         }
     }
 
+    /* See if this is extradata */
+    if (h->is_avc &&
+        buf_size >= 9 &&
+        buf[0] == 1 &&
+        (buf[4] & 0xFC) == 0xFC &&
+        (buf[5] & 0x1F) &&
+        buf[8] == 0x67) {
+
+        /* Skip the SPSs */
+        int cnt = buf[5] & 0x1f;
+        const uint8_t *p = buf + 6;
+        while (cnt--) {
+            int nalsize = AV_RB16(p) + 2;
+            if (nalsize > buf_size - (p - buf) || p[2] != 0x67)
+                goto not_extra;
+            p += nalsize;
+        }
+
+        /* Skip the PPSs */
+        cnt = *p++;
+        if (!cnt)
+            goto not_extra;
+        while (cnt--) {
+            int nalsize = AV_RB16(p) + 2;
+            if (nalsize > buf_size - (p - buf) || p[2] != 0x68)
+                goto not_extra;
+            p += nalsize;
+        }
+
+        /* Decode (new) extradata */
+        return ff_h264_decode_extradata(h, buf, buf_size);
+    }
+
+not_extra:
     parse_nal_units(s, avctx, buf, buf_size);
 
     if (h->sei_cpb_removal_delay >= 0) {
-- 
2.0.1.442.g7fe6834