h264_probe()

Originally committed as revision 14186 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/raw.c

@@ -347,6 +347,50 @@ static int mpeg4video_probe(AVProbeData *probe_packet)
     return 0;
 }
 
+static int h264_probe(AVProbeData *p)
+{
+    uint32_t code= -1;
+    int sps=0, pps=0, idr=0, res=0;
+    int i;
+
+    for(i=0; i<p->buf_size; i++){
+        code = (code<<8) + p->buf[i];
+        if ((code & 0xffffff00) == 0x100) {
+            int ref_idc= (code>>5)&3;
+            int type   = code & 0x1F;
+            static const int8_t ref_zero[32]={
+                2, 0, 0, 0, 0,-1, 1,-1,
+               -1, 1, 1, 1, 1,-1, 2, 2,
+                2, 2, 2, 0, 2, 2, 2, 2,
+                2, 2, 2, 2, 2, 2, 2, 2
+            };
+
+            if(code & 0x80) //forbidden bit
+                return 0;
+
+            if(ref_zero[type] == 1 && ref_idc)
+                return 0;
+            if(ref_zero[type] ==-1 && !ref_idc)
+                return 0;
+            if(ref_zero[type] == 2)
+                res++;
+
+            switch(type){
+            case     5:   idr++; break;
+            case     7:
+                if(p->buf[i+2]&0x0F)
+                    return 0;
+                sps++;
+                break;
+            case     8:   pps++; break;
+            }
+        }
+    }
+    if(sps && pps && idr && res<(sps+pps+idr))
+        return AVPROBE_SCORE_MAX/2+1; // +1 for .mpg
+    return 0;
+}
+
 static int h263_probe(AVProbeData *p)
 {
     int code;
@@ -647,7 +691,7 @@ AVInputFormat h264_demuxer = {
     "h264",
     NULL_IF_CONFIG_SMALL("raw H.264 video format"),
     0,
-    NULL /*mpegvideo_probe*/,
+    h264_probe,
     video_read_header,
     raw_read_partial_packet,
     .flags= AVFMT_GENERIC_INDEX,