mjpeg parser

Originally committed as revision 3634 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 72 insertions, 0 deletions

diff --git a/libavcodec/mjpeg.c b/libavcodec/mjpeg.c
index 8e6d90bc54..738b725185 100644
--- a/libavcodec/mjpeg.c
+++ b/libavcodec/mjpeg.c
@@ -896,6 +896,69 @@ static int mjpeg_decode_init(AVCodecContext *avctx)
     return 0;
 }
 
+
+/**
+ * finds the end of the current frame in the bitstream.
+ * @return the position of the first byte of the next frame, or -1
+ */
+static int find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
+    int vop_found, i;
+    uint16_t state;
+    
+    vop_found= pc->frame_start_found;
+    state= pc->state;
+    
+    i=0;
+    if(!vop_found){
+        for(i=0; i<buf_size; i++){
+            state= (state<<8) | buf[i];
+            if(state == 0xFFD8){
+                i++;
+                vop_found=1;
+                break;
+            }
+        }
+    }
+
+    if(vop_found){
+        /* EOF considered as end of frame */
+        if (buf_size == 0)
+            return 0;
+        for(; i<buf_size; i++){
+            state= (state<<8) | buf[i];
+            if(state == 0xFFD8){
+                pc->frame_start_found=0;
+                pc->state=0; 
+                return i-1;
+            }
+        }
+    }
+    pc->frame_start_found= vop_found;
+    pc->state= state;
+    return END_NOT_FOUND;
+}
+
+static int jpeg_parse(AVCodecParserContext *s,
+                           AVCodecContext *avctx,
+                           uint8_t **poutbuf, int *poutbuf_size, 
+                           const uint8_t *buf, int buf_size)
+{
+    ParseContext *pc = s->priv_data;
+    int next;
+    
+    next= find_frame_end(pc, buf, buf_size);
+
+    if (ff_combine_frame(pc, next, (uint8_t **)&buf, &buf_size) < 0) {
+        *poutbuf = NULL;
+        *poutbuf_size = 0;
+        return buf_size;
+    }
+
+    *poutbuf = (uint8_t *)buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
 /* quantize tables */
 static int mjpeg_decode_dqt(MJpegDecodeContext *s)
 {
@@ -2224,3 +2287,12 @@ AVCodec ljpeg_encoder = { //FIXME avoid MPV_* lossless jpeg shouldnt need them
     MPV_encode_end,
 };
 #endif
+
+AVCodecParser mjpeg_parser = {
+    { CODEC_ID_MJPEG },
+    sizeof(ParseContext),
+    NULL,
+    jpeg_parse,
+    ff_parse_close,
+};
+