Fix nuv decoder to use reget_buffer for non-keyframes and correctly

identify non-keyframe RTJPEG frames.

Originally committed as revision 15217 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/nuv.c

@@ -132,6 +132,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     NuvContext *c = avctx->priv_data;
     AVFrame *picture = data;
     int orig_size = buf_size;
+    int keyframe;
+    int result;
     enum {NUV_UNCOMPRESSED = '0', NUV_RTJPEG = '1',
           NUV_RTJPEG_IN_LZO = '2', NUV_LZO = '3',
           NUV_BLACK = 'N', NUV_COPY_LAST = 'L'} comptype;
@@ -159,6 +161,15 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
         return -1;
     }
     comptype = buf[1];
+    switch (comptype) {
+        case NUV_RTJPEG_IN_LZO:
+        case NUV_RTJPEG:
+            keyframe = !buf[2]; break;
+        case NUV_COPY_LAST:
+            keyframe = 0; break;
+        default:
+            keyframe = 1; break;
+    }
     // skip rest of the frameheader.
     buf = &buf[12];
     buf_size -= 12;
@@ -184,18 +195,19 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
         buf_size -= 12;
     }
 
-    if (c->pic.data[0])
+    if (keyframe && c->pic.data[0])
         avctx->release_buffer(avctx, &c->pic);
     c->pic.reference = 1;
     c->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_READABLE |
                           FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
-    if (avctx->get_buffer(avctx, &c->pic) < 0) {
+    result = keyframe ? avctx->get_buffer(avctx, &c->pic) : avctx->reget_buffer(avctx, &c->pic);
+    if (result < 0) {
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }
 
-    c->pic.pict_type = FF_I_TYPE;
-    c->pic.key_frame = 1;
+    c->pic.pict_type = keyframe ? FF_I_TYPE : FF_P_TYPE;
+    c->pic.key_frame = keyframe;
     // decompress/copy/whatever data
     switch (comptype) {
         case NUV_LZO:
@@ -220,8 +232,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
             break;
         }
         case NUV_COPY_LAST: {
-            c->pic.pict_type = FF_P_TYPE;
-            c->pic.key_frame = 0;
             /* nothing more to do here */
             break;
         }