avcodec_flush_buffers()

Originally committed as revision 420 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -5,8 +5,8 @@
 
 #define LIBAVCODEC_VERSION_INT 0x000406
 #define LIBAVCODEC_VERSION     "0.4.6"
-#define LIBAVCODEC_BUILD       4602
-#define LIBAVCODEC_BUILD_STR   "4602"
+#define LIBAVCODEC_BUILD       4603
+#define LIBAVCODEC_BUILD_STR   "4603"
 
 enum CodecID {
     CODEC_ID_NONE, 
@@ -340,6 +340,8 @@ int avcodec_close(AVCodecContext *avctx);
 
 void avcodec_register_all(void);
 
+void avcodec_flush_buffers(AVCodecContext *avctx);
+
 #ifdef FF_POSTPROCESS
 #ifndef MBC
 #define MBC 128

libavcodec/h263.c

@@ -1034,7 +1034,7 @@ static void mpeg4_encode_vol_header(MpegEncContext * s)
 
     if(s->low_delay){
         put_bits(&s->pb, 1, 1);		/* vol control parameters= yes */
-        put_bits(&s->pb, 2, 1);		/* chroma format 422 */
+        put_bits(&s->pb, 2, 1);		/* chroma format YUV 420/YV12 */
         put_bits(&s->pb, 1, s->low_delay);
         put_bits(&s->pb, 1, 0);		/* vbv parameters= no */
     }else{
@@ -2602,7 +2602,7 @@ int mpeg4_decode_picture_header(MpegEncContext * s)
         } else {
             vo_ver_id = 1;
         }
-        
+//printf("vo type:%d\n",s->vo_type);
         s->aspect_ratio_info= get_bits(&s->gb, 4);
 	if(s->aspect_ratio_info == EXTENDET_PAR){
             skip_bits(&s->gb, 8); //par_width

libavcodec/h263dec.c

@@ -135,7 +135,6 @@ static int h263_decode_frame(AVCodecContext *avctx,
     } else {
         ret = h263_decode_picture_header(s);
     }
-    if(ret==FRAME_SKIPED) return 0;
 
         /* After H263 & mpeg4 header decode we have the height, width,*/
         /* and other parameters. So then we could init the picture   */
@@ -154,9 +153,12 @@ static int h263_decode_frame(AVCodecContext *avctx,
             return -1;
     }
 
+    if(ret==FRAME_SKIPED) return 0;
     if (ret < 0)
         return -1;
-
+    /* skip b frames if we dont have reference frames */
+    if(s->num_available_buffers<2 && s->pict_type==B_TYPE) return 0;
+        
     MPV_frame_start(s);
 
 #ifdef DEBUG
@@ -222,7 +224,8 @@ static int h263_decode_frame(AVCodecContext *avctx,
             }
             MPV_decode_mb(s, s->block);
         }
-        if (avctx->draw_horiz_band) {
+        if (    avctx->draw_horiz_band 
+            && (s->num_available_buffers>=1 || (!s->has_b_frames)) ) {
             UINT8 *src_ptr[3];
             int y, h, offset;
             y = s->mb_y * 16;
@@ -279,7 +282,11 @@ static int h263_decode_frame(AVCodecContext *avctx,
     /* we substract 1 because it is added on utils.c    */
     avctx->frame_number = s->picture_number - 1;
 
-    *data_size = sizeof(AVPicture);
+    /* dont output the last pic after seeking 
+       note we allready added +1 for the current pix in MPV_frame_end(s) */
+    if(s->num_available_buffers>=2 || (!s->has_b_frames))
+        *data_size = sizeof(AVPicture);
+
     return buf_size;
 }
 

libavcodec/mpegvideo.c

@@ -629,6 +629,8 @@ void MPV_frame_end(MpegEncContext *s)
         s->last_non_b_pict_type= s->pict_type;
         s->last_non_b_qscale= s->qscale;
         s->last_non_b_mc_mb_var= s->mc_mb_var;
+        s->num_available_buffers++;
+        if(s->num_available_buffers>2) s->num_available_buffers= 2;
     }
 }
 

libavcodec/mpegvideo.h

@@ -129,6 +129,7 @@ typedef struct MpegEncContext {
     UINT8 *aux_picture[3];       /* aux picture (for B frames only) */
     UINT8 *aux_picture_base[3];  /* real start of the picture */
     UINT8 *current_picture[3];   /* buffer to store the decompressed current picture */
+    int num_available_buffers;   /* is 0 at the start & after seeking, after the first I frame its 1 after next I/P 2 */
     int last_dc[3];              /* last DC values for MPEG1 */
     INT16 *dc_val[3];            /* used for mpeg4 DC prediction, all 3 arrays must be continuous */
     int y_dc_scale, c_dc_scale;

libavcodec/utils.c

@@ -22,6 +22,7 @@
 #include "common.h"
 #include "dsputil.h"
 #include "avcodec.h"
+#include "mpegvideo.h"
 #ifdef HAVE_MALLOC_H
 #include <malloc.h>
 #else
@@ -479,6 +480,14 @@ PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
 #undef PCM_CODEC
 }
 
+/* this should be called after seeking and before trying to decode the next frame */
+void avcodec_flush_buffers(AVCodecContext *avctx)
+{
+    MpegEncContext *s = avctx->priv_data;
+    s->num_available_buffers=0;
+}
+
+
 static int encode_init(AVCodecContext *s)
 {
     return 0;