frame skip support

Originally committed as revision 3742 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -193,6 +193,8 @@ static int video_level = FF_LEVEL_UNKNOWN;
 static int nsse_weight = 8;
 static int subpel_quality= 8;
 static int lowres= 0;
+static int frame_skip_threshold= 0;
+static int frame_skip_factor= 0;
 extern int loop_input; /* currently a hack */
 
 static int gop_size = 12;
@@ -3223,6 +3225,8 @@ static void opt_output_file(const char *filename)
                 video_enc->level= video_level;
                 video_enc->nsse_weight= nsse_weight;
                 video_enc->me_subpel_quality= subpel_quality;
+                video_enc->frame_skip_threshold= frame_skip_threshold;
+                video_enc->frame_skip_factor= frame_skip_factor;
 
                 if(packet_size){
                     video_enc->rtp_mode= 1;
@@ -3949,6 +3953,8 @@ const OptionDef options[] = {
     { "subq", OPT_INT | HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)&subpel_quality}, "", "" },
     { "lowres", OPT_INT | HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)&lowres}, "", "" },
     { "vtag", HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)opt_video_tag}, "force video tag/fourcc", "fourcc/tag" },
+    { "skip_threshold", OPT_INT | HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)&frame_skip_threshold}, "frame skip threshold", "threshold" },
+    { "skip_factor", OPT_INT | HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)&frame_skip_factor}, "frame skip factor", "factor" },
 
     /* audio options */
     { "ab", HAS_ARG | OPT_AUDIO, {(void*)opt_audio_bitrate}, "set audio bitrate (in kbit/s)", "bitrate", },

libavcodec/avcodec.h

@@ -17,7 +17,7 @@ extern "C" {
 
 #define FFMPEG_VERSION_INT     0x000409
 #define FFMPEG_VERSION         "0.4.9-pre1"
-#define LIBAVCODEC_BUILD       4734
+#define LIBAVCODEC_BUILD       4735
 
 #define LIBAVCODEC_VERSION_INT FFMPEG_VERSION_INT
 #define LIBAVCODEC_VERSION     FFMPEG_VERSION
@@ -1683,12 +1683,26 @@ typedef struct AVCodecContext {
      int lowres;
 
     /**
-     * bistream width / height. may be different from width/height if lowres
+     * bitsream width / height. may be different from width/height if lowres
      * or other things are used
      * - encoding: unused
      * - decoding: set by user before init if known, codec should override / dynamically change if needed
      */
     int coded_width, coded_height;
+
+    /**
+     * frame skip threshold
+     * - encoding: set by user
+     * - decoding: unused
+     */
+    int frame_skip_threshold;
+
+    /**
+     * frame skip factor
+     * - encoding: set by user
+     * - decoding: unused
+     */
+    int frame_skip_factor;
 } AVCodecContext;
 
 

libavcodec/mpegvideo.c

@@ -2018,6 +2018,44 @@ static int load_input_picture(MpegEncContext *s, AVFrame *pic_arg){
     return 0;
 }
 
+static inline int block_max(DCTELEM *block){
+    int i, max;
+    
+    max=0;
+    for(i=0; i<64; i++){
+        int v= ABS(block[i]);
+        if(v>max) max= v;
+    }
+    return max;
+}
+
+static int skip_check(MpegEncContext *s, Picture *p, Picture *ref){
+    int x, y, plane;
+    int score=0;
+
+    for(plane=0; plane<3; plane++){
+        const int stride= p->linesize[plane];
+        const int bw= plane ? 1 : 2;
+        for(y=0; y<s->mb_height*bw; y++){
+            for(x=0; x<s->mb_width*bw; x++){
+                int v;
+                
+                s->dsp.diff_pixels(s->block[0], p->data[plane] + 8*(x + y*stride), ref->data[plane] + 8*(x + y*stride), stride);
+                v= block_max(s->block[0]);
+                
+                if(v>score) 
+                    score=v;
+            }
+        }
+    }
+
+    if(score < s->avctx->frame_skip_threshold)
+        return 1;
+    if(score < ((s->avctx->frame_skip_factor * s->lambda)>>8))
+        return 1;
+    return 0;
+}
+
 static void select_input_picture(MpegEncContext *s){
     int i;
 
@@ -2033,7 +2071,26 @@ static void select_input_picture(MpegEncContext *s){
             s->reordered_input_picture[0]->coded_picture_number= s->coded_picture_number++;
         }else{
             int b_frames;
+
+            if(s->avctx->frame_skip_threshold || s->avctx->frame_skip_factor){
+                if(skip_check(s, s->input_picture[0], s->next_picture_ptr)){
+//av_log(NULL, AV_LOG_DEBUG, "skip %p %Ld\n", s->input_picture[0]->data[0], s->input_picture[0]->pts);
+                
+                    if(s->input_picture[0]->type == FF_BUFFER_TYPE_SHARED){
+                        for(i=0; i<4; i++)
+                            s->input_picture[0]->data[i]= NULL;
+                        s->input_picture[0]->type= 0;            
+                    }else{
+                        assert(   s->input_picture[0]->type==FF_BUFFER_TYPE_USER 
+                               || s->input_picture[0]->type==FF_BUFFER_TYPE_INTERNAL);
             
+                        s->avctx->release_buffer(s->avctx, (AVFrame*)s->input_picture[0]);
+                    }
+
+                    goto no_output_pic;
+                }
+            }
+
             if(s->flags&CODEC_FLAG_PASS2){
                 for(i=0; i<s->max_b_frames+1; i++){
                     int pict_num= s->input_picture[0]->display_picture_number + i;
@@ -2116,7 +2173,7 @@ static void select_input_picture(MpegEncContext *s){
             }
         }
     }
-    
+no_output_pic:
     if(s->reordered_input_picture[0]){
         s->reordered_input_picture[0]->reference= s->reordered_input_picture[0]->pict_type!=B_TYPE ? 3 : 0;