[FFmpeg-cvslog] r14339 - trunk/libavcodec/h264.c

[Jeff Downs]

On Sun, 27 Jul 2008, Michael Niedermayer wrote:

[...]

> I think it is valuable.
> What about a MMCO_SLIDING_WINDOW that is placed in the array, that would
> be rather clean and easy to check for i think (unless i miss something)
> 

I did something similar - rather than discarding MMCO_END, I insert it. 
The check for sliding window then becomes simply !mmco_count.

	-Jeff
-------------- next part --------------
Index: libavcodec/h264.c
===================================================================
--- libavcodec/h264.c	(revision 14773)
+++ libavcodec/h264.c	(working copy)
@@ -3220,7 +3220,9 @@
 }
 
 /**
- * Executes the reference picture marking (memory management control operations).
+ * Executes the reference picture marking (memory management control 
+ * operations and sliding window).  mmco_count of 0 will simply perform
+ * sliding window ref picture marking
  */
 static int execute_ref_pic_marking(H264Context *h, MMCO *mmco, int mmco_count){
     MpegEncContext * const s = &h->s;
@@ -3228,8 +3230,7 @@
     int current_ref_assigned=0;
     Picture *pic;
 
-    if((s->avctx->debug&FF_DEBUG_MMCO) && mmco_count==0)
-        av_log(h->s.avctx, AV_LOG_DEBUG, "no mmco here\n");
+    assert(h->long_ref_count + h->short_ref_count <= h->sps.ref_frame_count);
 
     for(i=0; i<mmco_count; i++){
         int structure, frame_num;
@@ -3315,6 +3316,10 @@
             h->frame_num=
             s->current_picture_ptr->frame_num= 0;
             break;
+        case MMCO_END:
+            if((s->avctx->debug&FF_DEBUG_MMCO) && mmco_count==1)
+                av_log(h->s.avctx, AV_LOG_DEBUG, "no mmco here\n");
+            break;
         default: assert(0);
         }
     }
@@ -3351,10 +3356,14 @@
 
     if (h->long_ref_count + h->short_ref_count > h->sps.ref_frame_count){
 
-        /* We have too many reference frames, probably due to corrupted
-         * stream. Need to discard one frame. Prevents overrun of the
-         * short_ref and long_ref buffers.
+        /* We have too many reference frames; either due to sliding window or,
+         * if we processed MMCO ops, a corrupted/invalid stream. Need to
+         * discard one frame. 
+         * Also prevents overrun of the short_ref and long_ref buffers.
+         * One is always sufficient, since we added at most one picture this
+         * mmco processing cycle.
          */
+        if (mmco_count)
         av_log(h->s.avctx, AV_LOG_ERROR,
                "number of reference frames exceeds max (probably "
                "corrupt input), discarding one\n");
@@ -3391,8 +3400,10 @@
         }
     }else{
         if(get_bits1(gb)){ // adaptive_ref_pic_marking_mode_flag
-            for(i= 0; i<MAX_MMCO_COUNT; i++) {
-                MMCOOpcode opcode= get_ue_golomb(gb);
+            MMCOOpcode opcode;
+            i= 0;
+            do {
+                opcode= get_ue_golomb(gb);
 
                 h->mmco[i].opcode= opcode;
                 if(opcode==MMCO_SHORT2UNUSED || opcode==MMCO_SHORT2LONG){
@@ -3415,25 +3426,8 @@
                     av_log(h->s.avctx, AV_LOG_ERROR, "illegal memory management control operation %d\n", opcode);
                     return -1;
                 }
-                if(opcode == MMCO_END)
-                    break;
-            }
+            } while (++i<MAX_MMCO_COUNT && opcode != MMCO_END);
             h->mmco_index= i;
-        }else{
-            assert(h->long_ref_count + h->short_ref_count <= h->sps.ref_frame_count);
-
-            if(h->short_ref_count && h->long_ref_count + h->short_ref_count == h->sps.ref_frame_count &&
-                    !(FIELD_PICTURE && !s->first_field && s->current_picture_ptr->reference)) {
-                h->mmco[0].opcode= MMCO_SHORT2UNUSED;
-                h->mmco[0].short_pic_num= h->short_ref[ h->short_ref_count - 1 ]->frame_num;
-                h->mmco_index= 1;
-                if (FIELD_PICTURE) {
-                    h->mmco[0].short_pic_num *= 2;
-                    h->mmco[1].opcode= MMCO_SHORT2UNUSED;
-                    h->mmco[1].short_pic_num= h->mmco[0].short_pic_num + 1;
-                    h->mmco_index= 2;
-                }
-            }
         }
     }