avcodec video decoder: returns delayed frames at end of stream

Closes: #10331

modules/codec/avcodec/video.c

@@ -430,7 +430,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
     int b_null_size = false;
     block_t *p_block;
 
-    if( !pp_block || !*pp_block )
+    if( !pp_block )
         return NULL;
 
     if( !p_context->extradata_size && p_dec->fmt_in.i_extra )
@@ -444,12 +444,18 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
     }
 
     p_block = *pp_block;
+    if(!p_block && !(p_sys->p_codec->capabilities & CODEC_CAP_DELAY) )
+        return NULL;
+
     if( p_sys->b_delayed_open )
     {
+        if( p_block )
             block_Release( p_block );
         return NULL;
     }
 
+    if( p_block)
+    {
         if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
         {
             p_sys->i_pts = VLC_TS_INVALID; /* To make sure we recover properly */
@@ -472,6 +478,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
              * (ie all B except for H264 where it depends only on nal_ref_idc) */
             p_sys->i_late_frames = 0;
         }
+    }
 
     if( !p_dec->b_pace_control && (p_sys->i_late_frames > 0) &&
         (mdate() - p_sys->i_late_frames_start > INT64_C(5000000)) )
@@ -482,6 +489,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
                      "dropping frame (computer too slow ?)" );
             p_sys->i_pts = VLC_TS_INVALID; /* To make sure we recover properly */
         }
+        if( p_block )
             block_Release( p_block );
         p_sys->i_late_frames--;
         return NULL;
@@ -504,6 +512,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
             /* picture too late, won't decode
              * but break picture until a new I, and for mpeg4 ...*/
             p_sys->i_late_frames--; /* needed else it will never be decrease */
+            if( p_block )
                 block_Release( p_block );
             return NULL;
         }
@@ -512,7 +521,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
     {
         if( p_sys->b_hurry_up )
             p_context->skip_frame = p_sys->i_skip_frame;
-        if( !(p_block->i_flags & BLOCK_FLAG_PREROLL) )
+        if( !p_block || !(p_block->i_flags & BLOCK_FLAG_PREROLL) )
             b_drawpicture = 1;
         else
             b_drawpicture = 0;
@@ -540,7 +549,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
 
     /* Don't forget that libavcodec requires a little more bytes
      * that the real frame size */
-    if( p_block->i_buffer > 0 )
+    if( p_block && p_block->i_buffer > 0 )
     {
         p_sys->b_flush = ( p_block->i_flags & BLOCK_FLAG_END_OF_SEQUENCE ) != 0;
 
@@ -554,7 +563,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
                 FF_INPUT_BUFFER_PADDING_SIZE );
     }
 
-    while( p_block->i_buffer > 0 || p_sys->b_flush )
+    while( !p_block || p_block->i_buffer > 0 || p_sys->b_flush )
     {
         int i_used, b_gotpicture;
         picture_t *p_pic;
@@ -563,10 +572,19 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
         post_mt( p_sys );
 
         av_init_packet( &pkt );
+        if( p_block )
+        {
             pkt.data = p_block->p_buffer;
             pkt.size = p_block->i_buffer;
             pkt.pts = p_block->i_pts;
             pkt.dts = p_block->i_dts;
+        }
+        else
+        {
+            /* Return delayed frames if codec has CODEC_CAP_DELAY */
+            pkt.data = NULL;
+            pkt.size = 0;
+        }
 
 #if LIBAVCODEC_VERSION_MAJOR >= 54
         if( !p_sys->palette_sent )
@@ -580,8 +598,11 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
 #endif
 
         /* Make sure we don't reuse the same timestamps twice */
+        if( p_block )
+        {
             p_block->i_pts =
             p_block->i_dts = VLC_TS_INVALID;
+        }
 
         i_used = avcodec_decode_video2( p_context, p_sys->p_ff_pic,
                                        &b_gotpicture, &pkt );
@@ -601,6 +622,8 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
         if( p_sys->b_flush )
             p_sys->b_first_frame = true;
 
+        if( p_block )
+        {
             if( p_block->i_buffer <= 0 )
                 p_sys->b_flush = false;
 
@@ -621,6 +644,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
             /* Consumed bytes */
             p_block->i_buffer -= i_used;
             p_block->p_buffer += i_used;
+        }
 
         /* Nothing to display */
         if( !b_gotpicture )
@@ -673,7 +697,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
 
         /* Update frame late count (except when doing preroll) */
         mtime_t i_display_date = 0;
-        if( !(p_block->i_flags & BLOCK_FLAG_PREROLL) )
+        if( !p_block || !(p_block->i_flags & BLOCK_FLAG_PREROLL) )
             i_display_date = decoder_GetDisplayDate( p_dec, i_pts );
 
         if( i_display_date > 0 && i_display_date <= mdate() )
@@ -696,6 +720,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
             p_pic = ffmpeg_NewPictBuf( p_dec, p_context );
             if( !p_pic )
             {
+                if( p_block )
                     block_Release( p_block );
                 return NULL;
             }
@@ -749,6 +774,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
         }
     }
 
+    if( p_block )
         block_Release( p_block );
     return NULL;
 }