lavc: add a sample_aspect_ratio field to AVFrame

The sample aspect ratio is a per-frame property, so it makes sense to
define it in AVFrame rather than in the codec/stream context.
Simplify application-level sample aspect ratio information extraction,
and allow further simplifications.

avplay.c

@@ -1651,7 +1651,7 @@ static int input_request_frame(AVFilterLink *link)
 
     picref->pts = pts;
     picref->pos = pkt.pos;
-    picref->video->pixel_aspect = priv->is->video_st->codec->sample_aspect_ratio;
+    picref->video->pixel_aspect = priv->frame->sample_aspect_ratio;
     avfilter_start_frame(link, picref);
     avfilter_draw_slice(link, 0, link->h, 1);
     avfilter_end_frame(link);

cmdutils.c

@@ -1047,6 +1047,7 @@ int get_filtered_video_frame(AVFilterContext *ctx, AVFrame *frame,
     frame->top_field_first  = picref->video->top_field_first;
     frame->key_frame        = picref->video->key_frame;
     frame->pict_type        = picref->video->pict_type;
+    frame->sample_aspect_ratio = picref->video->pixel_aspect;
 
     return 1;
 }

libavcodec/avcodec.h

@@ -1258,6 +1258,13 @@ typedef struct AVFrame {
      * decoding: set by AVCodecContext.get_buffer()
      */
     uint8_t **extended_data;
+
+    /**
+     * sample aspect ratio for the video frame, 0/1 if unknown\unspecified
+     * - encoding: unused
+     * - decoding: Read by user.
+     */
+    AVRational sample_aspect_ratio;
 } AVFrame;
 
 struct AVCodecInternal;

libavcodec/pthread.c

@@ -599,6 +599,7 @@ int ff_thread_decode_frame(AVCodecContext *avctx,
         *picture = p->frame;
         *got_picture_ptr = p->got_frame;
         picture->pkt_dts = p->avpkt.dts;
+        picture->sample_aspect_ratio = avctx->sample_aspect_ratio;
 
         /*
          * A later call with avkpt->size == 0 may loop over all threads,

libavcodec/utils.c

@@ -584,6 +584,7 @@ void avcodec_get_frame_defaults(AVFrame *pic){
 
     pic->pts= AV_NOPTS_VALUE;
     pic->key_frame= 1;
+    pic->sample_aspect_ratio = (AVRational){0, 1};
 }
 
 AVFrame *avcodec_alloc_frame(void){
@@ -858,6 +859,7 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
             ret = avctx->codec->decode(avctx, picture, got_picture_ptr,
                               avpkt);
             picture->pkt_dts= avpkt->dts;
+            picture->sample_aspect_ratio = avctx->sample_aspect_ratio;
         }
 
         emms_c(); //needed to avoid an emms_c() call before every return;

libavfilter/vsrc_movie.c

@@ -248,8 +248,8 @@ static int movie_get_frame(AVFilterLink *outlink)
                     movie->frame->pkt_dts : movie->frame->pkt_pts;
 
                 movie->picref->pos                    = movie->frame->reordered_opaque;
-                movie->picref->video->pixel_aspect = st->sample_aspect_ratio.num ?
-                    st->sample_aspect_ratio : movie->codec_ctx->sample_aspect_ratio;
+                if (!movie->frame->sample_aspect_ratio.num)
+                    movie->picref->video->pixel_aspect = st->sample_aspect_ratio;
                 movie->picref->video->interlaced      = movie->frame->interlaced_frame;
                 movie->picref->video->top_field_first = movie->frame->top_field_first;
                 movie->picref->video->key_frame       = movie->frame->key_frame;