h264dec: do not export the chroma sample location immediately on parsing the SPS

This SPS is not necessarily the one that will be used. Export the chroma
location along with all the other SPS properties.

libavcodec/h264_ps.c

@@ -181,9 +181,10 @@ static inline int decode_vui_parameters(GetBitContext *gb, AVCodecContext *avctx
     /* chroma_location_info_present_flag */
     if (get_bits1(gb)) {
         /* chroma_sample_location_type_top_field */
-        avctx->chroma_sample_location = get_ue_golomb(gb) + 1;
+        sps->chroma_location = get_ue_golomb(gb) + 1;
         get_ue_golomb(gb);  /* chroma_sample_location_type_bottom_field */
-    }
+    } else
+        sps->chroma_location = AVCHROMA_LOC_LEFT;
 
     if (show_bits1(gb) && get_bits_left(gb) < 10) {
         av_log(avctx, AV_LOG_WARNING, "Truncated VUI (%d)\n", get_bits_left(gb));

libavcodec/h264_ps.h

@@ -77,6 +77,8 @@ typedef struct SPS {
     enum AVColorPrimaries color_primaries;
     enum AVColorTransferCharacteristic color_trc;
     enum AVColorSpace colorspace;
+    enum AVChromaLocation chroma_location;
+
     int timing_info_present_flag;
     uint32_t num_units_in_tick;
     uint32_t time_scale;

libavcodec/h264_slice.c

@@ -1086,6 +1086,7 @@ static int h264_init_ps(H264Context *h, const H264SliceContext *sl, int first_sl
             h->avctx->color_trc = h->sei.alternative_transfer.preferred_transfer_characteristics;
         }
     }
+    h->avctx->chroma_sample_location = sps->chroma_location;
 
     if (!h->context_initialized || must_reinit || needs_reinit) {
         int flush_changes = h->context_initialized;

libavcodec/h264dec.c

@@ -325,8 +325,6 @@ static int h264_init_context(AVCodecContext *avctx, H264Context *h)
 
     ff_h264_sei_uninit(&h->sei);
 
-    avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
-
     h->nb_slice_ctx = (avctx->active_thread_type & FF_THREAD_SLICE) ? avctx->thread_count : 1;
     h->slice_ctx = av_mallocz_array(h->nb_slice_ctx, sizeof(*h->slice_ctx));
     if (!h->slice_ctx) {