avcodec/libaomdec: export frame pict_type

Should fix ticket #9180

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/libaomdec.c

@@ -161,6 +161,7 @@ static int aom_decode(AVCodecContext *avctx, void *data, int *got_frame,
     AVFrame *picture      = data;
     const void *iter      = NULL;
     struct aom_image *img;
+    aom_codec_frame_flags_t av_unused flags;
     int ret;
 
     if (aom_codec_decode(&ctx->decoder, avpkt->data, avpkt->size, NULL) !=
@@ -198,6 +199,19 @@ static int aom_decode(AVCodecContext *avctx, void *data, int *got_frame,
         if ((ret = ff_get_buffer(avctx, picture, 0)) < 0)
             return ret;
 
+#ifdef AOM_CTRL_AOMD_GET_FRAME_FLAGS
+        ret = aom_codec_control(&ctx->decoder, AOMD_GET_FRAME_FLAGS, &flags);
+        if (ret == AOM_CODEC_OK) {
+            picture->key_frame = !!(flags & AOM_FRAME_IS_KEY);
+            if (flags & (AOM_FRAME_IS_KEY | AOM_FRAME_IS_INTRAONLY))
+                picture->pict_type = AV_PICTURE_TYPE_I;
+            else if (flags & AOM_FRAME_IS_SWITCH)
+                picture->pict_type = AV_PICTURE_TYPE_SP;
+            else
+                picture->pict_type = AV_PICTURE_TYPE_P;
+        }
+#endif
+
         av_reduce(&picture->sample_aspect_ratio.num,
                   &picture->sample_aspect_ratio.den,
                   picture->height * img->r_w,