Alloc hw_frames_ctx for hw frames wrapped in AVFrames.

libavcodec/mediacodecdec_common.c

@@ -326,6 +326,31 @@ static int mediacodec_wrap_hw_buffer(AVCodecContext *avctx,
     buffer->pts = info->presentationTimeUs;
 
     frame->data[3] = (uint8_t *)buffer;
+    
+    if (!frame->hw_frames_ctx) {
+        AVHWFramesContext* hwframes_ctx;
+        AVBufferRef* hw_frames_ctx = av_hwframe_ctx_alloc(avctx->hw_device_ctx);
+
+        if (!avctx->hw_frames_ctx) {
+            av_log(avctx, AV_LOG_ERROR, "av_hwframe_ctx_alloc failed\n");
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+
+        hwframes_ctx = (AVHWFramesContext*)hw_frames_ctx->data;
+        hwframes_ctx->width             = avctx->width;
+        hwframes_ctx->height            = avctx->height;
+        hwframes_ctx->format            = AV_PIX_FMT_MEDIACODEC;
+        hwframes_ctx->sw_format         = avctx->sw_pix_fmt;
+        ret = av_hwframe_ctx_init(avctx->hw_frames_ctx);
+
+        if (ret < 0) {
+            av_log(NULL, AV_LOG_ERROR, "Error initializing hwframe ctx\n");
+            av_buffer_unref(&hw_frames_ctx);
+            goto fail;
+        }
+        frame->hw_frames_ctx = av_buffer_ref(hw_frames_ctx);
+    }
 
     atomic_fetch_add(&s->hw_buffer_count, 1);
     av_log(avctx, AV_LOG_DEBUG,