diff --git a/modules/video_coding/codecs/test/videoprocessor.cc b/modules/video_coding/codecs/test/videoprocessor.cc
index 98ba07f764..0cf2fa0808 100644
--- a/modules/video_coding/codecs/test/videoprocessor.cc
+++ b/modules/video_coding/codecs/test/videoprocessor.cc
@@ -310,6 +310,25 @@ void VideoProcessor::SetRates(size_t bitrate_kbps, size_t framerate_fps) {
       << "Failed to update encoder with new rate " << bitrate_kbps << ".";
 }
 
+int32_t VideoProcessor::VideoProcessorDecodeCompleteCallback::Decoded(
+    VideoFrame& image) {
+  // Post the callback to the right task queue, if needed.
+  if (!task_queue_->IsCurrent()) {
+    // There might be a limited amount of output buffers, make a copy to make
+    // sure we don't block the decoder.
+    VideoFrame copy(I420Buffer::Copy(*image.video_frame_buffer()->ToI420()),
+                    image.rotation(), image.timestamp_us());
+    copy.set_timestamp(image.timestamp());
+
+    task_queue_->PostTask([this, copy]() {
+      video_processor_->FrameDecoded(copy, simulcast_svc_idx_);
+    });
+    return 0;
+  }
+  video_processor_->FrameDecoded(image, simulcast_svc_idx_);
+  return 0;
+}
+
 void VideoProcessor::FrameEncoded(
     const webrtc::EncodedImage& encoded_image,
     const webrtc::CodecSpecificInfo& codec_specific) {
diff --git a/modules/video_coding/codecs/test/videoprocessor.h b/modules/video_coding/codecs/test/videoprocessor.h
index d44ee1fc39..f3808f88c1 100644
--- a/modules/video_coding/codecs/test/videoprocessor.h
+++ b/modules/video_coding/codecs/test/videoprocessor.h
@@ -133,17 +133,7 @@ class VideoProcessor {
       RTC_DCHECK(task_queue_);
     }
 
-    int32_t Decoded(webrtc::VideoFrame& image) override {
-      // Post the callback to the right task queue, if needed.
-      if (!task_queue_->IsCurrent()) {
-        task_queue_->PostTask([this, image]() {
-          video_processor_->FrameDecoded(image, simulcast_svc_idx_);
-        });
-        return 0;
-      }
-      video_processor_->FrameDecoded(image, simulcast_svc_idx_);
-      return 0;
-    }
+    int32_t Decoded(webrtc::VideoFrame& image) override;
 
     int32_t Decoded(webrtc::VideoFrame& image,
                     int64_t decode_time_ms) override {