Step #4: Run VideoProcessor integration test batch mode on task queue.

webrtc/modules/video_coding/codecs/test/videoprocessor.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 140 matching lines @@
   RTC_DCHECK(encoder);
   RTC_DCHECK(decoder);
   RTC_DCHECK(packet_manipulator);
   RTC_DCHECK(analysis_frame_reader);
   RTC_DCHECK(analysis_frame_writer);
   RTC_DCHECK(stats);
 
   frame_infos_.reserve(num_frames_);
 }
 
+VideoProcessorImpl::~VideoProcessorImpl() = default;
+
 bool VideoProcessorImpl::Init() {
   RTC_DCHECK(!initialized_)
       << "This VideoProcessor has already been initialized.";
 
   // Calculate a factor used for bit rate calculations.
   bit_rate_factor_ = config_.codec_settings->maxFramerate * 0.001 * 8;  // bits
 
   // Setup required callbacks for the encoder/decoder.
   RTC_CHECK_EQ(encoder_->RegisterEncodeCompleteCallback(encode_callback_.get()),
                WEBRTC_VIDEO_CODEC_OK)
@@ skipping 25 matching lines @@
     printf("    Decoder implementation name: %s\n",
            decoder_->ImplementationName());
     PrintCodecSettings(config_.codec_settings);
   }
 
   initialized_ = true;
 
   return true;
 }
 
-VideoProcessorImpl::~VideoProcessorImpl() {
+void VideoProcessorImpl::DeregisterCallbacks() {
   encoder_->RegisterEncodeCompleteCallback(nullptr);

[brandtr, 2017/03/10 09:50:54]

Must be called on the task queue.

[tommi, 2017/03/10 09:57:12]

as a drive by comment, there aren't any thread or sequence checks in this class.
In this case it looks like you found out about it by hitting a check inside
RegisterEncodeCompleteCallback.
There aren't locks either in VideoProcessorImpl, which suggests that the class
is single threaded. I think it would be a good idea to add those checks both for
sake of runtime correctness/expectations and understanding how the class is
supposed to be used.

   decoder_->RegisterDecodeCompleteCallback(nullptr);
 }
 
 void VideoProcessorImpl::SetRates(int bit_rate, int frame_rate) {
   int set_rates_result = encoder_->SetRateAllocation(
       bitrate_allocator_->GetAllocation(bit_rate * 1000, frame_rate),
       frame_rate);
   RTC_DCHECK_GE(set_rates_result, 0)
       << "Failed to update encoder with new rate " << bit_rate;
   num_dropped_frames_ = 0;
@@ skipping 273 matching lines @@
   if (decoded_frame_writer_) {
     RTC_DCHECK_EQ(extracted_length, decoded_frame_writer_->FrameLength());
     RTC_CHECK(decoded_frame_writer_->WriteFrame(extracted_buffer.data()));
   }
 
   last_decoded_frame_buffer_ = std::move(extracted_buffer);
 }
 
 }  // namespace test
 }  // namespace webrtc