Reland "Rename stereo video codec to multiplex"

This is a reland of bbdabe50db0cf09f6007dda12a6476dc4602b174.

Original change's description:
> Rename stereo video codec to multiplex
>
> This CL only does the rename from"stereo" to multiplex". With this we have a
> better name that doesn't clash with audio's usage of stereo.
>
> Bug: webrtc:7671
> Change-Id: Iebc3fc20839025f1bc8bcf0e16141bf9744ef652
> Reviewed-on: https://webrtc-review.googlesource.com/43242
> Commit-Queue: Emircan Uysaler <emircan@webrtc.org>
> Reviewed-by: Niklas Enbom <niklas.enbom@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#21769}

TBR=niklas.enbom@webrtc.org

Bug: webrtc:7671
Change-Id: I6f38dc46126f279f334d52b56339b40acdc30511
Reviewed-on: https://webrtc-review.googlesource.com/45820
Reviewed-by: Emircan Uysaler <emircan@webrtc.org>
Commit-Queue: Emircan Uysaler <emircan@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21794}

modules/video_coding/codecs/multiplex/multiplex_decoder_adapter.cc

@@ -0,0 +1,216 @@
+/*
+ *  Copyright (c) 2017 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.
+ */
+
+#include "modules/video_coding/codecs/multiplex/include/multiplex_decoder_adapter.h"
+
+#include "api/video/i420_buffer.h"
+#include "api/video/video_frame_buffer.h"
+#include "common_video/include/video_frame.h"
+#include "common_video/include/video_frame_buffer.h"
+#include "common_video/libyuv/include/webrtc_libyuv.h"
+#include "rtc_base/keep_ref_until_done.h"
+#include "rtc_base/logging.h"
+
+namespace {
+void KeepBufferRefs(rtc::scoped_refptr<webrtc::VideoFrameBuffer>,
+                    rtc::scoped_refptr<webrtc::VideoFrameBuffer>) {}
+}  // anonymous namespace
+
+namespace webrtc {
+
+class MultiplexDecoderAdapter::AdapterDecodedImageCallback
+    : public webrtc::DecodedImageCallback {
+ public:
+  AdapterDecodedImageCallback(webrtc::MultiplexDecoderAdapter* adapter,
+                              AlphaCodecStream stream_idx)
+      : adapter_(adapter), stream_idx_(stream_idx) {}
+
+  void Decoded(VideoFrame& decoded_image,
+               rtc::Optional<int32_t> decode_time_ms,
+               rtc::Optional<uint8_t> qp) override {
+    if (!adapter_)
+      return;
+    adapter_->Decoded(stream_idx_, &decoded_image, decode_time_ms, qp);
+  }
+  int32_t Decoded(VideoFrame& decoded_image) override {
+    RTC_NOTREACHED();
+    return WEBRTC_VIDEO_CODEC_OK;
+  }
+  int32_t Decoded(VideoFrame& decoded_image, int64_t decode_time_ms) override {
+    RTC_NOTREACHED();
+    return WEBRTC_VIDEO_CODEC_OK;
+  }
+
+ private:
+  MultiplexDecoderAdapter* adapter_;
+  const AlphaCodecStream stream_idx_;
+};
+
+struct MultiplexDecoderAdapter::DecodedImageData {
+  explicit DecodedImageData(AlphaCodecStream stream_idx)
+      : stream_idx_(stream_idx),
+        decoded_image_(I420Buffer::Create(1 /* width */, 1 /* height */),
+                       0,
+                       0,
+                       kVideoRotation_0) {
+    RTC_DCHECK_EQ(kAXXStream, stream_idx);
+  }
+  DecodedImageData(AlphaCodecStream stream_idx,
+                   const VideoFrame& decoded_image,
+                   const rtc::Optional<int32_t>& decode_time_ms,
+                   const rtc::Optional<uint8_t>& qp)
+      : stream_idx_(stream_idx),
+        decoded_image_(decoded_image),
+        decode_time_ms_(decode_time_ms),
+        qp_(qp) {}
+  const AlphaCodecStream stream_idx_;
+  VideoFrame decoded_image_;
+  const rtc::Optional<int32_t> decode_time_ms_;
+  const rtc::Optional<uint8_t> qp_;
+
+ private:
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(DecodedImageData);
+};
+
+MultiplexDecoderAdapter::MultiplexDecoderAdapter(
+    VideoDecoderFactory* factory,
+    const SdpVideoFormat& associated_format)
+    : factory_(factory), associated_format_(associated_format) {}
+
+MultiplexDecoderAdapter::~MultiplexDecoderAdapter() {
+  Release();
+}
+
+int32_t MultiplexDecoderAdapter::InitDecode(const VideoCodec* codec_settings,
+                                            int32_t number_of_cores) {
+  RTC_DCHECK_EQ(kVideoCodecMultiplex, codec_settings->codecType);
+  VideoCodec settings = *codec_settings;
+  settings.codecType = PayloadStringToCodecType(associated_format_.name);
+  for (size_t i = 0; i < kAlphaCodecStreams; ++i) {
+    std::unique_ptr<VideoDecoder> decoder =
+        factory_->CreateVideoDecoder(associated_format_);
+    const int32_t rv = decoder->InitDecode(&settings, number_of_cores);
+    if (rv)
+      return rv;
+    adapter_callbacks_.emplace_back(
+        new MultiplexDecoderAdapter::AdapterDecodedImageCallback(
+            this, static_cast<AlphaCodecStream>(i)));
+    decoder->RegisterDecodeCompleteCallback(adapter_callbacks_.back().get());
+    decoders_.emplace_back(std::move(decoder));
+  }
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t MultiplexDecoderAdapter::Decode(
+    const EncodedImage& input_image,
+    bool missing_frames,
+    const RTPFragmentationHeader* /*fragmentation*/,
+    const CodecSpecificInfo* codec_specific_info,
+    int64_t render_time_ms) {
+  const MultiplexImage& image =
+      MultiplexEncodedImagePacker::Unpack(input_image);
+
+  if (image.component_count == 1) {
+    RTC_DCHECK(decoded_data_.find(input_image._timeStamp) ==
+               decoded_data_.end());
+    decoded_data_.emplace(std::piecewise_construct,
+                          std::forward_as_tuple(input_image._timeStamp),
+                          std::forward_as_tuple(kAXXStream));
+  }
+  int32_t rv = 0;
+  for (size_t i = 0; i < image.image_components.size(); i++) {
+    rv = decoders_[image.image_components[i].component_index]->Decode(
+        image.image_components[i].encoded_image, missing_frames, nullptr,
+        nullptr, render_time_ms);
+    if (rv != WEBRTC_VIDEO_CODEC_OK)
+      return rv;
+  }
+  return rv;
+}
+
+int32_t MultiplexDecoderAdapter::RegisterDecodeCompleteCallback(
+    DecodedImageCallback* callback) {
+  decoded_complete_callback_ = callback;
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t MultiplexDecoderAdapter::Release() {
+  for (auto& decoder : decoders_) {
+    const int32_t rv = decoder->Release();
+    if (rv)
+      return rv;
+  }
+  decoders_.clear();
+  adapter_callbacks_.clear();
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+void MultiplexDecoderAdapter::Decoded(AlphaCodecStream stream_idx,
+                                      VideoFrame* decoded_image,
+                                      rtc::Optional<int32_t> decode_time_ms,
+                                      rtc::Optional<uint8_t> qp) {
+  const auto& other_decoded_data_it =
+      decoded_data_.find(decoded_image->timestamp());
+  if (other_decoded_data_it != decoded_data_.end()) {
+    auto& other_image_data = other_decoded_data_it->second;
+    if (stream_idx == kYUVStream) {
+      RTC_DCHECK_EQ(kAXXStream, other_image_data.stream_idx_);
+      MergeAlphaImages(decoded_image, decode_time_ms, qp,
+                       &other_image_data.decoded_image_,
+                       other_image_data.decode_time_ms_, other_image_data.qp_);
+    } else {
+      RTC_DCHECK_EQ(kYUVStream, other_image_data.stream_idx_);
+      RTC_DCHECK_EQ(kAXXStream, stream_idx);
+      MergeAlphaImages(&other_image_data.decoded_image_,
+                       other_image_data.decode_time_ms_, other_image_data.qp_,
+                       decoded_image, decode_time_ms, qp);
+    }
+    decoded_data_.erase(decoded_data_.begin(), other_decoded_data_it);
+    return;
+  }
+  RTC_DCHECK(decoded_data_.find(decoded_image->timestamp()) ==
+             decoded_data_.end());
+  decoded_data_.emplace(
+      std::piecewise_construct,
+      std::forward_as_tuple(decoded_image->timestamp()),
+      std::forward_as_tuple(stream_idx, *decoded_image, decode_time_ms, qp));
+}
+
+void MultiplexDecoderAdapter::MergeAlphaImages(
+    VideoFrame* decoded_image,
+    const rtc::Optional<int32_t>& decode_time_ms,
+    const rtc::Optional<uint8_t>& qp,
+    VideoFrame* alpha_decoded_image,
+    const rtc::Optional<int32_t>& alpha_decode_time_ms,
+    const rtc::Optional<uint8_t>& alpha_qp) {
+  if (!alpha_decoded_image->timestamp()) {
+    decoded_complete_callback_->Decoded(*decoded_image, decode_time_ms, qp);
+    return;
+  }
+
+  rtc::scoped_refptr<webrtc::I420BufferInterface> yuv_buffer =
+      decoded_image->video_frame_buffer()->ToI420();
+  rtc::scoped_refptr<webrtc::I420BufferInterface> alpha_buffer =
+      alpha_decoded_image->video_frame_buffer()->ToI420();
+  RTC_DCHECK_EQ(yuv_buffer->width(), alpha_buffer->width());
+  RTC_DCHECK_EQ(yuv_buffer->height(), alpha_buffer->height());
+  rtc::scoped_refptr<I420ABufferInterface> merged_buffer = WrapI420ABuffer(
+      yuv_buffer->width(), yuv_buffer->height(), yuv_buffer->DataY(),
+      yuv_buffer->StrideY(), yuv_buffer->DataU(), yuv_buffer->StrideU(),
+      yuv_buffer->DataV(), yuv_buffer->StrideV(), alpha_buffer->DataY(),
+      alpha_buffer->StrideY(),
+      rtc::Bind(&KeepBufferRefs, yuv_buffer, alpha_buffer));
+
+  VideoFrame merged_image(merged_buffer, decoded_image->timestamp(),
+                          0 /* render_time_ms */, decoded_image->rotation());
+  decoded_complete_callback_->Decoded(merged_image, decode_time_ms, qp);
+}
+
+}  // namespace webrtc