Interface with webrtc through encoded frames

remoting/host/video_frame_recorder.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.

[Sergey Ulanov, 2016/04/12 18:57:31]

I deleted this file recently.

[Irfan, 2016/04/12 21:13:11]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/host/video_frame_recorder.h"
+
+#include <utility>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/macros.h"
+#include "base/single_thread_task_runner.h"
+#include "base/stl_util.h"
+#include "base/thread_task_runner_handle.h"
+#include "remoting/codec/video_encoder.h"
+#include "remoting/proto/video.pb.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_geometry.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_region.h"
+
+namespace remoting {
+
+static int64_t FrameContentSize(const webrtc::DesktopFrame* frame) {
+  DCHECK_GT(frame->stride(), 0);
+  return frame->stride() * frame->size().height();
+}
+
+// VideoEncoder wrapper used to intercept frames passed to a real VideoEncoder.
+class VideoFrameRecorder::RecordingVideoEncoder : public VideoEncoder {
+ public:
+  RecordingVideoEncoder(scoped_ptr<VideoEncoder> encoder,
+                        scoped_refptr<base::TaskRunner> recorder_task_runner,
+                        base::WeakPtr<VideoFrameRecorder> recorder);
+
+  base::WeakPtr<RecordingVideoEncoder> AsWeakPtr();
+
+  void set_enable_recording(bool enable_recording) {
+    DCHECK(!encoder_task_runner_.get() ||
+           encoder_task_runner_->BelongsToCurrentThread());
+    enable_recording_ = enable_recording;
+  }
+
+  // remoting::VideoEncoder interface.
+  void SetLosslessEncode(bool want_lossless) override;
+  void SetLosslessColor(bool want_lossless) override;
+  scoped_ptr<VideoPacket> Encode(const webrtc::DesktopFrame& frame,
+                                 uint32_t flags = 0) override;
+
+ private:
+  scoped_ptr<VideoEncoder> encoder_;
+  scoped_refptr<base::TaskRunner> recorder_task_runner_;
+  base::WeakPtr<VideoFrameRecorder> recorder_;
+
+  bool enable_recording_;
+  scoped_refptr<base::SingleThreadTaskRunner> encoder_task_runner_;
+
+  base::WeakPtrFactory<RecordingVideoEncoder> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(RecordingVideoEncoder);
+};
+
+VideoFrameRecorder::RecordingVideoEncoder::RecordingVideoEncoder(
+    scoped_ptr<VideoEncoder> encoder,
+    scoped_refptr<base::TaskRunner> recorder_task_runner,
+    base::WeakPtr<VideoFrameRecorder> recorder)
+    : encoder_(std::move(encoder)),
+      recorder_task_runner_(recorder_task_runner),
+      recorder_(recorder),
+      enable_recording_(false),
+      weak_factory_(this) {
+  DCHECK(encoder_);
+  DCHECK(recorder_task_runner_.get());
+}
+
+base::WeakPtr<VideoFrameRecorder::RecordingVideoEncoder>
+VideoFrameRecorder::RecordingVideoEncoder::AsWeakPtr() {
+  return weak_factory_.GetWeakPtr();
+}
+
+void VideoFrameRecorder::RecordingVideoEncoder::SetLosslessEncode(
+    bool want_lossless) {
+  encoder_->SetLosslessEncode(want_lossless);
+}
+
+void VideoFrameRecorder::RecordingVideoEncoder::SetLosslessColor(
+    bool want_lossless) {
+  encoder_->SetLosslessColor(want_lossless);
+}
+
+scoped_ptr<VideoPacket> VideoFrameRecorder::RecordingVideoEncoder::Encode(
+    const webrtc::DesktopFrame& frame,
+    uint32_t flags) {
+  // If this is the first Encode() then store the TaskRunner and inform the
+  // VideoFrameRecorder so it can post set_enable_recording() on it.
+  if (!encoder_task_runner_.get()) {
+    encoder_task_runner_ = base::ThreadTaskRunnerHandle::Get();
+    recorder_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&VideoFrameRecorder::SetEncoderTaskRunner,
+                              recorder_, encoder_task_runner_));
+  }
+
+  DCHECK(encoder_task_runner_->BelongsToCurrentThread());
+
+  if (enable_recording_) {
+    // Copy the frame and post it to the VideoFrameRecorder to store.
+    scoped_ptr<webrtc::DesktopFrame> frame_copy(
+        new webrtc::BasicDesktopFrame(frame.size()));
+    *frame_copy->mutable_updated_region() = frame.updated_region();
+    frame_copy->set_dpi(frame.dpi());
+    frame_copy->CopyPixelsFrom(frame.data(), frame.stride(),
+                               webrtc::DesktopRect::MakeSize(frame.size()));
+    recorder_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&VideoFrameRecorder::RecordFrame, recorder_,
+                              base::Passed(&frame_copy)));
+  }
+
+  return encoder_->Encode(frame, flags);
+}
+
+VideoFrameRecorder::VideoFrameRecorder()
+    : content_bytes_(0),
+      max_content_bytes_(0),
+      enable_recording_(false),
+      weak_factory_(this) {}
+
+VideoFrameRecorder::~VideoFrameRecorder() {
+  DetachVideoEncoderWrapper();
+}
+
+scoped_ptr<VideoEncoder> VideoFrameRecorder::WrapVideoEncoder(
+    scoped_ptr<VideoEncoder> encoder) {
+  DCHECK(!encoder_task_runner_.get());
+  DCHECK(!caller_task_runner_.get());
+  caller_task_runner_ = base::ThreadTaskRunnerHandle::Get();
+
+  scoped_ptr<RecordingVideoEncoder> recording_encoder(new RecordingVideoEncoder(
+      std::move(encoder), caller_task_runner_, weak_factory_.GetWeakPtr()));
+  recording_encoder_ = recording_encoder->AsWeakPtr();
+
+  return std::move(recording_encoder);
+}
+
+void VideoFrameRecorder::DetachVideoEncoderWrapper() {
+  DCHECK(!caller_task_runner_.get() ||
+         caller_task_runner_->BelongsToCurrentThread());
+
+  // Immediately detach the wrapper from this recorder.
+  weak_factory_.InvalidateWeakPtrs();
+
+  // Clean up any pending recorded frames.
+  STLDeleteElements(&recorded_frames_);
+  content_bytes_ = 0;
+
+  // Tell the wrapper to stop recording and posting frames to us.
+  if (encoder_task_runner_.get()) {
+    encoder_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&RecordingVideoEncoder::set_enable_recording,
+                              recording_encoder_, false));
+  }
+
+  // Detach this recorder from the calling and encode threads.
+  caller_task_runner_ = nullptr;
+  encoder_task_runner_ = nullptr;
+}
+
+void VideoFrameRecorder::SetEnableRecording(bool enable_recording) {
+  DCHECK(!caller_task_runner_.get() ||
+         caller_task_runner_->BelongsToCurrentThread());
+
+  if (enable_recording_ == enable_recording) {
+    return;
+  }
+  enable_recording_ = enable_recording;
+
+  if (encoder_task_runner_.get()) {
+    encoder_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&RecordingVideoEncoder::set_enable_recording,
+                              recording_encoder_, enable_recording_));
+  }
+}
+
+void VideoFrameRecorder::SetMaxContentBytes(int64_t max_content_bytes) {
+  DCHECK(!caller_task_runner_.get() ||
+         caller_task_runner_->BelongsToCurrentThread());
+  DCHECK_GE(max_content_bytes, 0);
+
+  max_content_bytes_ = max_content_bytes;
+}
+
+scoped_ptr<webrtc::DesktopFrame> VideoFrameRecorder::NextFrame() {
+  DCHECK(caller_task_runner_->BelongsToCurrentThread());
+
+  scoped_ptr<webrtc::DesktopFrame> frame;
+  if (!recorded_frames_.empty()) {
+    frame.reset(recorded_frames_.front());
+    recorded_frames_.pop_front();
+    content_bytes_ -= FrameContentSize(frame.get());
+    DCHECK_GE(content_bytes_, 0);
+  }
+
+  return frame;
+}
+
+void VideoFrameRecorder::SetEncoderTaskRunner(
+    scoped_refptr<base::TaskRunner> task_runner) {
+  DCHECK(caller_task_runner_->BelongsToCurrentThread());
+  DCHECK(!encoder_task_runner_.get());
+  DCHECK(task_runner.get());
+
+  encoder_task_runner_ = task_runner;
+
+  // If the caller already enabled recording, inform the recording encoder.
+  if (enable_recording_ && encoder_task_runner_.get()) {
+    encoder_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&RecordingVideoEncoder::set_enable_recording,
+                              recording_encoder_, enable_recording_));
+  }
+}
+
+void VideoFrameRecorder::RecordFrame(scoped_ptr<webrtc::DesktopFrame> frame) {
+  DCHECK(caller_task_runner_->BelongsToCurrentThread());
+
+  int64_t frame_bytes = FrameContentSize(frame.get());
+  DCHECK_GE(frame_bytes, 0);
+
+  // Purge existing frames until there is space for the new one.
+  while (content_bytes_ + frame_bytes > max_content_bytes_ &&
+         !recorded_frames_.empty()) {
+    scoped_ptr<webrtc::DesktopFrame> drop_frame(recorded_frames_.front());
+    recorded_frames_.pop_front();
+    content_bytes_ -= FrameContentSize(drop_frame.get());
+    DCHECK_GE(content_bytes_, 0);
+  }
+
+  // If the frame is still too big, ignore it.
+  if (content_bytes_ + frame_bytes > max_content_bytes_) {
+    return;
+  }
+
+  // Store the frame and update the content byte count.
+  recorded_frames_.push_back(frame.release());
+  content_bytes_ += frame_bytes;
+}
+
+}  // namespace remoting