MediaRecorder: wire the bitRate settings in Blink and content (2nd go)

content/renderer/media/video_track_recorder.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/video_track_recorder.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 60 matching lines @@
 // which is cached on first frame arrival, and is supposed to be the render IO
 // thread, but this is not enforced;
 // - uses an internal |encoding_thread_| for libvpx interactions, notably for
 // encoding (which might take some time).
 class VideoTrackRecorder::VpxEncoder final
     : public base::RefCountedThreadSafe<VpxEncoder> {
  public:
   static void ShutdownEncoder(scoped_ptr<base::Thread> encoding_thread,
                               ScopedVpxCodecCtxPtr encoder);
 
-  VpxEncoder(bool use_vp9, const OnEncodedVideoCB& on_encoded_video_callback);
+  VpxEncoder(bool use_vp9,
+             const OnEncodedVideoCB& on_encoded_video_callback,
+             int32_t bits_per_second);
 
   void StartFrameEncode(const scoped_refptr<VideoFrame>& frame,
                         base::TimeTicks capture_timestamp);
 
   void set_paused(bool paused) { paused_ = paused; }
 
  private:
   friend class base::RefCountedThreadSafe<VpxEncoder>;
   ~VpxEncoder();
 
   void EncodeOnEncodingThread(const scoped_refptr<VideoFrame>& frame,
                               base::TimeTicks capture_timestamp);
 
   void ConfigureEncoding(const gfx::Size& size);
 
   // Returns true if |codec_config_| has been filled in at least once.
   bool IsInitialized() const;
 
   // Estimate the frame duration from |frame| and |last_frame_timestamp_|.
   base::TimeDelta CalculateFrameDuration(
       const scoped_refptr<VideoFrame>& frame);
 
   // While |paused_|, frames are not encoded.
   bool paused_;
 
   // Force usage of VP9 for encoding, instead of VP8 which is the default.
   const bool use_vp9_;
 
+  // This callback should be exercised on IO thread.
+  const OnEncodedVideoCB on_encoded_video_callback_;
+
+  const int32_t bits_per_second_;

[Peter Beverloo, 2016/01/20 18:35:35]

nit: all other members have documentation

[mcasas, 2016/01/20 21:13:22]

Done.

+
   // Used to shutdown properly on the same thread we were created.
   const scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 
   // Task runner where frames to encode and reply callbacks must happen.
   scoped_refptr<base::SingleThreadTaskRunner> origin_task_runner_;
 
-  // This callback should be exercised on IO thread.
-  const OnEncodedVideoCB on_encoded_video_callback_;
-
   // Thread for encoding. Active for the lifetime of VpxEncoder. All variables
   // below this are used in this thread.
   scoped_ptr<base::Thread> encoding_thread_;
   // VP8 internal objects: configuration and encoder.
   vpx_codec_enc_cfg_t codec_config_;
   // |encoder_| is a special scoped pointer to guarantee proper destruction.
   // Again, it should only be accessed on |encoding_thread_|.
   ScopedVpxCodecCtxPtr encoder_;
 
   // The |VideoFrame::timestamp()| of the last encoded frame.  This is used to
   // predict the duration of the next frame.
   base::TimeDelta last_frame_timestamp_;
 
   DISALLOW_COPY_AND_ASSIGN(VpxEncoder);
 };
 
 // static
 void VideoTrackRecorder::VpxEncoder::ShutdownEncoder(
     scoped_ptr<base::Thread> encoding_thread,
     ScopedVpxCodecCtxPtr encoder) {
   DCHECK(encoding_thread->IsRunning());
   encoding_thread->Stop();
   // Both |encoding_thread| and |encoder| will be destroyed at end-of-scope.
 }
 
 VideoTrackRecorder::VpxEncoder::VpxEncoder(
     bool use_vp9,
-    const OnEncodedVideoCB& on_encoded_video_callback)
+    const OnEncodedVideoCB& on_encoded_video_callback,
+    int32_t bits_per_second)
     : paused_(false),
       use_vp9_(use_vp9),
+      on_encoded_video_callback_(on_encoded_video_callback),
+      bits_per_second_(bits_per_second),
       main_task_runner_(base::MessageLoop::current()->task_runner()),
-      on_encoded_video_callback_(on_encoded_video_callback),
       encoding_thread_(new base::Thread("EncodingThread")) {
   DCHECK(!on_encoded_video_callback_.is_null());
 
   codec_config_.g_timebase.den = 0;  // Not initialized.
 
   DCHECK(!encoding_thread_->IsRunning());
   encoding_thread_->Start();
 }
 
 VideoTrackRecorder::VpxEncoder::~VpxEncoder() {
@@ skipping 90 matching lines @@
     encoder_.reset();
   }
 
   const vpx_codec_iface_t* interface =
       use_vp9_ ? vpx_codec_vp9_cx() : vpx_codec_vp8_cx();
   const vpx_codec_err_t result = vpx_codec_enc_config_default(interface,
                                                               &codec_config_,
                                                               0 /* reserved */);
   DCHECK_EQ(VPX_CODEC_OK, result);
 
-  // Adjust default bit rate to account for the actual size.
   DCHECK_EQ(320u, codec_config_.g_w);
   DCHECK_EQ(240u, codec_config_.g_h);
   DCHECK_EQ(256u, codec_config_.rc_target_bitrate);
-  codec_config_.rc_target_bitrate = size.GetArea() *
-                                    codec_config_.rc_target_bitrate /
-                                    codec_config_.g_w / codec_config_.g_h;
+  // Use the selected bitrate or adjust default bit rate to account for the
+  // actual size.
+  if (bits_per_second_ > 0) {
+    codec_config_.rc_target_bitrate = bits_per_second_;
+  } else {
+    codec_config_.rc_target_bitrate = size.GetArea() *
+                                      codec_config_.rc_target_bitrate /
+                                      codec_config_.g_w / codec_config_.g_h;
+  }
   // Both VP8/VP9 configuration should be Variable BitRate by default.
   DCHECK_EQ(VPX_VBR, codec_config_.rc_end_usage);
   if (use_vp9_) {
     // Number of frames to consume before producing output.
     codec_config_.g_lag_in_frames = 0;
 
     // DCHECK that the profile selected by default is I420 (magic number 0).
     DCHECK_EQ(0u, codec_config_.g_profile);
   } else {
     // VP8 always produces frames instantaneously.
@@ skipping 63 matching lines @@
   // Make sure |predicted_frame_duration| is in a safe range of values.
   const TimeDelta kMaxFrameDuration = TimeDelta::FromSecondsD(1.0 / 8);
   const TimeDelta kMinFrameDuration = TimeDelta::FromMilliseconds(1);
   return std::min(kMaxFrameDuration, std::max(predicted_frame_duration,
                                               kMinFrameDuration));
 }
 
 VideoTrackRecorder::VideoTrackRecorder(
     bool use_vp9,
     const blink::WebMediaStreamTrack& track,
-    const OnEncodedVideoCB& on_encoded_video_callback)
+    const OnEncodedVideoCB& on_encoded_video_callback,
+    int32_t bits_per_second)
     : track_(track),
-      encoder_(new VpxEncoder(use_vp9, on_encoded_video_callback)) {
+      encoder_(
+          new VpxEncoder(use_vp9, on_encoded_video_callback, bits_per_second)) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(!track_.isNull());
   DCHECK(track_.extraData());
 
   // StartFrameEncode() will be called on Render IO thread.
   AddToVideoTrack(this,
                   base::Bind(&VideoTrackRecorder::VpxEncoder::StartFrameEncode,
                              encoder_),
                   track_);
 }
@@ skipping 16 matching lines @@
   encoder_->set_paused(false);
 }
 
 void VideoTrackRecorder::OnVideoFrameForTesting(
     const scoped_refptr<media::VideoFrame>& frame,
     base::TimeTicks timestamp) {
   encoder_->StartFrameEncode(frame, timestamp);
 }
 
 }  // namespace content