Cast: Fix threading issues in VideoEncoderImpl

media/cast/video_sender/video_encoder_impl.cc

 // Copyright 2014 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 "media/cast/video_sender/video_encoder.h"
 
 #include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/callback.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "media/base/video_frame.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/video_sender/video_encoder_impl.h"
 
 namespace media {
 namespace cast {
 
+namespace {
+
+typedef base::Callback<void(Vp8Encoder*)> PassEncoderCallback;
+
 void LogFrameEncodedEvent(const base::TimeTicks& now,
-                          CastEnvironment* const cast_environment,
+                          scoped_refptr<CastEnvironment> cast_environment,
                           const base::TimeTicks& capture_time) {
+  DCHECK(cast_environment->CurrentlyOn(CastEnvironment::MAIN));
   cast_environment->Logging()->InsertFrameEvent(now, kVideoFrameEncoded,
       GetVideoRtpTimestamp(capture_time), kFrameIdUnknown);
 }
 
+void InitializeVp8EncoderOnEncoderThread(
+    const scoped_refptr<CastEnvironment>& environment,
+    Vp8Encoder* vp8_encoder) {
+  DCHECK(environment->CurrentlyOn(CastEnvironment::VIDEO_ENCODER));
+  vp8_encoder->Initialize();
+}
+
+void EncodeVideoFrameOnEncoderThread(
+    scoped_refptr<CastEnvironment> environment,
+    Vp8Encoder* vp8_encoder,
+    const scoped_refptr<media::VideoFrame>& video_frame,
+    const base::TimeTicks& capture_time,
+    const VideoEncoderImpl::CodecDynamicConfig& dynamic_config,
+    const VideoEncoderImpl::FrameEncodedCallback& frame_encoded_callback) {
+  DCHECK(environment->CurrentlyOn(CastEnvironment::VIDEO_ENCODER));
+  if (dynamic_config.key_frame_requested) {
+    vp8_encoder->GenerateKeyFrame();
+  }
+  vp8_encoder->LatestFrameIdToReference(
+      dynamic_config.latest_frame_id_to_reference);
+  vp8_encoder->UpdateRates(dynamic_config.bit_rate);
+
+  scoped_ptr<transport::EncodedVideoFrame> encoded_frame(
+      new transport::EncodedVideoFrame());
+  bool retval = vp8_encoder->Encode(video_frame, encoded_frame.get());
+
+  base::TimeTicks now = environment->Clock()->NowTicks();
+  environment->PostTask(
+      CastEnvironment::MAIN, FROM_HERE,
+      base::Bind(LogFrameEncodedEvent, now, environment, capture_time));
+
+  if (!retval) {
+    VLOG(1) << "Encoding failed";
+    return;
+  }
+  if (encoded_frame->data.size() <= 0) {
+    VLOG(1) << "Encoding resulted in an empty frame";
+    return;
+  }
+  environment->PostTask(
+      CastEnvironment::MAIN, FROM_HERE,
+      base::Bind(
+          frame_encoded_callback,
+          base::Passed(&encoded_frame),
+          capture_time));
+}
+
+}  // namespace
+
 VideoEncoderImpl::VideoEncoderImpl(
     scoped_refptr<CastEnvironment> cast_environment,
     const VideoSenderConfig& video_config,
     uint8 max_unacked_frames)
     : video_config_(video_config),
       cast_environment_(cast_environment),
       skip_next_frame_(false),
       skip_count_(0) {
   if (video_config.codec == transport::kVp8) {
     vp8_encoder_.reset(new Vp8Encoder(video_config, max_unacked_frames));
+    cast_environment_->PostTask(
+        CastEnvironment::VIDEO_ENCODER, FROM_HERE,
+        base::Bind(
+            &InitializeVp8EncoderOnEncoderThread,
+            cast_environment,
+            vp8_encoder_.get()));
   } else {
     DCHECK(false) << "Invalid config";  // Codec not supported.
   }
 
   dynamic_config_.key_frame_requested = false;
   dynamic_config_.latest_frame_id_to_reference = kStartFrameId;
   dynamic_config_.bit_rate = video_config.start_bitrate;
 }
 
-VideoEncoderImpl::~VideoEncoderImpl() {}
+VideoEncoderImpl::~VideoEncoderImpl() {
+  DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
+  if (vp8_encoder_) {
+    cast_environment_->PostTask(
+        CastEnvironment::VIDEO_ENCODER, FROM_HERE,
+        base::Bind(&base::DeletePointer<Vp8Encoder>, vp8_encoder_.release()));
+  }
+}
 
 bool VideoEncoderImpl::EncodeVideoFrame(
     const scoped_refptr<media::VideoFrame>& video_frame,
     const base::TimeTicks& capture_time,
     const FrameEncodedCallback& frame_encoded_callback) {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
   if (video_config_.codec != transport::kVp8) return false;
 
   if (skip_next_frame_) {
     ++skip_count_;
     skip_next_frame_ = false;
     VLOG(1) << "Skip encoding frame";
     return false;
   }
 
   base::TimeTicks now = cast_environment_->Clock()->NowTicks();
   cast_environment_->Logging()->InsertFrameEvent(now, kVideoFrameSentToEncoder,
       GetVideoRtpTimestamp(capture_time), kFrameIdUnknown);
   cast_environment_->PostTask(CastEnvironment::VIDEO_ENCODER, FROM_HERE,
-      base::Bind(&VideoEncoderImpl::EncodeVideoFrameEncoderThread,
-                 base::Unretained(this), video_frame, capture_time,
-                 dynamic_config_, frame_encoded_callback));
+      base::Bind(&EncodeVideoFrameOnEncoderThread,
+                 cast_environment_,
+                 vp8_encoder_.get(),
+                 video_frame,
+                 capture_time,
+                 dynamic_config_,
+                 frame_encoded_callback));
 
   dynamic_config_.key_frame_requested = false;
   return true;
 }
 
-void VideoEncoderImpl::EncodeVideoFrameEncoderThread(
-    const scoped_refptr<media::VideoFrame>& video_frame,
-    const base::TimeTicks& capture_time,
-    const CodecDynamicConfig& dynamic_config,
-    const FrameEncodedCallback& frame_encoded_callback) {
-  DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::VIDEO_ENCODER));
-  if (dynamic_config.key_frame_requested) {
-    vp8_encoder_->GenerateKeyFrame();
-  }
-  vp8_encoder_->LatestFrameIdToReference(
-      dynamic_config.latest_frame_id_to_reference);
-  vp8_encoder_->UpdateRates(dynamic_config.bit_rate);
-
-  scoped_ptr<transport::EncodedVideoFrame> encoded_frame(
-      new transport::EncodedVideoFrame());
-  bool retval = vp8_encoder_->Encode(video_frame, encoded_frame.get());
-
-  base::TimeTicks now = cast_environment_->Clock()->NowTicks();
-  cast_environment_->PostTask(CastEnvironment::MAIN, FROM_HERE,
-      base::Bind(LogFrameEncodedEvent, now, cast_environment_, capture_time));
-
-  if (!retval) {
-    VLOG(1) << "Encoding failed";
-    return;
-  }
-  if (encoded_frame->data.size() <= 0) {
-    VLOG(1) << "Encoding resulted in an empty frame";
-    return;
-  }
-  cast_environment_->PostTask(CastEnvironment::MAIN, FROM_HERE,
-      base::Bind(frame_encoded_callback,
-          base::Passed(&encoded_frame), capture_time));
-}
-
 // Inform the encoder about the new target bit rate.
 void VideoEncoderImpl::SetBitRate(int new_bit_rate) {
   dynamic_config_.bit_rate = new_bit_rate;
 }
 
 // Inform the encoder to not encode the next frame.
 void VideoEncoderImpl::SkipNextFrame(bool skip_next_frame) {
   skip_next_frame_ = skip_next_frame;
 }
 
 // Inform the encoder to encode the next frame as a key frame.
 void VideoEncoderImpl::GenerateKeyFrame() {
   dynamic_config_.key_frame_requested = true;
 }
 
 // Inform the encoder to only reference frames older or equal to frame_id;
 void VideoEncoderImpl::LatestFrameIdToReference(uint32 frame_id) {
   dynamic_config_.latest_frame_id_to_reference = frame_id;
 }
 
 int VideoEncoderImpl::NumberOfSkippedFrames() const {
   return skip_count_;
 }
 
 }  //  namespace cast
 }  //  namespace media