Add power monitoring to the Cast VideoToolbox encoder.

media/cast/sender/h264_vt_encoder.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/sender/h264_vt_encoder.h"
 
 #include <string>
 #include <vector>
 
 #include "base/big_endian.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/power_monitor/power_monitor.h"
 #include "base/synchronization/lock.h"
 #include "media/base/mac/corevideo_glue.h"
 #include "media/base/mac/video_frame_mac.h"
 #include "media/cast/sender/video_frame_factory.h"
 
 namespace media {
 namespace cast {
 
 namespace {
 
@@ skipping 300 matching lines @@
           : STATUS_UNSUPPORTED_CODEC;
   cast_environment_->PostTask(
       CastEnvironment::MAIN, FROM_HERE,
       base::Bind(status_change_cb_, operational_status));
 
   if (operational_status == STATUS_INITIALIZED) {
     video_frame_factory_ =
         scoped_refptr<VideoFrameFactoryImpl>(new VideoFrameFactoryImpl(
             weak_factory_.GetWeakPtr(), cast_environment_));
   }
+
+  // Register for power state changes.
+  auto power_monitor = base::PowerMonitor::Get();
+  if (power_monitor) {
+    power_monitor->AddObserver(this);
+    VLOG(1) << "Registered for power state changes.";
+  } else {
+    DLOG(WARNING) << "No power monitor. Encoder may fail if power state change "
+                     "goes undetected.";
+  }
 }
 
 H264VideoToolboxEncoder::~H264VideoToolboxEncoder() {
   DestroyCompressionSession();
+  auto power_monitor = base::PowerMonitor::Get();
+  if (power_monitor)
+    power_monitor->RemoveObserver(this);
 }
 
 void H264VideoToolboxEncoder::ResetCompressionSession() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Notify that we're resetting the encoder.
   cast_environment_->PostTask(
       CastEnvironment::MAIN, FROM_HERE,
       base::Bind(status_change_cb_, STATUS_CODEC_REINIT_PENDING));
 
@@ skipping 252 matching lines @@
   if (!compression_session_)
     return;
 
   OSStatus status = videotoolbox_glue_->VTCompressionSessionCompleteFrames(
       compression_session_, CoreMediaGlue::CMTime{0, 0, 0, 0});
   if (status != noErr) {
     DLOG(ERROR) << " VTCompressionSessionCompleteFrames failed: " << status;
   }
 }
 
+void H264VideoToolboxEncoder::OnSuspend() {
+  VLOG(1)
+      << "OnSuspend: Emitting all frames and destroying compression session.";
+  EmitFrames();
+  DestroyCompressionSession();
+}
+
+void H264VideoToolboxEncoder::OnResume() {
+  VLOG(1) << "OnResume: Resetting compression session.";
+  ResetCompressionSession();

[miu, 2015/04/22 18:18:47]

I just realized: You shouldn't call ResetCompressionSession() if either:

1. video_frame_factory_ is null (i.e., was never set in the ctor).
2. frame_size_ is empty.

Since these would indicate there wasn't a compression session when OnSuspend()
was called.

[jfroy, 2015/04/22 18:24:36]

Thanks for pointing this out. I'll update the code and make sure to test that
case.

+}
+
 bool H264VideoToolboxEncoder::SetSessionProperty(CFStringRef key,
                                                  int32_t value) {
   base::ScopedCFTypeRef<CFNumberRef> cfvalue(
       CFNumberCreate(nullptr, kCFNumberSInt32Type, &value));
   return videotoolbox_glue_->VTSessionSetProperty(compression_session_, key,
                                                   cfvalue) == noErr;
 }
 
 bool H264VideoToolboxEncoder::SetSessionProperty(CFStringRef key, bool value) {
   CFBooleanRef cfvalue = (value) ? kCFBooleanTrue : kCFBooleanFalse;
@@ skipping 69 matching lines @@
     CopySampleBufferToAnnexBBuffer(sbuf, &encoded_frame->data, keyframe);
 
   encoder->cast_environment_->PostTask(
       CastEnvironment::MAIN, FROM_HERE,
       base::Bind(request->frame_encoded_callback,
                  base::Passed(&encoded_frame)));
 }
 
 }  // namespace cast
 }  // namespace media