1 // Copyright 2018 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "media/audio/audio_output_device_thread_callback.h"
6
7 #include <utility>
8
9 #include "base/logging.h"
10 #include "base/metrics/histogram_macros.h"
11 #include "base/trace_event/trace_event.h"
12
13 namespace media {
14
AudioOutputDeviceThreadCallback(const media::AudioParameters & audio_parameters,base::UnsafeSharedMemoryRegion shared_memory_region,media::AudioRendererSink::RenderCallback * render_callback)15 AudioOutputDeviceThreadCallback::AudioOutputDeviceThreadCallback(
16 const media::AudioParameters& audio_parameters,
17 base::UnsafeSharedMemoryRegion shared_memory_region,
18 media::AudioRendererSink::RenderCallback* render_callback)
19 : media::AudioDeviceThread::Callback(
20 audio_parameters,
21 ComputeAudioOutputBufferSize(audio_parameters),
22 /*segment count*/ 1),
23 shared_memory_region_(std::move(shared_memory_region)),
24 render_callback_(render_callback),
25 callback_num_(0) {
26 // CHECK that the shared memory is large enough. The memory allocated must be
27 // at least as large as expected.
28 CHECK(memory_length_ <= shared_memory_region_.GetSize());
29 }
30
31 AudioOutputDeviceThreadCallback::~AudioOutputDeviceThreadCallback() = default;
32
MapSharedMemory()33 void AudioOutputDeviceThreadCallback::MapSharedMemory() {
34 CHECK_EQ(total_segments_, 1u);
35 shared_memory_mapping_ = shared_memory_region_.MapAt(0, memory_length_);
36 CHECK(shared_memory_mapping_.IsValid());
37
38 media::AudioOutputBuffer* buffer =
39 reinterpret_cast<media::AudioOutputBuffer*>(
40 shared_memory_mapping_.memory());
41 output_bus_ = media::AudioBus::WrapMemory(audio_parameters_, buffer->audio);
42 output_bus_->set_is_bitstream_format(audio_parameters_.IsBitstreamFormat());
43 }
44
45 // Called whenever we receive notifications about pending data.
Process(uint32_t control_signal)46 void AudioOutputDeviceThreadCallback::Process(uint32_t control_signal) {
47 callback_num_++;
48
49 // Read and reset the number of frames skipped.
50 media::AudioOutputBuffer* buffer =
51 reinterpret_cast<media::AudioOutputBuffer*>(
52 shared_memory_mapping_.memory());
53 uint32_t frames_skipped = buffer->params.frames_skipped;
54 buffer->params.frames_skipped = 0;
55
56 TRACE_EVENT_BEGIN2("audio", "AudioOutputDevice::FireRenderCallback",
57 "callback_num", callback_num_, "frames skipped",
58 frames_skipped);
59
60 base::TimeDelta delay =
61 base::TimeDelta::FromMicroseconds(buffer->params.delay_us);
62
63 base::TimeTicks delay_timestamp =
64 base::TimeTicks() +
65 base::TimeDelta::FromMicroseconds(buffer->params.delay_timestamp_us);
66
67 DVLOG(4) << __func__ << " delay:" << delay << " delay_timestamp:" << delay
68 << " frames_skipped:" << frames_skipped;
69
70 // When playback starts, we get an immediate callback to Process to make sure
71 // that we have some data, we'll get another one after the device is awake and
72 // ingesting data, which is what we want to track with this trace.
73 if (callback_num_ == 2)
74 TRACE_EVENT_ASYNC_END0("audio", "StartingPlayback", this);
75
76 // Update the audio-delay measurement, inform about the number of skipped
77 // frames, and ask client to render audio. Since |output_bus_| is wrapping
78 // the shared memory the Render() call is writing directly into the shared
79 // memory.
80 render_callback_->Render(delay, delay_timestamp, frames_skipped,
81 output_bus_.get());
82
83 if (audio_parameters_.IsBitstreamFormat()) {
84 buffer->params.bitstream_data_size = output_bus_->GetBitstreamDataSize();
85 buffer->params.bitstream_frames = output_bus_->GetBitstreamFrames();
86 }
87
88 TRACE_EVENT_END2("audio", "AudioOutputDevice::FireRenderCallback",
89 "timestamp (ms)",
90 (delay_timestamp - base::TimeTicks()).InMillisecondsF(),
91 "delay (ms)", delay.InMillisecondsF());
92 }
93
CurrentThreadIsAudioDeviceThread()94 bool AudioOutputDeviceThreadCallback::CurrentThreadIsAudioDeviceThread() {
95 return thread_checker_.CalledOnValidThread();
96 }
97
InitializePlayStartTime()98 void AudioOutputDeviceThreadCallback::InitializePlayStartTime() {}
99
100 } // namespace media
101