media/audio/simple_sources.cc - chromium/src - Git at Google

 // Copyright (c) 2012 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/audio/simple_sources.h"

 #include <stddef.h>

 #include <algorithm>

 #include "base/files/file.h"
 #include "base/logging.h"
 #include "base/numerics/math_constants.h"
 #include "base/thread_annotations.h"
 #include "base/time/time.h"
 #include "media/audio/wav_audio_handler.h"
 #include "media/base/audio_bus.h"

 namespace media {
 namespace {
 // Opens |wav_filename|, reads it and loads it as a wav file. This function will
 // return a null pointer if we can't read the file or if it's malformed. The
 // caller takes ownership of the returned data. The size of the data is stored
 // in |read_length|.
 std::unique_ptr<char[]> ReadWavFile(const base::FilePath& wav_filename,
                                     size_t* read_length) {
   base::File wav_file(
       wav_filename, base::File::FLAG_OPEN | base::File::FLAG_READ);
   if (!wav_file.IsValid()) {
     LOG(ERROR) << "Failed to read " << wav_filename.value()
                << " as input to the fake device.";
     return nullptr;
   }

   int64_t wav_file_length = wav_file.GetLength();
   if (wav_file_length < 0) {
     LOG(ERROR) << "Failed to get size of " << wav_filename.value();
     return nullptr;
   }
   if (wav_file_length == 0) {
     LOG(ERROR) << "Input file to fake device is empty: "
                << wav_filename.value();
     return nullptr;
   }

   std::unique_ptr<char[]> data(new char[wav_file_length]);
   int read_bytes = wav_file.Read(0, data.get(), wav_file_length);
   if (read_bytes != wav_file_length) {
     LOG(ERROR) << "Failed to read all bytes of " << wav_filename.value();
     return nullptr;
   }
   *read_length = wav_file_length;
   return data;
 }

 // These values are based on experiments for local-to-local
 // PeerConnection to demonstrate audio/video synchronization.
 static const int kBeepDurationMilliseconds = 20;
 static const int kBeepFrequency = 400;

 // Intervals between two automatic beeps.
 static const int kAutomaticBeepIntervalInMs = 500;

 // Automatic beep will be triggered every |kAutomaticBeepIntervalInMs| unless
 // users explicitly call BeepOnce(), which will disable the automatic beep.
 class BeepContext {
  public:
   BeepContext() : beep_once_(false), automatic_beep_(true) {}

   void SetBeepOnce(bool enable) {
     base::AutoLock auto_lock(lock_);
     beep_once_ = enable;

     // Disable the automatic beep if users explicit set |beep_once_| to true.
     if (enable)
       automatic_beep_ = false;
   }

   bool beep_once() const {
     base::AutoLock auto_lock(lock_);
     return beep_once_;
   }

   bool automatic_beep() const {
     base::AutoLock auto_lock(lock_);
     return automatic_beep_;
   }

  private:
   mutable base::Lock lock_;
   bool beep_once_ GUARDED_BY(lock_);
   bool automatic_beep_ GUARDED_BY(lock_);
 };

 BeepContext* GetBeepContext() {
   static BeepContext* context = new BeepContext();
   return context;
 }

 }  // namespace

 //////////////////////////////////////////////////////////////////////////////
 // SineWaveAudioSource implementation.

 SineWaveAudioSource::SineWaveAudioSource(int channels,
                                          double freq, double sample_freq)
     : channels_(channels),
       f_(freq / sample_freq),
       time_state_(0),
       cap_(0),
       callbacks_(0),
       errors_(0) {
 }

 SineWaveAudioSource::~SineWaveAudioSource() = default;

 // The implementation could be more efficient if a lookup table is constructed
 // but it is efficient enough for our simple needs.
 int SineWaveAudioSource::OnMoreData(base::TimeDelta /* delay */,
                                     base::TimeTicks /* delay_timestamp */,
                                     int /* prior_frames_skipped */,
                                     AudioBus* dest) {
   base::AutoLock auto_lock(time_lock_);
   callbacks_++;

   // The table is filled with s(t) = kint16max*sin(Theta*t),
   // where Theta = 2*PI*fs.
   // We store the discrete time value |t| in a member to ensure that the
   // next pass starts at a correct state.
   int max_frames =
       cap_ > 0 ? std::min(dest->frames(), cap_ - time_state_) : dest->frames();
   for (int i = 0; i < max_frames; ++i)
     dest->channel(0)[i] = sin(2.0 * base::kPiDouble * f_ * time_state_++);
   for (int i = 1; i < dest->channels(); ++i) {
     memcpy(dest->channel(i), dest->channel(0),
            max_frames * sizeof(*dest->channel(i)));
   }
   return max_frames;
 }

 void SineWaveAudioSource::OnError() {
   errors_++;
 }

 void SineWaveAudioSource::CapSamples(int cap) {
   base::AutoLock auto_lock(time_lock_);
   DCHECK_GT(cap, 0);
   cap_ = cap;
 }

 void SineWaveAudioSource::Reset() {
   base::AutoLock auto_lock(time_lock_);
   time_state_ = 0;
 }

 FileSource::FileSource(const AudioParameters& params,
                        const base::FilePath& path_to_wav_file,
                        bool loop)
     : params_(params),
       path_to_wav_file_(path_to_wav_file),
       wav_file_read_pos_(0),
       load_failed_(false),
       looping_(loop) {}

 FileSource::~FileSource() = default;

 void FileSource::LoadWavFile(const base::FilePath& path_to_wav_file) {
   // Don't try again if we already failed.
   if (load_failed_)
     return;

   // Read the file, and put its data in a scoped_ptr so it gets deleted when
   // this class destructs. This data must be valid for the lifetime of
   // |wav_audio_handler_|.
   size_t length = 0u;
   raw_wav_data_ = ReadWavFile(path_to_wav_file, &length);
   if (!raw_wav_data_) {
     load_failed_ = true;
     return;
   }

   // Attempt to create a handler with this data. If the data is invalid, return.
   wav_audio_handler_ =
       WavAudioHandler::Create(base::StringPiece(raw_wav_data_.get(), length));
   if (!wav_audio_handler_) {
     LOG(ERROR) << "WAV data could be read but is not valid";
     load_failed_ = true;
     return;
   }

   // Hook us up so we pull in data from the file into the converter. We need to
   // modify the wav file's audio parameters since we'll be reading small slices
   // of it at a time and not the whole thing (like 10 ms at a time).
   AudioParameters file_audio_slice(
       AudioParameters::AUDIO_PCM_LOW_LATENCY,
       GuessChannelLayout(wav_audio_handler_->num_channels()),
       wav_audio_handler_->sample_rate(), params_.frames_per_buffer());

   file_audio_converter_.reset(
       new AudioConverter(file_audio_slice, params_, false));
   file_audio_converter_->AddInput(this);
 }

 int FileSource::OnMoreData(base::TimeDelta /* delay */,
                            base::TimeTicks /* delay_timestamp */,
                            int /* prior_frames_skipped */,
                            AudioBus* dest) {
   // Load the file if we haven't already. This load needs to happen on the
   // audio thread, otherwise we'll run on the UI thread on Mac for instance.
   // This will massively delay the first OnMoreData, but we'll catch up.
   if (!wav_audio_handler_)
     LoadWavFile(path_to_wav_file_);
   if (load_failed_)
     return 0;

   DCHECK(wav_audio_handler_.get());

   if (wav_audio_handler_->AtEnd(wav_file_read_pos_)) {
     if (looping_)
       Rewind();
     else
       return 0;
   }

   // This pulls data from ProvideInput.
   file_audio_converter_->Convert(dest);
   return dest->frames();
 }

 void FileSource::Rewind() {
   wav_file_read_pos_ = 0;
 }

 double FileSource::ProvideInput(AudioBus* audio_bus_into_converter,
                                 uint32_t frames_delayed) {
   // Unfilled frames will be zeroed by CopyTo.
   size_t bytes_written;
   wav_audio_handler_->CopyTo(audio_bus_into_converter, wav_file_read_pos_,
                              &bytes_written);
   wav_file_read_pos_ += bytes_written;
   return 1.0;
 }

 void FileSource::OnError() {}

 BeepingSource::BeepingSource(const AudioParameters& params)
     : buffer_size_(params.GetBytesPerBuffer(kSampleFormatU8)),
       buffer_(new uint8_t[buffer_size_]),
       params_(params),
       last_callback_time_(base::TimeTicks::Now()),
       beep_duration_in_buffers_(kBeepDurationMilliseconds *
                                 params.sample_rate() /
                                 params.frames_per_buffer() / 1000),
       beep_generated_in_buffers_(0),
       beep_period_in_frames_(params.sample_rate() / kBeepFrequency) {}

 BeepingSource::~BeepingSource() = default;

 int BeepingSource::OnMoreData(base::TimeDelta /* delay */,
                               base::TimeTicks /* delay_timestamp */,
                               int /* prior_frames_skipped */,
                               AudioBus* dest) {
   // Accumulate the time from the last beep.
   interval_from_last_beep_ += base::TimeTicks::Now() - last_callback_time_;

   memset(buffer_.get(), 128, buffer_size_);
   bool should_beep = false;
   BeepContext* beep_context = GetBeepContext();
   if (beep_context->automatic_beep()) {
     base::TimeDelta delta = interval_from_last_beep_ -
         base::TimeDelta::FromMilliseconds(kAutomaticBeepIntervalInMs);
     if (delta > base::TimeDelta()) {
       should_beep = true;
       interval_from_last_beep_ = delta;
     }
   } else {
     should_beep = beep_context->beep_once();
     beep_context->SetBeepOnce(false);
   }

   // If this object was instructed to generate a beep or has started to
   // generate a beep sound.
   if (should_beep || beep_generated_in_buffers_) {
     // Compute the number of frames to output high value. Then compute the
     // number of bytes based on channels.
     int high_frames = beep_period_in_frames_ / 2;
     int high_bytes = high_frames * params_.channels();

     // Separate high and low with the same number of bytes to generate a
     // square wave.
     int position = 0;
     while (position + high_bytes <= buffer_size_) {
       // Write high values first.
       memset(buffer_.get() + position, 255, high_bytes);
       // Then leave low values in the buffer with |high_bytes|.
       position += high_bytes * 2;
     }

     ++beep_generated_in_buffers_;
     if (beep_generated_in_buffers_ >= beep_duration_in_buffers_)
       beep_generated_in_buffers_ = 0;
   }

   last_callback_time_ = base::TimeTicks::Now();
   dest->FromInterleaved<UnsignedInt8SampleTypeTraits>(buffer_.get(),
                                                       dest->frames());
   return dest->frames();
 }

 void BeepingSource::OnError() {}

 void BeepingSource::BeepOnce() {
   GetBeepContext()->SetBeepOnce(true);
 }

 }  // namespace media
	// Copyright (c) 2012 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/audio/simple_sources.h"

	#include <stddef.h>

	#include <algorithm>

	#include "base/files/file.h"
	#include "base/logging.h"
	#include "base/numerics/math_constants.h"
	#include "base/thread_annotations.h"
	#include "base/time/time.h"
	#include "media/audio/wav_audio_handler.h"
	#include "media/base/audio_bus.h"

	namespace media {
	namespace {
	// Opens \|wav_filename\|, reads it and loads it as a wav file. This function will
	// return a null pointer if we can't read the file or if it's malformed. The
	// caller takes ownership of the returned data. The size of the data is stored
	// in \|read_length\|.
	std::unique_ptr<char[]> ReadWavFile(const base::FilePath& wav_filename,
	size_t* read_length) {
	base::File wav_file(
	wav_filename, base::File::FLAG_OPEN \| base::File::FLAG_READ);
	if (!wav_file.IsValid()) {
	LOG(ERROR) << "Failed to read " << wav_filename.value()
	<< " as input to the fake device.";
	return nullptr;
	}

	int64_t wav_file_length = wav_file.GetLength();
	if (wav_file_length < 0) {
	LOG(ERROR) << "Failed to get size of " << wav_filename.value();
	return nullptr;
	}
	if (wav_file_length == 0) {
	LOG(ERROR) << "Input file to fake device is empty: "
	<< wav_filename.value();
	return nullptr;
	}

	std::unique_ptr<char[]> data(new char[wav_file_length]);
	int read_bytes = wav_file.Read(0, data.get(), wav_file_length);
	if (read_bytes != wav_file_length) {
	LOG(ERROR) << "Failed to read all bytes of " << wav_filename.value();
	return nullptr;
	}
	*read_length = wav_file_length;
	return data;
	}

	// These values are based on experiments for local-to-local
	// PeerConnection to demonstrate audio/video synchronization.
	static const int kBeepDurationMilliseconds = 20;
	static const int kBeepFrequency = 400;

	// Intervals between two automatic beeps.
	static const int kAutomaticBeepIntervalInMs = 500;

	// Automatic beep will be triggered every \|kAutomaticBeepIntervalInMs\| unless
	// users explicitly call BeepOnce(), which will disable the automatic beep.
	class BeepContext {
	public:
	BeepContext() : beep_once_(false), automatic_beep_(true) {}

	void SetBeepOnce(bool enable) {
	base::AutoLock auto_lock(lock_);
	beep_once_ = enable;

	// Disable the automatic beep if users explicit set \|beep_once_\| to true.
	if (enable)
	automatic_beep_ = false;
	}

	bool beep_once() const {
	base::AutoLock auto_lock(lock_);
	return beep_once_;
	}

	bool automatic_beep() const {
	base::AutoLock auto_lock(lock_);
	return automatic_beep_;
	}

	private:
	mutable base::Lock lock_;
	bool beep_once_ GUARDED_BY(lock_);
	bool automatic_beep_ GUARDED_BY(lock_);
	};

	BeepContext* GetBeepContext() {
	static BeepContext* context = new BeepContext();
	return context;
	}

	} // namespace

	//////////////////////////////////////////////////////////////////////////////
	// SineWaveAudioSource implementation.

	SineWaveAudioSource::SineWaveAudioSource(int channels,
	double freq, double sample_freq)
	: channels_(channels),
	f_(freq / sample_freq),
	time_state_(0),
	cap_(0),
	callbacks_(0),
	errors_(0) {
	}

	SineWaveAudioSource::~SineWaveAudioSource() = default;

	// The implementation could be more efficient if a lookup table is constructed
	// but it is efficient enough for our simple needs.
	int SineWaveAudioSource::OnMoreData(base::TimeDelta /* delay */,
	base::TimeTicks /* delay_timestamp */,
	int /* prior_frames_skipped */,
	AudioBus* dest) {
	base::AutoLock auto_lock(time_lock_);
	callbacks_++;

	// The table is filled with s(t) = kint16maxsin(Thetat),
	// where Theta = 2PIfs.
	// We store the discrete time value \|t\| in a member to ensure that the
	// next pass starts at a correct state.
	int max_frames =
	cap_ > 0 ? std::min(dest->frames(), cap_ - time_state_) : dest->frames();
	for (int i = 0; i < max_frames; ++i)
	dest->channel(0)[i] = sin(2.0 * base::kPiDouble * f_ * time_state_++);
	for (int i = 1; i < dest->channels(); ++i) {
	memcpy(dest->channel(i), dest->channel(0),
	max_frames * sizeof(*dest->channel(i)));
	}
	return max_frames;
	}

	void SineWaveAudioSource::OnError() {
	errors_++;
	}

	void SineWaveAudioSource::CapSamples(int cap) {
	base::AutoLock auto_lock(time_lock_);
	DCHECK_GT(cap, 0);
	cap_ = cap;
	}

	void SineWaveAudioSource::Reset() {
	base::AutoLock auto_lock(time_lock_);
	time_state_ = 0;
	}

	FileSource::FileSource(const AudioParameters& params,
	const base::FilePath& path_to_wav_file,
	bool loop)
	: params_(params),
	path_to_wav_file_(path_to_wav_file),
	wav_file_read_pos_(0),
	load_failed_(false),
	looping_(loop) {}

	FileSource::~FileSource() = default;

	void FileSource::LoadWavFile(const base::FilePath& path_to_wav_file) {
	// Don't try again if we already failed.
	if (load_failed_)
	return;

	// Read the file, and put its data in a scoped_ptr so it gets deleted when
	// this class destructs. This data must be valid for the lifetime of
	// \|wav_audio_handler_\|.
	size_t length = 0u;
	raw_wav_data_ = ReadWavFile(path_to_wav_file, &length);
	if (!raw_wav_data_) {
	load_failed_ = true;
	return;
	}

	// Attempt to create a handler with this data. If the data is invalid, return.
	wav_audio_handler_ =
	WavAudioHandler::Create(base::StringPiece(raw_wav_data_.get(), length));
	if (!wav_audio_handler_) {
	LOG(ERROR) << "WAV data could be read but is not valid";
	load_failed_ = true;
	return;
	}

	// Hook us up so we pull in data from the file into the converter. We need to
	// modify the wav file's audio parameters since we'll be reading small slices
	// of it at a time and not the whole thing (like 10 ms at a time).
	AudioParameters file_audio_slice(
	AudioParameters::AUDIO_PCM_LOW_LATENCY,
	GuessChannelLayout(wav_audio_handler_->num_channels()),
	wav_audio_handler_->sample_rate(), params_.frames_per_buffer());

	file_audio_converter_.reset(
	new AudioConverter(file_audio_slice, params_, false));
	file_audio_converter_->AddInput(this);
	}

	int FileSource::OnMoreData(base::TimeDelta /* delay */,
	base::TimeTicks /* delay_timestamp */,
	int /* prior_frames_skipped */,
	AudioBus* dest) {
	// Load the file if we haven't already. This load needs to happen on the
	// audio thread, otherwise we'll run on the UI thread on Mac for instance.
	// This will massively delay the first OnMoreData, but we'll catch up.
	if (!wav_audio_handler_)
	LoadWavFile(path_to_wav_file_);
	if (load_failed_)
	return 0;

	DCHECK(wav_audio_handler_.get());

	if (wav_audio_handler_->AtEnd(wav_file_read_pos_)) {
	if (looping_)
	Rewind();
	else
	return 0;
	}

	// This pulls data from ProvideInput.
	file_audio_converter_->Convert(dest);
	return dest->frames();
	}

	void FileSource::Rewind() {
	wav_file_read_pos_ = 0;
	}

	double FileSource::ProvideInput(AudioBus* audio_bus_into_converter,
	uint32_t frames_delayed) {
	// Unfilled frames will be zeroed by CopyTo.
	size_t bytes_written;
	wav_audio_handler_->CopyTo(audio_bus_into_converter, wav_file_read_pos_,
	&bytes_written);
	wav_file_read_pos_ += bytes_written;
	return 1.0;
	}

	void FileSource::OnError() {}

	BeepingSource::BeepingSource(const AudioParameters& params)
	: buffer_size_(params.GetBytesPerBuffer(kSampleFormatU8)),
	buffer_(new uint8_t[buffer_size_]),
	params_(params),
	last_callback_time_(base::TimeTicks::Now()),
	beep_duration_in_buffers_(kBeepDurationMilliseconds *
	params.sample_rate() /
	params.frames_per_buffer() / 1000),
	beep_generated_in_buffers_(0),
	beep_period_in_frames_(params.sample_rate() / kBeepFrequency) {}

	BeepingSource::~BeepingSource() = default;

	int BeepingSource::OnMoreData(base::TimeDelta /* delay */,
	base::TimeTicks /* delay_timestamp */,
	int /* prior_frames_skipped */,
	AudioBus* dest) {
	// Accumulate the time from the last beep.
	interval_from_last_beep_ += base::TimeTicks::Now() - last_callback_time_;

	memset(buffer_.get(), 128, buffer_size_);
	bool should_beep = false;
	BeepContext* beep_context = GetBeepContext();
	if (beep_context->automatic_beep()) {
	base::TimeDelta delta = interval_from_last_beep_ -
	base::TimeDelta::FromMilliseconds(kAutomaticBeepIntervalInMs);
	if (delta > base::TimeDelta()) {
	should_beep = true;
	interval_from_last_beep_ = delta;
	}
	} else {
	should_beep = beep_context->beep_once();
	beep_context->SetBeepOnce(false);
	}

	// If this object was instructed to generate a beep or has started to
	// generate a beep sound.
	if (should_beep \|\| beep_generated_in_buffers_) {
	// Compute the number of frames to output high value. Then compute the
	// number of bytes based on channels.
	int high_frames = beep_period_in_frames_ / 2;
	int high_bytes = high_frames * params_.channels();

	// Separate high and low with the same number of bytes to generate a
	// square wave.
	int position = 0;
	while (position + high_bytes <= buffer_size_) {
	// Write high values first.
	memset(buffer_.get() + position, 255, high_bytes);
	// Then leave low values in the buffer with \|high_bytes\|.
	position += high_bytes * 2;
	}

	++beep_generated_in_buffers_;
	if (beep_generated_in_buffers_ >= beep_duration_in_buffers_)
	beep_generated_in_buffers_ = 0;
	}

	last_callback_time_ = base::TimeTicks::Now();
	dest->FromInterleaved<UnsignedInt8SampleTypeTraits>(buffer_.get(),
	dest->frames());
	return dest->frames();
	}

	void BeepingSource::OnError() {}

	void BeepingSource::BeepOnce() {
	GetBeepContext()->SetBeepOnce(true);
	}

	} // namespace media