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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_AUDIO_WAV_AUDIO_HANDLER_H_
#define MEDIA_AUDIO_WAV_AUDIO_HANDLER_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include "base/strings/string_piece.h"
#include "base/time/time.h"
#include "media/base/media_export.h"
namespace media {
class AudioBus;
// This class provides the input from wav file format. See
// https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
class MEDIA_EXPORT WavAudioHandler {
public:
// Supported audio format.
enum class AudioFormat : uint16_t {
kAudioFormatPCM = 0x0001,
kAudioFormatFloat = 0x0003,
kAudioFormatExtensible = 0xfffe
};
WavAudioHandler(const WavAudioHandler&) = delete;
WavAudioHandler& operator=(const WavAudioHandler&) = delete;
virtual ~WavAudioHandler();
// Create a WavAudioHandler using |wav_data|. If |wav_data| cannot be parsed
// correctly, the returned scoped_ptr will be null. The underlying memory for
// wav_data must survive for the lifetime of this class.
static std::unique_ptr<WavAudioHandler> Create(
const base::StringPiece wav_data);
// Returns true when cursor points to the end of the track.
bool AtEnd(size_t cursor) const;
// Copies the audio data to |bus| starting from the |cursor| and in
// the case of success stores the number of written bytes in
// |bytes_written|. |bytes_written| should not be NULL. Returns false if the
// operation was unsuccessful. Returns true otherwise.
bool CopyTo(AudioBus* bus, size_t cursor, size_t* bytes_written) const;
// Accessors.
const base::StringPiece& data() const { return data_; }
int num_channels() const { return static_cast<int>(num_channels_); }
int sample_rate() const { return static_cast<int>(sample_rate_); }
int bits_per_sample() const { return static_cast<int>(bits_per_sample_); }
AudioFormat audio_format() const { return audio_format_; }
int total_frames() const { return static_cast<int>(total_frames_); }
// Returns the duration of the entire audio chunk.
base::TimeDelta GetDuration() const;
private:
// Note: It is preferred to pass |audio_data| by value here.
WavAudioHandler(base::StringPiece audio_data,
uint16_t num_channels,
uint32_t sample_rate,
uint16_t bits_per_sample,
AudioFormat audio_format);
// Data part of the |wav_data_|.
const base::StringPiece data_;
const uint16_t num_channels_;
const uint32_t sample_rate_;
const uint16_t bits_per_sample_;
const AudioFormat audio_format_;
uint32_t total_frames_;
};
} // namespace media
#endif // MEDIA_AUDIO_WAV_AUDIO_HANDLER_H_
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