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/*
* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef COMMON_AUDIO_WAV_HEADER_H_
#define COMMON_AUDIO_WAV_HEADER_H_
#include <stddef.h>
#include <stdint.h>
#include <algorithm>
#include "rtc_base/checks.h"
namespace webrtc {
// Interface providing header reading functionality.
class WavHeaderReader {
public:
// Returns the number of bytes read.
virtual size_t Read(void* buf, size_t num_bytes) = 0;
virtual bool SeekForward(uint32_t num_bytes) = 0;
virtual ~WavHeaderReader() = default;
virtual int64_t GetPosition() = 0;
};
// Possible WAV formats.
enum class WavFormat {
kWavFormatPcm = 1, // PCM, each sample of size bytes_per_sample.
kWavFormatIeeeFloat = 3, // IEEE float.
kWavFormatALaw = 6, // 8-bit ITU-T G.711 A-law.
kWavFormatMuLaw = 7, // 8-bit ITU-T G.711 mu-law.
};
// Header sizes for supported WAV formats.
constexpr size_t kPcmWavHeaderSize = 44;
constexpr size_t kIeeeFloatWavHeaderSize = 58;
// Returns the size of the WAV header for the specified format.
constexpr size_t WavHeaderSize(WavFormat format) {
if (format == WavFormat::kWavFormatPcm) {
return kPcmWavHeaderSize;
}
RTC_CHECK_EQ(format, WavFormat::kWavFormatIeeeFloat);
return kIeeeFloatWavHeaderSize;
}
// Returns the maximum size of the supported WAV formats.
constexpr size_t MaxWavHeaderSize() {
return std::max(WavHeaderSize(WavFormat::kWavFormatPcm),
WavHeaderSize(WavFormat::kWavFormatIeeeFloat));
}
// Return true if the given parameters will make a well-formed WAV header.
bool CheckWavParameters(size_t num_channels,
int sample_rate,
WavFormat format,
size_t num_samples);
// Write a kWavHeaderSize bytes long WAV header to buf. The payload that
// follows the header is supposed to have the specified number of interleaved
// channels and contain the specified total number of samples of the specified
// type. The size of the header is returned in header_size. CHECKs the input
// parameters for validity.
void WriteWavHeader(size_t num_channels,
int sample_rate,
WavFormat format,
size_t num_samples,
uint8_t* buf,
size_t* header_size);
// Read a WAV header from an implemented WavHeaderReader and parse the values
// into the provided output parameters. WavHeaderReader is used because the
// header can be variably sized. Returns false if the header is invalid.
bool ReadWavHeader(WavHeaderReader* readable,
size_t* num_channels,
int* sample_rate,
WavFormat* format,
size_t* bytes_per_sample,
size_t* num_samples,
int64_t* data_start_pos);
} // namespace webrtc
#endif // COMMON_AUDIO_WAV_HEADER_H_
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