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