wav_header.h (3235B)
1 /* 2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef COMMON_AUDIO_WAV_HEADER_H_ 12 #define COMMON_AUDIO_WAV_HEADER_H_ 13 14 #include <stddef.h> 15 #include <stdint.h> 16 17 #include <algorithm> 18 19 #include "rtc_base/checks.h" 20 21 namespace webrtc { 22 23 // Interface providing header reading functionality. 24 class WavHeaderReader { 25 public: 26 // Returns the number of bytes read. 27 virtual size_t Read(void* buf, size_t num_bytes) = 0; 28 virtual bool SeekForward(uint32_t num_bytes) = 0; 29 virtual ~WavHeaderReader() = default; 30 virtual int64_t GetPosition() = 0; 31 }; 32 33 // Possible WAV formats. 34 enum class WavFormat { 35 kWavFormatPcm = 1, // PCM, each sample of size bytes_per_sample. 36 kWavFormatIeeeFloat = 3, // IEEE float. 37 kWavFormatALaw = 6, // 8-bit ITU-T G.711 A-law. 38 kWavFormatMuLaw = 7, // 8-bit ITU-T G.711 mu-law. 39 }; 40 41 // Header sizes for supported WAV formats. 42 constexpr size_t kPcmWavHeaderSize = 44; 43 constexpr size_t kIeeeFloatWavHeaderSize = 58; 44 45 // Returns the size of the WAV header for the specified format. 46 constexpr size_t WavHeaderSize(WavFormat format) { 47 if (format == WavFormat::kWavFormatPcm) { 48 return kPcmWavHeaderSize; 49 } 50 RTC_CHECK_EQ(format, WavFormat::kWavFormatIeeeFloat); 51 return kIeeeFloatWavHeaderSize; 52 } 53 54 // Returns the maximum size of the supported WAV formats. 55 constexpr size_t MaxWavHeaderSize() { 56 return std::max(WavHeaderSize(WavFormat::kWavFormatPcm), 57 WavHeaderSize(WavFormat::kWavFormatIeeeFloat)); 58 } 59 60 // Return true if the given parameters will make a well-formed WAV header. 61 bool CheckWavParameters(size_t num_channels, 62 int sample_rate, 63 WavFormat format, 64 size_t num_samples); 65 66 // Write a kWavHeaderSize bytes long WAV header to buf. The payload that 67 // follows the header is supposed to have the specified number of interleaved 68 // channels and contain the specified total number of samples of the specified 69 // type. The size of the header is returned in header_size. CHECKs the input 70 // parameters for validity. 71 void WriteWavHeader(size_t num_channels, 72 int sample_rate, 73 WavFormat format, 74 size_t num_samples, 75 uint8_t* buf, 76 size_t* header_size); 77 78 // Read a WAV header from an implemented WavHeaderReader and parse the values 79 // into the provided output parameters. WavHeaderReader is used because the 80 // header can be variably sized. Returns false if the header is invalid. 81 bool ReadWavHeader(WavHeaderReader* readable, 82 size_t* num_channels, 83 int* sample_rate, 84 WavFormat* format, 85 size_t* bytes_per_sample, 86 size_t* num_samples, 87 int64_t* data_start_pos); 88 89 } // namespace webrtc 90 91 #endif // COMMON_AUDIO_WAV_HEADER_H_