diff options
Diffstat (limited to 'third_party/libwebrtc/common_audio/wav_header.h')
-rw-r--r-- | third_party/libwebrtc/common_audio/wav_header.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/third_party/libwebrtc/common_audio/wav_header.h b/third_party/libwebrtc/common_audio/wav_header.h new file mode 100644 index 0000000000..2cccd7d34b --- /dev/null +++ b/third_party/libwebrtc/common_audio/wav_header.h @@ -0,0 +1,90 @@ +/* + * 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_ |