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74 lines
2.8 KiB
C
74 lines
2.8 KiB
C
/*
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* SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Unlicense OR CC0-1.0
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*/
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#pragma once
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Header structure for WAV file with only one data chunk
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*
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* @note See this for reference: http://soundfile.sapp.org/doc/WaveFormat/
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*
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* @note Assignment to variables in this struct directly is only possible for little endian architectures
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* (including Xtensa & RISC-V)
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*/
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typedef struct {
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struct {
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char chunk_id[4]; /*!< Contains the letters "RIFF" in ASCII form */
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uint32_t chunk_size; /*!< This is the size of the rest of the chunk following this number */
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char chunk_format[4]; /*!< Contains the letters "WAVE" */
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} descriptor_chunk; /*!< Canonical WAVE format starts with the RIFF header */
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struct {
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char subchunk_id[4]; /*!< Contains the letters "fmt " */
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uint32_t subchunk_size; /*!< This is the size of the rest of the Subchunk which follows this number */
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uint16_t audio_format; /*!< PCM = 1, values other than 1 indicate some form of compression */
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uint16_t num_of_channels; /*!< Mono = 1, Stereo = 2, etc. */
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uint32_t sample_rate; /*!< 8000, 44100, etc. */
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uint32_t byte_rate; /*!< ==SampleRate * NumChannels * BitsPerSample s/ 8 */
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uint16_t block_align; /*!< ==NumChannels * BitsPerSample / 8 */
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uint16_t bits_per_sample; /*!< 8 bits = 8, 16 bits = 16, etc. */
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} fmt_chunk; /*!< The "fmt " subchunk describes the sound data's format */
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struct {
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char subchunk_id[4]; /*!< Contains the letters "data" */
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uint32_t subchunk_size; /*!< ==NumSamples * NumChannels * BitsPerSample / 8 */
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int16_t data[0]; /*!< Holds raw audio data */
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} data_chunk; /*!< The "data" subchunk contains the size of the data and the actual sound */
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} wav_header_t;
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/**
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* @brief Default header for PCM format WAV files
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*
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*/
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#define WAV_HEADER_PCM_DEFAULT(wav_sample_size, wav_sample_bits, wav_sample_rate, wav_channel_num) { \
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.descriptor_chunk = { \
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.chunk_id = {'R', 'I', 'F', 'F'}, \
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.chunk_size = (wav_sample_size) + sizeof(wav_header_t) - 8, \
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.chunk_format = {'W', 'A', 'V', 'E'} \
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}, \
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.fmt_chunk = { \
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.subchunk_id = {'f', 'm', 't', ' '}, \
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.subchunk_size = 16, /* 16 for PCM */ \
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.audio_format = 1, /* 1 for PCM */ \
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.num_of_channels = (wav_channel_num), \
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.sample_rate = (wav_sample_rate), \
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.byte_rate = (wav_sample_bits) * (wav_sample_rate) * (wav_channel_num) / 8, \
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.block_align = (wav_sample_bits) * (wav_channel_num) / 8, \
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.bits_per_sample = (wav_sample_bits)\
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}, \
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.data_chunk = { \
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.subchunk_id = {'d', 'a', 't', 'a'}, \
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.subchunk_size = (wav_sample_size) \
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} \
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}
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#ifdef __cplusplus
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}
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#endif
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