esp-idf/examples/peripherals/i2s/common/format_wav.h
2022-12-29 16:31:03 +08:00

74 lines
2.8 KiB
C

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