mirror of
https://github.com/pret/pokeyellow.git
synced 2026-05-22 10:57:05 -05:00
100 lines
2.8 KiB
C
100 lines
2.8 KiB
C
#define PROGRAM_NAME "pcm"
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#define USAGE_OPTS "infile.wav outfile.pcm"
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#include "common.h"
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#define CHUNKID(b1, b2, b3, b4) (uint32_t)((uint32_t)(b1) | ((uint32_t)(b2) << 8) | ((uint32_t)(b3) << 16) | ((uint32_t)(b4) << 24))
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int32_t get_uint16le(uint8_t *data, long size, long i) {
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return i + 2 < size ? (int32_t)data[i] | ((int32_t)data[i + 1] << 8) : -1;
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}
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int64_t get_uint32le(uint8_t *data, long size, long i) {
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return i + 4 < size ? (int64_t)data[i] | ((int64_t)data[i + 1] << 8) | ((int64_t)data[i + 2] << 16) | ((int64_t)data[i + 3] << 24) : -1;
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}
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uint8_t *wav2pcm(uint8_t *wavdata, long wavsize, size_t *pcmsize) {
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int64_t fourcc = get_uint32le(wavdata, wavsize, 0);
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if (fourcc != CHUNKID('R', 'I', 'F', 'F')) {
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error_exit("WAV file does not start with 'RIFF'\n");
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}
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int64_t waveid = get_uint32le(wavdata, wavsize, 8);
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if (waveid != CHUNKID('W', 'A', 'V', 'E')) {
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error_exit("RIFF chunk does not start with 'WAVE'\n");
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}
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long sample_offset = 0;
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int64_t num_samples = 0;
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int64_t riffsize = get_uint32le(wavdata, wavsize, 4) + 8;
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for (long i = 12; i < riffsize;) {
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int64_t chunkid = get_uint32le(wavdata, wavsize, i);
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int64_t chunksize = get_uint32le(wavdata, wavsize, i + 4);
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if (chunksize == -1) {
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error_exit("Failed to read sub-chunk size\n");
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}
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i += 8;
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// Require 22050 Hz 8-bit PCM WAV audio
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if (chunkid == CHUNKID('f', 'm', 't', ' ')) {
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int32_t audio_format = get_uint16le(wavdata, wavsize, i);
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if (audio_format != 1) {
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error_exit("WAV data is not PCM format\n");
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}
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int32_t num_channels = get_uint16le(wavdata, wavsize, i + 2);
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if (num_channels != 1) {
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error_exit("WAV data is not mono\n");
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}
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int64_t sample_rate = get_uint32le(wavdata, wavsize, i + 4);
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if (sample_rate != 22050) {
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error_exit("WAV data is not 22050 Hz\n");
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}
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int32_t bits_per_sample = get_uint16le(wavdata, wavsize, i + 14);
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if (bits_per_sample != 8) {
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error_exit("WAV data is not 8-bit\n");
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}
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}
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else if (chunkid == CHUNKID('d', 'a', 't', 'a')) {
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sample_offset = i;
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num_samples = chunksize;
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break;
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}
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i += chunksize;
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}
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if (!num_samples) {
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error_exit("WAV data has no PCM samples\n");
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}
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// Pack 8 WAV samples per PCM byte, clamping each to 0 or 1
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*pcmsize = (size_t)((num_samples + 7) / 8);
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uint8_t *pcmdata = xmalloc(*pcmsize);
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for (int64_t i = 0; i < num_samples; i += 8) {
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uint8_t v = 0;
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for (int64_t j = 0; j < 8 && i + j < num_samples; j++) {
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v |= (wavdata[sample_offset + i + j] > 0x80) << (7 - j);
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}
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pcmdata[i / 8] = v;
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}
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return pcmdata;
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}
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int main(int argc, char *argv[]) {
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if (argc != 3) {
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usage_exit(1);
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}
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long wavsize;
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uint8_t *wavdata = read_u8(argv[1], &wavsize);
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size_t pcmsize;
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uint8_t *pcmdata = wav2pcm(wavdata, wavsize, &pcmsize);
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write_u8(argv[2], pcmdata, pcmsize);
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free(wavdata);
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free(pcmdata);
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return 0;
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}
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