mpv/TOOLS/302m_convert.c

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/**
* convert D-Cinema Audio (probably SMPTE 302M) to a
* wav file that MPlayer can play.
* Usage: 302m_convert <infile> <outfile>
*/
#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>
#include <byteswap.h>
#define le2me_32(x) (x)
#define le2me_16(x) (x)
#define be2me_16(x) bswap_16(x)
// From MPlayer libao/ao_pcm.c
#define WAV_ID_RIFF 0x46464952 /* "RIFF" */
#define WAV_ID_WAVE 0x45564157 /* "WAVE" */
#define WAV_ID_FMT 0x20746d66 /* "fmt " */
#define WAV_ID_DATA 0x61746164 /* "data" */
#define WAV_ID_PCM 0x0001
struct WaveHeader {
uint32_t riff;
uint32_t file_length;
uint32_t wave;
uint32_t fmt;
uint32_t fmt_length;
uint16_t fmt_tag;
uint16_t channels;
uint32_t sample_rate;
uint32_t bytes_per_second;
uint16_t block_align;
uint16_t bits;
uint32_t data;
uint32_t data_length;
};
static struct WaveHeader wavhdr = {
le2me_32(WAV_ID_RIFF),
le2me_32(0x7fffffff),
le2me_32(WAV_ID_WAVE),
le2me_32(WAV_ID_FMT),
le2me_32(16),
le2me_16(WAV_ID_PCM),
le2me_16(6),
le2me_32(96000),
le2me_32(1728000),
le2me_16(18),
le2me_16(24),
le2me_32(WAV_ID_DATA),
le2me_32(0x7fffffff),
};
// this format is completely braindead, and this bitorder
// is the result of pure guesswork (counting how often
// the bits flip), so it might be wrong.
void fixup(unsigned char *in_, unsigned char *out) {
int i;
unsigned char in[3] = {in_[0], in_[1], in_[2]};
unsigned char sync = in[2] & 0x0f; // sync flags
in[2] >>= 4;
out[2] = 0;
for (i = 0; i < 4; i++) {
out[2] <<= 1;
out[2] |= in[2] & 1;
in[2] >>= 1;
}
for (i = 0; i < 4; i++) {
out[2] <<= 1;
out[2] |= in[1] & 1;
in[1] >>= 1;
}
out[1] = 0;
for (i = 0; i < 4; i++) {
out[1] <<= 1;
out[1] |= in[1] & 1;
in[1] >>= 1;
}
for (i = 0; i < 4; i++) {
out[1] <<= 1;
out[1] |= in[0] & 1;
in[0] >>= 1;
}
out[0] = 0;
for (i = 0; i < 4; i++) {
out[0] <<= 1;
out[0] |= in[0] & 1;
in[0] >>= 1;
}
out[0] <<= 4;
out[0] |= sync; // sync flags go into lowest bits
// it seems those might also contain audio data,
// don't know if this is the right order then
// these might be also useful to detect the number
// of channels in case there are files with != 6 channels
}
int main(int argc, char *argv[]) {
FILE *in = fopen(argv[1], "r");
FILE *out = fopen(argv[2], "w");
int i;
uint16_t blocklen, unknown;
unsigned char *block;
if (!in) {
printf("Could not open %s for reading\n", argv[1]);
return EXIT_FAILURE;
}
if (!out) {
printf("Could not open %s for writing\n", argv[2]);
return EXIT_FAILURE;
}
fwrite(&wavhdr, 1, sizeof(wavhdr), out);
do {
fread(&blocklen, 2, 1, in);
blocklen = be2me_16(blocklen);
fread(&unknown, 2, 1, in);
block = malloc(blocklen);
blocklen = fread(block, 1, blocklen, in);
for (i = 0; i < blocklen; i += 3)
fixup(&block[i], &block[i]);
fwrite(block, 1, blocklen, out);
free(block);
} while (!feof(in));
return EXIT_SUCCESS;
}