/**
* Write callback. Called when decoder has decoded a single audio frame.
*
* @param decoder Decoder instance
* @param frame Decoded frame
* @param buffer Array of pointers to decoded channels of data
* @param client_data Client data set at initilisation
*
* @return Read status
*/
FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder* decoder, const FLAC__Frame* frame,
const FLAC__int32* const buffer[], void* client_data)
{
//TODO write to I2S
#ifdef TO_PORT
FILE *f = (FILE*)client_data;
const FLAC__uint32 total_size = (FLAC__uint32)(total_samples * channels * (bps/8));
size_t i;
(void)decoder;
if(total_samples == 0) {
fprintf(stderr, "ERROR: this example only works for FLAC files that have a total_samples count in STREAMINFO\n");
return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
}
if(channels != 2 || bps != 16) {
fprintf(stderr, "ERROR: this example only supports 16bit stereo streams\n");
return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
}
/* write WAVE header before we write the first frame */
if(frame->header.number.sample_number == 0) {
if(
fwrite("RIFF", 1, 4, f) < 4 ||
!write_little_endian_uint32(f, total_size + 36) ||
fwrite("WAVEfmt ", 1, 8, f) < 8 ||
!write_little_endian_uint32(f, 16) ||
!write_little_endian_uint16(f, 1) ||
!write_little_endian_uint16(f, (FLAC__uint16)channels) ||
!write_little_endian_uint32(f, sample_rate) ||
!write_little_endian_uint32(f, sample_rate * channels * (bps/8)) ||
!write_little_endian_uint16(f, (FLAC__uint16)(channels * (bps/8))) || /* block align */
!write_little_endian_uint16(f, (FLAC__uint16)bps) ||
fwrite("data", 1, 4, f) < 4 ||
!write_little_endian_uint32(f, total_size)
) {
fprintf(stderr, "ERROR: write error\n");
return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
}
}
/* write decoded PCM samples */
for(i = 0; i < frame->header.blocksize; i++) {
if(
!write_little_endian_int16(f, (FLAC__int16)buffer[0][i]) || /* left channel */
!write_little_endian_int16(f, (FLAC__int16)buffer[1][i]) /* right channel */
) {
fprintf(stderr, "ERROR: write error\n");
return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
}
}
#endif
return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}
/* @@@ not used (yet) */
static FLAC__bool write_little_endian_int32(FILE *f, FLAC__int32 x)
{
return write_little_endian_uint32(f, (FLAC__uint32)x);
}
static FLAC__bool generate_wav(const char *filename, unsigned sample_rate, unsigned channels, unsigned bps, unsigned samples, FLAC__bool strict)
{
const FLAC__bool waveformatextensible = strict && (channels > 2 || (bps%8));
/* ^^^^^^^
* (bps%8) allows 24 bps which is technically supposed to be WAVEFORMATEXTENSIBLE but we
* write 24bps as WAVEFORMATEX since it's unambiguous and matches how flac writes it
*/
const unsigned true_size = channels * ((bps+7)/8) * samples;
const unsigned padded_size = (true_size + 1) & (~1u);
const unsigned shift = (bps%8)? 8 - (bps%8) : 0;
FILE *f;
unsigned i;
if(0 == (f = fopen(filename, mode)))
return false;
if(fwrite("RIFF", 1, 4, f) < 4)
goto foo;
if(!write_little_endian_uint32(f, padded_size + (waveformatextensible?60:36)))
goto foo;
if(fwrite("WAVEfmt ", 1, 8, f) < 8)
goto foo;
if(!write_little_endian_uint32(f, waveformatextensible?40:16))
goto foo;
if(!write_little_endian_uint16(f, (FLAC__uint16)(waveformatextensible?65534:1)))
goto foo;
if(!write_little_endian_uint16(f, (FLAC__uint16)channels))
goto foo;
if(!write_little_endian_uint32(f, sample_rate))
goto foo;
if(!write_little_endian_uint32(f, sample_rate * channels * ((bps+7)/8)))
goto foo;
if(!write_little_endian_uint16(f, (FLAC__uint16)(channels * ((bps+7)/8)))) /* block align */
goto foo;
if(!write_little_endian_uint16(f, (FLAC__uint16)(bps+shift)))
goto foo;
if(waveformatextensible) {
if(!write_little_endian_uint16(f, (FLAC__uint16)22)) /* cbSize */
goto foo;
if(!write_little_endian_uint16(f, (FLAC__uint16)bps)) /* validBitsPerSample */
goto foo;
if(!write_little_endian_uint32(f, 0)) /* channelMask */
goto foo;
/* GUID = {0x00000001, 0x0000, 0x0010, {0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}} */
if(fwrite("\x01\x00\x00\x00\x00\x00\x10\x00\x80\x00\x00\xaa\x00\x38\x9b\x71", 1, 16, f) != 16)
goto foo;
}
if(fwrite("data", 1, 4, f) < 4)
goto foo;
if(!write_little_endian_uint32(f, true_size))
goto foo;
for(i = 0; i < true_size; i++)
if(fputc(GET_RANDOM_BYTE<<shift, f) == EOF)
goto foo;
for( ; i < padded_size; i++)
if(fputc(0, f) == EOF)
goto foo;
fclose(f);
return true;
foo:
fclose(f);
return false;
}