/* license:BSD-3-Clause * copyright-holders:Aaron Giles *************************************************************************** flac.c FLAC compression wrappers ***************************************************************************/ #include #include #include #define DR_FLAC_IMPLEMENTATION #include /*************************************************************************** * FLAC DECODER *************************************************************************** */ static size_t flac_decoder_read_callback(void *userdata, void *buffer, size_t bytes); static drflac_bool32 flac_decoder_seek_callback(void *userdata, int offset, drflac_seek_origin origin); static void flac_decoder_metadata_callback(void *userdata, drflac_metadata *metadata); static void flac_decoder_write_callback(void *userdata, void *buffer, size_t len); /* getters (valid after reset) */ static uint32_t sample_rate(flac_decoder *decoder) { return decoder->sample_rate; } static uint8_t channels(flac_decoder *decoder) { return decoder->channels; } static uint8_t bits_per_sample(flac_decoder *decoder) { return decoder->bits_per_sample; } /*------------------------------------------------- * flac_decoder - constructor *------------------------------------------------- */ int flac_decoder_init(flac_decoder *decoder) { decoder->decoder = NULL; decoder->sample_rate = 0; decoder->channels = 0; decoder->bits_per_sample = 0; decoder->compressed_offset = 0; decoder->compressed_start = NULL; decoder->compressed_length = 0; decoder->compressed2_start = NULL; decoder->compressed2_length = 0; decoder->uncompressed_offset = 0; decoder->uncompressed_length = 0; decoder->uncompressed_swap = 0; return 0; } /*------------------------------------------------- * flac_decoder - destructor *------------------------------------------------- */ void flac_decoder_free(flac_decoder* decoder) { if ((decoder != NULL) && (decoder->decoder != NULL)) drflac_close(decoder->decoder); decoder->decoder = NULL; } /*------------------------------------------------- * reset - reset state with the original * parameters *------------------------------------------------- */ static int flac_decoder_internal_reset(flac_decoder* decoder) { decoder->compressed_offset = 0; flac_decoder_free(decoder); decoder->decoder = drflac_open_with_metadata( flac_decoder_read_callback, flac_decoder_seek_callback, flac_decoder_metadata_callback, decoder, NULL); return (decoder->decoder != NULL); } /*------------------------------------------------- * reset - reset state with new memory parameters * and a custom-generated header *------------------------------------------------- */ int flac_decoder_reset(flac_decoder* decoder, uint32_t sample_rate, uint8_t num_channels, uint32_t block_size, const void *buffer, uint32_t length) { /* modify the template header with our parameters */ static const uint8_t s_header_template[0x2a] = { 0x66, 0x4C, 0x61, 0x43, /* +00: 'fLaC' stream header */ 0x80, /* +04: metadata block type 0 (STREAMINFO), */ /* flagged as last block */ 0x00, 0x00, 0x22, /* +05: metadata block length = 0x22 */ 0x00, 0x00, /* +08: minimum block size */ 0x00, 0x00, /* +0A: maximum block size */ 0x00, 0x00, 0x00, /* +0C: minimum frame size (0 == unknown) */ 0x00, 0x00, 0x00, /* +0F: maximum frame size (0 == unknown) */ 0x0A, 0xC4, 0x42, 0xF0, 0x00, 0x00, 0x00, 0x00, /* +12: sample rate (0x0ac44 == 44100), */ /* numchannels (2), sample bits (16), */ /* samples in stream (0 == unknown) */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* +1A: MD5 signature (0 == none) */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 /* +2A: start of stream data */ }; memcpy(decoder->custom_header, s_header_template, sizeof(s_header_template)); decoder->custom_header[0x08] = decoder->custom_header[0x0a] = (block_size*num_channels) >> 8; decoder->custom_header[0x09] = decoder->custom_header[0x0b] = (block_size*num_channels) & 0xff; decoder->custom_header[0x12] = sample_rate >> 12; decoder->custom_header[0x13] = sample_rate >> 4; decoder->custom_header[0x14] = (sample_rate << 4) | ((num_channels - 1) << 1); /* configure the header ahead of the provided buffer */ decoder->compressed_start = (const uint8_t *)(decoder->custom_header); decoder->compressed_length = sizeof(decoder->custom_header); decoder->compressed2_start = (const uint8_t *)(buffer); decoder->compressed2_length = length; return flac_decoder_internal_reset(decoder); } /*------------------------------------------------- * decode_interleaved - decode to an interleaved * sound stream *------------------------------------------------- */ int flac_decoder_decode_interleaved(flac_decoder* decoder, int16_t *samples, uint32_t num_samples, int swap_endian) { /* configure the uncompressed buffer */ memset(decoder->uncompressed_start, 0, sizeof(decoder->uncompressed_start)); decoder->uncompressed_start[0] = samples; decoder->uncompressed_offset = 0; decoder->uncompressed_length = num_samples; decoder->uncompressed_swap = swap_endian; #define BUFFER 2352 /* bytes per CD audio sector */ int16_t buffer[BUFFER]; uint32_t buf_samples = BUFFER / channels(decoder); /* loop until we get everything we want */ while (decoder->uncompressed_offset < decoder->uncompressed_length) { uint32_t frames = (num_samples < buf_samples ? num_samples : buf_samples); if (!drflac_read_pcm_frames_s16(decoder->decoder, frames, buffer)) return 0; flac_decoder_write_callback(decoder, buffer, frames*sizeof(*buffer)*channels(decoder)); num_samples -= frames; } return 1; } /*------------------------------------------------- * finish - finish up the decode *------------------------------------------------- */ uint32_t flac_decoder_finish(flac_decoder* decoder) { /* get the final decoding position and move forward */ drflac *flac = decoder->decoder; uint64_t position = decoder->compressed_offset; /* ugh... there's no function to obtain bytes used in drflac :-/ */ position -= DRFLAC_CACHE_L2_LINES_REMAINING(&flac->bs) * sizeof(drflac_cache_t); position -= DRFLAC_CACHE_L1_BITS_REMAINING(&flac->bs) / 8; position -= flac->bs.unalignedByteCount; /* adjust position if we provided the header */ if (position == 0) return 0; if (decoder->compressed_start == (const uint8_t *)(decoder->custom_header)) position -= decoder->compressed_length; flac_decoder_free(decoder); return position; } /*------------------------------------------------- * read_callback - handle reads from the input * stream *------------------------------------------------- */ #define MIN(x, y) ((x) < (y) ? (x) : (y)) static size_t flac_decoder_read_callback(void *userdata, void *buffer, size_t bytes) { flac_decoder* decoder = (flac_decoder*)userdata; uint8_t *dst = buffer; /* copy from primary buffer first */ uint32_t outputpos = 0; if (outputpos < bytes && decoder->compressed_offset < decoder->compressed_length) { uint32_t bytes_to_copy = MIN(bytes - outputpos, decoder->compressed_length - decoder->compressed_offset); memcpy(&dst[outputpos], decoder->compressed_start + decoder->compressed_offset, bytes_to_copy); outputpos += bytes_to_copy; decoder->compressed_offset += bytes_to_copy; } /* once we're out of that, copy from the secondary buffer */ if (outputpos < bytes && decoder->compressed_offset < decoder->compressed_length + decoder->compressed2_length) { uint32_t bytes_to_copy = MIN(bytes - outputpos, decoder->compressed2_length - (decoder->compressed_offset - decoder->compressed_length)); memcpy(&dst[outputpos], decoder->compressed2_start + decoder->compressed_offset - decoder->compressed_length, bytes_to_copy); outputpos += bytes_to_copy; decoder->compressed_offset += bytes_to_copy; } return outputpos; } /*------------------------------------------------- * metadata_callback - handle STREAMINFO metadata *------------------------------------------------- */ static void flac_decoder_metadata_callback(void *userdata, drflac_metadata *metadata) { flac_decoder *decoder = userdata; /* ignore all but STREAMINFO metadata */ if (metadata->type != DRFLAC_METADATA_BLOCK_TYPE_STREAMINFO) return; /* parse out the data we care about */ decoder->sample_rate = metadata->data.streaminfo.sampleRate; decoder->bits_per_sample = metadata->data.streaminfo.bitsPerSample; decoder->channels = metadata->data.streaminfo.channels; } /*------------------------------------------------- * write_callback - handle writes to the output * stream *------------------------------------------------- */ static void flac_decoder_write_callback(void *userdata, void *buffer, size_t bytes) { int sampnum, chan; int shift, blocksize; flac_decoder * decoder = (flac_decoder *)userdata; int16_t *sampbuf = (int16_t *)buffer; int sampch = channels(decoder); uint32_t offset = decoder->uncompressed_offset; uint16_t usample; /* interleaved case */ shift = decoder->uncompressed_swap ? 8 : 0; blocksize = bytes / (sampch * sizeof(sampbuf[0])); if (decoder->uncompressed_start[1] == NULL) { int16_t *dest = decoder->uncompressed_start[0] + offset * sampch; for (sampnum = 0; sampnum < blocksize && offset < decoder->uncompressed_length; sampnum++, offset++) for (chan = 0; chan < sampch; chan++) { usample = (uint16_t)*sampbuf++; *dest++ = (int16_t)((usample << shift) | (usample >> shift)); } } /* non-interleaved case */ else { for (sampnum = 0; sampnum < blocksize && offset < decoder->uncompressed_length; sampnum++, offset++) for (chan = 0; chan < sampch; chan++) { usample = (uint16_t)*sampbuf++; if (decoder->uncompressed_start[chan] != NULL) decoder->uncompressed_start[chan][offset] = (int16_t) ((usample << shift) | (usample >> shift)); } } decoder->uncompressed_offset = offset; } /*------------------------------------------------- * seek_callback - handle seeks on the output * stream *------------------------------------------------- */ static drflac_bool32 flac_decoder_seek_callback(void *userdata, int offset, drflac_seek_origin origin) { flac_decoder * decoder = (flac_decoder *)userdata; uint32_t length = decoder->compressed_length + decoder->compressed2_length; if (origin == drflac_seek_origin_start) { uint32_t pos = offset; if (pos <= length) { decoder->compressed_offset = pos; return 1; } } else if (origin == drflac_seek_origin_current) { uint32_t pos = decoder->compressed_offset + offset; if (pos <= length) { decoder->compressed_offset = pos; return 1; } } return 0; }