static status_t
decode_frameset(decoders_ALACDecoder *self,
unsigned *pcm_frames_read,
int *samples)
{
BitstreamReader *br = self->bitstream;
int channel_0[self->params.block_size];
int channel_1[self->params.block_size];
unsigned c = 0;
unsigned block_size = self->params.block_size;
unsigned channels = br->read(br, 3) + 1;
while (channels != 8) {
status_t status;
unsigned frame_block_size;
if ((channels != 1) && (channels != 2)) {
/*only handle 1 or 2 channel frames*/
return INVALID_FRAME_CHANNEL_COUNT;
} else if ((c + channels) > self->channels) {
/*ensure one doesn't decode too many channels*/
return EXCESSIVE_FRAME_CHANNEL_COUNT;
}
if ((status = decode_frame(br,
&(self->params),
self->bits_per_sample,
c == 0 ? &block_size : &frame_block_size,
channels,
channel_0,
channel_1)) != OK) {
return status;
} else if ((c != 0) && (block_size != frame_block_size)) {
return FRAME_BLOCK_SIZE_MISMATCH;
}
put_channel_data(samples,
c++,
self->channels,
block_size,
channel_0);
if (channels == 2) {
put_channel_data(samples,
c++,
self->channels,
block_size,
channel_1);
}
channels = br->read(br, 3) + 1;
}
br->byte_align(br);
*pcm_frames_read = block_size;
return OK;
}
static PyObject*
ALACDecoder_read(decoders_ALACDecoder* self, PyObject *args)
{
unsigned channel_count;
BitstreamReader* mdat = self->bitstream;
array_ia* frameset_channels = self->frameset_channels;
PyThreadState *thread_state;
/*return an empty framelist if total samples are exhausted*/
if (self->remaining_frames == 0) {
return empty_FrameList(self->audiotools_pcm,
self->channels,
self->bits_per_sample);
}
thread_state = PyEval_SaveThread();
if (!setjmp(*br_try(mdat))) {
frameset_channels->reset(frameset_channels);
/*get initial frame's channel count*/
channel_count = mdat->read(mdat, 3) + 1;
while (channel_count != 8) {
/*read a frame from the frameset into "channels"*/
if (read_frame(self, mdat,
frameset_channels, channel_count) != OK) {
br_etry(mdat);
PyEval_RestoreThread(thread_state);
PyErr_SetString(PyExc_ValueError, self->error_message);
return NULL;
} else {
/*ensure all frames have the same sample count*/
/*FIXME*/
/*read the channel count of the next frame
in the frameset, if any*/
channel_count = mdat->read(mdat, 3) + 1;
}
}
/*once all the frames in the frameset are read,
byte-align the output stream*/
mdat->byte_align(mdat);
br_etry(mdat);
PyEval_RestoreThread(thread_state);
/*decrement the remaining sample count*/
self->remaining_frames -= MIN(self->remaining_frames,
frameset_channels->_[0]->len);
/*convert ALAC channel assignment to standard audiotools assignment*/
alac_order_to_wave_order(frameset_channels);
/*finally, build and return framelist object from the sample data*/
return array_ia_to_FrameList(self->audiotools_pcm,
frameset_channels,
self->bits_per_sample);
} else {
br_etry(mdat);
PyEval_RestoreThread(thread_state);
PyErr_SetString(PyExc_IOError, "EOF during frame reading");
return NULL;
}
}
int main(int argc, char* argv[]) {
FILE* ogg_file;
OggReader* ogg_stream = NULL;
BitstreamReader* packet = NULL;
struct flac_STREAMINFO streaminfo;
uint16_t header_packets;
a_int* residuals = NULL;
a_int* qlp_coeffs = NULL;
aa_int* subframe_data = NULL;
a_int* framelist_data = NULL;
ogg_status result;
uint16_t crc16 = 0;
FrameList_int_to_char_converter converter;
unsigned pcm_size;
unsigned output_data_size = 1;
uint8_t* output_data = NULL;
audiotools__MD5Context md5;
unsigned char stream_md5sum[16];
const static unsigned char blank_md5sum[16] = {0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0};
if (argc < 2) {
fprintf(stderr, "*** Usage: %s <file.oga>\n", argv[0]);
return 1;
}
/*open input file for reading*/
if ((ogg_file = fopen(argv[1], "rb")) == NULL) {
fprintf(stderr, "*** %s: %s\n", argv[1], strerror(errno));
return 1;
} else {
/*open bitstream and setup temporary arrays/buffers*/
ogg_stream = oggreader_open(ogg_file);
packet = br_substream_new(BS_BIG_ENDIAN);
subframe_data = aa_int_new();
residuals = a_int_new();
qlp_coeffs = a_int_new();
framelist_data = a_int_new();
output_data = malloc(output_data_size);
}
/*the first packet should be the FLAC's STREAMINFO*/
if ((result = oggreader_next_packet(ogg_stream, packet)) == OGG_OK) {
if (!oggflac_read_streaminfo(packet, &streaminfo, &header_packets)) {
goto error;
} else {
converter = FrameList_get_int_to_char_converter(
streaminfo.bits_per_sample, 0, 1);
}
} else {
fprintf(stderr, "*** Error: %s\n", ogg_strerror(result));
goto error;
}
/*skip subsequent header packets*/
for (; header_packets > 0; header_packets--) {
if ((result = oggreader_next_packet(ogg_stream, packet)) != OGG_OK) {
fprintf(stderr, "*** Error: %s\n", ogg_strerror(result));
goto error;
}
}
/*initialize the output MD5 sum*/
audiotools__MD5Init(&md5);
/*add callback for CRC16 calculation*/
br_add_callback(packet, (bs_callback_f)flac_crc16, &crc16);
/*decode the next FrameList from the stream*/
result = oggreader_next_packet(ogg_stream, packet);
while (result != OGG_STREAM_FINISHED) {
if (result == OGG_OK) {
flac_status flac_status;
struct flac_frame_header frame_header;
unsigned channel;
subframe_data->reset(subframe_data);
if (!setjmp(*br_try(packet))) {
/*read frame header*/
if ((flac_status =
flacdec_read_frame_header(packet,
&streaminfo,
&frame_header)) != OK) {
fprintf(stderr, "*** Error: %s\n",
FlacDecoder_strerror(flac_status));
br_etry(packet);
goto error;
}
/*read 1 subframe per channel*/
for (channel = 0;
channel < frame_header.channel_count;
channel++)
if ((flac_status = flacdec_read_subframe(
packet,
qlp_coeffs,
residuals,
frame_header.block_size,
flacdec_subframe_bits_per_sample(&frame_header,
channel),
subframe_data->append(subframe_data))) != OK) {
fprintf(stderr, "*** Error: %s\n",
FlacDecoder_strerror(flac_status));
br_etry(packet);
goto error;
}
br_etry(packet);
} else {
br_etry(packet);
fprintf(stderr, "*** I/O Error reading FLAC frame\n");
goto error;
}
/*handle difference channels, if any*/
flacdec_decorrelate_channels(frame_header.channel_assignment,
subframe_data,
framelist_data);
/*check CRC-16*/
packet->byte_align(packet);
packet->read(packet, 16);
if (crc16 != 0) {
fprintf(stderr, "*** Error: invalid checksum in frame\n");
goto error;
}
/*turn FrameList into string of output*/
pcm_size = (streaminfo.bits_per_sample / 8) * framelist_data->len;
if (pcm_size > output_data_size) {
output_data_size = pcm_size;
output_data = realloc(output_data, output_data_size);
}
FrameList_samples_to_char(output_data,
framelist_data->_,
converter,
framelist_data->len,
streaminfo.bits_per_sample);
/*update MD5 sum*/
audiotools__MD5Update(&md5, output_data, pcm_size);
/*output string to stdout*/
fwrite(output_data, sizeof(unsigned char), pcm_size, stdout);
result = oggreader_next_packet(ogg_stream, packet);
} else {
/*some error reading Ogg stream*/
fprintf(stderr, "*** Error: %s\n", ogg_strerror(result));
goto error;
}
}
/*Ogg stream is finished so verify stream's MD5 sum*/
audiotools__MD5Final(stream_md5sum, &md5);
if (!((memcmp(streaminfo.md5sum, blank_md5sum, 16) == 0) ||
(memcmp(stream_md5sum, streaminfo.md5sum, 16) == 0))) {
fprintf(stderr, "*** MD5 mismatch at end of stream\n");
goto error;
}
/*close streams, temporary buffers*/
oggreader_close(ogg_stream);
packet->close(packet);
subframe_data->del(subframe_data);
residuals->del(residuals);
qlp_coeffs->del(qlp_coeffs);
framelist_data->del(framelist_data);
free(output_data);
return 0;
error:
oggreader_close(ogg_stream);
packet->close(packet);
subframe_data->del(subframe_data);
residuals->del(residuals);
qlp_coeffs->del(qlp_coeffs);
framelist_data->del(framelist_data);
free(output_data);
return 1;
}
