static int
read_audio_packet(DVDA_Packet_Reader* packets,
DVDA_Packet* packet, struct bs_buffer* packet_data)
{
if (packets->total_sectors) {
BitstreamReader* reader = packets->reader;
struct bs_buffer* buffer = reader->input.substream;
buf_reset(buffer);
if (!read_sector(packets->sectors, buffer)) {
if (buf_window_size(buffer) == 0) {
return 0;
}
if (!setjmp(*br_try(reader))) {
unsigned sync_bytes;
unsigned pad[6];
unsigned PTS_high;
unsigned PTS_mid;
unsigned PTS_low;
unsigned SCR_extension;
unsigned bitrate;
unsigned stuffing_count;
int audio_packet_found = 0;
/*read pack header*/
reader->parse(reader,
"32u 2u 3u 1u 15u 1u 15u 1u 9u 1u 22u 2u 5p 3u",
&sync_bytes, &(pad[0]), &PTS_high,
&(pad[1]), &PTS_mid, &(pad[2]),
&PTS_low, &(pad[3]), &SCR_extension,
&(pad[4]), &bitrate, &(pad[5]),
&stuffing_count);
if (sync_bytes != 0x000001BA) {
br_etry(reader);
return 1;
}
if ((pad[0] != 1) || (pad[1] != 1) || (pad[2] != 1) ||
(pad[3] != 1) || (pad[4] != 1) || (pad[5] != 3)) {
br_etry(reader);
return 1;
}
for (; stuffing_count; stuffing_count--) {
reader->skip(reader, 8);
}
/*read packets from sector until sector is empty*/
while (buf_window_size(buffer) > 0) {
unsigned start_code;
unsigned stream_id;
unsigned packet_length;
reader->parse(reader, "24u 8u 16u",
&start_code, &stream_id, &packet_length);
if (start_code != 0x000001) {
br_etry(reader);
return 1;
}
if (stream_id == 0xBD) {
/*audio packets are forwarded to packet*/
unsigned pad1_size;
unsigned pad2_size;
reader->parse(reader, "16p 8u", &pad1_size);
reader->skip_bytes(reader, pad1_size);
reader->parse(reader, "8u 8u 8p 8u",
&(packet->codec_ID),
&(packet->CRC),
&pad2_size);
if (packet->codec_ID == 0xA0) { /*PCM*/
reader->parse(reader,
"16u 8p 4u 4u 4u 4u 8p 8u 8p 8u",
&(packet->PCM.first_audio_frame),
&(packet->PCM.group_1_bps),
&(packet->PCM.group_2_bps),
&(packet->PCM.group_1_rate),
&(packet->PCM.group_2_rate),
&(packet->PCM.channel_assignment),
&(packet->PCM.CRC));
reader->skip_bytes(reader, pad2_size - 9);
} else { /*probably MLP*/
reader->skip_bytes(reader, pad2_size);
}
packet_length -= 3 + pad1_size + 4 + pad2_size;
buf_reset(packet_data);
while (packet_length) {
static uint8_t buffer[4096];
const unsigned to_read = MIN(packet_length, 4096);
reader->read_bytes(reader, buffer, to_read);
buf_write(packet_data, buffer, to_read);
packet_length -= to_read;
}
audio_packet_found = 1;
} else {
/*other packets are ignored*/
reader->skip_bytes(reader, packet_length);
}
}
/*return success if an audio packet was read*/
br_etry(reader);
if (audio_packet_found) {
return 0;
} else {
return 1;
}
} else {
/*error reading sector*/
br_etry(reader);
return 1;
}
} else {
/*error reading sector*/
return 1;
}
} else {
/*no more sectors, so return EOF*/
return 0;
}
}
static PyObject*
DVDA_Title_next_track(decoders_DVDA_Title *self, PyObject *args)
{
unsigned PTS_ticks;
DVDA_Packet next_packet;
struct bs_buffer* packet_data = self->packet_data;
unsigned i;
if (!PyArg_ParseTuple(args, "I", &PTS_ticks))
return NULL;
/*ensure previous track has been exhausted, if any*/
if (self->pcm_frames_remaining) {
PyErr_SetString(PyExc_ValueError,
"current track has not been exhausted");
return NULL;
}
/*read the next packet*/
if (read_audio_packet(self->packet_reader,
&next_packet, packet_data)) {
PyErr_SetString(PyExc_IOError,
"I/O error reading initialization packet");
return NULL;
}
#else
int
DVDA_Title_next_track(decoders_DVDA_Title *self, unsigned PTS_ticks)
{
DVDA_Packet next_packet;
struct bs_buffer* packet_data = self->packet_data;
unsigned i;
if (self->pcm_frames_remaining) {
fprintf(stderr, "current track has not been exhausted\n");
return 0;
}
if (read_audio_packet(self->packet_reader,
&next_packet, packet_data)) {
fprintf(stderr, "I/O error reading initialization packet\n");
return 0;
}
#endif
if (next_packet.codec_ID == PCM_CODEC_ID) {
/*if the packet is PCM, initialize Title's stream attributes
(bits-per-sample, sample rate, channel assignment/mask)
with values taken from the first packet*/
/*PCM stores stream attributes in the second padding block*/
self->bits_per_sample =
dvda_bits_per_sample(next_packet.PCM.group_1_bps);
self->sample_rate =
dvda_sample_rate(next_packet.PCM.group_1_rate);
self->channel_assignment =
next_packet.PCM.channel_assignment;
self->channel_count =
dvda_channel_count(next_packet.PCM.channel_assignment);
self->channel_mask =
dvda_channel_mask(next_packet.PCM.channel_assignment);
self->frame_codec = PCM;
init_aobpcm_decoder(&(self->pcm_decoder),
self->bits_per_sample,
self->channel_count);
buf_extend(packet_data, self->frames);
} else if (next_packet.codec_ID == MLP_CODEC_ID) {
/*if the packet is MLP,
check if the first frame starts with a major sync*/
enum {PACKET_DATA};
BitstreamReader* r = br_open_buffer(packet_data, BS_BIG_ENDIAN);
r->mark(r, PACKET_DATA);
if (!setjmp(*br_try(r))) {
unsigned sync_words;
unsigned stream_type;
r->parse(r, "32p 24u 8u", &sync_words, &stream_type);
if ((sync_words == 0xF8726F) && (stream_type == 0xBB)) {
/*if so, discard any unconsumed packet data
and initialize Title's stream attributes
with values taken from the major sync*/
unsigned group_1_bps;
unsigned group_2_bps;
unsigned group_1_rate;
unsigned group_2_rate;
r->parse(r, "4u 4u 4u 4u 11p 5u 48p",
&group_1_bps, &group_2_bps,
&group_1_rate, &group_2_rate,
&(self->channel_assignment));
self->bits_per_sample =
dvda_bits_per_sample(group_1_bps);
self->sample_rate =
dvda_sample_rate(group_1_rate);
self->channel_count =
dvda_channel_count(self->channel_assignment);
self->channel_mask =
dvda_channel_mask(self->channel_assignment);
self->frame_codec = MLP;
self->mlp_decoder->major_sync_read = 0;
r->rewind(r, PACKET_DATA);
r->unmark(r, PACKET_DATA);
br_etry(r);
r->close(r);
buf_reset(self->frames);
buf_extend(packet_data, self->frames);
} else {
/*if not, append packet data to any unconsumed data
and leave Title's stream attributes as they were*/
r->rewind(r, PACKET_DATA);
r->unmark(r, PACKET_DATA);
br_etry(r);
r->close(r);
buf_extend(packet_data, self->frames);
}
} else {
/*if I/O error reading major sync,
append packet data to any unconsumed data
and leave Title's stream attributes as they were*/
r->rewind(r, PACKET_DATA);
r->unmark(r, PACKET_DATA);
br_etry(r);
r->close(r);
buf_extend(packet_data, self->frames);
}
} else {
#ifndef STANDALONE
PyErr_SetString(PyExc_ValueError, "unknown codec ID");
return NULL;
#else
return 0;
#endif
}
/*convert PTS ticks to PCM frames based on sample rate*/
self->pcm_frames_remaining = (unsigned)round((double)PTS_ticks *
(double)self->sample_rate /
(double)PTS_PER_SECOND);
/*initalize codec's framelist with the proper number of channels*/
if (self->codec_framelist->len != self->channel_count) {
self->codec_framelist->reset(self->codec_framelist);
for (i = 0; i < self->channel_count; i++)
self->codec_framelist->append(self->codec_framelist);
}
#ifndef STANDALONE
Py_INCREF(Py_None);
return Py_None;
#else
return 1;
#endif
}