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p_ac3.cpp
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p_ac3.cpp
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/*
ogmmerge -- utility for splicing together ogg bitstreams
from component media subtypes
p_ac3.cpp
AC3 output module
Written by Moritz Bunkus <[email protected]>
Based on Xiph.org's 'oggmerge' found in their CVS repository
See http://www.xiph.org
Distributed under the GPL
see the file COPYING for details
or visit http://www.gnu.org/copyleft/gpl.html
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ogg/ogg.h>
#include "ogmmerge.h"
#include "queue.h"
#include "ac3_common.h"
#include "p_ac3.h"
#include "vorbis_header_utils.h"
ac3_packetizer_c::ac3_packetizer_c(unsigned long nsamples_per_sec,
int nchannels, int nbitrate,
audio_sync_t *nasync, range_t *nrange,
char **ncomments) throw (error_c) : q_c() {
serialno = create_unique_serial();
ogg_stream_init(&os, serialno);
packetno = 0;
bytes_output = 0;
memcpy(&async, nasync, sizeof(audio_sync_t));
memcpy(&range, nrange, sizeof(range_t));
comments = generate_vorbis_comment(ncomments);
old_granulepos = 0;
packet_buffer = NULL;
buffer_size = 0;
eos = 0;
set_params(nsamples_per_sec, nchannels, nbitrate);
}
ac3_packetizer_c::~ac3_packetizer_c() {
ogg_stream_clear(&os);
if (comments != NULL) {
vorbis_comment_clear(comments);
free(comments);
}
if (packet_buffer != NULL)
free(packet_buffer);
}
void ac3_packetizer_c::set_params(unsigned long nsamples_per_sec,
int nchannels, int nbitrate) {
samples_per_sec = nsamples_per_sec;
channels = nchannels;
bitrate = nbitrate;
}
void ac3_packetizer_c::add_to_buffer(char *buf, int size) {
char *new_buffer;
new_buffer = (char *)realloc(packet_buffer, buffer_size + size);
if (new_buffer == NULL)
die("realloc");
memcpy(new_buffer + buffer_size, buf, size);
packet_buffer = new_buffer;
buffer_size += size;
}
int ac3_packetizer_c::ac3_packet_available() {
int pos;
ac3_header_t ac3header;
if (packet_buffer == NULL)
return 0;
pos = find_ac3_header((unsigned char *)packet_buffer, buffer_size,
&ac3header);
if (pos < 0)
return 0;
return 1;
}
void ac3_packetizer_c::remove_ac3_packet(int pos, int framesize) {
int new_size;
char *temp_buf;
new_size = buffer_size - (pos + framesize);
if (new_size != 0) {
temp_buf = (char *)malloc(new_size);
if (temp_buf == NULL)
die("malloc");
memcpy(temp_buf, &packet_buffer[pos + framesize],
new_size);
} else
temp_buf = NULL;
free(packet_buffer);
packet_buffer = temp_buf;
buffer_size = new_size;
}
char *ac3_packetizer_c::get_ac3_packet(unsigned long *header,
ac3_header_t *ac3header) {
int pos;
char *buf;
double pims;
if (packet_buffer == NULL)
return 0;
pos = find_ac3_header((unsigned char *)packet_buffer, buffer_size, ac3header);
if (pos < 0)
return 0;
if ((pos + ac3header->bytes) > buffer_size)
return 0;
pims = ((double)ac3header->bytes) * 1000.0 /
((double)ac3header->bit_rate / 8.0);
if (async.displacement < 0) {
/*
* AC3 audio synchronization. displacement < 0 means skipping an
* appropriate number of packets at the beginning.
*/
async.displacement += (int)pims;
if (async.displacement > -(pims / 2))
async.displacement = 0;
remove_ac3_packet(pos, ac3header->bytes);
return 0;
}
if (verbose && (pos > 1))
fprintf(stdout, "ac3_packetizer: skipping %d bytes (no valid AC3 header "
"found). This might make audio/video go out of sync, but this "
"stream is damaged.\n", pos);
buf = (char *)malloc(ac3header->bytes);
if (buf == NULL)
die("malloc");
memcpy(buf, packet_buffer + pos, ac3header->bytes);
if (async.displacement > 0) {
/*
* AC3 audio synchronization. displacement > 0 is solved by duplicating
* the very first AC3 packet as often as necessary. I cannot create
* a packet with total silence because I don't know how, and simply
* settings the packet's values to 0 does not work as the AC3 header
* contains a CRC of its data.
*/
async.displacement -= (int)pims;
if (async.displacement < (pims / 2))
async.displacement = 0;
return buf;
}
remove_ac3_packet(pos, ac3header->bytes);
return buf;
}
void ac3_packetizer_c::produce_header_packets() {
stream_header sh;
unsigned char *tempbuf;
ogg_packet op;
int clen, res;
memset(&sh, 0, sizeof(sh));
strcpy(sh.streamtype, "audio");
memcpy(sh.subtype, "2000", 4);
put_uint32(&sh.size, sizeof(sh));
put_uint64(&sh.time_unit, 10000000);
put_uint64(&sh.samples_per_unit, samples_per_sec);
put_uint32(&sh.default_len, 1);
put_uint32(&sh.buffersize, samples_per_sec);
put_uint16(&sh.bits_per_sample, 2);
put_uint16(&sh.sh.audio.channels, channels);
put_uint16(&sh.sh.audio.blockalign, 1536);
put_uint32(&sh.sh.audio.avgbytespersec, bitrate * 1000 / 8);
tempbuf = (unsigned char *)malloc(sizeof(sh) + 1);
if (tempbuf == NULL)
die("malloc");
*tempbuf = PACKET_TYPE_HEADER;
memcpy((char *)&tempbuf[1], &sh, sizeof(sh));
op.packet = tempbuf;
op.bytes = 1 + get_uint32(&sh.size);
op.b_o_s = 1;
op.e_o_s = 0;
op.packetno = 0;
op.granulepos = 0;
/* submit it */
ogg_stream_packetin(&os, &op);
packetno++;
flush_pages(PACKET_TYPE_HEADER);
free(tempbuf);
/* Create the comments packet */
clen = -1 * comments_to_buffer(comments, NULL, 0);
tempbuf = (unsigned char *)malloc(clen);
if (tempbuf == NULL)
die("malloc");
op.packet = tempbuf;
op.bytes = clen;
op.b_o_s = 0;
op.e_o_s = 0;
op.granulepos = 0;
op.packetno = 1;
if ((res = comments_to_buffer(comments, (char *)op.packet, clen)) < 0) {
fprintf(stderr, "FATAL: p_ac3: comments_to_buffer returned %d, " \
"clen is %d\n", res, clen);
exit(1);
}
ogg_stream_packetin(&os, &op);
flush_pages(PACKET_TYPE_COMMENT);
packetno++;
free(tempbuf);
}
int ac3_packetizer_c::process(char *buf, int size, int last_frame) {
ogg_packet op;
int i, tmpsize;
unsigned char *bptr, *tempbuf;
char *packet;
unsigned long header;
ac3_header_t ac3header;
add_to_buffer(buf, size);
while ((packet = get_ac3_packet(&header, &ac3header)) != NULL) {
if (packetno == 0) {
set_params(ac3header.sample_rate, ac3header.channels,
ac3header.bit_rate / 1000);
produce_header_packets();
}
tempbuf = (unsigned char *)malloc(ac3header.bytes + 1 + sizeof(u_int16_t));
if (tempbuf == NULL)
die("malloc");
tempbuf[0] = (((sizeof(u_int16_t) & 3) << 6) +
((sizeof(u_int16_t) & 4) >> 1)) | PACKET_IS_SYNCPOINT;
op.bytes = ac3header.bytes + 1 + sizeof(u_int16_t);
bptr = (unsigned char *)&tempbuf[1];
for (i = 0, tmpsize = 1536; i < sizeof(u_int16_t); i++) {
*(bptr + i) = (unsigned char)(tmpsize & 0xFF);
tmpsize = tmpsize >> 8;
}
memcpy(&tempbuf[1 + sizeof(u_int16_t)], packet, ac3header.bytes);
op.packet = (unsigned char *)&tempbuf[0];
op.b_o_s = 0;
if (last_frame && !ac3_packet_available()) {
op.e_o_s = 1;
eos = 1;
} else
op.e_o_s = 0;
op.granulepos = (u_int64_t)((packetno - 2) * 1536 * async.linear);
op.packetno = packetno++;
ogg_stream_packetin(&os, &op);
if (force_flushing)
flush_pages();
bytes_output += ac3header.bytes;
free(tempbuf);
free(packet);
}
if (last_frame) {
flush_pages();
return 0;
} else {
if (!force_flushing)
queue_pages();
return EMOREDATA;
}
}
void ac3_packetizer_c::reset() {
}
void ac3_packetizer_c::produce_eos_packet() {
ogg_packet op;
if (eos)
return;
op.packet = (unsigned char *)"";
op.bytes = 1;
op.b_o_s = 0;
op.e_o_s = 1;
op.granulepos = (u_int64_t)((packetno - 2) * 1536);
op.packetno = packetno++;
ogg_stream_packetin(&os, &op);
flush_pages();
eos = 1;
}
stamp_t ac3_packetizer_c::make_timestamp(ogg_int64_t granulepos) {
stamp_t stamp;
#ifndef INCORRECT_INTERLEAVING
stamp = (stamp_t)((double)old_granulepos * (double)1000000.0 /
(double)samples_per_sec);
old_granulepos = granulepos;
#else
stamp = (stamp_t)((double)granulepos * 1000000.0 /
(double)samples_per_sec);
#endif
return stamp;
}