gstreamer/gst-libs/ext/mplex/mpastrm_in.cc
David Schleef 63294c0655 Moved from gst-plugins/ext/mplex/. See that directory for older changelogs.
Original commit message from CVS:
Moved from gst-plugins/ext/mplex/.  See that directory for older
changelogs.
2003-07-26 03:01:58 +00:00

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9.3 KiB
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/*
* audiostrm_in.c: MPEG Audio strem class members handling scanning
* and buffering raw input stream.
*
* Copyright (C) 2001 Andrew Stevens <andrew.stevens@philips.com>
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <config.h>
#include <math.h>
#include <stdlib.h>
#include "audiostrm.hh"
#include "outputstream.hh"
static const char *mpa_audio_version[4] = {
"2.5",
"2.0",
"reserved",
"1.0"
};
static const unsigned int mpa_bitrates_kbps[4][3][16] = {
{ /* MPEG audio V2.5 */
{0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0}
},
{ /*RESERVED*/ {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
},
{ /* MPEG audio V2 */
{0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0},
{0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0}
},
{ /* MPEG audio V1 */
{0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0},
{0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 0},
{0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0}
}
};
static const int mpa_freq_table[4][4] = {
/* MPEG audio V2.5 */
{11025, 12000, 8000, 0},
/* RESERVED */
{0, 0, 0, 0},
/* MPEG audio V2 */
{22050, 24000, 16000, 0},
/* MPEG audio V1 */
{44100, 48000, 32000, 0}
};
static const char mpa_stereo_mode[4][15] =
{ "stereo", "joint stereo", "dual channel", "single channel" };
static const char mpa_copyright_status[2][20] = { "no copyright", "copyright protected" };
static const char mpa_original_bit[2][10] = { "copy", "original" };
static const char mpa_emphasis_mode[4][20] =
{ "none", "50/15 microseconds", "reserved", "CCITT J.17" };
static const unsigned int mpa_slots[4] = { 12, 144, 144, 0 };
static const unsigned int mpa_samples[4] = { 384, 1152, 1152, 0 };
MPAStream::MPAStream (IBitStream & ibs, OutputStream & into):
AudioStream (ibs, into)
{
}
bool
MPAStream::Probe (IBitStream & bs)
{
return bs.getbits (11) == AUDIO_SYNCWORD;
}
/*************************************************************************
*
* Reads initial stream parameters and displays feedback banner to users
*
*************************************************************************/
void
MPAStream::Init (const int stream_num)
{
int padding_bit;
MuxStream::Init (AUDIO_STR_0 + stream_num, 0, // Buffer scale
muxinto.audio_buffer_size,
muxinto.vcd_zero_stuffing,
muxinto.buffers_in_audio, muxinto.always_buffers_in_audio);
mjpeg_info ("Scanning for header info: Audio stream %02x", AUDIO_STR_0 + stream_num);
InitAUbuffer ();
/* A.Stevens 2000 - update to be compatible up to MPEG2.5
*/
AU_start = bs.bitcount ();
if (bs.getbits (11) == AUDIO_SYNCWORD) {
num_syncword++;
version_id = bs.getbits (2);
layer = 3 - bs.getbits (2); /* 0..2 not 1..3!! */
protection = bs.get1bit ();
bit_rate_code = bs.getbits (4);
frequency = bs.getbits (2);
padding_bit = bs.get1bit ();
bs.get1bit ();
mode = bs.getbits (2);
mode_extension = bs.getbits (2);
copyright = bs.get1bit ();
original_copy = bs.get1bit ();
emphasis = bs.getbits (2);
framesize =
mpa_bitrates_kbps[version_id][layer][bit_rate_code] *
mpa_slots[layer] * 1000 / mpa_freq_table[version_id][frequency];
size_frames[0] = framesize;
size_frames[1] = framesize + (layer == 0 ? 4 : 1);
num_frames[padding_bit]++;
access_unit.start = AU_start;
access_unit.length = size_frames[padding_bit];
samples_per_second = mpa_freq_table[version_id][frequency];
/* Presentation time-stamping */
access_unit.PTS = static_cast < clockticks > (decoding_order) *
static_cast < clockticks > (mpa_samples[layer]) *
static_cast < clockticks > (CLOCKS) / samples_per_second;
access_unit.DTS = access_unit.PTS;
access_unit.dorder = decoding_order;
++decoding_order;
aunits.append (access_unit);
} else {
mjpeg_error ("Invalid MPEG Audio stream header.");
exit (1);
}
OutputHdrInfo ();
}
unsigned int
MPAStream::NominalBitRate ()
{
return mpa_bitrates_kbps[version_id][layer][bit_rate_code] * 128;
}
unsigned int
MPAStream::SizeFrame (int rate_code, int padding)
{
return mpa_bitrates_kbps[version_id][layer][rate_code] *
mpa_slots[layer] * 1000 / mpa_freq_table[version_id][frequency] + padding;
}
void
MPAStream::FillAUbuffer (unsigned int frames_to_buffer)
{
unsigned int i;
unsigned int padding_bit;
last_buffered_AU += frames_to_buffer;
mjpeg_debug ("Scanning %d MPEG audio frames to frame %d", frames_to_buffer, last_buffered_AU);
while (!bs.eos () &&
decoding_order < last_buffered_AU) {
skip = access_unit.length - 4;
if (skip & 0x1)
bs.getbits (8);
if (skip & 0x2)
bs.getbits (16);
skip = skip >> 2;
for (i = 0; i < skip; i++) {
bs.getbits (32);
}
prev_offset = AU_start;
AU_start = bs.bitcount ();
/* Check we have reached the end of have another catenated
stream to process before finishing ... */
if ((syncword = bs.getbits (11)) != AUDIO_SYNCWORD) {
if (!bs.eobs) {
/* There appears to be another catenated stream... */
int next;
mjpeg_warn ("End of component bit-stream ... seeking next");
/* Catenated stream must start on byte boundary */
syncword = (syncword << (8 - AU_start % 8));
next = bs.getbits (8 - (AU_start % 8));
AU_start = bs.bitcount () - 11;
syncword = syncword | next;
if (syncword != AUDIO_SYNCWORD) {
mjpeg_warn ("Failed to find start of next stream at %lld prev %lld !", AU_start / 8,
prev_offset / 8);
break;
}
} else
/* No catenated stream... finished! */
break;
}
// Skip version_id:2, layer:2, protection:1
(void) bs.getbits (5);
int rate_code = bs.getbits (4);
// Skip frequency
(void) bs.getbits (2);
padding_bit = bs.get1bit ();
access_unit.start = AU_start;
access_unit.length = SizeFrame (rate_code, padding_bit);
access_unit.PTS =
static_cast < clockticks > (decoding_order) * static_cast < clockticks >
(mpa_samples[layer]) * static_cast < clockticks > (CLOCKS)
/ samples_per_second;
access_unit.DTS = access_unit.PTS;
access_unit.dorder = decoding_order;
decoding_order++;
aunits.append (access_unit);
num_frames[padding_bit]++;
bs.getbits (9);
num_syncword++;
if (num_syncword >= old_frames + 10) {
mjpeg_debug ("Got %d frame headers.", num_syncword);
old_frames = num_syncword;
}
}
last_buffered_AU = decoding_order;
eoscan = bs.eos ();
}
void
MPAStream::Close ()
{
stream_length = AU_start >> 3;
mjpeg_info ("AUDIO_STATISTICS: %02x", stream_id);
mjpeg_info ("Audio stream length %lld bytes.", stream_length);
mjpeg_info ("Syncwords : %8u", num_syncword);
mjpeg_info ("Frames : %8u padded", num_frames[0]);
mjpeg_info ("Frames : %8u unpadded", num_frames[1]);
bs.close ();
}
/*************************************************************************
OutputAudioInfo
gibt gesammelte Informationen zu den Audio Access Units aus.
Prints information on audio access units
*************************************************************************/
void
MPAStream::OutputHdrInfo ()
{
unsigned int bitrate;
bitrate = mpa_bitrates_kbps[version_id][layer][bit_rate_code];
mjpeg_info ("AUDIO STREAM:");
mjpeg_info ("Audio version : %s", mpa_audio_version[version_id]);
mjpeg_info ("Layer : %8u", layer + 1);
if (protection == 0)
mjpeg_info ("CRC checksums : yes");
else
mjpeg_info ("CRC checksums : no");
if (bit_rate_code == 0)
mjpeg_info ("Bit rate : free");
else if (bit_rate_code == 0xf)
mjpeg_info ("Bit rate : reserved");
else
mjpeg_info ("Bit rate : %8u bytes/sec (%3u kbit/sec)", bitrate * 128, bitrate);
if (frequency == 3)
mjpeg_info ("Frequency : reserved");
else
mjpeg_info ("Frequency : %d Hz", mpa_freq_table[version_id][frequency]);
mjpeg_info ("Mode : %8u %s", mode, mpa_stereo_mode[mode]);
mjpeg_info ("Mode extension : %8u", mode_extension);
mjpeg_info ("Copyright bit : %8u %s", copyright, mpa_copyright_status[copyright]);
mjpeg_info ("Original/Copy : %8u %s", original_copy, mpa_original_bit[original_copy]);
mjpeg_info ("Emphasis : %8u %s", emphasis, mpa_emphasis_mode[emphasis]);
}
/*
* Local variables:
* c-file-style: "stroustrup"
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/