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