/* * audiostrm_in.c: MPEG Audio strem class members handling scanning * and buffering raw input stream. * * Copyright (C) 2001 Andrew Stevens * * * 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 #include #include #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: */