436 lines
8.7 KiB
436 lines
8.7 KiB
7 years ago
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/*
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frame.c - compact version of famous library mpg123
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Copyright (C) 2017 Uncle Mike
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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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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#include "mpg123.h"
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enum mpg123_channelcount
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{
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MPG123_MONO = 1,
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MPG123_STEREO = 2
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};
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// only the standard rates
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static const long my_rates[MPG123_RATES] =
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{
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8000, 11025, 12000,
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16000, 22050, 24000,
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32000, 44100, 48000,
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};
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static const int my_encodings[MPG123_ENCODINGS] =
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{
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MPG123_ENC_SIGNED_16,
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MPG123_ENC_UNSIGNED_16,
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};
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// the list of actually possible encodings.
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static const int good_encodings[] =
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{
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MPG123_ENC_SIGNED_16,
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MPG123_ENC_UNSIGNED_16,
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};
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// check if encoding is a valid one in this build.
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static int good_enc( const int enc )
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{
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size_t i;
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for( i = 0; i < sizeof( good_encodings ) / sizeof( int ); ++i )
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{
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if( enc == good_encodings[i] )
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return TRUE;
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}
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return FALSE;
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}
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void mpg123_rates( const long **list, size_t *number )
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{
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if( number != NULL ) *number = sizeof( my_rates ) / sizeof( long );
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if( list != NULL ) *list = my_rates;
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}
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// now that's a bit tricky... One build of the library knows only a subset of the encodings.
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void mpg123_encodings( const int **list, size_t *number )
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{
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if( number != NULL ) *number = sizeof( good_encodings ) / sizeof( int );
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if( list != NULL ) *list = good_encodings;
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}
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int mpg123_encsize( int encoding )
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{
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return sizeof( short );
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}
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static int rate2num( long r )
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{
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int i;
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for( i = 0; i < MPG123_RATES; i++ )
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{
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if( my_rates[i] == r )
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return i;
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}
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return -1;
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}
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static int enc2num( int encoding )
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{
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int i;
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for( i = 0; i < MPG123_ENCODINGS; ++i )
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{
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if( my_encodings[i] == encoding )
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return i;
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}
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return -1;
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}
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static int cap_fit( mpg123_handle_t *fr, audioformat_t *nf, int f0, int f2)
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{
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int i;
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int c = nf->channels - 1;
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int rn = rate2num( nf->rate );
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if( rn >= 0 )
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{
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for( i = f0; i <f2; i++ )
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{
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if( fr->p.audio_caps[c][rn][i] )
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{
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nf->encoding = my_encodings[i];
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return 1;
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}
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}
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}
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return 0;
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}
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static int freq_fit( mpg123_handle_t *fr, audioformat_t *nf, int f0, int f2 )
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{
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nf->rate = frame_freq( fr ) >> fr->p.down_sample;
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if( cap_fit( fr, nf, f0, f2 ))
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return 1;
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if( fr->p.flags & MPG123_AUTO_RESAMPLE )
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{
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nf->rate >>= 1;
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if( cap_fit( fr, nf, f0, f2 ))
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return 1;
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nf->rate >>= 1;
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if( cap_fit( fr, nf, f0, f2 ))
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return 1;
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}
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return 0;
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}
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// match constraints against supported audio formats, store possible setup in frame
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// return: -1: error; 0: no format change; 1: format change
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int frame_output_format( mpg123_handle_t *fr )
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{
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int f0 = 0;
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int f2 = MPG123_ENCODINGS;
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mpg123_parm_t *p = &fr->p;
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audioformat_t nf;
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// initialize new format, encoding comes later
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nf.channels = fr->stereo;
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// force stereo is stronger
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if( p->flags & MPG123_FORCE_MONO )
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nf.channels = 1;
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if( p->flags & MPG123_FORCE_STEREO )
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nf.channels = 2;
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if( freq_fit( fr, &nf, f0, 2 ))
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goto end; // try rates with 16bit
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if( freq_fit( fr, &nf, f0 <=2 ? 2 : f0, f2 ))
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goto end; // ... 8bit
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// try again with different stereoness
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if( nf.channels == 2 && !( p->flags & MPG123_FORCE_STEREO ))
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nf.channels = 1;
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else if( nf.channels == 1 && !( p->flags & MPG123_FORCE_MONO ))
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nf.channels = 2;
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if( freq_fit( fr, &nf, f0, 2 ))
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goto end; // try rates with 16bit
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if( freq_fit( fr, &nf, f0 <= 2 ? 2 : f0, f2 ))
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goto end; // ... 8bit
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fr->err = MPG123_BAD_OUTFORMAT;
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return -1;
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end:
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// here is the _good_ end.
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// we had a successful match, now see if there's a change
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if( nf.rate == fr->af.rate && nf.channels == fr->af.channels && nf.encoding == fr->af.encoding )
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{
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return 0; // the same format as before
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}
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else
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{ // a new format
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fr->af.rate = nf.rate;
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fr->af.channels = nf.channels;
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fr->af.encoding = nf.encoding;
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// cache the size of one sample in bytes, for ease of use.
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fr->af.encsize = mpg123_encsize( fr->af.encoding );
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if( fr->af.encsize < 1 )
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{
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fr->err = MPG123_BAD_OUTFORMAT;
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return -1;
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}
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// set up the decoder synth format. Might differ.
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// without high-precision synths, 16 bit signed is the basis for
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// everything higher than 8 bit.
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if( fr->af.encsize > 2 )
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{
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fr->af.dec_enc = MPG123_ENC_SIGNED_16;
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}
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else
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{
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switch( fr->af.encoding )
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{
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case MPG123_ENC_UNSIGNED_16:
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fr->af.dec_enc = MPG123_ENC_SIGNED_16;
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break;
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default:
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fr->af.dec_enc = fr->af.encoding;
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break;
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}
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}
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fr->af.dec_encsize = mpg123_encsize( fr->af.dec_enc );
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return 1;
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}
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}
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static int mpg123_fmt_none( mpg123_parm_t *mp )
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{
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if( mp == NULL )
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return MPG123_BAD_PARS;
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memset( mp->audio_caps, 0, sizeof( mp->audio_caps ));
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return MPG123_OK;
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}
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int mpg123_fmt_all( mpg123_parm_t *mp )
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{
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size_t rate, ch, enc;
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if( mp == NULL )
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return MPG123_BAD_PARS;
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for( ch = 0; ch < NUM_CHANNELS; ++ch )
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{
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for( rate = 0; rate < MPG123_RATES+1; ++rate )
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{
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for( enc = 0; enc < MPG123_ENCODINGS; ++enc )
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mp->audio_caps[ch][rate][enc] = good_enc( my_encodings[enc] );
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}
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}
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return MPG123_OK;
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}
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static int mpg123_fmt( mpg123_parm_t *mp, long rate, int channels, int encodings )
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{
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int ie, ic, ratei;
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int ch[2] = { 0, 1 };
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if( mp == NULL )
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return MPG123_BAD_PARS;
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if(!( channels & ( MPG123_MONO|MPG123_STEREO )))
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return MPG123_BAD_CHANNEL;
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if(!( channels & MPG123_STEREO ))
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ch[1] = 0;
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else if(!( channels & MPG123_MONO ))
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ch[0] = 1;
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ratei = rate2num( rate );
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if( ratei < 0 ) return MPG123_BAD_RATE;
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// now match the encodings
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for( ic = 0; ic < 2; ++ic )
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{
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for( ie = 0; ie < MPG123_ENCODINGS; ++ie )
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{
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if( good_enc( my_encodings[ie] ) && (( my_encodings[ie] & encodings ) == my_encodings[ie] ))
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mp->audio_caps[ch[ic]][ratei][ie] = 1;
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}
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if( ch[0] == ch[1] )
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break; // no need to do it again
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}
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return MPG123_OK;
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}
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static int mpg123_fmt_support( mpg123_parm_t *mp, long rate, int encoding )
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{
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int ratei, enci;
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int ch = 0;
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ratei = rate2num( rate );
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enci = enc2num( encoding );
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if( mp == NULL || ratei < 0 || enci < 0 )
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return 0;
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if( mp->audio_caps[0][ratei][enci] )
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ch |= MPG123_MONO;
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if( mp->audio_caps[1][ratei][enci] )
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ch |= MPG123_STEREO;
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return ch;
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}
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int mpg123_format_none( mpg123_handle_t *mh )
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{
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int r;
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if( mh == NULL )
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return MPG123_BAD_HANDLE;
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r = mpg123_fmt_none( &mh->p );
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if( r != MPG123_OK )
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{
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mh->err = r;
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return MPG123_ERR;
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}
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return r;
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}
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int mpg123_format_all( mpg123_handle_t *mh )
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{
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int r;
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if( mh == NULL )
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return MPG123_BAD_HANDLE;
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r = mpg123_fmt_all( &mh->p );
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if( r != MPG123_OK )
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{
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mh->err = r;
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return MPG123_ERR;
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}
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return r;
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}
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int mpg123_format( mpg123_handle_t *mh, long rate, int channels, int encodings )
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{
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int r;
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if( mh == NULL )
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return MPG123_BAD_HANDLE;
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r = mpg123_fmt( &mh->p, rate, channels, encodings );
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if( r != MPG123_OK )
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{
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mh->err = r;
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return MPG123_ERR;
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}
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return r;
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}
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int mpg123_format_support( mpg123_handle_t *mh, long rate, int encoding )
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{
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if( mh == NULL )
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return 0;
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return mpg123_fmt_support( &mh->p, rate, encoding );
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}
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// call this one to ensure that any valid format will be something different than this.
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void invalidate_format( audioformat_t *af )
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{
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af->encoding = 0;
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af->channels = 0;
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af->rate = 0;
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}
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// number of bytes the decoder produces.
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mpg_off_t decoder_synth_bytes( mpg123_handle_t *fr, mpg_off_t s )
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{
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return s * fr->af.dec_encsize * fr->af.channels;
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}
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// samples/bytes for output buffer after post-processing.
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// take into account: channels, bytes per sample -- NOT resampling!
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mpg_off_t samples_to_bytes( mpg123_handle_t *fr, mpg_off_t s )
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{
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return s * fr->af.encsize * fr->af.channels;
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}
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mpg_off_t bytes_to_samples( mpg123_handle_t *fr, mpg_off_t b )
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{
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return b / fr->af.encsize / fr->af.channels;
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}
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// number of bytes needed for decoding _and_ post-processing.
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mpg_off_t outblock_bytes( mpg123_handle_t *fr, mpg_off_t s )
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{
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int encsize = (fr->af.encsize > fr->af.dec_encsize ? fr->af.encsize : fr->af.dec_encsize);
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return s * encsize * fr->af.channels;
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}
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static void conv_s16_to_u16( outbuffer_t *buf )
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{
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int16_t *ssamples = (int16_t *)buf->data;
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uint16_t *usamples = (uint16_t *)buf->data;
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size_t count = buf->fill / sizeof( int16_t );
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size_t i;
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for( i = 0; i < count; ++i )
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{
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long tmp = (long)ssamples[i] + 32768;
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usamples[i] = (uint16_t)tmp;
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}
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}
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void postprocess_buffer( mpg123_handle_t *fr )
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{
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switch( fr->af.dec_enc )
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{
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case MPG123_ENC_SIGNED_16:
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switch( fr->af.encoding )
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{
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case MPG123_ENC_UNSIGNED_16:
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conv_s16_to_u16(&fr->buffer);
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break;
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}
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break;
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}
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}
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