/*------------------------------------------------------------------------------ File : mpega_decode.c Author : Stéphane TAVENARD $VER: mpega_decode.c 1.0 (23/06/1995) (C) Copyright 1995-1995 Stéphane TAVENARD All Rights Reserved #Rev| Date | Comment ----|----------|-------------------------------------------------------- 0 |27/05/1995| Initial revision ST 1 |23/06/1995| First release (aminet) ST ------------------------------------------------------------------------ MPEG Audio decode functions ------------------------------------------------------------------------------*/ #include #include #include #include #include "AudioPort.h" #include "AIFF.h" #include "mpega_decode_asm.h" #include "mpega_decode.h" frame_params *MPEGA_close( frame_params *fr_ps ) { if( !fr_ps ) return NULL; if( fr_ps->audio_port ) { AU_close( fr_ps->audio_port ); fr_ps->audio_port = NULL; } if( fr_ps->bs ) BSTR_close( fr_ps->bs ); fr_ps->bs = NULL; if( fr_ps->header ) free( fr_ps->header ); if( fr_ps->bit_alloc ) free( fr_ps->bit_alloc ); if( fr_ps->scfsi ) free( fr_ps->scfsi ); if( fr_ps->scale_index ) free( fr_ps->scale_index ); if( fr_ps->sample ) free( fr_ps->sample ); if( fr_ps->fraction ) free( fr_ps->fraction ); free( fr_ps ); return NULL; } frame_params *MPEGA_open( void ) { frame_params *fr_ps; fr_ps = (frame_params *)malloc( sizeof( frame_params ) ); if( !fr_ps ) return NULL; memset( fr_ps, 0, sizeof( frame_params ) ); fr_ps->header = (layer *)malloc( sizeof( layer ) ); if( !fr_ps->header ) return MPEGA_close( fr_ps ); memset( fr_ps->header, 0, sizeof( layer ) ); fr_ps->bit_alloc = (int *)malloc( sizeof( int ) * 2 * SBLIMIT ); if( !fr_ps->bit_alloc ) return MPEGA_close( fr_ps ); fr_ps->scfsi = (int *)malloc( sizeof( int ) * 2 * SBLIMIT ); if( !fr_ps->scfsi ) return MPEGA_close( fr_ps ); fr_ps->scale_index = (int *)malloc( sizeof( int ) * 2 * 3 * SBLIMIT ); if( !fr_ps->scale_index ) return MPEGA_close( fr_ps ); fr_ps->sample = (int *)malloc( sizeof( int ) * 2 * 3 * SBLIMIT ); if( !fr_ps->sample ) return MPEGA_close( fr_ps ); fr_ps->fraction = (INT *)malloc( sizeof( INT ) * 2 * 3 * SBLIMIT ); if( !fr_ps->fraction ) return MPEGA_close( fr_ps ); /* default values */ fr_ps->freq_div = 1; fr_ps->quality = 2; fr_ps->bitstream_buffer_size = BSTR_BUFFER_SIZE; return fr_ps; } #define OUT_BUFFER_SIZE (13824*4) static BOOL stereo_file = FALSE; static BYTE *l_file_buffer = NULL; static BYTE *r_file_buffer = NULL; static BYTE *stereo_file_buffer = NULL; static int init_file( frame_params *fr_ps ) { long buffer_byte_size; if( !fr_ps->out_file_name ) return 1; if( !fr_ps->out_file ) { if( strcmp( fr_ps->out_file_name, "stdout" ) == 0 ) { fr_ps->out_file = stdout; } else { fr_ps->out_file = fopen( fr_ps->out_file_name, "w+b" ); if( !fr_ps->out_file ) { fprintf( stderr, "Can't create file '%s'\n", fr_ps->out_file_name ); return 0; } } } if( fr_ps->out_file_type == MPEGA_FILETYPE_AIFF ) { if( AIFF_seek_to_sound_data( fr_ps->out_file ) == -1 ) { fclose( fr_ps->out_file ); fr_ps->out_file = NULL; return 0; } } fr_ps->out_buffer_size = OUT_BUFFER_SIZE; if( (fr_ps->stereo > 1) && !(fr_ps->mono_forced) ) stereo_file = TRUE; else stereo_file = FALSE; if( fr_ps->output_8bits ) buffer_byte_size = fr_ps->out_buffer_size; else buffer_byte_size = (fr_ps->out_buffer_size)*2; fr_ps->out_buffer[ 0 ] = fr_ps->out_buffer[ 1 ] = NULL; fr_ps->out_buffer[ 0 ] = (BYTE *)malloc( buffer_byte_size ); if( !fr_ps->out_buffer[ 0 ] ) exit( 0 ); if( stereo_file ) { fr_ps->out_buffer[ 1 ] = (BYTE *)malloc( buffer_byte_size ); if( !fr_ps->out_buffer[ 1 ] ) exit( 0 ); stereo_file_buffer = (BYTE *)malloc( buffer_byte_size * 2 ); if( !stereo_file_buffer ) exit( 0 ); } l_file_buffer = fr_ps->out_buffer[ 0 ]; r_file_buffer = fr_ps->out_buffer[ 1 ]; return 1; } static int write_file( frame_params *fr_ps ) /* WARNING length is not byte length, it's sample length (8 or 16 bits) */ { long buffer_byte_size; int write_length; register int i; if( fr_ps->out_write_length > 0 ) { if( fr_ps->output_8bits ) buffer_byte_size = fr_ps->out_write_length; else buffer_byte_size = fr_ps->out_write_length * 2; if( stereo_file ) { if( fr_ps->output_8bits ) { BYTE *l_sample, *r_sample, *buffer; buffer = stereo_file_buffer; l_sample = l_file_buffer; r_sample = r_file_buffer; for( i=0; iout_write_length; i++ ) { *buffer++ = *l_sample++; *buffer++ = *r_sample++; } } else { WORD *l_sample, *r_sample, *buffer; buffer = (WORD *)stereo_file_buffer; l_sample = (WORD *)l_file_buffer; r_sample = (WORD *)r_file_buffer; for( i=0; iout_write_length; i++ ) { *buffer++ = *l_sample++; *buffer++ = *r_sample++; } } write_length = fwrite( stereo_file_buffer, buffer_byte_size*2, 1, fr_ps->out_file ); } else { write_length = fwrite( l_file_buffer, buffer_byte_size, 1, fr_ps->out_file ); } if( !fr_ps->output_8bits ) write_length <<= 1; } else { write_length = 0; if ( fr_ps->out_file_type == MPEGA_FILETYPE_AIFF ) { IFF_AIFF pcm_aiff_data; pcm_aiff_data.numChannels = fr_ps->stereo; pcm_aiff_data.numSampleFrames = fr_ps->out_sample_length; if( fr_ps->output_8bits ) pcm_aiff_data.sampleSize = 8; else pcm_aiff_data.sampleSize = 16; pcm_aiff_data.sampleRate = fr_ps->out_sample_freq; pcm_aiff_data.sampleType = IFF_ID_SSND; pcm_aiff_data.blkAlgn.offset = 0; pcm_aiff_data.blkAlgn.blockSize = 0; if( AIFF_write_headers( fr_ps->out_file, &pcm_aiff_data ) == -1 ) { printf( "Could not write AIFF headers to \"%s\"\n", fr_ps->out_file_name ); } } fclose( fr_ps->out_file ); fr_ps->out_file = NULL; } fr_ps->out_buffer[ 0 ] = l_file_buffer; fr_ps->out_buffer[ 1 ] = r_file_buffer; fr_ps->out_write_length = 0; return write_length; } static int init_audio( frame_params *fr_ps ) { BYTE flags = 0; if( fr_ps->audio_port ) return; fr_ps->out_buffer_size = fr_ps->out_sample_freq * 2; /* 2 secs buffer */ if( fr_ps->out_buffer_size >= 0x20000L ) { fr_ps->out_buffer_size = 0x1FFFEL; } if( !fr_ps->output_8bits ) { flags |= AUF_16BITS; } if( (fr_ps->stereo > 1) && !(fr_ps->mono_forced) ) flags |= AUF_STEREO; fr_ps->audio_port = AU_open( flags, fr_ps->out_buffer_size ); if( !fr_ps->audio_port ) { fprintf( stderr, "Can't open audio port !\n" ); exit( 0 ); } fr_ps->audio_port->frequency = fr_ps->out_sample_freq; fprintf( stderr, "Audio output " ); if( flags & AUF_16BITS ) fprintf( stderr, "16-bit " ); else fprintf( stderr, "8-bit " ); if( flags & AUF_STEREO ) fprintf( stderr, "stereo " ); else fprintf( stderr, "mono " ); fprintf( stderr, "%ldHz ", fr_ps->audio_port->frequency ); fr_ps->audio_port->l_vol = fr_ps->audio_port->r_vol = 64; fr_ps->audio_port->filter_on = fr_ps->audio_filter; fr_ps->audio_port->flags = AUF_FILTER | AUF_FREQ | AUF_VOL; fr_ps->audio_port->mixing_frequency = fr_ps->mixing_frequency; if( fr_ps->mixing_frequency > 0 ) { fr_ps->audio_port->flags |= AUF_MIXING; fprintf( stderr, "mixing at %ldHz\n", fr_ps->mixing_frequency ); } else fprintf( stderr, "\n" ); fr_ps->audio_port->command = AUC_CONTROL; AU_write( fr_ps->audio_port ); fr_ps->out_buffer[ 0 ] = (BYTE *)fr_ps->audio_port->l_wave; fr_ps->out_buffer[ 1 ] = (BYTE *)fr_ps->audio_port->r_wave; return 1; } static int write_audio( frame_params *fr_ps ) { int write_length = 0; if( !fr_ps->audio_port ) return 0; if( fr_ps->out_write_length >= 0 ) { fr_ps->audio_port->flags &= ~(AUF_FILTER|AUF_FREQ|AUF_VOL); if( fr_ps->no_audio_wait ) fr_ps->audio_port->flags |= AUF_NOWAIT; fr_ps->audio_port->command = AUC_WRITE; fr_ps->audio_port->wave_length = fr_ps->out_write_length; AU_write( fr_ps->audio_port ); fr_ps->out_buffer[ 0 ] = (BYTE *)fr_ps->audio_port->l_wave; fr_ps->out_buffer[ 1 ] = (BYTE *)fr_ps->audio_port->r_wave; write_length = fr_ps->out_write_length; } fr_ps->out_write_length = 0; return write_length; } static int MPEGA_init_out( frame_params *fr_ps ) { if( fr_ps->play ) return init_audio( fr_ps ); else return init_file( fr_ps ); } static void MPEGA_read_CRC( frame_params *fr_ps ) { int old_crc; old_crc = BSTR_read_bits( fr_ps->bs, 16); } int MPEGA_seek_header( frame_params *fr_ps ) /*------------------------------------------ Seek, read and decode MPEG audio header */ { if( BSTR_end( fr_ps->bs ) ) return 0; if( !BSTR_seek_sync( fr_ps->bs, MPEGA_SYNC_WORD, MPEGA_SYNC_WORD_LNGTH ) ) return 0; if( !ASM_read_header( fr_ps ) ) return 0; ASM_decode_header( fr_ps ); if( fr_ps->header->error_protection ) MPEGA_read_CRC( fr_ps ); return 1; } int MPEGA_init_decode( frame_params *fr_ps ) /*------------------------------------------ Initialize MPEG Audio decoding (analys of first frame to setup buffers) */ { int scale_size; if( fr_ps->freq_div <= 0 ) fr_ps->freq_div = 1; fr_ps->sub_band_size = SBLIMIT / fr_ps->freq_div; ASM_init_decode( fr_ps->sub_band_size, fr_ps->output_8bits, fr_ps->quality ); if( !fr_ps->bs ) { fr_ps->bs = BSTR_open( fr_ps->bitstream_name, fr_ps->bitstream_buffer_size, BSTR_MODE_READ ); if( !fr_ps->bs ) { fprintf( stderr, "Can't open file '%s'\n", fr_ps->bitstream_name ); return 0; } } if( !MPEGA_seek_header( fr_ps ) ) return 0; /* Seek to start of bitstream */ if( !BSTR_rewind( fr_ps->bs ) ) return 0; fr_ps->out_sample_freq = fr_ps->bitstream_freq / fr_ps->freq_div; if( !MPEGA_init_out( fr_ps ) ) return 0; /* Initialize on first frame */ if( fr_ps->header->lay == 1 ) scale_size = SCALE_BLOCK; else if ( fr_ps->header->lay == 2 ) scale_size = 3 * SCALE_BLOCK; else return 0; fr_ps->out_write_level = fr_ps->out_buffer_size - scale_size * fr_ps->sub_band_size; fr_ps->got_bits = 0; fr_ps->frame_count = 0; fr_ps->out_write_length = 0; fr_ps->out_sample_length = 0; return 1; } int MPEGA_write_out( frame_params *fr_ps ) /*---------------------------------------- Write out_buffer to output media -> return written sample count */ { if( fr_ps->play ) return write_audio( fr_ps ); else return write_file( fr_ps ); } int MPEGA_decode_frame( frame_params *fr_ps ) /*------------------------------------------- Decode one MPEG Audio frame -> return 0 if frame can't be decoded or bitstream empty -> return out sample length decoded otherwise !!! length is not in byte, but in sample count (8 or 16 bits wide) */ { int sample_frame_length = 0; if( !MPEGA_seek_header( fr_ps ) ) return 0; switch( fr_ps->header->lay ) { case 1: { ASM_I_decode_bitalloc( fr_ps ); ASM_I_decode_scale( fr_ps ); if( fr_ps->mono_forced ) fr_ps->stereo = 1; ASM_I_decode_frame( fr_ps ); sample_frame_length = fr_ps->sub_band_size * SCALE_BLOCK; break; } case 2: { ASM_II_decode_bitalloc( fr_ps ); ASM_II_decode_scale( fr_ps ); if( fr_ps->mono_forced ) fr_ps->stereo = 1; ASM_II_decode_frame( fr_ps ); sample_frame_length = fr_ps->sub_band_size * 3 * SCALE_BLOCK; break; } } fr_ps->frame_count++; fr_ps->got_bits = BSTR_seek_tell( fr_ps->bs ); fr_ps->out_write_length += sample_frame_length; fr_ps->out_sample_length += sample_frame_length; return sample_frame_length; }