/***************************************************************************** * a52.c: A/52 basic parser ***************************************************************************** * Copyright (C) 2001-2002 VideoLAN * $Id: a52.c,v 1.19 2002/12/06 16:34:05 sam Exp $ * * Authors: St�phane Borel <stef@via.ecp.fr> * Christophe Massiot <massiot@via.ecp.fr> * Michel Lespinasse <walken@zoy.org> * Aaron Holtzman <aholtzma@ess.engr.uvic.ca> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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, USA. *****************************************************************************/ /***************************************************************************** * Preamble *****************************************************************************/ #include <stdio.h> #include <stdlib.h> #include <string.h> /* memcpy() */ #include <fcntl.h> #include <vlc/vlc.h> #include <vlc/decoder.h> #include <vlc/aout.h> #ifdef HAVE_UNISTD_H # include <unistd.h> #endif /***************************************************************************** * dec_thread_t : A52 pass-through thread descriptor *****************************************************************************/ typedef struct dec_thread_t { /* * Thread properties */ vlc_thread_t thread_id; /* id for thread functions */ /* * Input properties */ decoder_fifo_t * p_fifo; /* stores the PES stream data */ bit_stream_t bit_stream; /* * Output properties */ aout_instance_t * p_aout; /* opaque */ aout_input_t * p_aout_input; /* opaque */ audio_sample_format_t output_format; } dec_thread_t; /**************************************************************************** * Local prototypes ****************************************************************************/ static int OpenDecoder ( vlc_object_t * ); static int RunDecoder ( decoder_fifo_t * ); static void EndThread ( dec_thread_t * ); static int SyncInfo ( const byte_t *, int *, int *, int * ); /***************************************************************************** * Module descriptor *****************************************************************************/ vlc_module_begin(); set_description( _("A/52 parser") ); set_capability( "decoder", 100 ); set_callbacks( OpenDecoder, NULL ); vlc_module_end(); /***************************************************************************** * OpenDecoder: probe the decoder and return score *****************************************************************************/ static int OpenDecoder( vlc_object_t *p_this ) { decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this; if( p_fifo->i_fourcc != VLC_FOURCC('a','5','2',' ') && p_fifo->i_fourcc != VLC_FOURCC('a','5','2','b') ) { return VLC_EGENERIC; } p_fifo->pf_run = RunDecoder; return VLC_SUCCESS; } /**************************************************************************** * RunDecoder: the whole thing **************************************************************************** * This function is called just after the thread is launched. ****************************************************************************/ static int RunDecoder( decoder_fifo_t *p_fifo ) { dec_thread_t * p_dec; audio_date_t end_date; /* Allocate the memory needed to store the thread's structure */ p_dec = malloc( sizeof(dec_thread_t) ); if( p_dec == NULL ) { msg_Err( p_fifo, "out of memory" ); DecoderError( p_fifo ); return -1; } /* Initialize the thread properties */ p_dec->p_aout = NULL; p_dec->p_aout_input = NULL; p_dec->p_fifo = p_fifo; p_dec->output_format.i_format = VLC_FOURCC('a','5','2',' '); aout_DateSet( &end_date, 0 ); /* Init the bitstream */ if( InitBitstream( &p_dec->bit_stream, p_dec->p_fifo, NULL, NULL ) != VLC_SUCCESS ) { msg_Err( p_fifo, "cannot initialize bitstream" ); DecoderError( p_fifo ); free( p_dec ); return -1; } /* decoder thread's main loop */ while ( !p_dec->p_fifo->b_die && !p_dec->p_fifo->b_error ) { int i_bit_rate; unsigned int i_rate, i_original_channels, i_frame_size; mtime_t pts; byte_t p_header[7]; aout_buffer_t * p_buffer; /* Look for sync word - should be 0x0b77 */ RealignBits( &p_dec->bit_stream ); while ( (ShowBits( &p_dec->bit_stream, 16 ) ) != 0x0b77 && (!p_dec->p_fifo->b_die) && (!p_dec->p_fifo->b_error)) { RemoveBits( &p_dec->bit_stream, 8 ); } /* Set the Presentation Time Stamp */ NextPTS( &p_dec->bit_stream, &pts, NULL ); if ( pts != 0 && pts != aout_DateGet( &end_date ) ) { aout_DateSet( &end_date, pts ); } /* Get A/52 frame header */ GetChunk( &p_dec->bit_stream, p_header, 7 ); if( p_dec->p_fifo->b_die ) break; /* Check if frame is valid and get frame info */ i_frame_size = SyncInfo( p_header, &i_original_channels, &i_rate, &i_bit_rate ); if( !i_frame_size ) { msg_Warn( p_dec->p_fifo, "a52_syncinfo failed" ); continue; } if( (p_dec->p_aout_input != NULL) && ( (p_dec->output_format.i_rate != i_rate) || (p_dec->output_format.i_original_channels != i_original_channels) || (p_dec->output_format.i_bytes_per_frame != i_frame_size) ) ) { /* Parameters changed - this should not happen. */ aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input ); p_dec->p_aout_input = NULL; } /* Creating the audio input if not created yet. */ if( p_dec->p_aout_input == NULL ) { p_dec->output_format.i_rate = i_rate; p_dec->output_format.i_original_channels = i_original_channels; p_dec->output_format.i_physical_channels = i_original_channels & AOUT_CHAN_PHYSMASK; p_dec->output_format.i_bytes_per_frame = i_frame_size; p_dec->output_format.i_frame_length = A52_FRAME_NB; aout_DateInit( &end_date, i_rate ); p_dec->p_aout_input = aout_DecNew( p_dec->p_fifo, &p_dec->p_aout, &p_dec->output_format ); if ( p_dec->p_aout_input == NULL ) { p_dec->p_fifo->b_error = 1; break; } } if ( !aout_DateGet( &end_date ) ) { byte_t p_junk[3840]; /* We've just started the stream, wait for the first PTS. */ GetChunk( &p_dec->bit_stream, p_junk, i_frame_size - 7 ); continue; } p_buffer = aout_DecNewBuffer( p_dec->p_aout, p_dec->p_aout_input, A52_FRAME_NB ); if ( p_buffer == NULL ) return -1; p_buffer->start_date = aout_DateGet( &end_date ); p_buffer->end_date = aout_DateIncrement( &end_date, A52_FRAME_NB ); /* Get the whole frame. */ memcpy( p_buffer->p_buffer, p_header, 7 ); GetChunk( &p_dec->bit_stream, p_buffer->p_buffer + 7, i_frame_size - 7 ); if( p_dec->p_fifo->b_die ) { aout_DecDeleteBuffer( p_dec->p_aout, p_dec->p_aout_input, p_buffer ); break; } /* Send the buffer to the mixer. */ aout_DecPlay( p_dec->p_aout, p_dec->p_aout_input, p_buffer ); } /* If b_error is set, the spdif thread enters the error loop */ if( p_dec->p_fifo->b_error ) { DecoderError( p_dec->p_fifo ); } /* End of the spdif decoder thread */ EndThread( p_dec ); return 0; } /***************************************************************************** * EndThread : spdif thread destruction *****************************************************************************/ static void EndThread( dec_thread_t * p_dec ) { if ( p_dec->p_aout_input != NULL ) { aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input ); } CloseBitstream( &p_dec->bit_stream ); free( p_dec ); } /***************************************************************************** * SyncInfo: parse A52 sync info ***************************************************************************** * This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse, * since we don't want to oblige S/PDIF people to use liba52 just to get * their SyncInfo... *****************************************************************************/ static int SyncInfo( const byte_t * p_buf, int * pi_channels, int * pi_sample_rate, int * pi_bit_rate ) { static const uint8_t halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 }; static const int rate[] = { 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 576, 640 }; static const uint8_t lfeon[8] = { 0x10, 0x10, 0x04, 0x04, 0x04, 0x01, 0x04, 0x01 }; int frmsizecod; int bitrate; int half; int acmod; if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77)) /* syncword */ return 0; if (p_buf[5] >= 0x60) /* bsid >= 12 */ return 0; half = halfrate[p_buf[5] >> 3]; /* acmod, dsurmod and lfeon */ acmod = p_buf[6] >> 5; if ( (p_buf[6] & 0xf8) == 0x50 ) { /* Dolby surround = stereo + Dolby */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_DOLBYSTEREO; } else switch ( acmod ) { case 0x0: /* Dual-mono = stereo + dual-mono */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_DUALMONO; break; case 0x1: /* Mono */ *pi_channels = AOUT_CHAN_CENTER; break; case 0x2: /* Stereo */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT; break; case 0x3: /* 3F */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER; break; case 0x4: /* 2F1R */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER; break; case 0x5: /* 3F1R */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER | AOUT_CHAN_REARCENTER; break; case 0x6: /* 2F2R */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT; break; case 0x7: /* 3F2R */ *pi_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT; break; default: return 0; } if ( p_buf[6] & lfeon[acmod] ) *pi_channels |= AOUT_CHAN_LFE; frmsizecod = p_buf[4] & 63; if (frmsizecod >= 38) return 0; bitrate = rate [frmsizecod >> 1]; *pi_bit_rate = (bitrate * 1000) >> half; switch (p_buf[4] & 0xc0) { case 0: *pi_sample_rate = 48000 >> half; return 4 * bitrate; case 0x40: *pi_sample_rate = 44100 >> half; return 2 * (320 * bitrate / 147 + (frmsizecod & 1)); case 0x80: *pi_sample_rate = 32000 >> half; return 6 * bitrate; default: return 0; } }