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vdr/ac3dec/decode.c
2001-11-24 14:48:04 +01:00

313 lines
7.3 KiB
C

/*
* decode.c
*
* Copyright (C) Aaron Holtzman - May 1999
*
* This file is part of ac3dec, a free Dolby AC-3 stream decoder.
*
* ac3dec 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, or (at your option)
* any later version.
*
* ac3dec 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 GNU Make; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
*------------------------------------------------------------
*
* Thomas Mirlacher <dent@cosy.sbg.ac.at>
* added OMS support
* 11 Jan 2001
* Thomas Mirlacher <dent@cosy.sbg.ac.at>
* faster error response using jmp functions
*
* 9 Aug 2001
* Matjaz Thaler <matjaz.thaler@rd.iskraemeco.si>
* Added support for DVB-s PCI card
*
* 24 Nov 2001
* Andreas Schultz <aschultz@cs.uni-magdeburg.de>
* Added ac3_buffersize()
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/time.h>
#ifdef __OMS__
#include <oms/oms.h>
#include <oms/plugin/output_audio.h>
#endif
#include "ac3.h"
#include "ac3_internal.h"
#include "bitstream.h"
#include "downmix.h"
#include "srfft.h"
#include "imdct.h"
#include "exponent.h"
#include "coeff.h"
#include "bit_allocate.h"
#include "parse.h"
#include "crc.h"
#include "stats.h"
#include "rematrix.h"
#include "sanity_check.h"
#include "debug.h"
#ifndef __OMS__
//#include "audio_out.h"
#endif
//our global config structure
ac3_config_t ac3_config;
static audblk_t audblk;
static bsi_t bsi;
static syncinfo_t syncinfo;
#ifndef __OMS__
static uint32_t done_banner;
#endif
static uint32_t is_output_initialized = 0;
//the floating point samples for one audblk
static stream_samples_t samples;
//the integer samples for the entire frame (with enough space for 2 ch out)
//if this size change, be sure to change the size when muting
static int16_t s16_samples[2 * 6 * 256] __attribute__ ((aligned(16)));
// downmix stuff
static float cmixlev_lut[4] = { 0.707, 0.595, 0.500, 0.707 };
static float smixlev_lut[4] = { 0.707, 0.500, 0.0 , 0.500 };
static dm_par_t dm_par;
//Storage for the syncframe
#define BUFFER_MAX_SIZE 4096
static uint8_t buffer[BUFFER_MAX_SIZE];
static uint32_t buffer_size = 0;;
// for error handling
jmp_buf error_jmp_mark;
uint32_t ac3_buffersize()
{
return buffer_size;
}
static uint32_t decode_buffer_syncframe (syncinfo_t *syncinfo, uint8_t **start, uint8_t *end)
{
uint8_t *cur = *start;
uint16_t syncword = syncinfo->syncword;
uint32_t ret = 0;
// Find an ac3 sync frame.
while (syncword != 0x0b77) {
if (cur >= end)
goto done;
syncword = (syncword << 8) + *cur++;
}
//need the next 3 bytes to decide how big the frame is
while (buffer_size < 3) {
if(cur >= end)
goto done;
buffer[buffer_size++] = *cur++;
}
parse_syncinfo (syncinfo,buffer);
stats_print_syncinfo (syncinfo);
while (buffer_size < syncinfo->frame_size * 2 - 2) {
if(cur >= end)
goto done;
buffer[buffer_size++] = *cur++;
}
#if 0
// Check the crc over the entire frame
crc_init();
crc_process_frame (buffer, syncinfo->frame_size * 2 - 2);
if (!crc_validate()) {
fprintf(stderr,"** CRC failed - skipping frame **\n");
goto done;
}
#endif
//if we got to this point, we found a valid ac3 frame to decode
bitstream_init (buffer);
//get rid of the syncinfo struct as we already parsed it
bitstream_get (24);
//reset the syncword for next time
syncword = 0xffff;
buffer_size = 0;
ret = 1;
done:
syncinfo->syncword = syncword;
*start = cur;
return ret;
}
void inline decode_mute (void)
{
//mute the frame
memset (s16_samples, 0, sizeof(int16_t) * 256 * 2 * 6);
}
void ac3dec_init (void)
{
// FIXME - don't do that statically here
ac3_config.num_output_ch = 2;
ac3_config.flags = 0;
imdct_init ();
downmix_init ();
memset (&syncinfo, 0, sizeof (syncinfo));
memset (&bsi, 0, sizeof (bsi));
memset (&audblk, 0, sizeof (audblk));
sanity_check_init (&syncinfo,&bsi,&audblk);
}
#ifdef __OMS__
size_t ac3dec_decode_data (plugin_output_audio_t *output, uint8_t *data_start, uint8_t *data_end)
#else
size_t ac3dec_decode_data (uint8_t *data_start ,uint8_t *data_end, int ac3reset, int *input_pointer, int *output_pointer, char *ac3_data)
#endif
{
uint32_t i;
int datasize;
char *data;
if(ac3reset != 0){
syncinfo.syncword = 0xffff;
buffer_size = 0;
}
if (setjmp (error_jmp_mark) < 0) {
ac3dec_init ();
return 0;
}
while (decode_buffer_syncframe (&syncinfo, &data_start, data_end)) {
parse_bsi (&bsi);
#ifndef __OMS__
if(!done_banner) {
// stats_print_banner(&syncinfo,&bsi);
done_banner = 1;
}
#endif
// compute downmix parameters
// downmix to tow channels for now
dm_par.clev = 0.0; dm_par.slev = 0.0; dm_par.unit = 1.0;
if (bsi.acmod & 0x1) // have center
dm_par.clev = cmixlev_lut[bsi.cmixlev];
if (bsi.acmod & 0x4) // have surround channels
dm_par.slev = smixlev_lut[bsi.surmixlev];
dm_par.unit /= 1.0 + dm_par.clev + dm_par.slev;
dm_par.clev *= dm_par.unit;
dm_par.slev *= dm_par.unit;
for(i=0; i < 6; i++) {
//Initialize freq/time sample storage
memset (samples, 0, sizeof(float) * 256 * (bsi.nfchans + bsi.lfeon));
// Extract most of the audblk info from the bitstream
// (minus the mantissas
parse_audblk (&bsi,&audblk);
// Take the differential exponent data and turn it into
// absolute exponents
exponent_unpack (&bsi,&audblk);
// Figure out how many bits per mantissa
bit_allocate (syncinfo.fscod,&bsi,&audblk);
// Extract the mantissas from the stream and
// generate floating point frequency coefficients
coeff_unpack (&bsi,&audblk,samples);
if (bsi.acmod == 0x2)
rematrix (&audblk,samples);
// Convert the frequency samples into time samples
imdct (&bsi,&audblk,samples, &s16_samples[i * 2 * 256], &dm_par);
// Downmix into the requested number of channels
// and convert floating point to int16_t
// downmix(&bsi,samples,&s16_samples[i * 2 * 256]);
if (sanity_check(&syncinfo,&bsi,&audblk) < 0) {
HANDLE_ERROR ();
return 0;
}
continue;
}
if (!is_output_initialized) {
#ifdef __OMS__
plugin_output_audio_attr_t attr;
#ifdef __sun__
attr.format = 16;
#else
attr.format = AFMT_S16_NE;
#endif
attr.speed = syncinfo.sampling_rate;
attr.channels = 2;
// output->setup (&attr);
#else
// ao_functions->open (16, syncinfo.sampling_rate, 2);
#endif
is_output_initialized = 1;
}
#ifdef __OMS__
output->write (s16_samples, 256 * 6 * 2 * 2);
#else
// ao_functions->play(s16_samples, 256 * 6 * 2);
data = (char *)s16_samples;
datasize = 0;
while(datasize < 6144){
if(((*input_pointer+1) % AC3_BUFFER_SIZE) != *output_pointer){ // There is room in the sync_buffer
ac3_data[*input_pointer]=data[datasize];
datasize++;
*input_pointer = (*input_pointer+1) % AC3_BUFFER_SIZE;
}
else{
*input_pointer = *output_pointer = 0;
break;
}
}
#endif
}
decode_mute ();
return 0;
}