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/*
* Copyright (C) 2000-2001 the xine project
*
* This file is part of xine, a unix video player.
*
* xine 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.
*
* xine 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
*
* $Id: xine_decoder.c,v 1.2 2001/05/26 15:07:18 guenter Exp $
*
* stuff needed to turn libac3 into a xine decoder plugin
*/
/*
* FIXME: libac3 uses global variables (that are written to)
*/
#include <stdlib.h>
#include "audio_out.h"
#include "ac3.h"
#include "buffer.h"
#include "xine_internal.h"
#define FRAME_SIZE 4096
typedef struct ac3dec_decoder_s {
audio_decoder_t audio_decoder;
uint32_t pts;
uint8_t frame_buffer[FRAME_SIZE];
uint8_t *frame_ptr;
int sync_todo;
int frame_length, frame_todo;
uint16_t syncword;
ao_functions_t *audio_out;
int output_sampling_rate;
int output_open;
} ac3dec_decoder_t;
int ac3dec_can_handle (audio_decoder_t *this_gen, int buf_type) {
return ((buf_type & 0xFFFF0000) == BUF_AUDIO_AC3) ;
}
void ac3dec_init (audio_decoder_t *this_gen, ao_functions_t *audio_out) {
ac3dec_decoder_t *this = (ac3dec_decoder_t *) this_gen;
this->audio_out = audio_out;
ac3_init ();
this->syncword = 0;
this->sync_todo = 6;
this->output_open = 0;
}
void ac3dec_decode_data (audio_decoder_t *this_gen, buf_element_t *buf) {
ac3dec_decoder_t *this = (ac3dec_decoder_t *) this_gen;
uint8_t *current = buf->content;
uint8_t *end = buf->content + buf->size;
ac3_frame_t *ac3_frame;
int sampling_rate;
uint8_t byte;
this->pts = buf->PTS;
while (current != end) {
while (1) {
byte = *current++;
if (this->sync_todo>0) {
/* search and collect syncinfo */
if (this->syncword != 0x0b77) {
this->syncword = (this->syncword << 8) | byte;
if (this->syncword == 0x0b77) {
this->frame_buffer[0] = 0x0b;
this->frame_buffer[1] = 0x77;
this->sync_todo = 4;
this->frame_ptr = this->frame_buffer+2;
}
} else {
*this->frame_ptr++ = byte;
this->sync_todo--;
if (this->sync_todo==0) {
this->frame_length = ac3_frame_length (this->frame_buffer);
this->frame_todo = this->frame_length - 6;
}
}
} else {
*this->frame_ptr++ = byte;
this->frame_todo--;
if (this->frame_todo == 0)
break;
}
if (current == end)
return ;
}
/* now, decode this frame */
ac3_frame = ac3_decode_frame (this->frame_buffer);
/* output audio */
if (!this->output_open
|| (ac3_frame->sampling_rate != this->output_sampling_rate) ) {
if (this->output_open)
this->audio_out->close (this->audio_out);
this->output_open = (this->audio_out->open (this->audio_out, 16,
ac3_frame->sampling_rate,
AO_CAP_MODE_STEREO) == 1);
this->output_sampling_rate = ac3_frame->sampling_rate;
}
if (this->output_open) {
this->audio_out->write_audio_data (this->audio_out,
ac3_frame->audio_data,
256*6,
this->pts);
this->pts = 0;
}
/* done with frame, prepare for next one */
this->syncword = 0;
this->sync_todo = 6;
}
}
void ac3dec_close (audio_decoder_t *this_gen) {
ac3dec_decoder_t *this = (ac3dec_decoder_t *) this_gen;
if (this->output_open)
this->audio_out->close (this->audio_out);
}
static char *ac3dec_get_id(void) {
return "ac3dec";
}
audio_decoder_t *init_audio_decoder_plugin (int iface_version, config_values_t *cfg) {
ac3dec_decoder_t *this ;
if (iface_version != 1)
return NULL;
this = (ac3dec_decoder_t *) malloc (sizeof (ac3dec_decoder_t));
this->audio_decoder.interface_version = 1;
this->audio_decoder.can_handle = ac3dec_can_handle;
this->audio_decoder.init = ac3dec_init;
this->audio_decoder.decode_data = ac3dec_decode_data;
this->audio_decoder.close = ac3dec_close;
this->audio_decoder.get_identifier = ac3dec_get_id;
return (audio_decoder_t *) this;
}
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