--- /dev/null
+/*****************************************************************************
+ * a52.c: ATSC A/52 aka AC-3 decoder plugin for vlc.
+ * This plugin makes use of liba52 to decode A/52 audio
+ * (http://liba52.sf.net/).
+ *****************************************************************************
+ * Copyright (C) 2001 VideoLAN
+ * $Id: a52.c,v 1.1 2002/02/06 20:44:22 gbazin Exp $
+ *
+ * Authors: Gildas Bazin <gbazin@netcourrier.com>
+ *
+ * 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 <stdlib.h> /* malloc(), free() */
+#include <string.h> /* strdup() */
+
+#include <videolan/vlc.h>
+
+#include "audio_output.h"
+
+#include "stream_control.h"
+#include "input_ext-dec.h"
+
+#include "debug.h"
+
+#include <a52dec/a52.h> /* liba52 header file */
+#include "a52.h"
+
+#define AC3DEC_FRAME_SIZE 1536
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+static int decoder_Probe ( probedata_t * );
+static int decoder_Run ( decoder_config_t * );
+static int DecodeFrame ( a52_adec_thread_t * );
+static int InitThread ( a52_adec_thread_t * );
+static void EndThread ( a52_adec_thread_t * );
+
+static void BitstreamCallback ( bit_stream_t *, boolean_t );
+static void float2s16_2 ( float *, int16_t * );
+static __inline__ int16_t convert ( int32_t );
+
+/*****************************************************************************
+ * Capabilities
+ *****************************************************************************/
+void _M( adec_getfunctions )( function_list_t * p_function_list )
+{
+ p_function_list->pf_probe = decoder_Probe;
+ p_function_list->functions.dec.pf_run = decoder_Run;
+}
+
+/*****************************************************************************
+ * Build configuration tree.
+ *****************************************************************************/
+MODULE_CONFIG_START
+MODULE_CONFIG_STOP
+
+MODULE_INIT_START
+ SET_DESCRIPTION( "a52 ATSC A/52 aka AC-3 audio decoder plugin" )
+ ADD_CAPABILITY( DECODER, 40 )
+ ADD_SHORTCUT( "a52" )
+MODULE_INIT_STOP
+
+MODULE_ACTIVATE_START
+ _M( adec_getfunctions )( &p_module->p_functions->dec );
+MODULE_ACTIVATE_STOP
+
+MODULE_DEACTIVATE_START
+MODULE_DEACTIVATE_STOP
+
+/*****************************************************************************
+ * decoder_Probe: probe the decoder and return score
+ *****************************************************************************
+ * Tries to launch a decoder and return score so that the interface is able
+ * to choose.
+ *****************************************************************************/
+static int decoder_Probe( probedata_t *p_data )
+{
+ return ( p_data->i_type == AC3_AUDIO_ES );
+}
+
+/*****************************************************************************
+ * decoder_Run: this function is called just after the thread is created
+ *****************************************************************************/
+static int decoder_Run ( decoder_config_t *p_config )
+{
+ a52_adec_thread_t *p_a52_adec;
+
+ /* Allocate the memory needed to store the thread's structure */
+ p_a52_adec =
+ (a52_adec_thread_t *)malloc( sizeof(a52_adec_thread_t) );
+ if (p_a52_adec == NULL)
+ {
+ intf_ErrMsg ( "a52 error: not enough memory "
+ "for decoder_Run() to allocate p_a52_adec" );
+ DecoderError( p_config->p_decoder_fifo );
+ return( -1 );
+ }
+
+ /* FIXME */
+ p_a52_adec->i_channels = 2;
+
+ /*
+ * Initialize the thread properties
+ */
+ p_a52_adec->p_config = p_config;
+ p_a52_adec->p_fifo = p_a52_adec->p_config->p_decoder_fifo;
+ if( InitThread( p_a52_adec ) )
+ {
+ intf_ErrMsg( "a52 error: could not initialize thread" );
+ DecoderError( p_config->p_decoder_fifo );
+ free( p_a52_adec );
+ return( -1 );
+ }
+
+ /* liba52 decoder thread's main loop */
+ while( !p_a52_adec->p_fifo->b_die && !p_a52_adec->p_fifo->b_error )
+ {
+
+ /* look for sync word - should be 0x0b77 */
+ RealignBits(&p_a52_adec->bit_stream);
+ while( (ShowBits( &p_a52_adec->bit_stream, 16 ) ) != 0x0b77 &&
+ (!p_a52_adec->p_fifo->b_die) && (!p_a52_adec->p_fifo->b_error))
+ {
+ RemoveBits( &p_a52_adec->bit_stream, 8 );
+ }
+
+ /* get a52 frame header */
+ GetChunk( &p_a52_adec->bit_stream, p_a52_adec->p_frame_buffer, 7 );
+
+ /* check if frame is valid and get frame info */
+ p_a52_adec->frame_size = a52_syncinfo( p_a52_adec->p_frame_buffer,
+ &p_a52_adec->flags,
+ &p_a52_adec->sample_rate,
+ &p_a52_adec->bit_rate );
+
+ if( !p_a52_adec->frame_size )
+ {
+ intf_WarnMsg( 3, "a52: a52_syncinfo failed" );
+ continue;
+ }
+
+ if( DecodeFrame( p_a52_adec ) )
+ {
+ DecoderError( p_config->p_decoder_fifo );
+ free( p_a52_adec );
+ return( -1 );
+ }
+
+ }
+
+ /* If b_error is set, the decoder thread enters the error loop */
+ if( p_a52_adec->p_fifo->b_error )
+ {
+ DecoderError( p_a52_adec->p_fifo );
+ }
+
+ /* End of the liba52 decoder thread */
+ EndThread( p_a52_adec );
+
+ return( 0 );
+}
+
+/*****************************************************************************
+ * InitThread: initialize data before entering main loop
+ *****************************************************************************/
+static int InitThread( a52_adec_thread_t * p_a52_adec )
+{
+ intf_WarnMsg( 3, "a52: InitThread" );
+
+ /* Initialize liba52 */
+ p_a52_adec->p_decoded_samples = a52_init( 0 );
+ if( p_a52_adec->p_decoded_samples == NULL )
+ {
+ intf_ErrMsg ( "a52 error: InitThread() unable to initialize "
+ "liba52" );
+ return -1;
+ }
+
+ /* Init the BitStream */
+ InitBitstream( &p_a52_adec->bit_stream,
+ p_a52_adec->p_fifo,
+ BitstreamCallback, NULL );
+
+ return( 0 );
+}
+
+/*****************************************************************************
+ * DecodeFrame: decodes an ATSC A/52 frame.
+ *****************************************************************************/
+static int DecodeFrame( a52_adec_thread_t * p_a52_adec )
+{
+ sample_t sample_level = 1;
+ byte_t *p_buffer;
+ int i;
+
+ if( ( p_a52_adec->p_aout_fifo != NULL ) &&
+ ( p_a52_adec->p_aout_fifo->l_rate != p_a52_adec->sample_rate ) )
+ {
+ /* Make sure the output thread leaves the NextFrame() function */
+ vlc_mutex_lock (&(p_a52_adec->p_aout_fifo->data_lock));
+ aout_DestroyFifo (p_a52_adec->p_aout_fifo);
+ vlc_cond_signal (&(p_a52_adec->p_aout_fifo->data_wait));
+ vlc_mutex_unlock (&(p_a52_adec->p_aout_fifo->data_lock));
+
+ p_a52_adec->p_aout_fifo = NULL;
+ }
+
+ /* Creating the audio output fifo if not created yet */
+ if (p_a52_adec->p_aout_fifo == NULL )
+ {
+ p_a52_adec->p_aout_fifo = aout_CreateFifo( AOUT_ADEC_STEREO_FIFO,
+ p_a52_adec->i_channels,
+ p_a52_adec->sample_rate, 0,
+ AC3DEC_FRAME_SIZE * p_a52_adec->i_channels,
+ NULL );
+
+ if ( p_a52_adec->p_aout_fifo == NULL )
+ {
+ return( -1 );
+ }
+ }
+
+ /* Set the Presentation Time Stamp */
+ CurrentPTS( &p_a52_adec->bit_stream,
+ &p_a52_adec->p_aout_fifo->date[
+ p_a52_adec->p_aout_fifo->l_end_frame],
+ NULL );
+
+ if( !p_a52_adec->p_aout_fifo->date[
+ p_a52_adec->p_aout_fifo->l_end_frame] )
+ {
+ p_a52_adec->p_aout_fifo->date[
+ p_a52_adec->p_aout_fifo->l_end_frame] = LAST_MDATE;
+ }
+
+
+
+ p_buffer = ((byte_t *)p_a52_adec->p_aout_fifo->buffer) +
+ ( p_a52_adec->p_aout_fifo->l_end_frame * AC3DEC_FRAME_SIZE *
+ p_a52_adec->i_channels * sizeof(s16) );
+
+ /* FIXME */
+ p_a52_adec->flags = A52_STEREO | A52_ADJUST_LEVEL;
+
+ /* Get the complete frame */
+ GetChunk( &p_a52_adec->bit_stream, p_a52_adec->p_frame_buffer + 7,
+ p_a52_adec->frame_size - 7 );
+
+ /* do the actual decoding now */
+ a52_frame( &p_a52_adec->a52_state, p_a52_adec->p_frame_buffer,
+ &p_a52_adec->flags, &sample_level, 384 );
+
+ for( i = 0; i < 6; i++ )
+ {
+ if( a52_block(&p_a52_adec->a52_state, p_a52_adec->p_decoded_samples) )
+ intf_WarnMsg( 5, "a52: a52_block failed for block %i", i );
+
+ float2s16_2( p_a52_adec->p_decoded_samples,
+ ((int16_t *)p_buffer) + i * 256 * p_a52_adec->i_channels );
+ }
+
+
+ vlc_mutex_lock( &p_a52_adec->p_aout_fifo->data_lock );
+ p_a52_adec->p_aout_fifo->l_end_frame =
+ (p_a52_adec->p_aout_fifo->l_end_frame + 1) & AOUT_FIFO_SIZE;
+ vlc_cond_signal (&p_a52_adec->p_aout_fifo->data_wait);
+ vlc_mutex_unlock (&p_a52_adec->p_aout_fifo->data_lock);
+
+ return 0;
+}
+
+/*****************************************************************************
+ * EndThread : liba52 decoder thread destruction
+ *****************************************************************************/
+static void EndThread (a52_adec_thread_t *p_a52_adec)
+{
+ intf_WarnMsg ( 3, "a52: EndThread" );
+
+ /* If the audio output fifo was created, we destroy it */
+ if (p_a52_adec->p_aout_fifo != NULL)
+ {
+ aout_DestroyFifo (p_a52_adec->p_aout_fifo);
+
+ /* Make sure the output thread leaves the NextFrame() function */
+ vlc_mutex_lock (&(p_a52_adec->p_aout_fifo->data_lock));
+ vlc_cond_signal (&(p_a52_adec->p_aout_fifo->data_wait));
+ vlc_mutex_unlock (&(p_a52_adec->p_aout_fifo->data_lock));
+ }
+
+ free( p_a52_adec );
+
+}
+
+/*****************************************************************************
+ * float2s16_2 : converts floats to ints using a trick based on the IEEE
+ * floating-point format
+ *****************************************************************************/
+static __inline__ int16_t convert (int32_t i)
+{
+ if (i > 0x43c07fff)
+ return 32767;
+ else if (i < 0x43bf8000)
+ return -32768;
+ else
+ return i - 0x43c00000;
+}
+
+static void float2s16_2 (float * _f, int16_t * s16)
+{
+ int i;
+ int32_t * f = (int32_t *) _f;
+
+ for (i = 0; i < 256; i++) {
+ s16[2*i] = convert (f[i]);
+ s16[2*i+1] = convert (f[i+256]);
+ }
+}
+
+/*****************************************************************************
+ * BitstreamCallback: Import parameters from the new data/PES packet
+ *****************************************************************************
+ * This function is called by input's NextDataPacket.
+ *****************************************************************************/
+static void BitstreamCallback ( bit_stream_t * p_bit_stream,
+ boolean_t b_new_pes )
+{
+ if( b_new_pes )
+ {
+ /* Drop special AC3 header */
+ p_bit_stream->p_byte += 3;
+ }
+}
projects / vlc / commitdiff