1 /*****************************************************************************
2 * a52.c: A/52 basic parser
3 *****************************************************************************
4 * Copyright (C) 2001-2002 VideoLAN
5 * $Id: a52.c,v 1.14 2002/09/30 21:32:32 massiot Exp $
7 * Authors: Stéphane Borel <stef@via.ecp.fr>
8 * Christophe Massiot <massiot@via.ecp.fr>
9 * Michel Lespinasse <walken@zoy.org>
10 * Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
25 *****************************************************************************/
27 /*****************************************************************************
29 *****************************************************************************/
32 #include <string.h> /* memcpy() */
36 #include <vlc/decoder.h>
43 #define A52_FRAME_NB 1536
45 /*****************************************************************************
46 * dec_thread_t : A52 pass-through thread descriptor
47 *****************************************************************************/
48 typedef struct dec_thread_t
53 vlc_thread_t thread_id; /* id for thread functions */
58 decoder_fifo_t * p_fifo; /* stores the PES stream data */
59 bit_stream_t bit_stream;
64 aout_instance_t * p_aout; /* opaque */
65 aout_input_t * p_aout_input; /* opaque */
66 audio_sample_format_t output_format;
69 /****************************************************************************
71 ****************************************************************************/
72 static int OpenDecoder ( vlc_object_t * );
73 static int RunDecoder ( decoder_fifo_t * );
75 static void EndThread ( dec_thread_t * );
77 static int SyncInfo ( const byte_t *, int *, int *, int * );
79 /*****************************************************************************
81 *****************************************************************************/
83 set_description( _("A/52 parser") );
84 set_capability( "decoder", 100 );
85 set_callbacks( OpenDecoder, NULL );
88 /*****************************************************************************
89 * OpenDecoder: probe the decoder and return score
90 *****************************************************************************/
91 static int OpenDecoder( vlc_object_t *p_this )
93 decoder_fifo_t *p_fifo = (decoder_fifo_t*) p_this;
95 if( p_fifo->i_fourcc != VLC_FOURCC('a','5','2',' ')
96 && p_fifo->i_fourcc != VLC_FOURCC('a','5','2','b') )
101 p_fifo->pf_run = RunDecoder;
105 /****************************************************************************
106 * RunDecoder: the whole thing
107 ****************************************************************************
108 * This function is called just after the thread is launched.
109 ****************************************************************************/
110 static int RunDecoder( decoder_fifo_t *p_fifo )
112 dec_thread_t * p_dec;
113 audio_date_t end_date;
115 /* Allocate the memory needed to store the thread's structure */
116 p_dec = malloc( sizeof(dec_thread_t) );
119 msg_Err( p_fifo, "out of memory" );
120 DecoderError( p_fifo );
124 /* Initialize the thread properties */
125 p_dec->p_aout = NULL;
126 p_dec->p_aout_input = NULL;
127 p_dec->p_fifo = p_fifo;
128 p_dec->output_format.i_format = VLC_FOURCC('a','5','2',' ');
130 /* Init the bitstream */
131 InitBitstream( &p_dec->bit_stream, p_dec->p_fifo,
134 /* decoder thread's main loop */
135 while ( !p_dec->p_fifo->b_die && !p_dec->p_fifo->b_error )
137 int i_frame_size, i_channels, i_rate, i_bit_rate;
140 aout_buffer_t * p_buffer;
142 /* Look for sync word - should be 0x0b77 */
143 RealignBits( &p_dec->bit_stream );
144 while ( (ShowBits( &p_dec->bit_stream, 16 ) ) != 0x0b77 &&
145 (!p_dec->p_fifo->b_die) && (!p_dec->p_fifo->b_error))
147 RemoveBits( &p_dec->bit_stream, 8 );
150 /* Set the Presentation Time Stamp */
151 NextPTS( &p_dec->bit_stream, &pts, NULL );
152 if ( pts != 0 && pts != aout_DateGet( &end_date ) )
154 aout_DateSet( &end_date, pts );
157 /* Get A/52 frame header */
158 GetChunk( &p_dec->bit_stream, p_header, 7 );
159 if( p_dec->p_fifo->b_die ) break;
161 /* Check if frame is valid and get frame info */
162 i_frame_size = SyncInfo( p_header, &i_channels, &i_rate,
167 msg_Warn( p_dec->p_fifo, "a52_syncinfo failed" );
171 if( (p_dec->p_aout_input != NULL) &&
172 ( (p_dec->output_format.i_rate != i_rate)
173 || (p_dec->output_format.i_channels != i_channels)
174 || (p_dec->output_format.i_bytes_per_frame != i_frame_size) ) )
176 /* Parameters changed - this should not happen. */
177 aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
178 p_dec->p_aout_input = NULL;
181 /* Creating the audio input if not created yet. */
182 if( p_dec->p_aout_input == NULL )
184 p_dec->output_format.i_rate = i_rate;
185 p_dec->output_format.i_channels = i_channels;
186 p_dec->output_format.i_bytes_per_frame = i_frame_size;
187 p_dec->output_format.i_frame_length = A52_FRAME_NB;
188 aout_DateInit( &end_date, i_rate );
189 p_dec->p_aout_input = aout_DecNew( p_dec->p_fifo,
191 &p_dec->output_format );
193 if ( p_dec->p_aout_input == NULL )
195 p_dec->p_fifo->b_error = 1;
200 if ( !aout_DateGet( &end_date ) )
204 /* We've just started the stream, wait for the first PTS. */
205 GetChunk( &p_dec->bit_stream, p_junk, i_frame_size - 7 );
209 p_buffer = aout_DecNewBuffer( p_dec->p_aout, p_dec->p_aout_input,
211 if ( p_buffer == NULL ) return -1;
212 p_buffer->start_date = aout_DateGet( &end_date );
213 p_buffer->end_date = aout_DateIncrement( &end_date,
216 /* Get the whole frame. */
217 memcpy( p_buffer->p_buffer, p_header, 7 );
218 GetChunk( &p_dec->bit_stream, p_buffer->p_buffer + 7,
220 if( p_dec->p_fifo->b_die )
222 aout_DecDeleteBuffer( p_dec->p_aout, p_dec->p_aout_input,
227 /* Send the buffer to the mixer. */
228 aout_DecPlay( p_dec->p_aout, p_dec->p_aout_input, p_buffer );
231 /* If b_error is set, the spdif thread enters the error loop */
232 if( p_dec->p_fifo->b_error )
234 DecoderError( p_dec->p_fifo );
237 /* End of the spdif decoder thread */
243 /*****************************************************************************
244 * EndThread : spdif thread destruction
245 *****************************************************************************/
246 static void EndThread( dec_thread_t * p_dec )
248 if ( p_dec->p_aout_input != NULL )
250 aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
256 /****************************************************************************
257 * SyncInfo: parse A52 sync info
258 ****************************************************************************
259 * This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
260 * since we don't want to oblige S/PDIF people to use liba52 just to get
262 ****************************************************************************/
263 int SyncInfo( const byte_t * p_buf, int * pi_channels, int * pi_sample_rate,
266 static const u8 halfrate[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3};
267 static const int rate[] = { 32, 40, 48, 56, 64, 80, 96, 112,
268 128, 160, 192, 224, 256, 320, 384, 448,
270 static const u8 lfeon[8] = {0x10, 0x10, 0x04, 0x04, 0x04, 0x01, 0x04, 0x01};
276 if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77)) /* syncword */
279 if (p_buf[5] >= 0x60) /* bsid >= 12 */
281 half = halfrate[p_buf[5] >> 3];
283 /* acmod, dsurmod and lfeon */
284 acmod = p_buf[6] >> 5;
285 if ( p_buf[6] & 0xf8 )
287 *pi_channels = AOUT_CHAN_DOLBY;
289 else switch ( acmod )
291 case 0x0: *pi_channels = AOUT_CHAN_CHANNEL; break;
292 case 0x1: *pi_channels = AOUT_CHAN_MONO; break;
293 case 0x2: *pi_channels = AOUT_CHAN_STEREO; break;
294 case 0x3: *pi_channels = AOUT_CHAN_3F; break;
295 case 0x4: *pi_channels = AOUT_CHAN_2F1R; break;
296 case 0x5: *pi_channels = AOUT_CHAN_3F1R; break;
297 case 0x6: *pi_channels = AOUT_CHAN_2F2R; break;
298 case 0x7: *pi_channels = AOUT_CHAN_3F2R; break;
299 case 0x8: *pi_channels = AOUT_CHAN_CHANNEL1; break;
300 case 0x9: *pi_channels = AOUT_CHAN_CHANNEL2; break;
303 if ( p_buf[6] & lfeon[acmod] ) *pi_channels |= AOUT_CHAN_LFE;
305 frmsizecod = p_buf[4] & 63;
306 if (frmsizecod >= 38)
308 bitrate = rate [frmsizecod >> 1];
309 *pi_bit_rate = (bitrate * 1000) >> half;
311 switch (p_buf[4] & 0xc0) {
313 *pi_sample_rate = 48000 >> half;
316 *pi_sample_rate = 44100 >> half;
317 return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
319 *pi_sample_rate = 32000 >> half;