1 /*****************************************************************************
2 * a52.c: parse A/52 audio sync info and packetize the stream
3 *****************************************************************************
4 * Copyright (C) 2001-2002 the VideoLAN team
7 * Authors: Stéphane Borel <stef@via.ecp.fr>
8 * Christophe Massiot <massiot@via.ecp.fr>
9 * Gildas Bazin <gbazin@videolan.org>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
24 *****************************************************************************/
26 /*****************************************************************************
28 *****************************************************************************/
30 #include <vlc_codec.h>
32 #include <vlc_input.h>
33 #include <vlc_block_helper.h>
35 #define A52_HEADER_SIZE 7
37 /*****************************************************************************
38 * decoder_sys_t : decoder descriptor
39 *****************************************************************************/
43 vlc_bool_t b_packetizer;
50 block_bytestream_t bytestream;
55 audio_date_t end_date;
58 int i_frame_size, i_bit_rate;
59 unsigned int i_rate, i_channels, i_channels_conf;
74 /****************************************************************************
76 ****************************************************************************/
77 static int OpenDecoder ( vlc_object_t * );
78 static int OpenPacketizer( vlc_object_t * );
79 static void CloseDecoder ( vlc_object_t * );
80 static void *DecodeBlock ( decoder_t *, block_t ** );
82 static int SyncInfo ( const byte_t *, unsigned int *, unsigned int *,
83 unsigned int *, int * );
85 static uint8_t *GetOutBuffer ( decoder_t *, void ** );
86 static aout_buffer_t *GetAoutBuffer( decoder_t * );
87 static block_t *GetSoutBuffer( decoder_t * );
89 /*****************************************************************************
91 *****************************************************************************/
93 set_description( _("A/52 parser") );
94 set_capability( "decoder", 100 );
95 set_callbacks( OpenDecoder, CloseDecoder );
96 set_category( CAT_INPUT );
97 set_subcategory( SUBCAT_INPUT_ACODEC );
100 set_description( _("A/52 audio packetizer") );
101 set_capability( "packetizer", 10 );
102 set_callbacks( OpenPacketizer, CloseDecoder );
105 /*****************************************************************************
106 * OpenDecoder: probe the decoder and return score
107 *****************************************************************************/
108 static int OpenDecoder( vlc_object_t *p_this )
110 decoder_t *p_dec = (decoder_t*)p_this;
111 decoder_sys_t *p_sys;
113 if( p_dec->fmt_in.i_codec != VLC_FOURCC('a','5','2',' ')
114 && p_dec->fmt_in.i_codec != VLC_FOURCC('a','5','2','b') )
119 /* Allocate the memory needed to store the decoder's structure */
120 if( ( p_dec->p_sys = p_sys =
121 (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
123 msg_Err( p_dec, "out of memory" );
128 p_sys->b_packetizer = VLC_FALSE;
129 p_sys->i_state = STATE_NOSYNC;
130 aout_DateSet( &p_sys->end_date, 0 );
132 p_sys->bytestream = block_BytestreamInit( p_dec );
133 p_sys->i_input_rate = INPUT_RATE_DEFAULT;
135 /* Set output properties */
136 p_dec->fmt_out.i_cat = AUDIO_ES;
137 p_dec->fmt_out.i_codec = VLC_FOURCC('a','5','2',' ');
138 p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
141 p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
143 p_dec->pf_packetize = (block_t *(*)(decoder_t *, block_t **))
149 static int OpenPacketizer( vlc_object_t *p_this )
151 decoder_t *p_dec = (decoder_t*)p_this;
153 int i_ret = OpenDecoder( p_this );
155 if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = VLC_TRUE;
160 /****************************************************************************
161 * DecodeBlock: the whole thing
162 ****************************************************************************
163 * This function is called just after the thread is launched.
164 ****************************************************************************/
165 static void *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
167 decoder_sys_t *p_sys = p_dec->p_sys;
168 uint8_t p_header[A52_HEADER_SIZE];
172 if( !pp_block || !*pp_block ) return NULL;
174 if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
176 if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
178 p_sys->i_state = STATE_NOSYNC;
179 block_BytestreamFlush( &p_sys->bytestream );
181 // aout_DateSet( &p_sys->end_date, 0 );
182 block_Release( *pp_block );
186 if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
188 /* We've just started the stream, wait for the first PTS. */
189 block_Release( *pp_block );
193 if( (*pp_block)->i_rate > 0 )
194 p_sys->i_input_rate = (*pp_block)->i_rate;
196 block_BytestreamPush( &p_sys->bytestream, *pp_block );
200 switch( p_sys->i_state )
203 while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
206 if( p_header[0] == 0x0b && p_header[1] == 0x77 )
208 p_sys->i_state = STATE_SYNC;
211 block_SkipByte( &p_sys->bytestream );
213 if( p_sys->i_state != STATE_SYNC )
215 block_BytestreamFlush( &p_sys->bytestream );
222 /* New frame, set the Presentation Time Stamp */
223 p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
224 if( p_sys->i_pts != 0 &&
225 p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
227 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
229 p_sys->i_state = STATE_HEADER;
232 /* Get A/52 frame header (A52_HEADER_SIZE bytes) */
233 if( block_PeekBytes( &p_sys->bytestream, p_header,
234 A52_HEADER_SIZE ) != VLC_SUCCESS )
240 /* Check if frame is valid and get frame info */
241 p_sys->i_frame_size = SyncInfo( p_header,
243 &p_sys->i_channels_conf,
245 &p_sys->i_bit_rate );
246 if( !p_sys->i_frame_size )
248 msg_Dbg( p_dec, "emulated sync word" );
249 block_SkipByte( &p_sys->bytestream );
250 p_sys->i_state = STATE_NOSYNC;
253 p_sys->i_state = STATE_NEXT_SYNC;
255 case STATE_NEXT_SYNC:
256 /* TODO: If pp_block == NULL, flush the buffer without checking the
259 /* Check if next expected frame contains the sync word */
260 if( block_PeekOffsetBytes( &p_sys->bytestream,
261 p_sys->i_frame_size, p_header, 2 )
268 if( p_sys->b_packetizer &&
269 p_header[0] == 0 && p_header[1] == 0 )
271 /* A52 wav files and audio CD's use stuffing */
272 p_sys->i_state = STATE_GET_DATA;
276 if( p_header[0] != 0x0b || p_header[1] != 0x77 )
278 msg_Dbg( p_dec, "emulated sync word "
279 "(no sync on following frame)" );
280 p_sys->i_state = STATE_NOSYNC;
281 block_SkipByte( &p_sys->bytestream );
284 p_sys->i_state = STATE_SEND_DATA;
288 /* Make sure we have enough data.
289 * (Not useful if we went through NEXT_SYNC) */
290 if( block_WaitBytes( &p_sys->bytestream,
291 p_sys->i_frame_size ) != VLC_SUCCESS )
296 p_sys->i_state = STATE_SEND_DATA;
298 case STATE_SEND_DATA:
299 if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
301 //p_dec->b_error = VLC_TRUE;
305 /* Copy the whole frame into the buffer. When we reach this point
306 * we already know we have enough data available. */
307 block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
309 /* Make sure we don't reuse the same pts twice */
310 if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
311 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
313 /* So p_block doesn't get re-added several times */
314 *pp_block = block_BytestreamPop( &p_sys->bytestream );
316 p_sys->i_state = STATE_NOSYNC;
325 /*****************************************************************************
326 * CloseDecoder: clean up the decoder
327 *****************************************************************************/
328 static void CloseDecoder( vlc_object_t *p_this )
330 decoder_t *p_dec = (decoder_t*)p_this;
331 decoder_sys_t *p_sys = p_dec->p_sys;
333 block_BytestreamRelease( &p_sys->bytestream );
338 /*****************************************************************************
340 *****************************************************************************/
341 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
343 decoder_sys_t *p_sys = p_dec->p_sys;
346 if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
348 msg_Info( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",
349 p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
351 aout_DateInit( &p_sys->end_date, p_sys->i_rate );
352 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
355 p_dec->fmt_out.audio.i_rate = p_sys->i_rate;
356 p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
357 p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
358 p_dec->fmt_out.audio.i_frame_length = A52_FRAME_NB;
360 p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
361 p_dec->fmt_out.audio.i_physical_channels =
362 p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
364 p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate;
366 if( p_sys->b_packetizer )
368 block_t *p_sout_buffer = GetSoutBuffer( p_dec );
369 p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
370 *pp_out_buffer = p_sout_buffer;
374 aout_buffer_t *p_aout_buffer = GetAoutBuffer( p_dec );
375 p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
376 *pp_out_buffer = p_aout_buffer;
382 /*****************************************************************************
384 *****************************************************************************/
385 static aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
387 decoder_sys_t *p_sys = p_dec->p_sys;
388 aout_buffer_t *p_buf;
390 p_buf = p_dec->pf_aout_buffer_new( p_dec, A52_FRAME_NB );
391 if( p_buf == NULL ) return NULL;
393 p_buf->start_date = aout_DateGet( &p_sys->end_date );
394 p_buf->end_date = aout_DateIncrement( &p_sys->end_date,
395 A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT );
400 /*****************************************************************************
402 *****************************************************************************/
403 static block_t *GetSoutBuffer( decoder_t *p_dec )
405 decoder_sys_t *p_sys = p_dec->p_sys;
408 p_block = block_New( p_dec, p_sys->i_frame_size );
409 if( p_block == NULL ) return NULL;
411 p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
414 aout_DateIncrement( &p_sys->end_date,
415 A52_FRAME_NB * p_sys->i_input_rate / INPUT_RATE_DEFAULT ) -
421 /*****************************************************************************
422 * SyncInfo: parse A/52 sync info
423 *****************************************************************************
424 * This code is borrowed from liba52 by Aaron Holtzman & Michel Lespinasse,
425 * since we don't want to oblige S/PDIF people to use liba52 just to get
427 *****************************************************************************/
428 static int SyncInfo( const byte_t * p_buf,
429 unsigned int * pi_channels,
430 unsigned int * pi_channels_conf,
431 unsigned int * pi_sample_rate, int * pi_bit_rate )
433 static const uint8_t halfrate[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3 };
434 static const int rate[] = { 32, 40, 48, 56, 64, 80, 96, 112,
435 128, 160, 192, 224, 256, 320, 384, 448,
437 static const uint8_t lfeon[8] = { 0x10, 0x10, 0x04, 0x04,
438 0x04, 0x01, 0x04, 0x01 };
444 if ((p_buf[0] != 0x0b) || (p_buf[1] != 0x77)) /* syncword */
447 if (p_buf[5] >= 0x60) /* bsid >= 12 */
449 half = halfrate[p_buf[5] >> 3];
451 /* acmod, dsurmod and lfeon */
452 acmod = p_buf[6] >> 5;
453 if ( (p_buf[6] & 0xf8) == 0x50 )
455 /* Dolby surround = stereo + Dolby */
457 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
458 | AOUT_CHAN_DOLBYSTEREO;
460 else switch ( acmod )
463 /* Dual-mono = stereo + dual-mono */
465 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
466 | AOUT_CHAN_DUALMONO;
471 *pi_channels_conf = AOUT_CHAN_CENTER;
476 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
481 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
487 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
488 | AOUT_CHAN_REARCENTER;
493 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
494 | AOUT_CHAN_REARCENTER;
499 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
500 | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
505 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
506 | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
512 if ( p_buf[6] & lfeon[acmod] )
515 *pi_channels_conf |= AOUT_CHAN_LFE;
518 frmsizecod = p_buf[4] & 63;
519 if (frmsizecod >= 38)
521 bitrate = rate [frmsizecod >> 1];
522 *pi_bit_rate = (bitrate * 1000) >> half;
524 switch (p_buf[4] & 0xc0) {
526 *pi_sample_rate = 48000 >> half;
529 *pi_sample_rate = 44100 >> half;
530 return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
532 *pi_sample_rate = 32000 >> half;