git.sesse.net Git - vlc/blob - modules/codec/lpcm.c

   1 /*****************************************************************************
   2  * lpcm.c: lpcm decoder module
   3  *****************************************************************************
   4  * Copyright (C) 1999-2001 VideoLAN
   5  * $Id: lpcm.c,v 1.17 2003/09/02 20:19:25 gbazin Exp $
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   8  *          Henri Fallon <henri@videolan.org>
   9  *          Christophe Massiot <massiot@via.ecp.fr>
  10  *
  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.
  15  *
  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.
  20  *
  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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29 #include <stdlib.h>                                      /* malloc(), free() */
  30 #include <string.h>                                    /* memcpy(), memset() */
  31
  32 #include <vlc/vlc.h>
  33 #include <vlc/aout.h>
  34 #include <vlc/decoder.h>
  35 #include <input_ext-dec.h>
  36
  37 #ifdef HAVE_UNISTD_H
  38 #   include <unistd.h>                                           /* getpid() */
  39 #endif
  40
  41 /*****************************************************************************
  42  * dec_thread_t : lpcm decoder thread descriptor
  43  *****************************************************************************/
  44 typedef struct dec_thread_t
  45 {
  46     /*
  47      * Input properties
  48      */
  49     decoder_fifo_t *    p_fifo;                /* stores the PES stream data */
  50     /* Some filters don't handle well too small buffers (coreaudio resampler).
  51      * Thus an aout buffer will be two PES packets. */
  52     pes_packet_t *      p_buffered_pes;
  53     data_packet_t *     p_buffered_data;
  54     size_t              i_buffered_size;
  55
  56     /*
  57      * Output properties
  58      */
  59     aout_instance_t        *p_aout;
  60     aout_input_t           *p_aout_input;
  61     audio_sample_format_t   output_format;
  62     audio_date_t            end_date;
  63 } dec_thread_t;
  64
  65 /*
  66  * LPCM header :
  67  * - PES header
  68  * - private stream ID (16 bits) == 0xA0 -> not in the bitstream
  69  * - frame number (8 bits)
  70  * - unknown (16 bits) == 0x0003 ?
  71  * - unknown (4 bits)
  72  * - current frame (4 bits)
  73  * - unknown (2 bits)
  74  * - frequency (2 bits) 0 == 48 kHz, 1 == 32 kHz, 2 == ?, 3 == ?
  75  * - unknown (1 bit)
  76  * - number of channels - 1 (3 bits) 1 == 2 channels
  77  * - start code (8 bits) == 0x80
  78  */
  79
  80 #define LPCM_HEADER_LEN 6
  81
  82 /*****************************************************************************
  83  * Local prototypes
  84  *****************************************************************************/
  85 static int  OpenDecoder    ( vlc_object_t * );
  86 static int  RunDecoder     ( decoder_fifo_t * );
  87
  88 static void DecodeFrame    ( dec_thread_t * );
  89 static void EndThread      ( dec_thread_t * );
  90
  91 /*****************************************************************************
  92  * Module descriptor
  93  *****************************************************************************/
  94 vlc_module_begin();
  95     set_description( _("linear PCM audio parser") );
  96     set_capability( "decoder", 100 );
  97     set_callbacks( OpenDecoder, NULL );
  98 vlc_module_end();
  99
 100 /*****************************************************************************
 101  * OpenDecoder: probe the decoder and return score
 102  *****************************************************************************/
 103 static int OpenDecoder( vlc_object_t *p_this )
 104 {
 105     decoder_t *p_dec = (decoder_t*)p_this;
 106
 107     if( p_dec->p_fifo->i_fourcc != VLC_FOURCC('l','p','c','m')
 108          && p_dec->p_fifo->i_fourcc != VLC_FOURCC('l','p','c','b') )
 109     {
 110         return VLC_EGENERIC;
 111     }
 112
 113     p_dec->pf_run = RunDecoder;
 114     return VLC_SUCCESS;
 115 }
 116
 117 /*****************************************************************************
 118  * RunDecoder: the lpcm decoder
 119  *****************************************************************************/
 120 static int RunDecoder( decoder_fifo_t * p_fifo )
 121 {
 122     dec_thread_t *   p_dec;
 123
 124     /* Allocate the memory needed to store the thread's structure */
 125     if( (p_dec = (dec_thread_t *)malloc( sizeof(dec_thread_t)) )
 126             == NULL)
 127     {
 128         msg_Err( p_fifo, "out of memory" );
 129         DecoderError( p_fifo );
 130         return -1;
 131     }
 132
 133     /* Initialize the thread properties */
 134     p_dec->p_fifo = p_fifo;
 135     p_dec->i_buffered_size = 0;
 136
 137     p_dec->output_format.i_format = VLC_FOURCC('s','1','6','b');
 138     p_dec->p_aout = NULL;
 139     p_dec->p_aout_input = NULL;
 140
 141     /* LPCM decoder thread's main loop */
 142     while ( (!p_dec->p_fifo->b_die) && (!p_dec->p_fifo->b_error) )
 143     {
 144         DecodeFrame(p_dec);
 145     }
 146
 147     /* If b_error is set, the lpcm decoder thread enters the error loop */
 148     if ( p_dec->p_fifo->b_error )
 149     {
 150         DecoderError( p_dec->p_fifo );
 151     }
 152
 153     /* End of the lpcm decoder thread */
 154     EndThread( p_dec );
 155
 156     return 0;
 157 }
 158
 159 /*****************************************************************************
 160  * DecodeFrame: decodes a frame.
 161  *****************************************************************************/
 162 static void DecodeFrame( dec_thread_t * p_dec )
 163 {
 164     pes_packet_t *     p_pes;
 165     data_packet_t *    p_data;
 166     aout_buffer_t *    p_buffer;
 167     void *             p_dest;
 168     mtime_t            i_pts;
 169     uint8_t            i_header;
 170     unsigned int       i_rate = 0, i_original_channels = 0, i_size;
 171     int                i;
 172
 173     input_ExtractPES( p_dec->p_fifo, &p_pes );
 174     if ( !p_pes )
 175     {
 176         p_dec->p_fifo->b_error = 1;
 177         return;
 178     }
 179
 180     /* Compute the size of the PES - i_pes_size includes the PES header. */
 181     p_data = p_pes->p_first;
 182     i_size = 0;
 183     while ( p_data != NULL )
 184     {
 185         i_size += p_data->p_payload_end - p_data->p_payload_start;
 186         p_data = p_data->p_next;
 187     }
 188     if ( i_size < LPCM_HEADER_LEN )
 189     {
 190         msg_Err(p_dec->p_fifo, "PES packet is too short");
 191         input_DeletePES( p_dec->p_fifo->p_packets_mgt, p_pes );
 192         return;
 193     }
 194
 195     i_pts = p_pes->i_pts;
 196     if( i_pts != 0 && i_pts != aout_DateGet( &p_dec->end_date ) )
 197     {
 198         aout_DateSet( &p_dec->end_date, i_pts );
 199     }
 200
 201     p_data = p_pes->p_first;
 202     /* It necessarily contains one byte. */
 203     /* Get LPCM header. */
 204
 205     /* Drop the first four bytes. */
 206     for ( i = 0; i < 4; i++ )
 207     {
 208         if ( p_data->p_payload_end == p_data->p_payload_start )
 209         {
 210             p_data = p_data->p_next;
 211         }
 212         p_data->p_payload_start++;
 213     }
 214
 215     i_header = p_data->p_payload_start[0];
 216     p_data->p_payload_start++;
 217
 218     switch ( (i_header >> 4) & 0x3 )
 219     {
 220     case 0:
 221         i_rate = 48000;
 222         break;
 223     case 1:
 224         i_rate = 96000;
 225         break;
 226     case 2:
 227         i_rate = 44100;
 228         break;
 229     case 3:
 230         i_rate = 32000;
 231         break;
 232     }
 233
 234     switch ( i_header & 0x7 )
 235     {
 236     case 0:
 237         i_original_channels = AOUT_CHAN_CENTER;
 238         break;
 239     case 1:
 240         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 241         break;
 242     case 2:
 243         /* This is unsure. */
 244         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_LFE;
 245         break;
 246     case 3:
 247         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 248                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 249         break;
 250     case 4:
 251         /* This is unsure. */
 252         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 253                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 254                                | AOUT_CHAN_LFE;
 255         break;
 256     case 5:
 257         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 258                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 259                                | AOUT_CHAN_CENTER | AOUT_CHAN_LFE;
 260         break;
 261     case 6:
 262         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 263                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 264                                | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
 265                                | AOUT_CHAN_MIDDLERIGHT;
 266         break;
 267     case 7:
 268         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 269                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 270                                | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
 271                                | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE;
 272         break;
 273     }
 274
 275     /* Check frame sync and drop it. */
 276     if ( p_data->p_payload_end == p_data->p_payload_start )
 277     {
 278         p_data = p_data->p_next;
 279     }
 280     if ( p_data->p_payload_start[0] != 0x80 )
 281     {
 282         msg_Warn(p_dec->p_fifo, "no frame sync");
 283         input_DeletePES( p_dec->p_fifo->p_packets_mgt, p_pes );
 284         return;
 285     }
 286     p_data->p_payload_start++;
 287
 288     if( (p_dec->p_aout_input != NULL) &&
 289         ( (p_dec->output_format.i_rate != i_rate)
 290             || (p_dec->output_format.i_original_channels
 291                   != i_original_channels) ) )
 292     {
 293         /* Parameters changed - this should not happen. */
 294         aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
 295         p_dec->p_aout_input = NULL;
 296     }
 297
 298     /* Creating the audio input if not created yet. */
 299     if( p_dec->p_aout_input == NULL )
 300     {
 301         p_dec->output_format.i_rate = i_rate;
 302         p_dec->output_format.i_original_channels = i_original_channels;
 303         p_dec->output_format.i_physical_channels
 304                    = i_original_channels & AOUT_CHAN_PHYSMASK;
 305         aout_DateInit( &p_dec->end_date, i_rate );
 306         aout_DateSet( &p_dec->end_date, i_pts );
 307         p_dec->p_aout_input = aout_DecNew( p_dec->p_fifo,
 308                                            &p_dec->p_aout,
 309                                            &p_dec->output_format );
 310
 311         if ( p_dec->p_aout_input == NULL )
 312         {
 313             p_dec->p_fifo->b_error = 1;
 314             input_DeletePES( p_dec->p_fifo->p_packets_mgt, p_pes );
 315             return;
 316         }
 317
 318         if ( p_dec->i_buffered_size )
 319         {
 320             input_DeletePES( p_dec->p_fifo->p_packets_mgt,
 321                              p_dec->p_buffered_pes );
 322             p_dec->i_buffered_size = 0;
 323         }
 324     }
 325
 326     if ( !aout_DateGet( &p_dec->end_date ) )
 327     {
 328         /* We've just started the stream, wait for the first PTS. */
 329         input_DeletePES( p_dec->p_fifo->p_packets_mgt, p_pes );
 330         return;
 331     }
 332
 333     if ( p_dec->i_buffered_size != 0 )
 334     {
 335         p_buffer = aout_DecNewBuffer( p_dec->p_aout, p_dec->p_aout_input,
 336                 (i_size - LPCM_HEADER_LEN + p_dec->i_buffered_size)
 337                     / p_dec->output_format.i_bytes_per_frame );
 338
 339         if( p_buffer == NULL )
 340         {
 341             msg_Err( p_dec->p_fifo, "cannot get aout buffer" );
 342             p_dec->p_fifo->b_error = 1;
 343             input_DeletePES( p_dec->p_fifo->p_packets_mgt, p_pes );
 344             return;
 345         }
 346         p_buffer->start_date = aout_DateGet( &p_dec->end_date );
 347         p_buffer->end_date = aout_DateIncrement( &p_dec->end_date,
 348                 (i_size - LPCM_HEADER_LEN + p_dec->i_buffered_size)
 349                     / p_dec->output_format.i_bytes_per_frame );
 350
 351         /* Get the whole frame. */
 352         p_dest = p_buffer->p_buffer;
 353
 354         while ( p_dec->p_buffered_data != NULL )
 355         {
 356             p_dec->p_fifo->p_vlc->pf_memcpy( p_dest,
 357                     p_dec->p_buffered_data->p_payload_start,
 358                     p_dec->p_buffered_data->p_payload_end
 359                      - p_dec->p_buffered_data->p_payload_start );
 360             p_dest += p_dec->p_buffered_data->p_payload_end
 361                          - p_dec->p_buffered_data->p_payload_start;
 362             p_dec->p_buffered_data = p_dec->p_buffered_data->p_next;
 363         }
 364         input_DeletePES( p_dec->p_fifo->p_packets_mgt,
 365                          p_dec->p_buffered_pes );
 366
 367         p_dest = p_buffer->p_buffer + p_dec->i_buffered_size;
 368
 369         while ( p_data != NULL )
 370         {
 371             p_dec->p_fifo->p_vlc->pf_memcpy( p_dest, p_data->p_payload_start,
 372                     p_data->p_payload_end - p_data->p_payload_start );
 373             p_dest += p_data->p_payload_end - p_data->p_payload_start;
 374             p_data = p_data->p_next;
 375         }
 376         input_DeletePES( p_dec->p_fifo->p_packets_mgt, p_pes );
 377
 378         /* Send the buffer to the aout core. */
 379         aout_DecPlay( p_dec->p_aout, p_dec->p_aout_input, p_buffer );
 380
 381         p_dec->i_buffered_size = 0;
 382     }
 383     else
 384     {
 385         p_dec->i_buffered_size = i_size - LPCM_HEADER_LEN;
 386         p_dec->p_buffered_pes = p_pes;
 387         p_dec->p_buffered_data = p_data;
 388     }
 389 }
 390
 391 /*****************************************************************************
 392  * EndThread : lpcm decoder thread destruction
 393  *****************************************************************************/
 394 static void EndThread( dec_thread_t * p_dec )
 395 {
 396     if( p_dec->p_aout_input != NULL )
 397     {
 398         aout_DecDelete( p_dec->p_aout, p_dec->p_aout_input );
 399     }
 400
 401     if ( p_dec->i_buffered_size )
 402     {
 403         input_DeletePES( p_dec->p_fifo->p_packets_mgt,
 404                          p_dec->p_buffered_pes );
 405         p_dec->i_buffered_size = 0;
 406     }
 407
 408     free( p_dec );
 409 }