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

   1 /*****************************************************************************
   2  * lpcm.c: lpcm decoder/packetizer module
   3  *****************************************************************************
   4  * Copyright (C) 1999-2005 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   8  *          Henri Fallon <henri@videolan.org>
   9  *          Christophe Massiot <massiot@via.ecp.fr>
  10  *          Gildas Bazin <gbazin@videolan.org>
  11  *
  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.
  16  *
  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.
  21  *
  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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc/vlc.h>
  35 #include <vlc_codec.h>
  36 #include <vlc_aout.h>
  37
  38 /*****************************************************************************
  39  * decoder_sys_t : lpcm decoder descriptor
  40  *****************************************************************************/
  41 struct decoder_sys_t
  42 {
  43     /* Module mode */
  44     vlc_bool_t b_packetizer;
  45
  46     /*
  47      * Output properties
  48      */
  49     audio_date_t end_date;
  50
  51 };
  52
  53 /*
  54  * LPCM header :
  55  * - PES header
  56  * - private stream ID (16 bits) == 0xA0 -> not in the bitstream
  57  *
  58  * - frame number (8 bits)
  59  * - unknown (16 bits) == 0x0003 ?
  60  * - unknown (4 bits)
  61  * - current frame (4 bits)
  62  * - unknown (2 bits)
  63  * - frequency (2 bits) 0 == 48 kHz, 1 == 32 kHz, 2 == ?, 3 == ?
  64  * - unknown (1 bit)
  65  * - number of channels - 1 (3 bits) 1 == 2 channels
  66  * - start code (8 bits) == 0x80
  67  */
  68
  69 #define LPCM_HEADER_LEN 6
  70
  71 /*****************************************************************************
  72  * Local prototypes
  73  *****************************************************************************/
  74 static int  OpenDecoder   ( vlc_object_t * );
  75 static int  OpenPacketizer( vlc_object_t * );
  76 static void CloseDecoder  ( vlc_object_t * );
  77
  78 static void *DecodeFrame  ( decoder_t *, block_t ** );
  79
  80 /*****************************************************************************
  81  * Module descriptor
  82  *****************************************************************************/
  83 vlc_module_begin();
  84
  85     set_category( CAT_INPUT );
  86     set_subcategory( SUBCAT_INPUT_ACODEC );
  87     set_description( _("Linear PCM audio decoder") );
  88     set_capability( "decoder", 100 );
  89     set_callbacks( OpenDecoder, CloseDecoder );
  90
  91     add_submodule();
  92     set_description( _("Linear PCM audio packetizer") );
  93     set_capability( "packetizer", 100 );
  94     set_callbacks( OpenPacketizer, CloseDecoder );
  95
  96 vlc_module_end();
  97
  98 /*****************************************************************************
  99  * OpenDecoder: probe the decoder and return score
 100  *****************************************************************************/
 101 static int OpenDecoder( vlc_object_t *p_this )
 102 {
 103     decoder_t *p_dec = (decoder_t*)p_this;
 104     decoder_sys_t *p_sys;
 105
 106     if( p_dec->fmt_in.i_codec != VLC_FOURCC('l','p','c','m')
 107          && p_dec->fmt_in.i_codec != VLC_FOURCC('l','p','c','b') )
 108     {
 109         return VLC_EGENERIC;
 110     }
 111
 112     /* Allocate the memory needed to store the decoder's structure */
 113     if( ( p_dec->p_sys = p_sys =
 114           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 115     {
 116         msg_Err( p_dec, "out of memory" );
 117         return VLC_EGENERIC;
 118     }
 119
 120     /* Misc init */
 121     p_sys->b_packetizer = VLC_FALSE;
 122     aout_DateSet( &p_sys->end_date, 0 );
 123
 124     /* Set output properties */
 125     p_dec->fmt_out.i_cat = AUDIO_ES;
 126
 127     if( p_dec->fmt_out.audio.i_bitspersample == 24 )
 128     {
 129         p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
 130     }
 131     else
 132     {
 133         p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
 134         p_dec->fmt_out.audio.i_bitspersample = 16;
 135     }
 136
 137     /* Set callback */
 138     p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
 139         DecodeFrame;
 140     p_dec->pf_packetize    = (block_t *(*)(decoder_t *, block_t **))
 141         DecodeFrame;
 142
 143     return VLC_SUCCESS;
 144 }
 145
 146 static int OpenPacketizer( vlc_object_t *p_this )
 147 {
 148     decoder_t *p_dec = (decoder_t*)p_this;
 149
 150     int i_ret = OpenDecoder( p_this );
 151
 152     if( i_ret != VLC_SUCCESS ) return i_ret;
 153
 154     p_dec->p_sys->b_packetizer = VLC_TRUE;
 155
 156     p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
 157
 158     return i_ret;
 159 }
 160
 161 /*****************************************************************************
 162  * DecodeFrame: decodes an lpcm frame.
 163  ****************************************************************************
 164  * Beware, this function must be fed with complete frames (PES packet).
 165  *****************************************************************************/
 166 static void *DecodeFrame( decoder_t *p_dec, block_t **pp_block )
 167 {
 168     decoder_sys_t *p_sys = p_dec->p_sys;
 169     block_t       *p_block;
 170     unsigned int  i_rate = 0, i_original_channels = 0, i_channels = 0;
 171     int           i_frame_length, i_bitspersample;
 172     uint8_t       i_header;
 173
 174     if( !pp_block || !*pp_block ) return NULL;
 175
 176     p_block = *pp_block;
 177     *pp_block = NULL; /* So the packet doesn't get re-sent */
 178
 179     /* Date management */
 180     if( p_block->i_pts > 0 &&
 181         p_block->i_pts != aout_DateGet( &p_sys->end_date ) )
 182     {
 183         aout_DateSet( &p_sys->end_date, p_block->i_pts );
 184     }
 185
 186     if( !aout_DateGet( &p_sys->end_date ) )
 187     {
 188         /* We've just started the stream, wait for the first PTS. */
 189         block_Release( p_block );
 190         return NULL;
 191     }
 192
 193     if( p_block->i_buffer <= LPCM_HEADER_LEN )
 194     {
 195         msg_Err(p_dec, "frame is too short");
 196         block_Release( p_block );
 197         return NULL;
 198     }
 199
 200     i_header = p_block->p_buffer[4];
 201     switch ( (i_header >> 4) & 0x3 )
 202     {
 203     case 0:
 204         i_rate = 48000;
 205         break;
 206     case 1:
 207         i_rate = 96000;
 208         break;
 209     case 2:
 210         i_rate = 44100;
 211         break;
 212     case 3:
 213         i_rate = 32000;
 214         break;
 215     }
 216
 217     i_channels = (i_header & 0x7);
 218     switch ( i_channels )
 219     {
 220     case 0:
 221         i_original_channels = AOUT_CHAN_CENTER;
 222         break;
 223     case 1:
 224         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 225         break;
 226     case 2:
 227         /* This is unsure. */
 228         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_LFE;
 229         break;
 230     case 3:
 231         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 232                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 233         break;
 234     case 4:
 235         /* This is unsure. */
 236         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 237                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 238                                | AOUT_CHAN_LFE;
 239         break;
 240     case 5:
 241         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 242                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 243                                | AOUT_CHAN_CENTER | AOUT_CHAN_LFE;
 244         break;
 245     case 6:
 246         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 247                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 248                                | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
 249                                | AOUT_CHAN_MIDDLERIGHT;
 250         break;
 251     case 7:
 252         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 253                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 254                                | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
 255                                | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE;
 256         break;
 257     }
 258
 259     switch ( (i_header >> 6) & 0x3 )
 260     {
 261     case 2:
 262         p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
 263         p_dec->fmt_out.audio.i_bitspersample = 24;
 264         i_bitspersample = 24;
 265         break;
 266     case 1:
 267         p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
 268         p_dec->fmt_out.audio.i_bitspersample = 24;
 269         i_bitspersample = 20;
 270         break;
 271     case 0:
 272     default:
 273         p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
 274         p_dec->fmt_out.audio.i_bitspersample = 16;
 275         i_bitspersample = 16;
 276         break;
 277     }
 278
 279     /* Check frame sync and drop it. */
 280     if( p_block->p_buffer[5] != 0x80 )
 281     {
 282         msg_Warn( p_dec, "no frame sync" );
 283         block_Release( p_block );
 284         return NULL;
 285     }
 286
 287     /* Set output properties */
 288     if( p_dec->fmt_out.audio.i_rate != i_rate )
 289     {
 290         aout_DateInit( &p_sys->end_date, i_rate );
 291         aout_DateSet( &p_sys->end_date, p_block->i_pts );
 292     }
 293     p_dec->fmt_out.audio.i_rate = i_rate;
 294     p_dec->fmt_out.audio.i_channels = i_channels + 1;
 295     p_dec->fmt_out.audio.i_original_channels = i_original_channels;
 296     p_dec->fmt_out.audio.i_physical_channels
 297         = i_original_channels & AOUT_CHAN_PHYSMASK;
 298
 299     i_frame_length = (p_block->i_buffer - LPCM_HEADER_LEN) /
 300         p_dec->fmt_out.audio.i_channels * 8 / i_bitspersample;
 301
 302     if( p_sys->b_packetizer )
 303     {
 304         p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
 305         p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
 306         p_block->i_length =
 307             aout_DateIncrement( &p_sys->end_date, i_frame_length ) -
 308             p_block->i_pts;
 309
 310         /* Just pass on the incoming frame */
 311         return p_block;
 312     }
 313     else
 314     {
 315         aout_buffer_t *p_aout_buffer;
 316         p_aout_buffer = p_dec->pf_aout_buffer_new( p_dec, i_frame_length );
 317         if( p_aout_buffer == NULL ) return NULL;
 318
 319         p_aout_buffer->start_date = aout_DateGet( &p_sys->end_date );
 320         p_aout_buffer->end_date =
 321             aout_DateIncrement( &p_sys->end_date, i_frame_length );
 322
 323         p_block->p_buffer += LPCM_HEADER_LEN;
 324         p_block->i_buffer -= LPCM_HEADER_LEN;
 325
 326         /* 20/24 bits LPCM use special packing */
 327         if( i_bitspersample == 24 )
 328         {
 329             uint8_t *p_out = p_aout_buffer->p_buffer;
 330
 331             while( p_block->i_buffer / 12 )
 332             {
 333                 /* Sample 1 */
 334                 p_out[0] = p_block->p_buffer[0];
 335                 p_out[1] = p_block->p_buffer[1];
 336                 p_out[2] = p_block->p_buffer[8];
 337                 /* Sample 2 */
 338                 p_out[3] = p_block->p_buffer[2];
 339                 p_out[4] = p_block->p_buffer[3];
 340                 p_out[5] = p_block->p_buffer[9];
 341                 /* Sample 3 */
 342                 p_out[6] = p_block->p_buffer[4];
 343                 p_out[7] = p_block->p_buffer[5];
 344                 p_out[8] = p_block->p_buffer[10];
 345                 /* Sample 4 */
 346                 p_out[9] = p_block->p_buffer[6];
 347                 p_out[10] = p_block->p_buffer[7];
 348                 p_out[11] = p_block->p_buffer[11];
 349
 350                 p_block->i_buffer -= 12;
 351                 p_block->p_buffer += 12;
 352                 p_out += 12;
 353             }
 354         }
 355         else if( i_bitspersample == 20 )
 356         {
 357             uint8_t *p_out = p_aout_buffer->p_buffer;
 358
 359             while( p_block->i_buffer / 10 )
 360             {
 361                 /* Sample 1 */
 362                 p_out[0] = p_block->p_buffer[0];
 363                 p_out[1] = p_block->p_buffer[1];
 364                 p_out[2] = p_block->p_buffer[8] & 0xF0;
 365                 /* Sample 2 */
 366                 p_out[3] = p_block->p_buffer[2];
 367                 p_out[4] = p_block->p_buffer[3];
 368                 p_out[5] = p_block->p_buffer[8] << 4;
 369                 /* Sample 3 */
 370                 p_out[6] = p_block->p_buffer[4];
 371                 p_out[7] = p_block->p_buffer[5];
 372                 p_out[8] = p_block->p_buffer[9] & 0xF0;
 373                 /* Sample 4 */
 374                 p_out[9] = p_block->p_buffer[6];
 375                 p_out[10] = p_block->p_buffer[7];
 376                 p_out[11] = p_block->p_buffer[9] << 4;
 377
 378                 p_block->i_buffer -= 10;
 379                 p_block->p_buffer += 10;
 380                 p_out += 12;
 381             }
 382         }
 383         else
 384         {
 385             memcpy( p_aout_buffer->p_buffer,
 386                     p_block->p_buffer, p_block->i_buffer );
 387         }
 388
 389         block_Release( p_block );
 390         return p_aout_buffer;
 391     }
 392 }
 393
 394 /*****************************************************************************
 395  * CloseDecoder : lpcm decoder destruction
 396  *****************************************************************************/
 397 static void CloseDecoder( vlc_object_t *p_this )
 398 {
 399     decoder_t *p_dec = (decoder_t*)p_this;
 400     free( p_dec->p_sys );
 401 }