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