git.sesse.net Git - vlc/blob - modules/audio_filter/converter/dtstospdif.c

   1 /*****************************************************************************
   2  * dtstospdif.c : encapsulates DTS frames into S/PDIF packets
   3  *****************************************************************************
   4  * Copyright (C) 2003, 2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Jon Lech Johansen <jon-vl@nanocrew.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33
  34
  35 #ifdef HAVE_UNISTD_H
  36 #   include <unistd.h>
  37 #endif
  38
  39 #include <vlc_aout.h>
  40
  41 /*****************************************************************************
  42  * Local structures
  43  *****************************************************************************/
  44 struct aout_filter_sys_t
  45 {
  46     /* 3 DTS frames have to be packed into an S/PDIF frame.
  47      * We accumulate DTS frames from the decoder until we have enough to
  48      * send. */
  49
  50     uint8_t *p_buf;
  51
  52     mtime_t start_date;
  53
  54     int i_frames;
  55     unsigned int i_frame_size;
  56 };
  57
  58 /*****************************************************************************
  59  * Local prototypes
  60  *****************************************************************************/
  61 static int  Create    ( vlc_object_t * );
  62 static void Close     ( vlc_object_t * );
  63 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  64                         aout_buffer_t * );
  65
  66 /*****************************************************************************
  67  * Module descriptor
  68  *****************************************************************************/
  69 vlc_module_begin ()
  70     set_category( CAT_AUDIO )
  71     set_subcategory( SUBCAT_AUDIO_MISC )
  72     set_description( N_("Audio filter for DTS->S/PDIF encapsulation") )
  73     set_capability( "audio filter", 10 )
  74     set_callbacks( Create, Close )
  75 vlc_module_end ()
  76
  77 /*****************************************************************************
  78  * Create:
  79  *****************************************************************************/
  80 static int Create( vlc_object_t *p_this )
  81 {
  82     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  83
  84     if( p_filter->input.i_format != VLC_FOURCC('d','t','s',' ') ||
  85         ( p_filter->output.i_format != VLC_FOURCC('s','p','d','i') &&
  86           p_filter->output.i_format != VLC_FOURCC('s','p','d','b') ) )
  87     {
  88         return -1;
  89     }
  90
  91     /* Allocate the memory needed to store the module's structure */
  92     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
  93     if( p_filter->p_sys == NULL )
  94         return VLC_ENOMEM;
  95     memset( p_filter->p_sys, 0, sizeof(struct aout_filter_sys_t) );
  96     p_filter->p_sys->p_buf = 0;
  97
  98     p_filter->pf_do_work = DoWork;
  99     p_filter->b_in_place = 1;
 100
 101     return 0;
 102 }
 103
 104 /*****************************************************************************
 105  * Close: free our resources
 106  *****************************************************************************/
 107 static void Close( vlc_object_t * p_this )
 108 {
 109     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 110     if( p_filter->p_sys->i_frame_size ) free( p_filter->p_sys->p_buf );
 111     free( p_filter->p_sys );
 112 }
 113
 114 /*****************************************************************************
 115  * DoWork: convert a buffer
 116  *****************************************************************************/
 117 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 118                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 119 {
 120     uint32_t i_ac5_spdif_type = 0;
 121     uint16_t i_fz = p_in_buf->i_nb_samples * 4;
 122     uint16_t i_frame, i_length = p_in_buf->i_nb_bytes;
 123     static const uint8_t p_sync_le[6] = { 0x72, 0xF8, 0x1F, 0x4E, 0x00, 0x00 };
 124     static const uint8_t p_sync_be[6] = { 0xF8, 0x72, 0x4E, 0x1F, 0x00, 0x00 };
 125
 126     if( p_in_buf->i_nb_bytes != p_filter->p_sys->i_frame_size )
 127     {
 128         /* Frame size changed, reset everything */
 129         msg_Warn( p_aout, "Frame size changed from %u to %u, "
 130                           "resetting everything.",
 131                   p_filter->p_sys->i_frame_size,
 132                   (unsigned)p_in_buf->i_nb_bytes );
 133
 134         p_filter->p_sys->i_frame_size = p_in_buf->i_nb_bytes;
 135         p_filter->p_sys->p_buf = realloc( p_filter->p_sys->p_buf,
 136                                           p_in_buf->i_nb_bytes * 3 );
 137         p_filter->p_sys->i_frames = 0;
 138     }
 139
 140     /* Backup frame */
 141     vlc_memcpy( p_filter->p_sys->p_buf + p_in_buf->i_nb_bytes *
 142                   p_filter->p_sys->i_frames,
 143                 p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 144
 145     p_filter->p_sys->i_frames++;
 146
 147     if( p_filter->p_sys->i_frames < 3 )
 148     {
 149         if( p_filter->p_sys->i_frames == 1 )
 150             /* We'll need the starting date */
 151             p_filter->p_sys->start_date = p_in_buf->start_date;
 152
 153         /* Not enough data */
 154         p_out_buf->i_nb_samples = 0;
 155         p_out_buf->i_nb_bytes = 0;
 156         return;
 157     }
 158
 159     p_filter->p_sys->i_frames = 0;
 160
 161     for( i_frame = 0; i_frame < 3; i_frame++ )
 162     {
 163         uint16_t i_length_padded = i_length;
 164         uint8_t * p_out = p_out_buf->p_buffer + (i_frame * i_fz);
 165         uint8_t * p_in = p_filter->p_sys->p_buf + (i_frame * i_length);
 166
 167         switch( p_in_buf->i_nb_samples )
 168         {
 169             case  512: i_ac5_spdif_type = 0x0B; break;
 170             case 1024: i_ac5_spdif_type = 0x0C; break;
 171             case 2048: i_ac5_spdif_type = 0x0D; break;
 172         }
 173
 174         /* Copy the S/PDIF headers. */
 175         if( p_filter->output.i_format == VLC_FOURCC('s','p','d','b') )
 176         {
 177             vlc_memcpy( p_out, p_sync_be, 6 );
 178             p_out[5] = i_ac5_spdif_type;
 179             p_out[6] = (( i_length ) >> 5 ) & 0xFF;
 180             p_out[7] = ( i_length << 3 ) & 0xFF;
 181         }
 182         else
 183         {
 184             vlc_memcpy( p_out, p_sync_le, 6 );
 185             p_out[4] = i_ac5_spdif_type;
 186             p_out[6] = ( i_length << 3 ) & 0xFF;
 187             p_out[7] = (( i_length ) >> 5 ) & 0xFF;
 188         }
 189
 190         if( ( (p_in[0] == 0x1F || p_in[0] == 0x7F) && p_filter->output.i_format == VLC_FOURCC('s','p','d','i') ) ||
 191             ( (p_in[0] == 0xFF || p_in[0] == 0xFE) && p_filter->output.i_format == VLC_FOURCC('s','p','d','b') ) )
 192         {
 193             /* We are dealing with a big endian bitstream and a little endian output
 194              * or a little endian bitstream and a big endian output.
 195              * Byteswap the stream */
 196 #ifdef HAVE_SWAB
 197             swab( p_in, p_out + 8, i_length );
 198 #else
 199             uint16_t i;
 200             uint8_t * p_tmp, tmp;
 201             p_tmp = p_out + 8;
 202             for( i = i_length / 2 ; i-- ; )
 203             {
 204                 tmp = p_in[0]; /* in-place filter */
 205                 p_tmp[0] = p_in[1];
 206                 p_tmp[1] = tmp;
 207                 p_tmp += 2; p_in += 2;
 208             }
 209 #endif
 210             /* If i_length is odd, we have to adjust swapping a bit.. */
 211             if( i_length & 1 )
 212             {
 213                 p_out[8+i_length-1] = 0;
 214                 p_out[8+i_length] = p_in[i_length-1];
 215                 i_length_padded++;
 216             }
 217         }
 218         else
 219         {
 220             vlc_memcpy( p_out + 8, p_in, i_length );
 221         }
 222
 223         if( i_fz > i_length + 8 )
 224         {
 225             vlc_memset( p_out + 8 + i_length_padded, 0,
 226                         i_fz - i_length_padded - 8 );
 227         }
 228     }
 229
 230     p_out_buf->start_date = p_filter->p_sys->start_date;
 231     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples * 3;
 232     p_out_buf->i_nb_bytes = p_out_buf->i_nb_samples * 4;
 233 }