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 #include <vlc/vlc.h>
  28
  29
  30 #ifdef HAVE_UNISTD_H
  31 #   include <unistd.h>
  32 #endif
  33
  34 #include <vlc_aout.h>
  35
  36 /*****************************************************************************
  37  * Local structures
  38  *****************************************************************************/
  39 struct aout_filter_sys_t
  40 {
  41     /* 3 DTS frames have to be packed into an S/PDIF frame.
  42      * We accumulate DTS frames from the decoder until we have enough to
  43      * send. */
  44
  45     uint8_t *p_buf;
  46
  47     mtime_t start_date;
  48
  49     int i_frames;
  50     unsigned int i_frame_size;
  51 };
  52
  53 /*****************************************************************************
  54  * Local prototypes
  55  *****************************************************************************/
  56 static int  Create    ( vlc_object_t * );
  57 static void Close     ( vlc_object_t * );
  58 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  59                         aout_buffer_t * );
  60
  61 /*****************************************************************************
  62  * Module descriptor
  63  *****************************************************************************/
  64 vlc_module_begin();
  65     set_category( CAT_AUDIO );
  66     set_subcategory( SUBCAT_AUDIO_MISC );
  67     set_description( _("Audio filter for DTS->S/PDIF encapsulation") );
  68     set_capability( "audio filter", 10 );
  69     set_callbacks( Create, Close );
  70 vlc_module_end();
  71
  72 /*****************************************************************************
  73  * Create:
  74  *****************************************************************************/
  75 static int Create( vlc_object_t *p_this )
  76 {
  77     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  78
  79     if( p_filter->input.i_format != VLC_FOURCC('d','t','s',' ') ||
  80         ( p_filter->output.i_format != VLC_FOURCC('s','p','d','i') &&
  81           p_filter->output.i_format != VLC_FOURCC('s','p','d','b') ) )
  82     {
  83         return -1;
  84     }
  85
  86     /* Allocate the memory needed to store the module's structure */
  87     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
  88     if( p_filter->p_sys == NULL )
  89     {
  90         msg_Err( p_filter, "out of memory" );
  91         return VLC_ENOMEM;
  92     }
  93     memset( p_filter->p_sys, 0, sizeof(struct aout_filter_sys_t) );
  94     p_filter->p_sys->p_buf = 0;
  95
  96     p_filter->pf_do_work = DoWork;
  97     p_filter->b_in_place = 1;
  98
  99     return 0;
 100 }
 101
 102 /*****************************************************************************
 103  * Close: free our resources
 104  *****************************************************************************/
 105 static void Close( vlc_object_t * p_this )
 106 {
 107     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 108     if( p_filter->p_sys->i_frame_size ) free( p_filter->p_sys->p_buf );
 109     free( p_filter->p_sys );
 110 }
 111
 112 /*****************************************************************************
 113  * DoWork: convert a buffer
 114  *****************************************************************************/
 115 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 116                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 117 {
 118     uint32_t i_ac5_spdif_type = 0;
 119     uint16_t i_fz = p_in_buf->i_nb_samples * 4;
 120     uint16_t i_frame, i_length = p_in_buf->i_nb_bytes;
 121     static const uint8_t p_sync_le[6] = { 0x72, 0xF8, 0x1F, 0x4E, 0x00, 0x00 };
 122     static const uint8_t p_sync_be[6] = { 0xF8, 0x72, 0x4E, 0x1F, 0x00, 0x00 };
 123
 124     if( p_in_buf->i_nb_bytes != p_filter->p_sys->i_frame_size )
 125     {
 126         /* Frame size changed, reset everything */
 127         p_filter->p_sys->i_frame_size = p_in_buf->i_nb_bytes;
 128         p_filter->p_sys->p_buf = realloc( p_filter->p_sys->p_buf,
 129                                           p_in_buf->i_nb_bytes * 3 );
 130         p_filter->p_sys->i_frames = 0;
 131     }
 132
 133     /* Backup frame */
 134     p_filter->p_libvlc->pf_memcpy( p_filter->p_sys->p_buf + p_in_buf->i_nb_bytes *
 135                                 p_filter->p_sys->i_frames, p_in_buf->p_buffer,
 136                                 p_in_buf->i_nb_bytes );
 137
 138     p_filter->p_sys->i_frames++;
 139
 140     if( p_filter->p_sys->i_frames < 3 )
 141     {
 142         if( !p_filter->p_sys->i_frames )
 143             /* We'll need the starting date */
 144             p_filter->p_sys->start_date = p_in_buf->start_date;
 145
 146         /* Not enough data */
 147         p_out_buf->i_nb_samples = 0;
 148         p_out_buf->i_nb_bytes = 0;
 149         return;
 150     }
 151
 152     p_filter->p_sys->i_frames = 0;
 153
 154     for( i_frame = 0; i_frame < 3; i_frame++ )
 155     {
 156         byte_t * p_out = p_out_buf->p_buffer + (i_frame * i_fz);
 157         byte_t * p_in = p_filter->p_sys->p_buf + (i_frame * i_length);
 158
 159         switch( p_in_buf->i_nb_samples )
 160         {
 161             case  512: i_ac5_spdif_type = 0x0B; break;
 162             case 1024: i_ac5_spdif_type = 0x0C; break;
 163             case 2048: i_ac5_spdif_type = 0x0D; break;
 164         }
 165
 166         /* Copy the S/PDIF headers. */
 167         if( p_filter->output.i_format == VLC_FOURCC('s','p','d','b') )
 168         {
 169             p_filter->p_libvlc->pf_memcpy( p_out, p_sync_be, 6 );
 170             p_out[5] = i_ac5_spdif_type;
 171             p_out[6] = (( i_length ) >> 5 ) & 0xFF;
 172             p_out[7] = ( i_length << 3 ) & 0xFF;
 173         }
 174         else
 175         {
 176             p_filter->p_libvlc->pf_memcpy( p_out, p_sync_le, 6 );
 177             p_out[4] = i_ac5_spdif_type;
 178             p_out[6] = ( i_length << 3 ) & 0xFF;
 179             p_out[7] = (( i_length ) >> 5 ) & 0xFF;
 180         }
 181
 182         if( ( (p_in[0] == 0x1F || p_in[0] == 0x7F) && p_filter->output.i_format == VLC_FOURCC('s','p','d','i') ) ||
 183             ( (p_in[0] == 0xFF || p_in[0] == 0xFE) && p_filter->output.i_format == VLC_FOURCC('s','p','d','b') ) )
 184         {
 185             /* We are dealing with a big endian bitstream and a little endian output
 186              * or a little endian bitstream and a big endian output.
 187              * Byteswap the stream */
 188 #ifdef HAVE_SWAB
 189             swab( p_in, p_out + 8, i_length );
 190 #else
 191             uint16_t i;
 192             byte_t * p_tmp, tmp;
 193             p_tmp = p_out + 8;
 194             for( i = i_length / 2 ; i-- ; )
 195             {
 196                 tmp = p_in[0]; /* in-place filter */
 197                 p_tmp[0] = p_in[1];
 198                 p_tmp[1] = tmp;
 199                 p_tmp += 2; p_in += 2;
 200             }
 201 #endif
 202         }
 203         else
 204         {
 205             p_filter->p_libvlc->pf_memcpy( p_out + 8, p_in, i_length );
 206         }
 207
 208         if( i_fz > i_length + 8 )
 209         {
 210             p_filter->p_libvlc->pf_memset( p_out + 8 + i_length, 0,
 211                                         i_fz - i_length - 8 );
 212         }
 213     }
 214
 215     p_out_buf->start_date = p_filter->p_sys->start_date;
 216     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples * 3;
 217     p_out_buf->i_nb_bytes = p_out_buf->i_nb_samples * 4;
 218 }