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 #include <vlc_aout.h>
  35 #include <vlc_filter.h>
  36
  37 /*****************************************************************************
  38  * Local structures
  39  *****************************************************************************/
  40 struct filter_sys_t
  41 {
  42     mtime_t start_date;
  43
  44     /* 3 DTS frames have to be packed into an S/PDIF frame.
  45      * We accumulate DTS frames from the decoder until we have enough to
  46      * send. */
  47     size_t i_frame_size;
  48     uint8_t *p_buf;
  49     unsigned i_frames;
  50 };
  51
  52 /*****************************************************************************
  53  * Local prototypes
  54  *****************************************************************************/
  55 static int  Create    ( vlc_object_t * );
  56 static void Close     ( vlc_object_t * );
  57 static block_t *DoWork( filter_t *, block_t * );
  58
  59 /*****************************************************************************
  60  * Module descriptor
  61  *****************************************************************************/
  62 vlc_module_begin ()
  63     set_category( CAT_AUDIO )
  64     set_subcategory( SUBCAT_AUDIO_MISC )
  65     set_description( N_("Audio filter for DTS->S/PDIF encapsulation") )
  66     set_capability( "audio filter2", 10 )
  67     set_callbacks( Create, Close )
  68 vlc_module_end ()
  69
  70 /*****************************************************************************
  71  * Create:
  72  *****************************************************************************/
  73 static int Create( vlc_object_t *p_this )
  74 {
  75     filter_t * p_filter = (filter_t *)p_this;
  76     filter_sys_t *p_sys;
  77
  78     if( p_filter->fmt_in.audio.i_format != VLC_CODEC_DTS ||
  79         ( p_filter->fmt_out.audio.i_format != VLC_CODEC_SPDIFL &&
  80           p_filter->fmt_out.audio.i_format != VLC_CODEC_SPDIFB ) )
  81     {
  82         return VLC_EGENERIC;
  83     }
  84
  85     /* Allocate the memory needed to store the module's structure */
  86     p_sys = p_filter->p_sys = malloc( sizeof(*p_sys) );
  87     if( !p_sys )
  88         return VLC_ENOMEM;
  89     p_sys->p_buf = NULL;
  90     p_sys->i_frame_size = 0;
  91     p_sys->i_frames = 0;
  92
  93     p_filter->pf_audio_filter = DoWork;
  94
  95     return VLC_SUCCESS;
  96 }
  97
  98 /*****************************************************************************
  99  * Close: free our resources
 100  *****************************************************************************/
 101 static void Close( vlc_object_t * p_this )
 102 {
 103     filter_t * p_filter = (filter_t *)p_this;
 104
 105     free( p_filter->p_sys->p_buf );
 106     free( p_filter->p_sys );
 107 }
 108
 109 /*****************************************************************************
 110  * DoWork: convert a buffer
 111  *****************************************************************************/
 112 static block_t *DoWork( filter_t * p_filter, block_t * p_in_buf )
 113 {
 114     uint32_t i_ac5_spdif_type = 0;
 115     uint16_t i_fz = p_in_buf->i_nb_samples * 4;
 116     uint16_t i_frame, i_length = p_in_buf->i_buffer;
 117     static const uint8_t p_sync_le[6] = { 0x72, 0xF8, 0x1F, 0x4E, 0x00, 0x00 };
 118     static const uint8_t p_sync_be[6] = { 0xF8, 0x72, 0x4E, 0x1F, 0x00, 0x00 };
 119
 120     if( p_in_buf->i_buffer != p_filter->p_sys->i_frame_size )
 121     {
 122         /* Frame size changed, reset everything */
 123         msg_Warn( p_filter, "Frame size changed from %zu to %zu, "
 124                           "resetting everything.",
 125                   p_filter->p_sys->i_frame_size, p_in_buf->i_buffer );
 126
 127         p_filter->p_sys->i_frame_size = p_in_buf->i_buffer;
 128         p_filter->p_sys->p_buf = realloc( p_filter->p_sys->p_buf,
 129                                           p_in_buf->i_buffer * 3 );
 130         p_filter->p_sys->i_frames = 0;
 131     }
 132
 133     /* Backup frame */
 134     /* TODO: keeping the blocks in a list would save one memcpy */
 135     vlc_memcpy( p_filter->p_sys->p_buf + p_in_buf->i_buffer *
 136                   p_filter->p_sys->i_frames,
 137                 p_in_buf->p_buffer, p_in_buf->i_buffer );
 138
 139     p_filter->p_sys->i_frames++;
 140
 141     if( p_filter->p_sys->i_frames < 3 )
 142     {
 143         if( p_filter->p_sys->i_frames == 1 )
 144             /* We'll need the starting date */
 145             p_filter->p_sys->start_date = p_in_buf->i_pts;
 146
 147         /* Not enough data */
 148         block_Release( p_in_buf );
 149         return NULL;
 150     }
 151
 152     p_filter->p_sys->i_frames = 0;
 153     block_t *p_out_buf = filter_NewAudioBuffer( p_filter,
 154                                                 12 * p_in_buf->i_nb_samples );
 155     if( !p_out_buf )
 156         goto out;
 157
 158     for( i_frame = 0; i_frame < 3; i_frame++ )
 159     {
 160         uint16_t i_length_padded = i_length;
 161         uint8_t * p_out = p_out_buf->p_buffer + (i_frame * i_fz);
 162         uint8_t * p_in = p_filter->p_sys->p_buf + (i_frame * i_length);
 163
 164         switch( p_in_buf->i_nb_samples )
 165         {
 166             case  512: i_ac5_spdif_type = 0x0B; break;
 167             case 1024: i_ac5_spdif_type = 0x0C; break;
 168             case 2048: i_ac5_spdif_type = 0x0D; break;
 169         }
 170
 171         /* Copy the S/PDIF headers. */
 172         if( p_filter->fmt_out.audio.i_format == VLC_CODEC_SPDIFB )
 173         {
 174             vlc_memcpy( p_out, p_sync_be, 6 );
 175             p_out[5] = i_ac5_spdif_type;
 176             p_out[6] = (( i_length ) >> 5 ) & 0xFF;
 177             p_out[7] = ( i_length << 3 ) & 0xFF;
 178         }
 179         else
 180         {
 181             vlc_memcpy( p_out, p_sync_le, 6 );
 182             p_out[4] = i_ac5_spdif_type;
 183             p_out[6] = ( i_length << 3 ) & 0xFF;
 184             p_out[7] = (( i_length ) >> 5 ) & 0xFF;
 185         }
 186
 187         if( ( (p_in[0] == 0x1F || p_in[0] == 0x7F) && p_filter->fmt_out.audio.i_format == VLC_CODEC_SPDIFL ) ||
 188             ( (p_in[0] == 0xFF || p_in[0] == 0xFE) && p_filter->fmt_out.audio.i_format == VLC_CODEC_SPDIFB ) )
 189         {
 190             /* We are dealing with a big endian bitstream and a little endian output
 191              * or a little endian bitstream and a big endian output.
 192              * Byteswap the stream */
 193             swab( p_in, p_out + 8, i_length );
 194
 195             /* If i_length is odd, we have to adjust swapping a bit.. */
 196             if( i_length & 1 )
 197             {
 198                 p_out[8+i_length-1] = 0;
 199                 p_out[8+i_length] = p_in[i_length-1];
 200                 i_length_padded++;
 201             }
 202         }
 203         else
 204         {
 205             vlc_memcpy( p_out + 8, p_in, i_length );
 206         }
 207
 208         if( i_fz > i_length + 8 )
 209         {
 210             vlc_memset( p_out + 8 + i_length_padded, 0,
 211                         i_fz - i_length_padded - 8 );
 212         }
 213     }
 214
 215     p_out_buf->i_pts = 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_buffer = p_out_buf->i_nb_samples * 4;
 218 out:
 219     block_Release( p_in_buf );
 220     return p_out_buf;
 221 }