1 /*****************************************************************************
2 * a52tospdif.c : encapsulates A/52 frames into S/PDIF packets
3 *****************************************************************************
4 * Copyright (C) 2002, 2006 the VideoLAN team
7 * Authors: Christophe Massiot <massiot@via.ecp.fr>
8 * Stéphane Borel <stef@via.ecp.fr>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
23 *****************************************************************************/
25 /*****************************************************************************
27 *****************************************************************************/
33 #include <vlc_common.h>
34 #include <vlc_plugin.h>
37 #include <vlc_filter.h>
39 /*****************************************************************************
41 *****************************************************************************/
42 static int Create ( vlc_object_t * );
43 static block_t *DoWork( filter_t *, block_t * );
45 /*****************************************************************************
47 *****************************************************************************/
49 set_category( CAT_AUDIO )
50 set_subcategory( SUBCAT_AUDIO_MISC )
51 set_description( N_("Audio filter for A/52->S/PDIF encapsulation") )
52 set_capability( "audio filter", 10 )
53 set_callbacks( Create, NULL )
56 /*****************************************************************************
58 *****************************************************************************/
59 static int Create( vlc_object_t *p_this )
61 filter_t * p_filter = (filter_t *)p_this;
63 if ( p_filter->fmt_in.audio.i_format != VLC_CODEC_A52 ||
64 ( p_filter->fmt_out.audio.i_format != VLC_CODEC_SPDIFB &&
65 p_filter->fmt_out.audio.i_format != VLC_CODEC_SPDIFL ) )
70 p_filter->pf_audio_filter = DoWork;
75 /*****************************************************************************
76 * DoWork: convert a buffer
77 *****************************************************************************/
78 static block_t *DoWork( filter_t * p_filter, block_t *p_in_buf )
80 /* AC3 is natively big endian. Most SPDIF devices have the native
81 * endianness of the computer system.
82 * On Mac OS X however, little endian devices are also common.
84 static const uint8_t p_sync_le[6] = { 0x72, 0xF8, 0x1F, 0x4E, 0x01, 0x00 };
85 static const uint8_t p_sync_be[6] = { 0xF8, 0x72, 0x4E, 0x1F, 0x00, 0x01 };
86 uint16_t i_frame_size = p_in_buf->i_buffer / 2;
87 uint8_t * p_in = p_in_buf->p_buffer;
89 block_t *p_out_buf = filter_NewAudioBuffer( p_filter, AOUT_SPDIF_SIZE );
92 uint8_t * p_out = p_out_buf->p_buffer;
94 /* Copy the S/PDIF headers. */
95 if( p_filter->fmt_out.audio.i_format == VLC_CODEC_SPDIFB )
97 vlc_memcpy( p_out, p_sync_be, 6 );
98 p_out[4] = p_in[5] & 0x7; /* bsmod */
99 p_out[6] = (i_frame_size >> 4) & 0xff;
100 p_out[7] = (i_frame_size << 4) & 0xff;
101 vlc_memcpy( &p_out[8], p_in, i_frame_size * 2 );
105 vlc_memcpy( p_out, p_sync_le, 6 );
106 p_out[5] = p_in[5] & 0x7; /* bsmod */
107 p_out[6] = (i_frame_size << 4) & 0xff;
108 p_out[7] = (i_frame_size >> 4) & 0xff;
109 swab( p_in, &p_out[8], i_frame_size * 2 );
111 vlc_memset( p_out + 8 + i_frame_size * 2, 0,
112 AOUT_SPDIF_SIZE - i_frame_size * 2 - 8 );
114 p_out_buf->i_dts = p_in_buf->i_dts;
115 p_out_buf->i_pts = p_in_buf->i_pts;
116 p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
117 p_out_buf->i_buffer = AOUT_SPDIF_SIZE;
119 block_Release( p_in_buf );