1 /*****************************************************************************
2 * a52tospdif.c : encapsulates A/52 frames into S/PDIF packets
3 *****************************************************************************
4 * Copyright (C) 2002 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
23 *****************************************************************************/
25 /*****************************************************************************
27 *****************************************************************************/
28 #include <stdlib.h> /* malloc(), free() */
37 #include "audio_output.h"
38 #include "aout_internal.h"
40 /*****************************************************************************
42 *****************************************************************************/
43 static int Create ( vlc_object_t * );
44 static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
47 /*****************************************************************************
49 *****************************************************************************/
51 set_category( CAT_AUDIO );
52 set_subcategory( SUBCAT_AUDIO_MISC );
53 set_description( _("audio filter for A/52->S/PDIF encapsulation") );
54 set_capability( "audio filter", 10 );
55 set_callbacks( Create, NULL );
58 /*****************************************************************************
60 *****************************************************************************/
61 static int Create( vlc_object_t *p_this )
63 aout_filter_t * p_filter = (aout_filter_t *)p_this;
65 if ( p_filter->input.i_format != VLC_FOURCC('a','5','2',' ')
66 || p_filter->output.i_format != VLC_FOURCC('s','p','d','i') )
71 p_filter->pf_do_work = DoWork;
72 p_filter->b_in_place = 0;
77 /*****************************************************************************
78 * DoWork: convert a buffer
79 *****************************************************************************/
80 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
81 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
83 /* It is not entirely clear which endianness the AC3 stream should have.
84 * I have been told endianness does not matter, AC3 can be both endian.
85 * But then, I could not get it to work on Mac OS X and a JVC RX-6000R
86 * decoder without using little endian. So right now, I convert to little
90 static const uint8_t p_sync[6] = { 0x72, 0xF8, 0x1F, 0x4E, 0x01, 0x00 };
95 uint16_t i_length = p_in_buf->i_nb_bytes;
97 byte_t * p_in = p_in_buf->p_buffer;
98 byte_t * p_out = p_out_buf->p_buffer;
100 /* Copy the S/PDIF headers. */
101 memcpy( p_out, p_sync, 6 );
102 pi_length = (p_out + 6);
103 *pi_length = (i_length * 8) & 0xff;
104 *(pi_length + 1) = (i_length * 8) >> 8;
107 swab( p_in, p_out + 8, i_length );
110 for ( i = i_length / 2 ; i-- ; )
114 p_tmp += 2; p_in += 2;
118 p_filter->p_vlc->pf_memset( p_out + 8 + i_length, 0,
119 AOUT_SPDIF_SIZE - i_length - 8 );
121 p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
122 p_out_buf->i_nb_bytes = AOUT_SPDIF_SIZE;