1 /*****************************************************************************
2 * a52.c : raw A/52 stream input module for vlc
3 *****************************************************************************
4 * Copyright (C) 2001 the VideoLAN team
7 * Authors: Gildas Bazin <gbazin@netcourrier.com>
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.
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.
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 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
28 #include <vlc_demux.h>
29 #include <vlc_codec.h>
35 /*****************************************************************************
37 *****************************************************************************/
38 static int Open ( vlc_object_t * );
39 static void Close ( vlc_object_t * );
42 set_category( CAT_INPUT );
43 set_subcategory( SUBCAT_INPUT_DEMUX );
44 set_description( _("Raw A/52 demuxer") );
45 set_capability( "demux2", 145 );
46 set_callbacks( Open, Close );
47 add_shortcut( "a52" );
50 /*****************************************************************************
52 *****************************************************************************/
53 static int Demux ( demux_t * );
54 static int Control( demux_t *, int, va_list );
62 decoder_t *p_packetizer;
65 vlc_bool_t b_big_endian;
68 static int CheckSync( uint8_t *p_peek, vlc_bool_t *p_big_endian );
70 #define PCM_FRAME_SIZE (1536 * 4)
71 #define A52_PACKET_SIZE (4 * PCM_FRAME_SIZE)
72 #define A52_MAX_HEADER_SIZE 10
75 /*****************************************************************************
76 * Open: initializes ES structures
77 *****************************************************************************/
78 static int Open( vlc_object_t * p_this )
80 demux_t *p_demux = (demux_t*)p_this;
84 vlc_bool_t b_big_endian = 0; /* Arbitrary initialisation */
86 /* Check if we are dealing with a WAV file */
87 if( stream_Peek( p_demux->s, &p_peek, 12 ) == 12 &&
88 !memcmp( p_peek, "RIFF", 4 ) && !memcmp( p_peek + 8, "WAVE", 4 ) )
92 /* Skip the wave header */
94 while( stream_Peek( p_demux->s, &p_peek, i_peek ) == i_peek &&
95 memcmp( p_peek + i_peek - 8, "data", 4 ) )
97 i_peek += GetDWLE( p_peek + i_peek - 4 ) + 8;
100 /* TODO: should check wave format and sample_rate */
102 /* Some A52 wav files don't begin with a sync code so we do a more
103 * extensive search */
104 i_size = stream_Peek( p_demux->s, &p_peek, i_peek + A52_PACKET_SIZE * 2);
105 i_size -= (PCM_FRAME_SIZE + A52_MAX_HEADER_SIZE);
107 while( i_peek < i_size )
109 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
110 /* The data is stored in 16 bits words */
114 /* Check following sync code */
115 if( CheckSync( p_peek + i_peek + PCM_FRAME_SIZE,
116 &b_big_endian ) != VLC_SUCCESS )
127 /* Have a peep at the show. */
128 CHECK_PEEK( p_peek, i_peek + A52_MAX_HEADER_SIZE * 2 );
130 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
132 if( strncmp( p_demux->psz_demux, "a52", 3 ) )
138 msg_Err( p_demux, "this doesn't look like a A52 audio stream, "
139 "continuing anyway" );
142 /* Fill p_demux fields */
143 STANDARD_DEMUX_INIT; p_sys = p_demux->p_sys;
144 p_sys->b_start = VLC_TRUE;
145 p_sys->i_mux_rate = 0;
146 p_sys->b_big_endian = b_big_endian;
148 /* Load the A52 packetizer */
149 INIT_APACKETIZER( p_sys->p_packetizer, 'a', '5', '2', ' ' );
150 LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "A52" );
152 /* Create one program */
153 p_sys->p_es = es_out_Add( p_demux->out, &p_sys->p_packetizer->fmt_in );
158 /*****************************************************************************
159 * Close: frees unused data
160 *****************************************************************************/
161 static void Close( vlc_object_t * p_this )
163 demux_t *p_demux = (demux_t*)p_this;
164 demux_sys_t *p_sys = p_demux->p_sys;
166 DESTROY_PACKETIZER( p_sys->p_packetizer );
170 /*****************************************************************************
171 * Demux: reads and demuxes data packets
172 *****************************************************************************
173 * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
174 *****************************************************************************/
175 static int Demux( demux_t *p_demux )
177 demux_sys_t *p_sys = p_demux->p_sys;
178 block_t *p_block_in, *p_block_out;
181 int64_t i_pos = stream_Tell( p_demux->s );
182 if( i_pos % 2 ) stream_Read( p_demux->s, NULL, 1 );
184 if( !( p_block_in = stream_Block( p_demux->s, A52_PACKET_SIZE ) ) )
189 if( !p_sys->b_big_endian && p_block_in->i_buffer )
191 /* Convert to big endian */
194 swab(p_block_in->p_buffer, p_block_in->p_buffer, p_block_in->i_buffer);
199 p_tmp = p_block_in->p_buffer;
200 for( i = p_block_in->i_buffer / 2 ; i-- ; )
211 p_block_in->i_pts = p_block_in->i_dts = 1;
213 p_block_in->i_pts = p_block_in->i_dts = 0;
215 while( (p_block_out = p_sys->p_packetizer->pf_packetize(
216 p_sys->p_packetizer, &p_block_in )) )
218 p_sys->b_start = VLC_FALSE;
222 block_t *p_next = p_block_out->p_next;
224 /* We assume a constant bitrate */
225 if( p_block_out->i_length )
228 p_block_out->i_buffer * I64C(1000000)/p_block_out->i_length;
232 es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
234 es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
236 p_block_out = p_next;
243 /*****************************************************************************
245 *****************************************************************************/
246 static int Control( demux_t *p_demux, int i_query, va_list args )
248 demux_sys_t *p_sys = p_demux->p_sys;
249 if( i_query == DEMUX_SET_TIME )
252 return demux2_vaControlHelper( p_demux->s,
254 8*p_sys->i_mux_rate, 1, i_query, args );
257 /*****************************************************************************
258 * CheckSync: Check if buffer starts with an A52 sync code
259 *****************************************************************************/
260 static int CheckSync( uint8_t *p_peek, vlc_bool_t *p_big_endian )
262 /* Little endian version of the bitstream */
263 if( p_peek[0] == 0x77 && p_peek[1] == 0x0b &&
264 p_peek[4] < 0x60 /* bsid < 12 */ )
266 *p_big_endian = VLC_FALSE;
269 /* Big endian version of the bitstream */
270 else if( p_peek[0] == 0x0b && p_peek[1] == 0x77 &&
271 p_peek[5] < 0x60 /* bsid < 12 */ )
273 *p_big_endian = VLC_TRUE;