1 /*****************************************************************************
2 * a52.c : raw A/52 stream input module for vlc
3 *****************************************************************************
4 * Copyright (C) 2001-2007 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 *****************************************************************************/
31 #include <vlc_common.h>
32 #include <vlc_plugin.h>
33 #include <vlc_demux.h>
34 #include <vlc_codec.h>
40 /*****************************************************************************
42 *****************************************************************************/
43 static int Open ( vlc_object_t * );
44 static void Close ( vlc_object_t * );
47 set_category( CAT_INPUT );
48 set_subcategory( SUBCAT_INPUT_DEMUX );
49 set_description( N_("Raw A/52 demuxer") );
50 set_capability( "demux", 145 );
51 set_callbacks( Open, Close );
52 add_shortcut( "a52" );
55 /*****************************************************************************
57 *****************************************************************************/
58 static int Demux ( demux_t * );
59 static int Control( demux_t *, int, va_list );
67 decoder_t *p_packetizer;
70 mtime_t i_time_offset;
76 static int CheckSync( const uint8_t *p_peek, bool *p_big_endian );
78 #define PCM_FRAME_SIZE (1536 * 4)
79 #define A52_PACKET_SIZE (1024)
80 #define A52_PEEK_SIZE (4 * PCM_FRAME_SIZE)
81 #define A52_PROBE_SIZE (512*1024)
82 #define A52_MAX_HEADER_SIZE 10
84 /*****************************************************************************
85 * Open: initializes ES structures
86 *****************************************************************************/
87 static int Open( vlc_object_t * p_this )
89 demux_t *p_demux = (demux_t*)p_this;
91 const uint8_t *p_peek;
93 bool b_big_endian = 0; /* Arbitrary initialisation */
95 /* Check if we are dealing with a WAV file */
96 if( stream_Peek( p_demux->s, &p_peek, 12+8 ) == 12+8 &&
97 !memcmp( p_peek, "RIFF", 4 ) && !memcmp( &p_peek[8], "WAVE", 4 ) )
99 /* Skip the wave header */
101 while( memcmp( p_peek + i_peek - 8, "data", 4 ) )
103 uint32_t i_len = GetDWLE( p_peek + i_peek - 4 );
104 if( i_len > A52_PROBE_SIZE || i_peek + i_len > A52_PROBE_SIZE )
108 if( stream_Peek( p_demux->s, &p_peek, i_peek ) != i_peek )
112 /* TODO: should check wave format and sample_rate */
114 /* Some A52 wav files don't begin with a sync code so we do a more
115 * extensive search */
116 int i_size = stream_Peek( p_demux->s, &p_peek, i_peek + A52_PEEK_SIZE * 2);
117 i_size -= (PCM_FRAME_SIZE + A52_MAX_HEADER_SIZE);
119 while( i_peek < i_size )
121 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
122 /* The data is stored in 16 bits words */
126 /* Check following sync code */
127 if( CheckSync( p_peek + i_peek + PCM_FRAME_SIZE,
128 &b_big_endian ) != VLC_SUCCESS )
139 /* Have a peep at the show. */
140 CHECK_PEEK( p_peek, i_peek + A52_MAX_HEADER_SIZE * 2 );
142 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
144 if( !p_demux->b_force )
148 msg_Err( p_demux, "this doesn't look like a A52 audio stream, "
149 "continuing anyway" );
152 /* Fill p_demux fields */
153 DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;
154 p_sys->b_start = true;
155 p_sys->i_mux_rate = 0;
156 p_sys->b_big_endian = b_big_endian;
158 p_sys->i_time_offset = 0;
160 /* Load the A52 packetizer */
161 INIT_APACKETIZER( p_sys->p_packetizer, 'a', '5', '2', ' ' );
162 LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "A52" );
164 /* Create one program */
165 p_sys->p_es = es_out_Add( p_demux->out, &p_sys->p_packetizer->fmt_in );
170 /*****************************************************************************
171 * Close: frees unused data
172 *****************************************************************************/
173 static void Close( vlc_object_t * p_this )
175 demux_t *p_demux = (demux_t*)p_this;
176 demux_sys_t *p_sys = p_demux->p_sys;
178 DESTROY_PACKETIZER( p_sys->p_packetizer );
182 /*****************************************************************************
183 * Demux: reads and demuxes data packets
184 *****************************************************************************
185 * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
186 *****************************************************************************/
187 static int Demux( demux_t *p_demux )
189 demux_sys_t *p_sys = p_demux->p_sys;
190 block_t *p_block_in, *p_block_out;
193 int64_t i_pos = stream_Tell( p_demux->s );
194 if( i_pos % 2 ) stream_Read( p_demux->s, NULL, 1 );
196 if( !( p_block_in = stream_Block( p_demux->s, A52_PACKET_SIZE ) ) )
201 if( !p_sys->b_big_endian && p_block_in->i_buffer )
203 /* Convert to big endian */
206 swab(p_block_in->p_buffer, p_block_in->p_buffer, p_block_in->i_buffer);
211 p_tmp = p_block_in->p_buffer;
212 for( i = p_block_in->i_buffer / 2 ; i-- ; )
223 p_block_in->i_pts = p_block_in->i_dts = 1;
225 p_block_in->i_pts = p_block_in->i_dts = 0;
227 while( (p_block_out = p_sys->p_packetizer->pf_packetize(
228 p_sys->p_packetizer, &p_block_in )) )
230 p_sys->b_start = false;
234 block_t *p_next = p_block_out->p_next;
236 /* We assume a constant bitrate */
237 if( p_block_out->i_length )
240 p_block_out->i_buffer * INT64_C(1000000)/p_block_out->i_length;
242 p_sys->i_pts = p_block_out->i_pts;
244 /* Correct timestamp */
245 p_block_out->i_pts += p_sys->i_time_offset;
246 p_block_out->i_dts += p_sys->i_time_offset;
249 es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
251 es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
253 p_block_out = p_next;
260 /*****************************************************************************
262 *****************************************************************************/
263 static int Control( demux_t *p_demux, int i_query, va_list args )
265 demux_sys_t *p_sys = p_demux->p_sys;
272 case DEMUX_HAS_UNSUPPORTED_META:
273 pb_bool = (bool*)va_arg( args, bool* );
278 pi64 = (int64_t*)va_arg( args, int64_t * );
279 *pi64 = p_sys->i_pts + p_sys->i_time_offset;
282 case DEMUX_SET_TIME: /* TODO implement a high precicsion seek */
284 i_ret = demux_vaControlHelper( p_demux->s,
286 8*p_sys->i_mux_rate, 1, i_query, args );
287 if( !i_ret && p_sys->i_mux_rate > 0 &&
288 ( i_query == DEMUX_SET_POSITION || i_query == DEMUX_SET_TIME ) )
291 const int64_t i_time = INT64_C(1000000) * stream_Tell(p_demux->s) /
294 /* Fix time_offset */
296 p_sys->i_time_offset = i_time - p_sys->i_pts;
302 /*****************************************************************************
303 * CheckSync: Check if buffer starts with an A52 sync code
304 *****************************************************************************/
305 static int CheckSync( const uint8_t *p_peek, bool *p_big_endian )
307 /* Little endian version of the bitstream */
308 if( p_peek[0] == 0x77 && p_peek[1] == 0x0b &&
309 p_peek[4] < 0x60 /* bsid < 12 */ )
311 *p_big_endian = false;
314 /* Big endian version of the bitstream */
315 else if( p_peek[0] == 0x0b && p_peek[1] == 0x77 &&
316 p_peek[5] < 0x60 /* bsid < 12 */ )
318 *p_big_endian = true;