1 /*****************************************************************************
2 * a52.c : raw A/52 stream input module for vlc
3 *****************************************************************************
4 * Copyright (C) 2001 VideoLAN
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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
22 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
28 #include <vlc/input.h>
29 #include <vlc_codec.h>
35 /*****************************************************************************
37 *****************************************************************************/
38 static int Open ( vlc_object_t * );
39 static void Close ( vlc_object_t * );
42 set_description( _("Raw A/52 demuxer") );
43 set_capability( "demux2", 145 );
44 set_callbacks( Open, Close );
45 add_shortcut( "a52" );
48 /*****************************************************************************
50 *****************************************************************************/
51 static int Demux ( demux_t * );
52 static int Control( demux_t *, int, va_list );
60 decoder_t *p_packetizer;
63 vlc_bool_t b_big_endian;
66 static int CheckSync( uint8_t *p_peek, vlc_bool_t *p_big_endian );
68 #define PCM_FRAME_SIZE (1536 * 4)
69 #define A52_PACKET_SIZE (4 * PCM_FRAME_SIZE)
70 #define A52_MAX_HEADER_SIZE 10
73 /*****************************************************************************
74 * Open: initializes ES structures
75 *****************************************************************************/
76 static int Open( vlc_object_t * p_this )
78 demux_t *p_demux = (demux_t*)p_this;
82 vlc_bool_t b_big_endian;
84 /* Check if we are dealing with a WAV file */
85 if( stream_Peek( p_demux->s, &p_peek, 12 ) == 12 &&
86 !strncmp( p_peek, "RIFF", 4 ) && !strncmp( &p_peek[8], "WAVE", 4 ) )
90 /* Skip the wave header */
92 while( stream_Peek( p_demux->s, &p_peek, i_peek ) == i_peek &&
93 strncmp( p_peek + i_peek - 8, "data", 4 ) )
95 i_peek += GetDWLE( p_peek + i_peek - 4 ) + 8;
98 /* TODO: should check wave format and sample_rate */
100 /* Some A52 wav files don't begin with a sync code so we do a more
101 * extensive search */
102 i_size = stream_Peek( p_demux->s, &p_peek, i_peek + A52_PACKET_SIZE * 2);
103 i_size -= (PCM_FRAME_SIZE + A52_MAX_HEADER_SIZE);
105 while( i_peek < i_size )
107 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
108 /* The data is stored in 16 bits words */
112 /* Check following sync code */
113 if( CheckSync( p_peek + i_peek + PCM_FRAME_SIZE,
114 &b_big_endian ) != VLC_SUCCESS )
125 /* Have a peep at the show. */
126 if( stream_Peek( p_demux->s, &p_peek, i_peek + A52_MAX_HEADER_SIZE * 2 ) <
127 i_peek + A52_MAX_HEADER_SIZE * 2 )
129 /* Stream too short */
130 msg_Warn( p_demux, "cannot peek()" );
134 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
136 if( strncmp( p_demux->psz_demux, "a52", 3 ) )
142 msg_Err( p_demux, "this doesn't look like a A52 audio stream, "
143 "continuing anyway" );
146 /* Fill p_demux fields */
147 p_demux->pf_demux = Demux;
148 p_demux->pf_control = Control;
149 p_demux->p_sys = p_sys = malloc( sizeof( demux_sys_t ) );
150 p_sys->b_start = VLC_TRUE;
151 p_sys->i_mux_rate = 0;
152 p_sys->b_big_endian = b_big_endian;
155 * Load the A52 packetizer
157 p_sys->p_packetizer = vlc_object_create( p_demux, VLC_OBJECT_DECODER );
158 p_sys->p_packetizer->pf_decode_audio = 0;
159 p_sys->p_packetizer->pf_decode_video = 0;
160 p_sys->p_packetizer->pf_decode_sub = 0;
161 p_sys->p_packetizer->pf_packetize = 0;
163 /* Initialization of decoder structure */
164 es_format_Init( &p_sys->p_packetizer->fmt_in, AUDIO_ES,
165 VLC_FOURCC( 'a', '5', '2', ' ' ) );
167 p_sys->p_packetizer->p_module =
168 module_Need( p_sys->p_packetizer, "packetizer", NULL, 0 );
169 if( !p_sys->p_packetizer->p_module )
171 msg_Err( p_demux, "cannot find A52 packetizer" );
175 /* Create one program */
176 p_sys->p_es = es_out_Add( p_demux->out, &p_sys->p_packetizer->fmt_in );
181 /*****************************************************************************
182 * Close: frees unused data
183 *****************************************************************************/
184 static void Close( vlc_object_t * p_this )
186 demux_t *p_demux = (demux_t*)p_this;
187 demux_sys_t *p_sys = p_demux->p_sys;
190 module_Unneed( p_sys->p_packetizer, p_sys->p_packetizer->p_module );
192 /* Delete the decoder */
193 vlc_object_destroy( p_sys->p_packetizer );
198 /*****************************************************************************
199 * Demux: reads and demuxes data packets
200 *****************************************************************************
201 * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
202 *****************************************************************************/
203 static int Demux( demux_t *p_demux )
205 demux_sys_t *p_sys = p_demux->p_sys;
206 block_t *p_block_in, *p_block_out;
209 int64_t i_pos = stream_Tell( p_demux->s );
210 if( i_pos % 2 ) stream_Read( p_demux->s, NULL, 1 );
212 if( !( p_block_in = stream_Block( p_demux->s, A52_PACKET_SIZE ) ) )
217 if( !p_sys->b_big_endian && p_block_in->i_buffer )
219 /* Convert to big endian */
222 swab(p_block_in->p_buffer, p_block_in->p_buffer, p_block_in->i_buffer);
227 p_tmp = p_block_in->p_buffer;
228 for( i = p_block_in->i_buffer / 2 ; i-- ; )
239 p_block_in->i_pts = p_block_in->i_dts = 1;
241 p_block_in->i_pts = p_block_in->i_dts = 0;
243 while( (p_block_out = p_sys->p_packetizer->pf_packetize(
244 p_sys->p_packetizer, &p_block_in )) )
246 p_sys->b_start = VLC_FALSE;
250 block_t *p_next = p_block_out->p_next;
252 /* We assume a constant bitrate */
253 if( p_block_out->i_length )
256 p_block_out->i_buffer * I64C(1000000)/p_block_out->i_length;
260 es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
262 es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
264 p_block_out = p_next;
271 /*****************************************************************************
273 *****************************************************************************/
274 static int Control( demux_t *p_demux, int i_query, va_list args )
276 demux_sys_t *p_sys = p_demux->p_sys;
277 if( i_query == DEMUX_SET_TIME )
280 return demux2_vaControlHelper( p_demux->s,
282 8*p_sys->i_mux_rate, 1, i_query, args );
285 /*****************************************************************************
286 * CheckSync: Check if buffer starts with an A52 sync code
287 *****************************************************************************/
288 static int CheckSync( uint8_t *p_peek, vlc_bool_t *p_big_endian )
290 /* Little endian version of the bitstream */
291 if( p_peek[0] == 0x77 && p_peek[1] == 0x0b &&
292 p_peek[4] < 0x60 /* bsid < 12 */ )
294 *p_big_endian = VLC_FALSE;
297 /* Big endian version of the bitstream */
298 else if( p_peek[0] == 0x0b && p_peek[1] == 0x77 &&
299 p_peek[5] < 0x60 /* bsid < 12 */ )
301 *p_big_endian = VLC_TRUE;