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 *****************************************************************************/
32 #include <vlc_demux.h>
33 #include <vlc_codec.h>
39 /*****************************************************************************
41 *****************************************************************************/
42 static int Open ( vlc_object_t * );
43 static void Close ( vlc_object_t * );
46 set_category( CAT_INPUT );
47 set_subcategory( SUBCAT_INPUT_DEMUX );
48 set_description( _("Raw A/52 demuxer") );
49 set_capability( "demux", 145 );
50 set_callbacks( Open, Close );
51 add_shortcut( "a52" );
54 /*****************************************************************************
56 *****************************************************************************/
57 static int Demux ( demux_t * );
58 static int Control( demux_t *, int, va_list );
66 decoder_t *p_packetizer;
72 static int CheckSync( const uint8_t *p_peek, bool *p_big_endian );
74 #define PCM_FRAME_SIZE (1536 * 4)
75 #define A52_PACKET_SIZE (4 * PCM_FRAME_SIZE)
76 #define A52_MAX_HEADER_SIZE 10
79 /*****************************************************************************
80 * Open: initializes ES structures
81 *****************************************************************************/
82 static int Open( vlc_object_t * p_this )
84 demux_t *p_demux = (demux_t*)p_this;
86 const uint8_t *p_peek;
88 bool b_big_endian = 0; /* Arbitrary initialisation */
90 /* Check if we are dealing with a WAV file */
91 if( stream_Peek( p_demux->s, &p_peek, 12 ) == 12 &&
92 !memcmp( p_peek, "RIFF", 4 ) && !memcmp( p_peek + 8, "WAVE", 4 ) )
96 /* Skip the wave header */
98 while( stream_Peek( p_demux->s, &p_peek, i_peek ) == i_peek &&
99 memcmp( p_peek + i_peek - 8, "data", 4 ) )
101 i_peek += GetDWLE( p_peek + i_peek - 4 ) + 8;
104 /* TODO: should check wave format and sample_rate */
106 /* Some A52 wav files don't begin with a sync code so we do a more
107 * extensive search */
108 i_size = stream_Peek( p_demux->s, &p_peek, i_peek + A52_PACKET_SIZE * 2);
109 i_size -= (PCM_FRAME_SIZE + A52_MAX_HEADER_SIZE);
111 while( i_peek < i_size )
113 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
114 /* The data is stored in 16 bits words */
118 /* Check following sync code */
119 if( CheckSync( p_peek + i_peek + PCM_FRAME_SIZE,
120 &b_big_endian ) != VLC_SUCCESS )
131 /* Have a peep at the show. */
132 CHECK_PEEK( p_peek, i_peek + A52_MAX_HEADER_SIZE * 2 );
134 if( CheckSync( p_peek + i_peek, &b_big_endian ) != VLC_SUCCESS )
136 if( !p_demux->b_force )
140 msg_Err( p_demux, "this doesn't look like a A52 audio stream, "
141 "continuing anyway" );
144 /* Fill p_demux fields */
145 DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;
146 p_sys->b_start = true;
147 p_sys->i_mux_rate = 0;
148 p_sys->b_big_endian = b_big_endian;
150 /* Load the A52 packetizer */
151 INIT_APACKETIZER( p_sys->p_packetizer, 'a', '5', '2', ' ' );
152 LOAD_PACKETIZER_OR_FAIL( p_sys->p_packetizer, "A52" );
154 /* Create one program */
155 p_sys->p_es = es_out_Add( p_demux->out, &p_sys->p_packetizer->fmt_in );
160 /*****************************************************************************
161 * Close: frees unused data
162 *****************************************************************************/
163 static void Close( vlc_object_t * p_this )
165 demux_t *p_demux = (demux_t*)p_this;
166 demux_sys_t *p_sys = p_demux->p_sys;
168 DESTROY_PACKETIZER( p_sys->p_packetizer );
172 /*****************************************************************************
173 * Demux: reads and demuxes data packets
174 *****************************************************************************
175 * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
176 *****************************************************************************/
177 static int Demux( demux_t *p_demux )
179 demux_sys_t *p_sys = p_demux->p_sys;
180 block_t *p_block_in, *p_block_out;
183 int64_t i_pos = stream_Tell( p_demux->s );
184 if( i_pos % 2 ) stream_Read( p_demux->s, NULL, 1 );
186 if( !( p_block_in = stream_Block( p_demux->s, A52_PACKET_SIZE ) ) )
191 if( !p_sys->b_big_endian && p_block_in->i_buffer )
193 /* Convert to big endian */
196 swab(p_block_in->p_buffer, p_block_in->p_buffer, p_block_in->i_buffer);
201 p_tmp = p_block_in->p_buffer;
202 for( i = p_block_in->i_buffer / 2 ; i-- ; )
213 p_block_in->i_pts = p_block_in->i_dts = 1;
215 p_block_in->i_pts = p_block_in->i_dts = 0;
217 while( (p_block_out = p_sys->p_packetizer->pf_packetize(
218 p_sys->p_packetizer, &p_block_in )) )
220 p_sys->b_start = false;
224 block_t *p_next = p_block_out->p_next;
226 /* We assume a constant bitrate */
227 if( p_block_out->i_length )
230 p_block_out->i_buffer * INT64_C(1000000)/p_block_out->i_length;
234 es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block_out->i_dts );
236 es_out_Send( p_demux->out, p_sys->p_es, p_block_out );
238 p_block_out = p_next;
245 /*****************************************************************************
247 *****************************************************************************/
248 static int Control( demux_t *p_demux, int i_query, va_list args )
250 demux_sys_t *p_sys = p_demux->p_sys;
251 if( i_query == DEMUX_SET_TIME )
255 else if( i_query == DEMUX_HAS_UNSUPPORTED_META )
257 bool *pb_bool = (bool*)va_arg( args, bool* );
263 return demux_vaControlHelper( p_demux->s,
265 8*p_sys->i_mux_rate, 1, i_query, args );
269 /*****************************************************************************
270 * CheckSync: Check if buffer starts with an A52 sync code
271 *****************************************************************************/
272 static int CheckSync( const uint8_t *p_peek, bool *p_big_endian )
274 /* Little endian version of the bitstream */
275 if( p_peek[0] == 0x77 && p_peek[1] == 0x0b &&
276 p_peek[4] < 0x60 /* bsid < 12 */ )
278 *p_big_endian = false;
281 /* Big endian version of the bitstream */
282 else if( p_peek[0] == 0x0b && p_peek[1] == 0x77 &&
283 p_peek[5] < 0x60 /* bsid < 12 */ )
285 *p_big_endian = true;