1 /*****************************************************************************
2 * lpcm.c: lpcm decoder/packetizer module
3 *****************************************************************************
4 * Copyright (C) 1999-2005 the VideoLAN team
7 * Authors: Samuel Hocevar <sam@zoy.org>
8 * Henri Fallon <henri@videolan.org>
9 * Christophe Massiot <massiot@via.ecp.fr>
10 * Gildas Bazin <gbazin@videolan.org>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
27 /*****************************************************************************
29 *****************************************************************************/
31 #include <vlc_codec.h>
34 /*****************************************************************************
35 * decoder_sys_t : lpcm decoder descriptor
36 *****************************************************************************/
40 vlc_bool_t b_packetizer;
45 audio_date_t end_date;
52 * - private stream ID (16 bits) == 0xA0 -> not in the bitstream
54 * - frame number (8 bits)
55 * - unknown (16 bits) == 0x0003 ?
57 * - current frame (4 bits)
59 * - frequency (2 bits) 0 == 48 kHz, 1 == 32 kHz, 2 == ?, 3 == ?
61 * - number of channels - 1 (3 bits) 1 == 2 channels
62 * - start code (8 bits) == 0x80
65 #define LPCM_HEADER_LEN 6
67 /*****************************************************************************
69 *****************************************************************************/
70 static int OpenDecoder ( vlc_object_t * );
71 static int OpenPacketizer( vlc_object_t * );
72 static void CloseDecoder ( vlc_object_t * );
74 static void *DecodeFrame ( decoder_t *, block_t ** );
76 /*****************************************************************************
78 *****************************************************************************/
81 set_category( CAT_INPUT );
82 set_subcategory( SUBCAT_INPUT_ACODEC );
83 set_description( _("Linear PCM audio decoder") );
84 set_capability( "decoder", 100 );
85 set_callbacks( OpenDecoder, CloseDecoder );
88 set_description( _("Linear PCM audio packetizer") );
89 set_capability( "packetizer", 100 );
90 set_callbacks( OpenPacketizer, CloseDecoder );
94 /*****************************************************************************
95 * OpenDecoder: probe the decoder and return score
96 *****************************************************************************/
97 static int OpenDecoder( vlc_object_t *p_this )
99 decoder_t *p_dec = (decoder_t*)p_this;
100 decoder_sys_t *p_sys;
102 if( p_dec->fmt_in.i_codec != VLC_FOURCC('l','p','c','m')
103 && p_dec->fmt_in.i_codec != VLC_FOURCC('l','p','c','b') )
108 /* Allocate the memory needed to store the decoder's structure */
109 if( ( p_dec->p_sys = p_sys =
110 (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
112 msg_Err( p_dec, "out of memory" );
117 p_sys->b_packetizer = VLC_FALSE;
118 aout_DateSet( &p_sys->end_date, 0 );
120 /* Set output properties */
121 p_dec->fmt_out.i_cat = AUDIO_ES;
123 if( p_dec->fmt_out.audio.i_bitspersample == 24 )
125 p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
129 p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
130 p_dec->fmt_out.audio.i_bitspersample = 16;
134 p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
136 p_dec->pf_packetize = (block_t *(*)(decoder_t *, block_t **))
142 static int OpenPacketizer( vlc_object_t *p_this )
144 decoder_t *p_dec = (decoder_t*)p_this;
146 int i_ret = OpenDecoder( p_this );
148 if( i_ret != VLC_SUCCESS ) return i_ret;
150 p_dec->p_sys->b_packetizer = VLC_TRUE;
152 p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
157 /*****************************************************************************
158 * DecodeFrame: decodes an lpcm frame.
159 ****************************************************************************
160 * Beware, this function must be fed with complete frames (PES packet).
161 *****************************************************************************/
162 static void *DecodeFrame( decoder_t *p_dec, block_t **pp_block )
164 decoder_sys_t *p_sys = p_dec->p_sys;
166 unsigned int i_rate = 0, i_original_channels = 0, i_channels = 0;
167 int i_frame_length, i_bitspersample;
170 if( !pp_block || !*pp_block ) return NULL;
173 *pp_block = NULL; /* So the packet doesn't get re-sent */
175 /* Date management */
176 if( p_block->i_pts > 0 &&
177 p_block->i_pts != aout_DateGet( &p_sys->end_date ) )
179 aout_DateSet( &p_sys->end_date, p_block->i_pts );
182 if( !aout_DateGet( &p_sys->end_date ) )
184 /* We've just started the stream, wait for the first PTS. */
185 block_Release( p_block );
189 if( p_block->i_buffer <= LPCM_HEADER_LEN )
191 msg_Err(p_dec, "frame is too short");
192 block_Release( p_block );
196 i_header = p_block->p_buffer[4];
197 switch ( (i_header >> 4) & 0x3 )
213 i_channels = (i_header & 0x7);
214 switch ( i_channels )
217 i_original_channels = AOUT_CHAN_CENTER;
220 i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
223 /* This is unsure. */
224 i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_LFE;
227 i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
228 | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
231 /* This is unsure. */
232 i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
233 | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
237 i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
238 | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
239 | AOUT_CHAN_CENTER | AOUT_CHAN_LFE;
242 i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
243 | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
244 | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
245 | AOUT_CHAN_MIDDLERIGHT;
248 i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
249 | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
250 | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
251 | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE;
255 switch ( (i_header >> 6) & 0x3 )
258 p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
259 p_dec->fmt_out.audio.i_bitspersample = 24;
260 i_bitspersample = 24;
263 p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
264 p_dec->fmt_out.audio.i_bitspersample = 24;
265 i_bitspersample = 20;
269 p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
270 p_dec->fmt_out.audio.i_bitspersample = 16;
271 i_bitspersample = 16;
275 /* Check frame sync and drop it. */
276 if( p_block->p_buffer[5] != 0x80 )
278 msg_Warn( p_dec, "no frame sync" );
279 block_Release( p_block );
283 /* Set output properties */
284 if( p_dec->fmt_out.audio.i_rate != i_rate )
286 aout_DateInit( &p_sys->end_date, i_rate );
287 aout_DateSet( &p_sys->end_date, p_block->i_pts );
289 p_dec->fmt_out.audio.i_rate = i_rate;
290 p_dec->fmt_out.audio.i_channels = i_channels + 1;
291 p_dec->fmt_out.audio.i_original_channels = i_original_channels;
292 p_dec->fmt_out.audio.i_physical_channels
293 = i_original_channels & AOUT_CHAN_PHYSMASK;
295 i_frame_length = (p_block->i_buffer - LPCM_HEADER_LEN) /
296 p_dec->fmt_out.audio.i_channels * 8 / i_bitspersample;
298 if( p_sys->b_packetizer )
300 p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
301 p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
303 aout_DateIncrement( &p_sys->end_date, i_frame_length ) -
306 /* Just pass on the incoming frame */
311 aout_buffer_t *p_aout_buffer;
312 p_aout_buffer = p_dec->pf_aout_buffer_new( p_dec, i_frame_length );
313 if( p_aout_buffer == NULL ) return NULL;
315 p_aout_buffer->start_date = aout_DateGet( &p_sys->end_date );
316 p_aout_buffer->end_date =
317 aout_DateIncrement( &p_sys->end_date, i_frame_length );
319 p_block->p_buffer += LPCM_HEADER_LEN;
320 p_block->i_buffer -= LPCM_HEADER_LEN;
322 /* 20/24 bits LPCM use special packing */
323 if( i_bitspersample == 24 )
325 uint8_t *p_out = p_aout_buffer->p_buffer;
327 while( p_block->i_buffer / 12 )
330 p_out[0] = p_block->p_buffer[0];
331 p_out[1] = p_block->p_buffer[1];
332 p_out[2] = p_block->p_buffer[8];
334 p_out[3] = p_block->p_buffer[2];
335 p_out[4] = p_block->p_buffer[3];
336 p_out[5] = p_block->p_buffer[9];
338 p_out[6] = p_block->p_buffer[4];
339 p_out[7] = p_block->p_buffer[5];
340 p_out[8] = p_block->p_buffer[10];
342 p_out[9] = p_block->p_buffer[6];
343 p_out[10] = p_block->p_buffer[7];
344 p_out[11] = p_block->p_buffer[11];
346 p_block->i_buffer -= 12;
347 p_block->p_buffer += 12;
351 else if( i_bitspersample == 20 )
353 uint8_t *p_out = p_aout_buffer->p_buffer;
355 while( p_block->i_buffer / 10 )
358 p_out[0] = p_block->p_buffer[0];
359 p_out[1] = p_block->p_buffer[1];
360 p_out[2] = p_block->p_buffer[8] & 0xF0;
362 p_out[3] = p_block->p_buffer[2];
363 p_out[4] = p_block->p_buffer[3];
364 p_out[5] = p_block->p_buffer[8] << 4;
366 p_out[6] = p_block->p_buffer[4];
367 p_out[7] = p_block->p_buffer[5];
368 p_out[8] = p_block->p_buffer[9] & 0xF0;
370 p_out[9] = p_block->p_buffer[6];
371 p_out[10] = p_block->p_buffer[7];
372 p_out[11] = p_block->p_buffer[9] << 4;
374 p_block->i_buffer -= 10;
375 p_block->p_buffer += 10;
381 memcpy( p_aout_buffer->p_buffer,
382 p_block->p_buffer, p_block->i_buffer );
385 block_Release( p_block );
386 return p_aout_buffer;
390 /*****************************************************************************
391 * CloseDecoder : lpcm decoder destruction
392 *****************************************************************************/
393 static void CloseDecoder( vlc_object_t *p_this )
395 decoder_t *p_dec = (decoder_t*)p_this;
396 free( p_dec->p_sys );