1 /*****************************************************************************
2  * common.c : audio output management of common data structures
3  *****************************************************************************
4  * Copyright (C) 2002-2007 VLC authors and VideoLAN
5  * $Id: f7dbc575578979ffa5588155fef8c08f4d2e14c5 $
6  *
7  * Authors: Christophe Massiot <massiot@via.ecp.fr>
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
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 Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public License
20  * along with this program; if not, write to the Free Software Foundation,
21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
22  *****************************************************************************/
23 
24 #ifdef HAVE_CONFIG_H
25 # include "config.h"
26 #endif
27 
28 #include <limits.h>
29 #include <assert.h>
30 
31 #include <vlc_common.h>
32 #include <vlc_aout.h>
33 #include "aout_internal.h"
34 
35 /*
36  * Formats management (internal and external)
37  */
38 
39 /*****************************************************************************
40  * aout_BitsPerSample : get the number of bits per sample
41  *****************************************************************************/
aout_BitsPerSample(vlc_fourcc_t i_format)42 unsigned int aout_BitsPerSample( vlc_fourcc_t i_format )
43 {
44     switch( vlc_fourcc_GetCodec( AUDIO_ES, i_format ) )
45     {
46     case VLC_CODEC_U8:
47     case VLC_CODEC_S8:
48     case VLC_CODEC_ALAW:
49     case VLC_CODEC_MULAW:
50         return 8;
51 
52     case VLC_CODEC_U16L:
53     case VLC_CODEC_S16L:
54     case VLC_CODEC_U16B:
55     case VLC_CODEC_S16B:
56         return 16;
57 
58     case VLC_CODEC_U24L:
59     case VLC_CODEC_S24L:
60     case VLC_CODEC_U24B:
61     case VLC_CODEC_S24B:
62         return 24;
63 
64     case VLC_CODEC_S24L32:
65     case VLC_CODEC_S24B32:
66     case VLC_CODEC_U32L:
67     case VLC_CODEC_U32B:
68     case VLC_CODEC_S32L:
69     case VLC_CODEC_S32B:
70     case VLC_CODEC_F32L:
71     case VLC_CODEC_F32B:
72         return 32;
73 
74     case VLC_CODEC_F64L:
75     case VLC_CODEC_F64B:
76         return 64;
77 
78     default:
79         /* For these formats the caller has to indicate the parameters
80          * by hand. */
81         return 0;
82     }
83 }
84 
85 /*****************************************************************************
86  * aout_FormatPrepare : compute the number of bytes per frame & frame length
87  *****************************************************************************/
aout_FormatPrepare(audio_sample_format_t * p_format)88 void aout_FormatPrepare( audio_sample_format_t * p_format )
89 {
90 
91     unsigned i_channels = aout_FormatNbChannels( p_format );
92     if( i_channels > 0 )
93         p_format->i_channels = i_channels;
94     p_format->i_bitspersample = aout_BitsPerSample( p_format->i_format );
95     if( p_format->i_bitspersample > 0 )
96     {
97         p_format->i_bytes_per_frame = ( p_format->i_bitspersample / 8 )
98                                     * p_format->i_channels;
99         p_format->i_frame_length = 1;
100     }
101 }
102 
103 /*****************************************************************************
104  * aout_FormatPrintChannels : print a channel in a human-readable form
105  *****************************************************************************/
aout_FormatPrintChannels(const audio_sample_format_t * p_format)106 const char * aout_FormatPrintChannels( const audio_sample_format_t * p_format )
107 {
108     if (p_format->channel_type == AUDIO_CHANNEL_TYPE_AMBISONICS)
109         return "Ambisonics";
110 
111     /* AUDIO_CHANNEL_TYPE_BITMAP */
112     switch ( p_format->i_physical_channels )
113     {
114     case AOUT_CHAN_LEFT:
115     case AOUT_CHAN_RIGHT:
116     case AOUT_CHAN_CENTER:
117         if ( (p_format->i_physical_channels & AOUT_CHAN_CENTER)
118               || (p_format->i_physical_channels
119                    & (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)) )
120             return "Mono";
121         else if ( p_format->i_physical_channels & AOUT_CHAN_LEFT )
122             return "Left";
123         return "Right";
124     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT:
125         if ( p_format->i_chan_mode & AOUT_CHANMODE_DOLBYSTEREO )
126             return "Dolby";
127         else if ( p_format->i_chan_mode & AOUT_CHANMODE_DUALMONO )
128             return "Dual-mono";
129         else if ( p_format->i_physical_channels == AOUT_CHAN_CENTER )
130             return "Stereo/Mono";
131         else if ( !(p_format->i_physical_channels & AOUT_CHAN_RIGHT) )
132             return "Stereo/Left";
133         else if ( !(p_format->i_physical_channels & AOUT_CHAN_LEFT) )
134             return "Stereo/Right";
135         return "Stereo";
136     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER:
137         return "3F";
138     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER:
139         return "2F1R";
140     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
141           | AOUT_CHAN_REARCENTER:
142         return "3F1R";
143     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
144           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT:
145         return "2F2R";
146     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
147           | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT:
148         return "2F2M";
149     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
150           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT:
151         return "3F2R";
152     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
153           | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT:
154         return "3F2M";
155 
156     case AOUT_CHAN_CENTER | AOUT_CHAN_LFE:
157         if ( (p_format->i_physical_channels & AOUT_CHAN_CENTER)
158               || (p_format->i_physical_channels
159                    & (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)) )
160             return "Mono/LFE";
161         else if ( p_format->i_physical_channels & AOUT_CHAN_LEFT )
162             return "Left/LFE";
163         return "Right/LFE";
164     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_LFE:
165         if ( p_format->i_chan_mode & AOUT_CHANMODE_DOLBYSTEREO )
166             return "Dolby/LFE";
167         else if ( p_format->i_chan_mode & AOUT_CHANMODE_DUALMONO )
168             return "Dual-mono/LFE";
169         else if ( p_format->i_physical_channels == AOUT_CHAN_CENTER )
170             return "Mono/LFE";
171         else if ( !(p_format->i_physical_channels & AOUT_CHAN_RIGHT) )
172             return "Stereo/Left/LFE";
173         else if ( !(p_format->i_physical_channels & AOUT_CHAN_LEFT) )
174             return "Stereo/Right/LFE";
175          return "Stereo/LFE";
176     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER | AOUT_CHAN_LFE:
177         return "3F/LFE";
178     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER
179           | AOUT_CHAN_LFE:
180         return "2F1R/LFE";
181     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
182           | AOUT_CHAN_REARCENTER | AOUT_CHAN_LFE:
183         return "3F1R/LFE";
184     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
185           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_LFE:
186         return "2F2R/LFE";
187     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
188           | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE:
189         return "2F2M/LFE";
190     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
191           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_LFE:
192         return "3F2R/LFE";
193     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
194           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_REARCENTER
195           | AOUT_CHAN_LFE:
196         return "3F3R/LFE";
197     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
198           | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE:
199         return "3F2M/LFE";
200     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
201           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_MIDDLELEFT
202           | AOUT_CHAN_MIDDLERIGHT:
203         return "2F2M2R";
204     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
205           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_MIDDLELEFT
206           | AOUT_CHAN_MIDDLERIGHT:
207         return "3F2M2R";
208     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
209           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_MIDDLELEFT
210           | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE:
211         return "3F2M2R/LFE";
212     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
213           | AOUT_CHAN_REARCENTER | AOUT_CHAN_MIDDLELEFT
214           | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE:
215         return "3F2M1R/LFE";
216     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
217           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_REARCENTER
218           | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE:
219         return "3F2M3R/LFE";
220     }
221 
222     return "Unknown-chan-mask";
223 }
224 
225 #undef aout_FormatPrint
226 /**
227  * Prints an audio sample format in a human-readable form.
228  */
aout_FormatPrint(vlc_object_t * obj,const char * psz_text,const audio_sample_format_t * p_format)229 void aout_FormatPrint( vlc_object_t *obj, const char *psz_text,
230                        const audio_sample_format_t *p_format )
231 {
232     msg_Dbg( obj, "%s '%4.4s' %d Hz %s frame=%d samples/%d bytes", psz_text,
233              (char *)&p_format->i_format, p_format->i_rate,
234              aout_FormatPrintChannels( p_format ),
235              p_format->i_frame_length, p_format->i_bytes_per_frame );
236 }
237 
238 #undef aout_FormatsPrint
239 /**
240  * Prints two formats in a human-readable form
241  */
aout_FormatsPrint(vlc_object_t * obj,const char * psz_text,const audio_sample_format_t * p_format1,const audio_sample_format_t * p_format2)242 void aout_FormatsPrint( vlc_object_t *obj, const char * psz_text,
243                         const audio_sample_format_t * p_format1,
244                         const audio_sample_format_t * p_format2 )
245 {
246     msg_Dbg( obj, "%s '%4.4s'->'%4.4s' %d Hz->%d Hz %s->%s",
247              psz_text,
248              (char *)&p_format1->i_format, (char *)&p_format2->i_format,
249              p_format1->i_rate, p_format2->i_rate,
250              aout_FormatPrintChannels( p_format1 ),
251              aout_FormatPrintChannels( p_format2 ) );
252 }
253 
254 /*****************************************************************************
255  * aout_CheckChannelReorder : Check if we need to do some channel re-ordering
256  *****************************************************************************/
aout_CheckChannelReorder(const uint32_t * chans_in,const uint32_t * chans_out,uint32_t mask,uint8_t * restrict table)257 unsigned aout_CheckChannelReorder( const uint32_t *chans_in,
258                                    const uint32_t *chans_out,
259                                    uint32_t mask, uint8_t *restrict table )
260 {
261     static_assert(AOUT_CHAN_MAX <= (sizeof (mask) * CHAR_BIT), "Missing bits");
262 
263     unsigned channels = 0;
264 
265     if( chans_in == NULL )
266         chans_in = pi_vlc_chan_order_wg4;
267     if( chans_out == NULL )
268         chans_out = pi_vlc_chan_order_wg4;
269 
270     for( unsigned i = 0; chans_in[i]; i++ )
271     {
272         const uint32_t chan = chans_in[i];
273         if( !(mask & chan) )
274             continue;
275 
276         unsigned index = 0;
277         for( unsigned j = 0; chan != chans_out[j]; j++ )
278             if( mask & chans_out[j] )
279                 index++;
280 
281         table[channels++] = index;
282     }
283 
284     for( unsigned i = 0; i < channels; i++ )
285         if( table[i] != i )
286             return channels;
287     return 0;
288 }
289 
290 /**
291  * Reorders audio samples within a block of linear audio interleaved samples.
292  * \param ptr start address of the block of samples
293  * \param bytes size of the block in bytes (must be a multiple of the product
294  *              of the channels count and the sample size)
295  * \param channels channels count (also length of the chans_table table)
296  * \param chans_table permutation table to reorder the channels
297  *                    (usually computed by aout_CheckChannelReorder())
298  * \param fourcc sample format (must be a linear sample format)
299  * \note The samples must be naturally aligned in memory.
300  */
aout_ChannelReorder(void * ptr,size_t bytes,uint8_t channels,const uint8_t * restrict chans_table,vlc_fourcc_t fourcc)301 void aout_ChannelReorder( void *ptr, size_t bytes, uint8_t channels,
302                           const uint8_t *restrict chans_table, vlc_fourcc_t fourcc )
303 {
304     if( unlikely(bytes == 0) )
305         return;
306 
307     assert( channels != 0 );
308 
309     /* The audio formats supported in audio output are inlined. For other
310      * formats (used in demuxers and muxers), memcpy() is used to avoid
311      * breaking type punning. */
312 #define REORDER_TYPE(type) \
313 do { \
314     const size_t frames = (bytes / sizeof (type)) / channels; \
315     type *buf = ptr; \
316 \
317     for( size_t i = 0; i < frames; i++ ) \
318     { \
319         type tmp[AOUT_CHAN_MAX]; \
320 \
321         for( size_t j = 0; j < channels; j++ ) \
322             tmp[chans_table[j]] = buf[j]; \
323         memcpy( buf, tmp, sizeof (type) * channels ); \
324         buf += channels; \
325     } \
326 } while(0)
327 
328     if( likely(channels <= AOUT_CHAN_MAX) )
329     {
330         switch( fourcc )
331         {
332             case VLC_CODEC_U8:   REORDER_TYPE(uint8_t); return;
333             case VLC_CODEC_S16N: REORDER_TYPE(int16_t); return;
334             case VLC_CODEC_FL32: REORDER_TYPE(float);   return;
335             case VLC_CODEC_S32N: REORDER_TYPE(int32_t); return;
336             case VLC_CODEC_FL64: REORDER_TYPE(double);  return;
337         }
338     }
339 
340     unsigned size = aout_BitsPerSample( fourcc ) / 8;
341     assert( size != 0 && size <= 8 );
342 
343     const size_t frames = bytes / (size * channels);
344     unsigned char *buf = ptr;
345 
346     for( size_t i = 0; i < frames; i++ )
347     {
348         unsigned char tmp[256 * 8];
349 
350         for( size_t j = 0; j < channels; j++ )
351              memcpy( tmp + size * chans_table[j], buf + size * j, size );
352          memcpy( buf, tmp, size * channels );
353          buf += size * channels;
354     }
355 }
356 
357 /**
358  * Interleaves audio samples within a block of samples.
359  * \param dst destination buffer for interleaved samples
360  * \param srcv source buffers (one per plane) of uninterleaved samples
361  * \param samples number of samples (per channel/per plane)
362  * \param chans channels/planes count
363  * \param fourcc sample format (must be a linear sample format)
364  * \note The samples must be naturally aligned in memory.
365  * \warning Destination and source buffers MUST NOT overlap.
366  */
aout_Interleave(void * restrict dst,const void * const * srcv,unsigned samples,unsigned chans,vlc_fourcc_t fourcc)367 void aout_Interleave( void *restrict dst, const void *const *srcv,
368                       unsigned samples, unsigned chans, vlc_fourcc_t fourcc )
369 {
370 #define INTERLEAVE_TYPE(type) \
371 do { \
372     type *d = dst; \
373     for( size_t i = 0; i < chans; i++ ) { \
374         const type *s = srcv[i]; \
375         for( size_t j = 0, k = 0; j < samples; j++, k += chans ) \
376             d[k] = *(s++); \
377         d++; \
378     } \
379 } while(0)
380 
381     switch( fourcc )
382     {
383         case VLC_CODEC_U8:   INTERLEAVE_TYPE(uint8_t);  break;
384         case VLC_CODEC_S16N: INTERLEAVE_TYPE(int16_t);  break;
385         case VLC_CODEC_FL32: INTERLEAVE_TYPE(float);    break;
386         case VLC_CODEC_S32N: INTERLEAVE_TYPE(int32_t);  break;
387         case VLC_CODEC_FL64: INTERLEAVE_TYPE(double);   break;
388         default:             vlc_assert_unreachable();
389     }
390 #undef INTERLEAVE_TYPE
391 }
392 
393 /**
394  * Deinterleaves audio samples within a block of samples.
395  * \param dst destination buffer for planar samples
396  * \param src source buffer with interleaved samples
397  * \param samples number of samples (per channel/per plane)
398  * \param chans channels/planes count
399  * \param fourcc sample format (must be a linear sample format)
400  * \note The samples must be naturally aligned in memory.
401  * \warning Destination and source buffers MUST NOT overlap.
402  */
aout_Deinterleave(void * restrict dst,const void * restrict src,unsigned samples,unsigned chans,vlc_fourcc_t fourcc)403 void aout_Deinterleave( void *restrict dst, const void *restrict src,
404                       unsigned samples, unsigned chans, vlc_fourcc_t fourcc )
405 {
406 #define DEINTERLEAVE_TYPE(type) \
407 do { \
408     type *d = dst; \
409     const type *s = src; \
410     for( size_t i = 0; i < chans; i++ ) { \
411         for( size_t j = 0, k = 0; j < samples; j++, k += chans ) \
412             *(d++) = s[k]; \
413         s++; \
414     } \
415 } while(0)
416 
417     switch( fourcc )
418     {
419         case VLC_CODEC_U8:   DEINTERLEAVE_TYPE(uint8_t);  break;
420         case VLC_CODEC_S16N: DEINTERLEAVE_TYPE(int16_t);  break;
421         case VLC_CODEC_FL32: DEINTERLEAVE_TYPE(float);    break;
422         case VLC_CODEC_S32N: DEINTERLEAVE_TYPE(int32_t);  break;
423         case VLC_CODEC_FL64: DEINTERLEAVE_TYPE(double);   break;
424         default:             vlc_assert_unreachable();
425     }
426 #undef DEINTERLEAVE_TYPE
427 }
428 
429 /*****************************************************************************
430  * aout_ChannelExtract:
431  *****************************************************************************/
ExtractChannel(uint8_t * pi_dst,int i_dst_channels,const uint8_t * pi_src,int i_src_channels,int i_sample_count,const int * pi_selection,int i_bytes)432 static inline void ExtractChannel( uint8_t *pi_dst, int i_dst_channels,
433                                    const uint8_t *pi_src, int i_src_channels,
434                                    int i_sample_count,
435                                    const int *pi_selection, int i_bytes )
436 {
437     for( int i = 0; i < i_sample_count; i++ )
438     {
439         for( int j = 0; j < i_dst_channels; j++ )
440             memcpy( &pi_dst[j * i_bytes], &pi_src[pi_selection[j] * i_bytes], i_bytes );
441         pi_dst += i_dst_channels * i_bytes;
442         pi_src += i_src_channels * i_bytes;
443     }
444 }
445 
aout_ChannelExtract(void * p_dst,int i_dst_channels,const void * p_src,int i_src_channels,int i_sample_count,const int * pi_selection,int i_bits_per_sample)446 void aout_ChannelExtract( void *p_dst, int i_dst_channels,
447                           const void *p_src, int i_src_channels,
448                           int i_sample_count, const int *pi_selection, int i_bits_per_sample )
449 {
450     /* It does not work in place */
451     assert( p_dst != p_src );
452 
453     /* Force the compiler to inline for the specific cases so it can optimize */
454     if( i_bits_per_sample == 8 )
455         ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 1 );
456     else  if( i_bits_per_sample == 16 )
457         ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 2 );
458     else  if( i_bits_per_sample == 32 )
459         ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 4 );
460     else  if( i_bits_per_sample == 64 )
461         ExtractChannel( p_dst, i_dst_channels, p_src, i_src_channels, i_sample_count, pi_selection, 8 );
462 }
463 
aout_CheckChannelExtraction(int * pi_selection,uint32_t * pi_layout,int * pi_channels,const uint32_t pi_order_dst[AOUT_CHAN_MAX],const uint32_t * pi_order_src,int i_channels)464 bool aout_CheckChannelExtraction( int *pi_selection,
465                                   uint32_t *pi_layout, int *pi_channels,
466                                   const uint32_t pi_order_dst[AOUT_CHAN_MAX],
467                                   const uint32_t *pi_order_src, int i_channels )
468 {
469     static_assert(AOUT_CHAN_MAX <= (sizeof (*pi_order_dst) * CHAR_BIT),
470                   "Missing bits");
471 
472     uint32_t i_layout = 0;
473     int i_out = 0;
474     int pi_index[AOUT_CHAN_MAX];
475 
476     /* */
477     if( !pi_order_dst )
478         pi_order_dst = pi_vlc_chan_order_wg4;
479 
480     /* */
481     for( int i = 0; i < i_channels; i++ )
482     {
483         /* Ignore unknown or duplicated channels or not present in output */
484         if( !pi_order_src[i] || (i_layout & pi_order_src[i]) )
485             continue;
486 
487         for( int j = 0; j < AOUT_CHAN_MAX; j++ )
488         {
489             if( pi_order_dst[j] == pi_order_src[i] )
490             {
491                 assert( i_out < AOUT_CHAN_MAX );
492                 pi_index[i_out++] = i;
493                 i_layout |= pi_order_src[i];
494                 break;
495             }
496         }
497     }
498 
499     /* */
500     for( int i = 0, j = 0; i < AOUT_CHAN_MAX; i++ )
501     {
502         for( int k = 0; k < i_out; k++ )
503         {
504             if( pi_order_dst[i] == pi_order_src[pi_index[k]] )
505             {
506                 pi_selection[j++] = pi_index[k];
507                 break;
508             }
509         }
510     }
511 
512     *pi_layout = i_layout;
513     *pi_channels = i_out;
514 
515     for( int i = 0; i < i_out; i++ )
516     {
517         if( pi_selection[i] != i )
518             return true;
519     }
520     return i_out != i_channels;
521 }
522 
523 /* Return the order in which filters should be inserted */
FilterOrder(const char * psz_name)524 static int FilterOrder( const char *psz_name )
525 {
526     static const struct {
527         const char psz_name[10];
528         int        i_order;
529     } filter[] = {
530         { "equalizer",  0 },
531     };
532     for( unsigned i = 0; i < ARRAY_SIZE(filter); i++ )
533     {
534         if( !strcmp( filter[i].psz_name, psz_name ) )
535             return filter[i].i_order;
536     }
537     return INT_MAX;
538 }
539 
540 /* This function will add or remove a module from a string list (colon
541  * separated). It will return true if there is a modification
542  * In case p_aout is NULL, we will use configuration instead of variable */
aout_ChangeFilterString(vlc_object_t * p_obj,vlc_object_t * p_aout,const char * psz_variable,const char * psz_name,bool b_add)543 bool aout_ChangeFilterString( vlc_object_t *p_obj, vlc_object_t *p_aout,
544                               const char *psz_variable,
545                               const char *psz_name, bool b_add )
546 {
547     if( *psz_name == '\0' )
548         return false;
549 
550     char *psz_list;
551     if( p_aout )
552     {
553         psz_list = var_GetString( p_aout, psz_variable );
554     }
555     else
556     {
557         psz_list = var_InheritString( p_obj, psz_variable );
558     }
559 
560     /* Split the string into an array of filters */
561     int i_count = 1;
562     for( char *p = psz_list; p && *p; p++ )
563         i_count += *p == ':';
564     i_count += b_add;
565 
566     const char **ppsz_filter = calloc( i_count, sizeof(*ppsz_filter) );
567     if( !ppsz_filter )
568     {
569         free( psz_list );
570         return false;
571     }
572     bool b_present = false;
573     i_count = 0;
574     for( char *p = psz_list; p && *p; )
575     {
576         char *psz_end = strchr(p, ':');
577         if( psz_end )
578             *psz_end++ = '\0';
579         else
580             psz_end = p + strlen(p);
581         if( *p )
582         {
583             b_present |= !strcmp( p, psz_name );
584             ppsz_filter[i_count++] = p;
585         }
586         p = psz_end;
587     }
588     if( b_present == b_add )
589     {
590         free( ppsz_filter );
591         free( psz_list );
592         return false;
593     }
594 
595     if( b_add )
596     {
597         int i_order = FilterOrder( psz_name );
598         int i;
599         for( i = 0; i < i_count; i++ )
600         {
601             if( FilterOrder( ppsz_filter[i] ) > i_order )
602                 break;
603         }
604         if( i < i_count )
605             memmove( &ppsz_filter[i+1], &ppsz_filter[i], (i_count - i) * sizeof(*ppsz_filter) );
606         ppsz_filter[i] = psz_name;
607         i_count++;
608     }
609     else
610     {
611         for( int i = 0; i < i_count; i++ )
612         {
613             if( !strcmp( ppsz_filter[i], psz_name ) )
614                 ppsz_filter[i] = "";
615         }
616     }
617     size_t i_length = 0;
618     for( int i = 0; i < i_count; i++ )
619         i_length += 1 + strlen( ppsz_filter[i] );
620 
621     char *psz_new = malloc( i_length + 1 );
622 
623     if( unlikely( !psz_new ) )
624     {
625         free( ppsz_filter );
626         free( psz_list );
627         return false;
628     }
629 
630     *psz_new = '\0';
631     for( int i = 0; i < i_count; i++ )
632     {
633         if( *ppsz_filter[i] == '\0' )
634             continue;
635         if( *psz_new )
636             strcat( psz_new, ":" );
637         strcat( psz_new, ppsz_filter[i] );
638     }
639     free( ppsz_filter );
640     free( psz_list );
641 
642     var_SetString( p_obj, psz_variable, psz_new );
643     if( p_aout )
644         var_SetString( p_aout, psz_variable, psz_new );
645     free( psz_new );
646 
647     return true;
648 }
649