1 /*
2 ** Copyright (C) 1999-2012 Erik de Castro Lopo <erikd@mega-nerd.com>
3 **
4 ** This program is free software; you can redistribute it and/or modify
5 ** it under the terms of the GNU Lesser General Public License as published by
6 ** the Free Software Foundation; either version 2.1 of the License, or
7 ** (at your option) any later version.
8 **
9 ** This program is distributed in the hope that it will be useful,
10 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
11 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 ** GNU Lesser General Public License for more details.
13 **
14 ** You should have received a copy of the GNU Lesser General Public License
15 ** along with this program; if not, write to the Free Software
16 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19
20 #include "sfconfig.h"
21
22 #include <stdio.h>
23 #include <stdlib.h>
24
25 #if HAVE_UNISTD_H
26 #include <unistd.h>
27 #else
28 #include "sf_unistd.h"
29 #endif
30
31 #include <string.h>
32 #include <errno.h>
33
34 #include "common.h"
35
36 typedef struct
37 { int le_float ;
38 int be_float ;
39 int le_int_24_32 ;
40 int be_int_24_32 ;
41 } VOTE ;
42
43
44 static void vote_for_format (VOTE * vote, const unsigned char * data, int datalen) ;
45
46 int
audio_detect(SF_PRIVATE * psf,AUDIO_DETECT * ad,const unsigned char * data,int datalen)47 audio_detect (SF_PRIVATE * psf, AUDIO_DETECT *ad, const unsigned char * data, int datalen)
48 { VOTE vote ;
49
50 if (psf == NULL)
51 return 0 ;
52
53 if (ad == NULL || datalen < 256)
54 return 0 ;
55
56 vote_for_format (&vote, data, datalen) ;
57
58 psf_log_printf (psf, "audio_detect :\n"
59 " le_float : %d\n"
60 " be_float : %d\n"
61 " le_int_24_32 : %d\n"
62 " be_int_24_32 : %d\n",
63 vote.le_float, vote.be_float, vote.le_int_24_32, vote.be_int_24_32) ;
64
65 if (0) puts (psf->parselog.buf) ;
66
67 if (ad->endianness == SF_ENDIAN_LITTLE && vote.le_float > (3 * datalen) / 4)
68 { /* Almost certainly 32 bit floats. */
69 return SF_FORMAT_FLOAT ;
70 } ;
71
72 if (ad->endianness == SF_ENDIAN_LITTLE && vote.le_int_24_32 > (3 * datalen) / 4)
73 { /* Almost certainly 24 bit data stored in 32 bit ints. */
74 return SF_FORMAT_PCM_32 ;
75 } ;
76
77 return 0 ;
78 } /* data_detect */
79
80 static void
vote_for_format(VOTE * vote,const unsigned char * data,int datalen)81 vote_for_format (VOTE * vote, const unsigned char * data, int datalen)
82 {
83 int k ;
84
85 memset (vote, 0, sizeof (VOTE)) ;
86
87 datalen -= datalen % 4 ;
88
89 for (k = 0 ; k < datalen ; k ++)
90 { if ((k % 4) == 0)
91 { if (data [k] == 0 && data [k + 1] != 0)
92 vote->le_int_24_32 += 4 ;
93
94 if (data [2] != 0 && data [3] == 0)
95 vote->le_int_24_32 += 4 ;
96
97 if (data [0] != 0 && data [3] > 0x43 && data [3] < 0x4B)
98 vote->le_float += 4 ;
99
100 if (data [3] != 0 && data [0] > 0x43 && data [0] < 0x4B)
101 vote->be_float += 4 ;
102 } ;
103 } ;
104
105 return ;
106 } /* vote_for_format */
107
108