1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
/*
* ac3.c: Frontend Status Monitor plugin for the Video Disk Recorder
*
* See the README file for copyright information and how to reach the author.
*
* AC3 Audio Header: http://www.atsc.org/standards/a_52a.pdf
*/
#include "tools.h"
#include "ac3.h"
int cFemonAC3::bitrateS[32] =
{
32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 576, 640, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
int cFemonAC3::frequencieS[4] =
{
480, 441, 320, 0
};
int cFemonAC3::frameS[3][32] =
{
{64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 640, 768, 896, 1024, 1152, 1280, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{69, 87, 104, 121, 139, 174, 208, 243, 278, 348, 417, 487, 557, 696, 835, 975, 1114, 1253, 1393, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{96, 120, 144, 168, 192, 240, 288, 336, 384, 480, 576, 672, 768, 960, 1152, 1344, 1536, 1728, 1920, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
};
cFemonAC3::cFemonAC3(cFemonAC3If *audioHandlerP)
: audioHandlerM(audioHandlerP)
{
}
cFemonAC3::~cFemonAC3()
{
}
bool cFemonAC3::processAudio(const uint8_t *bufP, int lenP)
{
int fscod, frmsizcod, bsmod, acmod;
int centermixlevel = AUDIO_CENTER_MIX_LEVEL_INVALID;
int surroundmixlevel = AUDIO_SURROUND_MIX_LEVEL_INVALID;
int dolbysurroundmode = AUDIO_DOLBY_SURROUND_MODE_INVALID;
cFemonBitStream bs(bufP, lenP * 8);
if (!audioHandlerM)
return false;
// skip PES header
if (!PesLongEnough(lenP))
return false;
bs.SkipBits(8 * PesPayloadOffset(bufP));
// http://rmworkshop.com/dvd_info/related_info/ac3hdr.htm
// AC3 audio detection
if (bs.GetBits(16) != 0x0B77) // syncword
return false;
bs.SkipBits(16); // CRC1
fscod = bs.GetBits(2); // sampling rate values
frmsizcod = bs.GetBits(6); // frame size code
bs.SkipBits(5); // bitstream id
bsmod = bs.GetBits(3); // bitstream mode
acmod = bs.GetBits(3); // audio coding mode
// 3 front channels
if ((acmod & 0x01) && (acmod != 0x01))
centermixlevel = bs.GetBits(2);
// if a surround channel exists
if (acmod & 0x04)
surroundmixlevel = bs.GetBits(2);
// if in 2/0 mode
if (acmod == 0x02)
dolbysurroundmode = bs.GetBits(2);
audioHandlerM->SetAC3Bitrate(1000 * bitrateS[frmsizcod >> 1]);
audioHandlerM->SetAC3SamplingFrequency(100 * frequencieS[fscod]);
audioHandlerM->SetAC3Bitstream(bsmod);
audioHandlerM->SetAC3AudioCoding(acmod);
audioHandlerM->SetAC3CenterMix(centermixlevel);
audioHandlerM->SetAC3SurroundMix(surroundmixlevel);
audioHandlerM->SetAC3DolbySurround(dolbysurroundmode);
audioHandlerM->SetAC3LFE(bs.GetBit()); // low frequency effects on
audioHandlerM->SetAC3Dialog(bs.GetBits(5)); // dialog normalization
return true;
}
|
