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
|
/* audiomixerreader.cpp -- implements a class to read samples from Audacity
*
* 17-Jun-08 RBD created based on audiofilereader.cpp
*/
#include "assert.h"
#include "stdlib.h"
#include "audioreader.h"
#include "allegro.h"
#include "scorealign-glue.h"
#include "audiomixerreader.h"
double Audio_mixer_reader::get_sample_rate()
{
return sample_rate;
}
Audio_mixer_reader::Audio_mixer_reader(void *mixer_,
mixer_process_fn fn_ptr, int chans,
double srate, double end_time)
{
mixer = mixer_; // store in member variable
mixer_process = fn_ptr;
buffer = NULL;
buffer_len = 0;
index = 0;
channels = chans;
sample_rate = srate;
total_frames = end_time * srate + 0.5 /* for rounding */;
}
long Audio_mixer_reader::get_frames()
{
// precondition: mixer is valid and no samples have been read
return total_frames;
}
long Audio_mixer_reader::read(float *data, long n)
{
for (int i = 0; i < n; i++) { // fill data
float sum = 0;
// note: assume mixer returns stereo (interleaved)
for (int chan = 0; chan < channels; chan++) {
// sum over channels within a frame
if (index >= buffer_len * channels) {
buffer_len =
(*mixer_process) (mixer, &buffer, AMR_BUFFER_FRAMES);
// frame_count = mixer->Process(AMR_BUFFER_FRAMES);
// buffer = (float *) mixer->GetBuffer();
index = 0;
if (buffer_len == 0) { // no more samples to read
// but we processed i
return i;
}
}
sum += buffer[index++];
}
data[i] = sum;
}
return n; // when end is reached, n will be 0, but the caller shouldn't
// be asking for samples beyond the end because the caller knows
// how many samples to ask for.
}
void Audio_mixer_reader::close()
{
// mixer is deleted by the creator of this object, so don't delete here
buffer = NULL;
}
void Audio_mixer_reader::print_info()
{
printf(" Audacity mixer at @ %p\n", mixer);
printf(" sample rate %g\n", get_sample_rate());
printf(" total frames %d\n", get_frames());
}
|
