summaryrefslogtreecommitdiffstats
path: root/src/resampler.c
blob: c2d791741d01ff5f2e994740abd4e83543d126d2 (plain)
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
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
#include <stdlib.h>
#include <assert.h>

#include <samplerate.h>

#include "resampler.h"
#include "sconv.h"

struct resampler {
    struct pa_sample_spec i_ss, o_ss;
    float* i_buf, *o_buf;
    unsigned i_alloc, o_alloc;
    size_t i_sz, o_sz;

    int channels;

    convert_to_float32_func_t to_float32_func;
    convert_from_float32_func_t from_float32_func;
    SRC_STATE *src_state;
};

struct resampler* resampler_new(const struct pa_sample_spec *a, const struct pa_sample_spec *b) {
    struct resampler *r;
    int err;
    assert(a && b && pa_sample_spec_valid(a) && pa_sample_spec_valid(b));

    if (a->channels != b->channels && a->channels != 1 && b->channels != 1)
        goto fail;

    if (a->format == PA_SAMPLE_ALAW || a->format == PA_SAMPLE_ULAW || b->format == PA_SAMPLE_ALAW || b->format == PA_SAMPLE_ULAW)
        goto fail;

    r = malloc(sizeof(struct resampler));
    assert(r);

    r->channels = a->channels;
    if (b->channels < r->channels)
        r->channels = b->channels;
    
    r->i_buf = r->o_buf = NULL;
    r->i_alloc = r->o_alloc = 0;

    if (a->rate != b->rate) {
        r->src_state = src_new(SRC_SINC_FASTEST, r->channels, &err);
        if (err != 0 || !r->src_state)
            goto fail;
    } else
        r->src_state = NULL;

    r->i_ss = *a;
    r->o_ss = *b;

    r->i_sz = pa_sample_size(a);
    r->o_sz = pa_sample_size(b);

    r->to_float32_func = get_convert_to_float32_function(a->format);
    r->from_float32_func = get_convert_from_float32_function(b->format);

    assert(r->to_float32_func && r->from_float32_func);
    
    return r;
    
fail:
    if (r)
        free(r);
    
    return NULL;
}

void resampler_free(struct resampler *r) {
    assert(r);
    if (r->src_state)
        src_delete(r->src_state);
    free(r->i_buf);
    free(r->o_buf);
    free(r);
}

size_t resampler_request(struct resampler *r, size_t out_length) {
    assert(r && (out_length % r->o_sz) == 0);
    
    return (((out_length / r->o_sz)*r->i_ss.rate)/r->o_ss.rate) * r->i_sz;
}


void resampler_run(struct resampler *r, const struct memchunk *in, struct memchunk *out) {
    unsigned i_nchannels, o_nchannels, ins, ons, eff_ins, eff_ons;
    float *cbuf;
    assert(r && in && out && in->length && in->memblock && (in->length % r->i_sz) == 0);

    /* How many input samples? */
    ins = in->length/r->i_sz;

    /* How much space for output samples? */
    if (r->src_state)
        ons = (ins*r->o_ss.rate/r->i_ss.rate)+1024;
    else
        ons = ins;
    
    /* How many channels? */
    if (r->i_ss.channels == r->o_ss.channels) {
        i_nchannels = o_nchannels = 1;
        eff_ins = ins*r->i_ss.channels; /* effective samples */
        eff_ons = ons*r->o_ss.channels;
    } else {
        i_nchannels = r->i_ss.channels;
        o_nchannels = r->o_ss.channels;
        eff_ins = ins;
        eff_ons = ons;
    }
    
    out->memblock = memblock_new(out->length = (ons*r->o_sz));
    out->index = 0;
    assert(out->memblock);

    if (r->i_alloc < eff_ins)
        r->i_buf = realloc(r->i_buf, sizeof(float) * (r->i_alloc = eff_ins));
    assert(r->i_buf);
    
    r->to_float32_func(eff_ins, in->memblock->data+in->index, i_nchannels, r->i_buf);

    if (r->src_state) {
        int ret;
        SRC_DATA data;

        if (r->o_alloc < eff_ons)
            r->o_buf = realloc(r->o_buf, sizeof(float) * (r->o_alloc = eff_ons));
        assert(r->o_buf);

        data.data_in = r->i_buf;
        data.input_frames = ins;

        data.data_out = r->o_buf;
        data.output_frames = ons;
        
        data.src_ratio = (double) r->o_ss.rate / r->i_ss.rate;
        data.end_of_input = 0;
        
        ret = src_process(r->src_state, &data);
        assert(ret == 0);
        assert((unsigned) data.input_frames_used == ins);
        
        cbuf = r->o_buf;
        ons = data.output_frames_gen;

        if (r->i_ss.channels == r->o_ss.channels) 
            eff_ons = ons*r->o_ss.channels;
        else
            eff_ons = ons;
    } else
        cbuf = r->i_buf;

    r->from_float32_func(eff_ons, cbuf, out->memblock->data+out->index, o_nchannels);
    out->length = ons*r->o_sz;
}