1/***
2  This file is part of PulseAudio.
3
4  Copyright 2004-2006 Lennart Poettering
5
6  PulseAudio is free software; you can redistribute it and/or modify
7  it under the terms of the GNU Lesser General Public License as published
8  by the Free Software Foundation; either version 2.1 of the License,
9  or (at your option) any later version.
10
11  PulseAudio is distributed in the hope that it will be useful, but
12  WITHOUT ANY WARRANTY; without even the implied warranty of
13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  General Public License for more details.
15
16  You should have received a copy of the GNU Lesser General Public License
17  along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
18***/
19
20#ifdef HAVE_CONFIG_H
21#include <config.h>
22#endif
23
24#include <pulse/xmalloc.h>
25#include "pulsecore/ffmpeg/avcodec.h"
26
27#include <pulsecore/resampler.h>
28
29struct ffmpeg_data { /* data specific to ffmpeg */
30    struct AVResampleContext *state;
31};
32
33static unsigned ffmpeg_resample(pa_resampler *r, const pa_memchunk *input, unsigned in_n_frames, pa_memchunk *output, unsigned *out_n_frames) {
34    unsigned used_frames = 0, c;
35    int previous_consumed_frames = -1;
36    struct ffmpeg_data *ffmpeg_data;
37
38    pa_assert(r);
39    pa_assert(input);
40    pa_assert(output);
41    pa_assert(out_n_frames);
42
43    ffmpeg_data = r->impl.data;
44
45    for (c = 0; c < r->work_channels; c++) {
46        unsigned u;
47        pa_memblock *b, *w;
48        int16_t *p, *t, *k, *q, *s;
49        int consumed_frames;
50
51        /* Allocate a new block */
52        b = pa_memblock_new(r->mempool, in_n_frames * sizeof(int16_t));
53        p = pa_memblock_acquire(b);
54
55        /* Now copy the input data, splitting up channels */
56        t = (int16_t*) pa_memblock_acquire_chunk(input) + c;
57        k = p;
58        for (u = 0; u < in_n_frames; u++) {
59            *k = *t;
60            t += r->work_channels;
61            k ++;
62        }
63        pa_memblock_release(input->memblock);
64
65        /* Allocate buffer for the result */
66        w = pa_memblock_new(r->mempool, *out_n_frames * sizeof(int16_t));
67        q = pa_memblock_acquire(w);
68
69        /* Now, resample */
70        used_frames = (unsigned) av_resample(ffmpeg_data->state,
71                                             q, p,
72                                             &consumed_frames,
73                                             (int) in_n_frames, (int) *out_n_frames,
74                                             c >= (unsigned) (r->work_channels-1));
75
76        pa_memblock_release(b);
77        pa_memblock_unref(b);
78
79        pa_assert(consumed_frames <= (int) in_n_frames);
80        pa_assert(previous_consumed_frames == -1 || consumed_frames == previous_consumed_frames);
81        previous_consumed_frames = consumed_frames;
82
83        /* And place the results in the output buffer */
84        s = (int16_t *) pa_memblock_acquire_chunk(output) + c;
85        for (u = 0; u < used_frames; u++) {
86            *s = *q;
87            q++;
88            s += r->work_channels;
89        }
90        pa_memblock_release(output->memblock);
91        pa_memblock_release(w);
92        pa_memblock_unref(w);
93    }
94
95    *out_n_frames = used_frames;
96
97    return in_n_frames - previous_consumed_frames;
98}
99
100static void ffmpeg_free(pa_resampler *r) {
101    struct ffmpeg_data *ffmpeg_data;
102
103    pa_assert(r);
104
105    ffmpeg_data = r->impl.data;
106    if (ffmpeg_data->state)
107        av_resample_close(ffmpeg_data->state);
108}
109
110int pa_resampler_ffmpeg_init(pa_resampler *r) {
111    struct ffmpeg_data *ffmpeg_data;
112
113    pa_assert(r);
114
115    ffmpeg_data = pa_xnew(struct ffmpeg_data, 1);
116
117    /* We could probably implement different quality levels by
118     * adjusting the filter parameters here. However, ffmpeg
119     * internally only uses these hardcoded values, so let's use them
120     * here for now as well until ffmpeg makes this configurable. */
121
122    if (!(ffmpeg_data->state = av_resample_init((int) r->o_ss.rate, (int) r->i_ss.rate, 16, 10, 0, 0.8))) {
123        pa_xfree(ffmpeg_data);
124        return -1;
125    }
126
127    r->impl.free = ffmpeg_free;
128    r->impl.resample = ffmpeg_resample;
129    r->impl.data = (void *) ffmpeg_data;
130
131    return 0;
132}
133