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
29 struct ffmpeg_data { /* data specific to ffmpeg */
30 struct AVResampleContext *state;
31 };
32
ffmpeg_resample(pa_resampler * r,const pa_memchunk * input,unsigned in_n_frames,pa_memchunk * output,unsigned * out_n_frames)33 static 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
ffmpeg_free(pa_resampler * r)100 static 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
pa_resampler_ffmpeg_init(pa_resampler * r)110 int 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