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libvo-amrwbenc.c
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1 /*
2  * AMR Audio encoder stub
3  * Copyright (c) 2003 the ffmpeg project
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <vo-amrwbenc/enc_if.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 
26 #include "libavutil/avstring.h"
27 #include "libavutil/internal.h"
28 #include "libavutil/mem.h"
29 #include "libavutil/opt.h"
30 #include "avcodec.h"
31 #include "internal.h"
32 
33 #define MAX_PACKET_SIZE (1 + (477 + 7) / 8)
34 
35 typedef struct AMRWBContext {
37  void *state;
38  int mode;
40  int allow_dtx;
41 } AMRWBContext;
42 
43 static const AVOption options[] = {
44  { "dtx", "Allow DTX (generate comfort noise)", offsetof(AMRWBContext, allow_dtx), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM },
45  { NULL }
46 };
47 
48 static const AVClass amrwb_class = {
50 };
51 
52 static int get_wb_bitrate_mode(int bitrate, void *log_ctx)
53 {
54  /* make the correspondance between bitrate and mode */
55  static const int rates[] = { 6600, 8850, 12650, 14250, 15850, 18250,
56  19850, 23050, 23850 };
57  int i, best = -1, min_diff = 0;
58  char log_buf[200];
59 
60  for (i = 0; i < 9; i++) {
61  if (rates[i] == bitrate)
62  return i;
63  if (best < 0 || abs(rates[i] - bitrate) < min_diff) {
64  best = i;
65  min_diff = abs(rates[i] - bitrate);
66  }
67  }
68  /* no bitrate matching exactly, log a warning */
69  snprintf(log_buf, sizeof(log_buf), "bitrate not supported: use one of ");
70  for (i = 0; i < 9; i++)
71  av_strlcatf(log_buf, sizeof(log_buf), "%.2fk, ", rates[i] / 1000.f);
72  av_strlcatf(log_buf, sizeof(log_buf), "using %.2fk", rates[best] / 1000.f);
73  av_log(log_ctx, AV_LOG_WARNING, "%s\n", log_buf);
74 
75  return best;
76 }
77 
79 {
80  AMRWBContext *s = avctx->priv_data;
81 
82  if (avctx->sample_rate != 16000 && avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL) {
83  av_log(avctx, AV_LOG_ERROR, "Only 16000Hz sample rate supported\n");
84  return AVERROR(ENOSYS);
85  }
86 
87  if (avctx->channels != 1) {
88  av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
89  return AVERROR(ENOSYS);
90  }
91 
92  s->mode = get_wb_bitrate_mode(avctx->bit_rate, avctx);
93  s->last_bitrate = avctx->bit_rate;
94 
95  avctx->frame_size = 320;
96  avctx->delay = 80;
97 
98  s->state = E_IF_init();
99 
100  return 0;
101 }
102 
104 {
105  AMRWBContext *s = avctx->priv_data;
106 
107  E_IF_exit(s->state);
108  return 0;
109 }
110 
111 static int amr_wb_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
112  const AVFrame *frame, int *got_packet_ptr)
113 {
114  AMRWBContext *s = avctx->priv_data;
115  const int16_t *samples = (const int16_t *)frame->data[0];
116  int size, ret;
117 
118  if ((ret = ff_alloc_packet2(avctx, avpkt, MAX_PACKET_SIZE)) < 0)
119  return ret;
120 
121  if (s->last_bitrate != avctx->bit_rate) {
122  s->mode = get_wb_bitrate_mode(avctx->bit_rate, avctx);
123  s->last_bitrate = avctx->bit_rate;
124  }
125  size = E_IF_encode(s->state, s->mode, samples, avpkt->data, s->allow_dtx);
126  if (size <= 0 || size > MAX_PACKET_SIZE) {
127  av_log(avctx, AV_LOG_ERROR, "Error encoding frame\n");
128  return AVERROR(EINVAL);
129  }
130 
131  if (frame->pts != AV_NOPTS_VALUE)
132  avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->delay);
133 
134  avpkt->size = size;
135  *got_packet_ptr = 1;
136  return 0;
137 }
138 
140  .name = "libvo_amrwbenc",
141  .type = AVMEDIA_TYPE_AUDIO,
142  .id = AV_CODEC_ID_AMR_WB,
143  .priv_data_size = sizeof(AMRWBContext),
145  .encode2 = amr_wb_encode_frame,
147  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
149  .long_name = NULL_IF_CONFIG_SMALL("Android VisualOn AMR-WB "
150  "(Adaptive Multi-Rate Wide-Band)"),
151  .priv_class = &amrwb_class,
152 };