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/opt.h"
29 #include "avcodec.h"
30 #include "codec_internal.h"
31 #include "encode.h"
32 #include "internal.h"
33 
34 #define MAX_PACKET_SIZE  (1 + (477 + 7) / 8)
35 
36 typedef struct AMRWBContext {
37     AVClass *av_class;
38     void  *state;
39     int    mode;
40     int    last_bitrate;
41     int    allow_dtx;
42 } AMRWBContext;
43 
44 static const AVOption options[] = {
45     { "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 },
46     { NULL }
47 };
48 
49 static const AVClass amrwb_class = {
50     .class_name = "libvo_amrwbenc",
51     .item_name  = av_default_item_name,
52     .option     = options,
53     .version    = LIBAVUTIL_VERSION_INT,
54 };
55 
get_wb_bitrate_mode(int bitrate, void *log_ctx)56 static int get_wb_bitrate_mode(int bitrate, void *log_ctx)
57 {
58     /* make the correspondence between bitrate and mode */
59     static const int rates[] = {  6600,  8850, 12650, 14250, 15850, 18250,
60                                  19850, 23050, 23850 };
61     int i, best = -1, min_diff = 0;
62     char log_buf[200];
63 
64     for (i = 0; i < 9; i++) {
65         if (rates[i] == bitrate)
66             return i;
67         if (best < 0 || abs(rates[i] - bitrate) < min_diff) {
68             best     = i;
69             min_diff = abs(rates[i] - bitrate);
70         }
71     }
72     /* no bitrate matching exactly, log a warning */
73     snprintf(log_buf, sizeof(log_buf), "bitrate not supported: use one of ");
74     for (i = 0; i < 9; i++)
75         av_strlcatf(log_buf, sizeof(log_buf), "%.2fk, ", rates[i]    / 1000.f);
76     av_strlcatf(log_buf, sizeof(log_buf), "using %.2fk", rates[best] / 1000.f);
77     av_log(log_ctx, AV_LOG_WARNING, "%s\n", log_buf);
78 
79     return best;
80 }
81 
amr_wb_encode_init(AVCodecContext *avctx)82 static av_cold int amr_wb_encode_init(AVCodecContext *avctx)
83 {
84     AMRWBContext *s = avctx->priv_data;
85 
86     if (avctx->sample_rate != 16000 && avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL) {
87         av_log(avctx, AV_LOG_ERROR, "Only 16000Hz sample rate supported\n");
88         return AVERROR(ENOSYS);
89     }
90 
91     if (avctx->ch_layout.nb_channels != 1) {
92         av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
93         return AVERROR(ENOSYS);
94     }
95 
96     s->mode            = get_wb_bitrate_mode(avctx->bit_rate, avctx);
97     s->last_bitrate    = avctx->bit_rate;
98 
99     avctx->frame_size  = 320;
100     avctx->initial_padding =  80;
101 
102     s->state     = E_IF_init();
103 
104     return 0;
105 }
106 
amr_wb_encode_close(AVCodecContext *avctx)107 static int amr_wb_encode_close(AVCodecContext *avctx)
108 {
109     AMRWBContext *s = avctx->priv_data;
110 
111     E_IF_exit(s->state);
112     return 0;
113 }
114 
amr_wb_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)115 static int amr_wb_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
116                                const AVFrame *frame, int *got_packet_ptr)
117 {
118     AMRWBContext *s = avctx->priv_data;
119     const int16_t *samples = (const int16_t *)frame->data[0];
120     int size, ret;
121 
122     if ((ret = ff_alloc_packet(avctx, avpkt, MAX_PACKET_SIZE)) < 0)
123         return ret;
124 
125     if (s->last_bitrate != avctx->bit_rate) {
126         s->mode         = get_wb_bitrate_mode(avctx->bit_rate, avctx);
127         s->last_bitrate = avctx->bit_rate;
128     }
129     size = E_IF_encode(s->state, s->mode, samples, avpkt->data, s->allow_dtx);
130     if (size <= 0 || size > MAX_PACKET_SIZE) {
131         av_log(avctx, AV_LOG_ERROR, "Error encoding frame\n");
132         return AVERROR(EINVAL);
133     }
134 
135     if (frame->pts != AV_NOPTS_VALUE)
136         avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->initial_padding);
137 
138     avpkt->size = size;
139     *got_packet_ptr = 1;
140     return 0;
141 }
142 
143 const FFCodec ff_libvo_amrwbenc_encoder = {
144     .p.name         = "libvo_amrwbenc",
145     .p.long_name    = NULL_IF_CONFIG_SMALL("Android VisualOn AMR-WB "
146                                            "(Adaptive Multi-Rate Wide-Band)"),
147     .p.type         = AVMEDIA_TYPE_AUDIO,
148     .p.id           = AV_CODEC_ID_AMR_WB,
149     .p.priv_class   = &amrwb_class,
150     .p.wrapper_name = "libvo_amrwbenc",
151     .priv_data_size = sizeof(AMRWBContext),
152     .init           = amr_wb_encode_init,
153     FF_CODEC_ENCODE_CB(amr_wb_encode_frame),
154     .close          = amr_wb_encode_close,
155     .p.sample_fmts  = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
156                                                      AV_SAMPLE_FMT_NONE },
157 };
158