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libavcodec/libvo-amrwbenc.c

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00001 /*
00002  * AMR Audio encoder stub
00003  * Copyright (c) 2003 the ffmpeg project
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include <vo-amrwbenc/enc_if.h>
00023 
00024 #include "avcodec.h"
00025 #include "libavutil/avstring.h"
00026 #include "libavutil/opt.h"
00027 
00028 typedef struct AMRWBContext {
00029     AVClass *av_class;
00030     void  *state;
00031     int    mode;
00032     int    last_bitrate;
00033     int    allow_dtx;
00034 } AMRWBContext;
00035 
00036 static const AVOption options[] = {
00037     { "dtx", "Allow DTX (generate comfort noise)", offsetof(AMRWBContext, allow_dtx), AV_OPT_TYPE_INT, { 0 }, 0, 1, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM },
00038     { NULL }
00039 };
00040 
00041 static const AVClass class = {
00042     "libvo_amrwbenc", av_default_item_name, options, LIBAVUTIL_VERSION_INT
00043 };
00044 
00045 static int get_wb_bitrate_mode(int bitrate, void *log_ctx)
00046 {
00047     /* make the correspondance between bitrate and mode */
00048     static const int rates[] = {  6600,  8850, 12650, 14250, 15850, 18250,
00049                                  19850, 23050, 23850 };
00050     int i, best = -1, min_diff = 0;
00051     char log_buf[200];
00052 
00053     for (i = 0; i < 9; i++) {
00054         if (rates[i] == bitrate)
00055             return i;
00056         if (best < 0 || abs(rates[i] - bitrate) < min_diff) {
00057             best     = i;
00058             min_diff = abs(rates[i] - bitrate);
00059         }
00060     }
00061     /* no bitrate matching exactly, log a warning */
00062     snprintf(log_buf, sizeof(log_buf), "bitrate not supported: use one of ");
00063     for (i = 0; i < 9; i++)
00064         av_strlcatf(log_buf, sizeof(log_buf), "%.2fk, ", rates[i]    / 1000.f);
00065     av_strlcatf(log_buf, sizeof(log_buf), "using %.2fk", rates[best] / 1000.f);
00066     av_log(log_ctx, AV_LOG_WARNING, "%s\n", log_buf);
00067 
00068     return best;
00069 }
00070 
00071 static av_cold int amr_wb_encode_init(AVCodecContext *avctx)
00072 {
00073     AMRWBContext *s = avctx->priv_data;
00074 
00075     if (avctx->sample_rate != 16000) {
00076         av_log(avctx, AV_LOG_ERROR, "Only 16000Hz sample rate supported\n");
00077         return AVERROR(ENOSYS);
00078     }
00079 
00080     if (avctx->channels != 1) {
00081         av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
00082         return AVERROR(ENOSYS);
00083     }
00084 
00085     s->mode            = get_wb_bitrate_mode(avctx->bit_rate, avctx);
00086     s->last_bitrate    = avctx->bit_rate;
00087 
00088     avctx->frame_size  = 320;
00089     avctx->coded_frame = avcodec_alloc_frame();
00090 
00091     s->state     = E_IF_init();
00092 
00093     return 0;
00094 }
00095 
00096 static int amr_wb_encode_close(AVCodecContext *avctx)
00097 {
00098     AMRWBContext *s = avctx->priv_data;
00099 
00100     E_IF_exit(s->state);
00101     av_freep(&avctx->coded_frame);
00102     return 0;
00103 }
00104 
00105 static int amr_wb_encode_frame(AVCodecContext *avctx,
00106                                unsigned char *frame/*out*/,
00107                                int buf_size, void *data/*in*/)
00108 {
00109     AMRWBContext *s = avctx->priv_data;
00110     int size;
00111 
00112     if (s->last_bitrate != avctx->bit_rate) {
00113         s->mode         = get_wb_bitrate_mode(avctx->bit_rate, avctx);
00114         s->last_bitrate = avctx->bit_rate;
00115     }
00116     size = E_IF_encode(s->state, s->mode, data, frame, s->allow_dtx);
00117     return size;
00118 }
00119 
00120 AVCodec ff_libvo_amrwbenc_encoder = {
00121     .name           = "libvo_amrwbenc",
00122     .type           = AVMEDIA_TYPE_AUDIO,
00123     .id             = CODEC_ID_AMR_WB,
00124     .priv_data_size = sizeof(AMRWBContext),
00125     .init           = amr_wb_encode_init,
00126     .encode         = amr_wb_encode_frame,
00127     .close          = amr_wb_encode_close,
00128     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00129     .long_name = NULL_IF_CONFIG_SMALL("Android VisualOn Adaptive Multi-Rate "
00130                                       "(AMR) Wide-Band"),
00131     .priv_class = &class,
00132 };
00133 
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