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ffmpeg / libavcodec / libvo-amrwbenc.c @ 900a129f

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/*
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 * AMR Audio encoder stub
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 * Copyright (c) 2003 the ffmpeg project
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include <vo-amrwbenc/enc_if.h>
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#include "avcodec.h"
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static const char wb_bitrate_unsupported[] =
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    "bitrate not supported: use one of 6.6k, 8.85k, 12.65k, 14.25k, 15.85k, "
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    "18.25k, 19.85k, 23.05k, or 23.85k\n";
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typedef struct AMRWB_bitrates {
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    int rate;
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    int mode;
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} AMRWB_bitrates;
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typedef struct AMRWBContext {
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    void  *state;
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    int    mode;
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    int    allow_dtx;
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} AMRWBContext;
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static int getWBBitrateMode(int bitrate)
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{
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    /* make the correspondance between bitrate and mode */
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    AMRWB_bitrates rates[] = { { 6600, 0},
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                               { 8850, 1},
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                               {12650, 2},
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                               {14250, 3},
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                               {15850, 4},
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                               {18250, 5},
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                               {19850, 6},
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                               {23050, 7},
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                               {23850, 8}, };
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    int i;
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    for (i = 0; i < 9; i++)
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        if (rates[i].rate == bitrate)
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            return rates[i].mode;
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    /* no bitrate matching, return an error */
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    return -1;
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}
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static av_cold int amr_wb_encode_init(AVCodecContext *avctx)
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{
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    AMRWBContext *s = avctx->priv_data;
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    if (avctx->sample_rate != 16000) {
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        av_log(avctx, AV_LOG_ERROR, "Only 16000Hz sample rate supported\n");
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        return AVERROR(ENOSYS);
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    }
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    if (avctx->channels != 1) {
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        av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
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        return AVERROR(ENOSYS);
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    }
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    if ((s->mode = getWBBitrateMode(avctx->bit_rate)) < 0) {
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        av_log(avctx, AV_LOG_ERROR, wb_bitrate_unsupported);
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        return AVERROR(ENOSYS);
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    }
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    avctx->frame_size  = 320;
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    avctx->coded_frame = avcodec_alloc_frame();
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    s->state     = E_IF_init();
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    s->allow_dtx = 0;
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    return 0;
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}
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static int amr_wb_encode_close(AVCodecContext *avctx)
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{
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    AMRWBContext *s = avctx->priv_data;
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    E_IF_exit(s->state);
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    av_freep(&avctx->coded_frame);
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    return 0;
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}
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static int amr_wb_encode_frame(AVCodecContext *avctx,
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                               unsigned char *frame/*out*/,
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                               int buf_size, void *data/*in*/)
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{
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    AMRWBContext *s = avctx->priv_data;
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    int size;
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    if ((s->mode = getWBBitrateMode(avctx->bit_rate)) < 0) {
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        av_log(avctx, AV_LOG_ERROR, wb_bitrate_unsupported);
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        return AVERROR(ENOSYS);
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    }
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    size = E_IF_encode(s->state, s->mode, data, frame, s->allow_dtx);
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    return size;
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}
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AVCodec ff_libvo_amrwbenc_encoder = {
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    "libvo_amrwbenc",
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    CODEC_TYPE_AUDIO,
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    CODEC_ID_AMR_WB,
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    sizeof(AMRWBContext),
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    amr_wb_encode_init,
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    amr_wb_encode_frame,
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    amr_wb_encode_close,
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    NULL,
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    .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
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    .long_name = NULL_IF_CONFIG_SMALL("libvo-amrwbenc Adaptive Multi-Rate "
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                                      "(AMR) Wide-Band"),
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};