PeerStreamer

/*

 * AMR Audio encoder stub

 * Copyright (c) 2003 the ffmpeg project

 *

 * This file is part of Libav.

 *

 * Libav is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * Libav is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <vo-amrwbenc/enc_if.h>

#include "avcodec.h"

static const char wb_bitrate_unsupported[] =

    "bitrate not supported: use one of 6.6k, 8.85k, 12.65k, 14.25k, 15.85k, "

    "18.25k, 19.85k, 23.05k, or 23.85k\n";

typedef struct AMRWB_bitrates {

    int rate;

    int mode;

} AMRWB_bitrates;

typedef struct AMRWBContext {

    void  *state;

    int    mode;

    int    allow_dtx;

} AMRWBContext;

static int getWBBitrateMode(int bitrate)

{

    /* make the correspondance between bitrate and mode */

    AMRWB_bitrates rates[] = { { 6600, 0},

                               { 8850, 1},

                               {12650, 2},

                               {14250, 3},

                               {15850, 4},

                               {18250, 5},

                               {19850, 6},

                               {23050, 7},

                               {23850, 8}, };

    int i;

    for (i = 0; i < 9; i++)

        if (rates[i].rate == bitrate)

            return rates[i].mode;

    /* no bitrate matching, return an error */

    return -1;

}

static av_cold int amr_wb_encode_init(AVCodecContext *avctx)

{

    AMRWBContext *s = avctx->priv_data;

    if (avctx->sample_rate != 16000) {

        av_log(avctx, AV_LOG_ERROR, "Only 16000Hz sample rate supported\n");

        return AVERROR(ENOSYS);

    }

    if (avctx->channels != 1) {

        av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");

        return AVERROR(ENOSYS);

    }

    if ((s->mode = getWBBitrateMode(avctx->bit_rate)) < 0) {

        av_log(avctx, AV_LOG_ERROR, wb_bitrate_unsupported);

        return AVERROR(ENOSYS);

    }

    avctx->frame_size  = 320;

    avctx->coded_frame = avcodec_alloc_frame();

    s->state     = E_IF_init();

    s->allow_dtx = 0;

    return 0;

}

static int amr_wb_encode_close(AVCodecContext *avctx)

{

    AMRWBContext *s = avctx->priv_data;

    E_IF_exit(s->state);

    av_freep(&avctx->coded_frame);

    return 0;

}

static int amr_wb_encode_frame(AVCodecContext *avctx,

                               unsigned char *frame/*out*/,

                               int buf_size, void *data/*in*/)

{

    AMRWBContext *s = avctx->priv_data;

    int size;

    if ((s->mode = getWBBitrateMode(avctx->bit_rate)) < 0) {

        av_log(avctx, AV_LOG_ERROR, wb_bitrate_unsupported);

        return AVERROR(ENOSYS);

    }

    size = E_IF_encode(s->state, s->mode, data, frame, s->allow_dtx);

    return size;

}

AVCodec ff_libvo_amrwbenc_encoder = {

    "libvo_amrwbenc",

    CODEC_TYPE_AUDIO,

    CODEC_ID_AMR_WB,

    sizeof(AMRWBContext),

    amr_wb_encode_init,

    amr_wb_encode_frame,

    amr_wb_encode_close,

    NULL,

    .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},

    .long_name = NULL_IF_CONFIG_SMALL("libvo-amrwbenc Adaptive Multi-Rate "

                                      "(AMR) Wide-Band"),

};