PeerStreamer

/*

 * ADTS muxer.

 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>

 *                    Mans Rullgard <mans@mansr.com>

 *

 * 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 "libavcodec/get_bits.h"

#include "libavcodec/put_bits.h"

#include "libavcodec/avcodec.h"

#include "libavcodec/mpeg4audio.h"

#include "avformat.h"

#include "adts.h"

int ff_adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf, int size)

{

    GetBitContext gb;

    PutBitContext pb;

    MPEG4AudioConfig m4ac;

    int off;

    init_get_bits(&gb, buf, size * 8);

    off = ff_mpeg4audio_get_config(&m4ac, buf, size);

    if (off < 0)

        return off;

    skip_bits_long(&gb, off);

    adts->objecttype        = m4ac.object_type - 1;

    adts->sample_rate_index = m4ac.sampling_index;

    adts->channel_conf      = m4ac.chan_config;

    if (adts->objecttype > 3U) {

        av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);

        return -1;

    }

    if (adts->sample_rate_index == 15) {

        av_log(s, AV_LOG_ERROR, "Escape sample rate index illegal in ADTS\n");

        return -1;

    }

    if (get_bits(&gb, 1)) {

        av_log(s, AV_LOG_ERROR, "960/120 MDCT window is not allowed in ADTS\n");

        return -1;

    }

    if (get_bits(&gb, 1)) {

        av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");

        return -1;

    }

    if (!adts->channel_conf) {

        init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE);

        put_bits(&pb, 3, 5); //ID_PCE

        adts->pce_size = (ff_copy_pce_data(&pb, &gb) + 3) / 8;

        flush_put_bits(&pb);

    }

    adts->write_adts = 1;

    return 0;

}

static int adts_write_header(AVFormatContext *s)

{

    ADTSContext *adts = s->priv_data;

    AVCodecContext *avc = s->streams[0]->codec;

    if (avc->extradata_size > 0 &&

            ff_adts_decode_extradata(s, adts, avc->extradata, avc->extradata_size) < 0)

        return -1;

    return 0;

}

int ff_adts_write_frame_header(ADTSContext *ctx,

                               uint8_t *buf, int size, int pce_size)

{

    PutBitContext pb;

    init_put_bits(&pb, buf, ADTS_HEADER_SIZE);

    /* adts_fixed_header */

    put_bits(&pb, 12, 0xfff);   /* syncword */

    put_bits(&pb, 1, 0);        /* ID */

    put_bits(&pb, 2, 0);        /* layer */

    put_bits(&pb, 1, 1);        /* protection_absent */

    put_bits(&pb, 2, ctx->objecttype); /* profile_objecttype */

    put_bits(&pb, 4, ctx->sample_rate_index);

    put_bits(&pb, 1, 0);        /* private_bit */

    put_bits(&pb, 3, ctx->channel_conf); /* channel_configuration */

    put_bits(&pb, 1, 0);        /* original_copy */

    put_bits(&pb, 1, 0);        /* home */

    /* adts_variable_header */

    put_bits(&pb, 1, 0);        /* copyright_identification_bit */

    put_bits(&pb, 1, 0);        /* copyright_identification_start */

    put_bits(&pb, 13, ADTS_HEADER_SIZE + size + pce_size); /* aac_frame_length */

    put_bits(&pb, 11, 0x7ff);   /* adts_buffer_fullness */

    put_bits(&pb, 2, 0);        /* number_of_raw_data_blocks_in_frame */

    flush_put_bits(&pb);

    return 0;

}

static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)

{

    ADTSContext *adts = s->priv_data;

    AVIOContext *pb = s->pb;

    uint8_t buf[ADTS_HEADER_SIZE];

    if (!pkt->size)

        return 0;

    if (adts->write_adts) {

        ff_adts_write_frame_header(adts, buf, pkt->size, adts->pce_size);

        avio_write(pb, buf, ADTS_HEADER_SIZE);

        if (adts->pce_size) {

            avio_write(pb, adts->pce_data, adts->pce_size);

            adts->pce_size = 0;

        }

    }

    avio_write(pb, pkt->data, pkt->size);

    avio_flush(pb);

    return 0;

}

AVOutputFormat ff_adts_muxer = {

    "adts",

    NULL_IF_CONFIG_SMALL("ADTS AAC"),

    "audio/aac",

    "aac,adts",

    sizeof(ADTSContext),

    CODEC_ID_AAC,

    CODEC_ID_NONE,

    adts_write_header,

    adts_write_packet,

};