PeerStreamer

/*

 * Common AAC and AC-3 parser

 * Copyright (c) 2003 Fabrice Bellard

 * Copyright (c) 2003 Michael Niedermayer

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

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

 */

#include "parser.h"

#include "aac_ac3_parser.h"

int ff_aac_ac3_parse(AVCodecParserContext *s1,

                     AVCodecContext *avctx,

                     const uint8_t **poutbuf, int *poutbuf_size,

                     const uint8_t *buf, int buf_size)

{

    AACAC3ParseContext *s = s1->priv_data;

    ParseContext *pc = &s->pc;

    int len, i;

    int new_frame_start;

get_next:

    i=END_NOT_FOUND;

    if(s->remaining_size <= buf_size){

        if(s->remaining_size && !s->need_next_header){

            i= s->remaining_size;

            s->remaining_size = 0;

        }else{ //we need a header first

            len=0;

            for(i=s->remaining_size; i<buf_size; i++){

                s->state = (s->state<<8) + buf[i];

                if((len=s->sync(s->state, s, &s->need_next_header, &new_frame_start)))

                    break;

            }

            if(len<=0){

                i=END_NOT_FOUND;

            }else{

                s->state=0;

                i-= s->header_size -1;

                s->remaining_size = len;

                if(!new_frame_start || pc->index+i<=0){

                    s->remaining_size += i;

                    goto get_next;

                }

            }

        }

    }

    if(ff_combine_frame(pc, i, &buf, &buf_size)<0){

        s->remaining_size -= FFMIN(s->remaining_size, buf_size);

        *poutbuf = NULL;

        *poutbuf_size = 0;

        return buf_size;

    }

    *poutbuf = buf;

    *poutbuf_size = buf_size;

    /* update codec info */

    avctx->sample_rate = s->sample_rate;

    if(s->codec_id)

        avctx->codec_id = s->codec_id;

    /* allow downmixing to stereo (or mono for AC-3) */

    if(avctx->request_channels > 0 &&

            avctx->request_channels < s->channels &&

            (avctx->request_channels <= 2 ||

            (avctx->request_channels == 1 &&

            (avctx->codec_id == CODEC_ID_AC3 ||

             avctx->codec_id == CODEC_ID_EAC3)))) {

        avctx->channels = avctx->request_channels;

    } else {

        avctx->channels = s->channels;

        avctx->channel_layout = s->channel_layout;

    }

    avctx->bit_rate = s->bit_rate;

    avctx->frame_size = s->samples;

    return i;

}