yading@10: /*
yading@10:  * Common AAC and AC-3 parser
yading@10:  * Copyright (c) 2003 Fabrice Bellard
yading@10:  * Copyright (c) 2003 Michael Niedermayer
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "libavutil/common.h"
yading@10: #include "parser.h"
yading@10: #include "aac_ac3_parser.h"
yading@10: 
yading@10: int ff_aac_ac3_parse(AVCodecParserContext *s1,
yading@10:                      AVCodecContext *avctx,
yading@10:                      const uint8_t **poutbuf, int *poutbuf_size,
yading@10:                      const uint8_t *buf, int buf_size)
yading@10: {
yading@10:     AACAC3ParseContext *s = s1->priv_data;
yading@10:     ParseContext *pc = &s->pc;
yading@10:     int len, i;
yading@10:     int new_frame_start;
yading@10: 
yading@10: get_next:
yading@10:     i=END_NOT_FOUND;
yading@10:     if(s->remaining_size <= buf_size){
yading@10:         if(s->remaining_size && !s->need_next_header){
yading@10:             i= s->remaining_size;
yading@10:             s->remaining_size = 0;
yading@10:         }else{ //we need a header first
yading@10:             len=0;
yading@10:             for(i=s->remaining_size; i<buf_size; i++){
yading@10:                 s->state = (s->state<<8) + buf[i];
yading@10:                 if((len=s->sync(s->state, s, &s->need_next_header, &new_frame_start)))
yading@10:                     break;
yading@10:             }
yading@10:             if(len<=0){
yading@10:                 i=END_NOT_FOUND;
yading@10:             }else{
yading@10:                 s->state=0;
yading@10:                 i-= s->header_size -1;
yading@10:                 s->remaining_size = len;
yading@10:                 if(!new_frame_start || pc->index+i<=0){
yading@10:                     s->remaining_size += i;
yading@10:                     goto get_next;
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     if(ff_combine_frame(pc, i, &buf, &buf_size)<0){
yading@10:         s->remaining_size -= FFMIN(s->remaining_size, buf_size);
yading@10:         *poutbuf = NULL;
yading@10:         *poutbuf_size = 0;
yading@10:         return buf_size;
yading@10:     }
yading@10: 
yading@10:     *poutbuf = buf;
yading@10:     *poutbuf_size = buf_size;
yading@10: 
yading@10:     /* update codec info */
yading@10:     if(s->codec_id)
yading@10:         avctx->codec_id = s->codec_id;
yading@10: 
yading@10:     /* Due to backwards compatible HE-AAC the sample rate, channel count,
yading@10:        and total number of samples found in an AAC ADTS header are not
yading@10:        reliable. Bit rate is still accurate because the total frame duration in
yading@10:        seconds is still correct (as is the number of bits in the frame). */
yading@10:     if (avctx->codec_id != AV_CODEC_ID_AAC) {
yading@10:         avctx->sample_rate = s->sample_rate;
yading@10: 
yading@10:         /* allow downmixing to stereo (or mono for AC-3) */
yading@10:         if(avctx->request_channels > 0 &&
yading@10:                 avctx->request_channels < s->channels &&
yading@10:                 (avctx->request_channels <= 2 ||
yading@10:                 (avctx->request_channels == 1 &&
yading@10:                 (avctx->codec_id == AV_CODEC_ID_AC3 ||
yading@10:                  avctx->codec_id == AV_CODEC_ID_EAC3)))) {
yading@10:             avctx->channels = avctx->request_channels;
yading@10:         } else {
yading@10:             avctx->channels = s->channels;
yading@10:             avctx->channel_layout = s->channel_layout;
yading@10:         }
yading@10:         s1->duration = s->samples;
yading@10:         avctx->audio_service_type = s->service_type;
yading@10:     }
yading@10: 
yading@10:     avctx->bit_rate = s->bit_rate;
yading@10: 
yading@10:     return i;
yading@10: }