1/* 2 * Common AAC and AC-3 parser 3 * Copyright (c) 2003 Fabrice Bellard 4 * Copyright (c) 2003 Michael Niedermayer 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "parser.h" 24#include "aac_ac3_parser.h" 25 26int ff_aac_ac3_parse(AVCodecParserContext *s1, 27 AVCodecContext *avctx, 28 const uint8_t **poutbuf, int *poutbuf_size, 29 const uint8_t *buf, int buf_size) 30{ 31 AACAC3ParseContext *s = s1->priv_data; 32 ParseContext *pc = &s->pc; 33 int len, i; 34 int new_frame_start; 35 36get_next: 37 i=END_NOT_FOUND; 38 if(s->remaining_size <= buf_size){ 39 if(s->remaining_size && !s->need_next_header){ 40 i= s->remaining_size; 41 s->remaining_size = 0; 42 }else{ //we need a header first 43 len=0; 44 for(i=s->remaining_size; i<buf_size; i++){ 45 s->state = (s->state<<8) + buf[i]; 46 if((len=s->sync(s->state, s, &s->need_next_header, &new_frame_start))) 47 break; 48 } 49 if(len<=0){ 50 i=END_NOT_FOUND; 51 }else{ 52 s->state=0; 53 i-= s->header_size -1; 54 s->remaining_size = len; 55 if(!new_frame_start || pc->index+i<=0){ 56 s->remaining_size += i; 57 goto get_next; 58 } 59 } 60 } 61 } 62 63 if(ff_combine_frame(pc, i, &buf, &buf_size)<0){ 64 s->remaining_size -= FFMIN(s->remaining_size, buf_size); 65 *poutbuf = NULL; 66 *poutbuf_size = 0; 67 return buf_size; 68 } 69 70 *poutbuf = buf; 71 *poutbuf_size = buf_size; 72 73 /* update codec info */ 74 avctx->sample_rate = s->sample_rate; 75 if(s->codec_id) 76 avctx->codec_id = s->codec_id; 77 78 /* allow downmixing to stereo (or mono for AC-3) */ 79 if(avctx->request_channels > 0 && 80 avctx->request_channels < s->channels && 81 (avctx->request_channels <= 2 || 82 (avctx->request_channels == 1 && 83 (avctx->codec_id == CODEC_ID_AC3 || 84 avctx->codec_id == CODEC_ID_EAC3)))) { 85 avctx->channels = avctx->request_channels; 86 } else { 87 avctx->channels = s->channels; 88 } 89 avctx->bit_rate = s->bit_rate; 90 avctx->frame_size = s->samples; 91 92 return i; 93} 94