00001 /* 00002 * Common AAC and AC-3 parser 00003 * Copyright (c) 2003 Fabrice Bellard 00004 * Copyright (c) 2003 Michael Niedermayer 00005 * 00006 * This file is part of FFmpeg. 00007 * 00008 * FFmpeg is free software; you can redistribute it and/or 00009 * modify it under the terms of the GNU Lesser General Public 00010 * License as published by the Free Software Foundation; either 00011 * version 2.1 of the License, or (at your option) any later version. 00012 * 00013 * FFmpeg is distributed in the hope that it will be useful, 00014 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00016 * Lesser General Public License for more details. 00017 * 00018 * You should have received a copy of the GNU Lesser General Public 00019 * License along with FFmpeg; if not, write to the Free Software 00020 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00021 */ 00022 00023 #include "parser.h" 00024 #include "aac_ac3_parser.h" 00025 00026 int ff_aac_ac3_parse(AVCodecParserContext *s1, 00027 AVCodecContext *avctx, 00028 const uint8_t **poutbuf, int *poutbuf_size, 00029 const uint8_t *buf, int buf_size) 00030 { 00031 AACAC3ParseContext *s = s1->priv_data; 00032 ParseContext *pc = &s->pc; 00033 int len, i; 00034 int new_frame_start; 00035 00036 get_next: 00037 i=END_NOT_FOUND; 00038 if(s->remaining_size <= buf_size){ 00039 if(s->remaining_size && !s->need_next_header){ 00040 i= s->remaining_size; 00041 s->remaining_size = 0; 00042 }else{ //we need a header first 00043 len=0; 00044 for(i=s->remaining_size; i<buf_size; i++){ 00045 s->state = (s->state<<8) + buf[i]; 00046 if((len=s->sync(s->state, s, &s->need_next_header, &new_frame_start))) 00047 break; 00048 } 00049 if(len<=0){ 00050 i=END_NOT_FOUND; 00051 }else{ 00052 s->state=0; 00053 i-= s->header_size -1; 00054 s->remaining_size = len; 00055 if(!new_frame_start || pc->index+i<=0){ 00056 s->remaining_size += i; 00057 goto get_next; 00058 } 00059 } 00060 } 00061 } 00062 00063 if(ff_combine_frame(pc, i, &buf, &buf_size)<0){ 00064 s->remaining_size -= FFMIN(s->remaining_size, buf_size); 00065 *poutbuf = NULL; 00066 *poutbuf_size = 0; 00067 return buf_size; 00068 } 00069 00070 *poutbuf = buf; 00071 *poutbuf_size = buf_size; 00072 00073 /* update codec info */ 00074 avctx->sample_rate = s->sample_rate; 00075 if(s->codec_id) 00076 avctx->codec_id = s->codec_id; 00077 00078 /* allow downmixing to stereo (or mono for AC-3) */ 00079 if(avctx->request_channels > 0 && 00080 avctx->request_channels < s->channels && 00081 (avctx->request_channels <= 2 || 00082 (avctx->request_channels == 1 && 00083 (avctx->codec_id == CODEC_ID_AC3 || 00084 avctx->codec_id == CODEC_ID_EAC3)))) { 00085 avctx->channels = avctx->request_channels; 00086 } else { 00087 avctx->channels = s->channels; 00088 } 00089 avctx->bit_rate = s->bit_rate; 00090 avctx->frame_size = s->samples; 00091 00092 return i; 00093 }