Libav 0.7.1
|
00001 /* 00002 * H.263 parser 00003 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> 00004 * 00005 * This file is part of Libav. 00006 * 00007 * Libav is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * Libav is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with Libav; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00027 #include "parser.h" 00028 #include "h263_parser.h" 00029 00030 int ff_h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){ 00031 int vop_found, i; 00032 uint32_t state; 00033 00034 vop_found= pc->frame_start_found; 00035 state= pc->state; 00036 00037 i=0; 00038 if(!vop_found){ 00039 for(i=0; i<buf_size; i++){ 00040 state= (state<<8) | buf[i]; 00041 if(state>>(32-22) == 0x20){ 00042 i++; 00043 vop_found=1; 00044 break; 00045 } 00046 } 00047 } 00048 00049 if(vop_found){ 00050 for(; i<buf_size; i++){ 00051 state= (state<<8) | buf[i]; 00052 if(state>>(32-22) == 0x20){ 00053 pc->frame_start_found=0; 00054 pc->state=-1; 00055 return i-3; 00056 } 00057 } 00058 } 00059 pc->frame_start_found= vop_found; 00060 pc->state= state; 00061 00062 return END_NOT_FOUND; 00063 } 00064 00065 static int h263_parse(AVCodecParserContext *s, 00066 AVCodecContext *avctx, 00067 const uint8_t **poutbuf, int *poutbuf_size, 00068 const uint8_t *buf, int buf_size) 00069 { 00070 ParseContext *pc = s->priv_data; 00071 int next; 00072 00073 next= ff_h263_find_frame_end(pc, buf, buf_size); 00074 00075 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 00076 *poutbuf = NULL; 00077 *poutbuf_size = 0; 00078 return buf_size; 00079 } 00080 00081 *poutbuf = buf; 00082 *poutbuf_size = buf_size; 00083 return next; 00084 } 00085 00086 AVCodecParser ff_h263_parser = { 00087 { CODEC_ID_H263 }, 00088 sizeof(ParseContext), 00089 NULL, 00090 h263_parse, 00091 ff_parse_close, 00092 };