1/* 2 * H.263 parser 3 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file 24 * H.263 parser 25 */ 26 27#include "parser.h" 28#include "h263_parser.h" 29 30int ff_h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){ 31 int vop_found, i; 32 uint32_t state; 33 34 vop_found= pc->frame_start_found; 35 state= pc->state; 36 37 i=0; 38 if(!vop_found){ 39 for(i=0; i<buf_size; i++){ 40 state= (state<<8) | buf[i]; 41 if(state>>(32-22) == 0x20){ 42 i++; 43 vop_found=1; 44 break; 45 } 46 } 47 } 48 49 if(vop_found){ 50 for(; i<buf_size; i++){ 51 state= (state<<8) | buf[i]; 52 if(state>>(32-22) == 0x20){ 53 pc->frame_start_found=0; 54 pc->state=-1; 55 return i-3; 56 } 57 } 58 } 59 pc->frame_start_found= vop_found; 60 pc->state= state; 61 62 return END_NOT_FOUND; 63} 64 65static int h263_parse(AVCodecParserContext *s, 66 AVCodecContext *avctx, 67 const uint8_t **poutbuf, int *poutbuf_size, 68 const uint8_t *buf, int buf_size) 69{ 70 ParseContext *pc = s->priv_data; 71 int next; 72 73 next= ff_h263_find_frame_end(pc, buf, buf_size); 74 75 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 76 *poutbuf = NULL; 77 *poutbuf_size = 0; 78 return buf_size; 79 } 80 81 *poutbuf = buf; 82 *poutbuf_size = buf_size; 83 return next; 84} 85 86AVCodecParser h263_parser = { 87 { CODEC_ID_H263 }, 88 sizeof(ParseContext), 89 NULL, 90 h263_parse, 91 ff_parse_close, 92}; 93