/* * H.263 parser * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * H.263 parser */ #include "parser.h" #include "h263_parser.h" int ff_h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){ int vop_found, i; uint32_t state; vop_found= pc->frame_start_found; state= pc->state; i=0; if(!vop_found){ for(i=0; i<buf_size; i++){ state= (state<<8) | buf[i]; if(state>>(32-22) == 0x20){ i++; vop_found=1; break; } } } if(vop_found){ for(; i<buf_size; i++){ state= (state<<8) | buf[i]; if(state>>(32-22) == 0x20){ pc->frame_start_found=0; pc->state=-1; return i-3; } } } pc->frame_start_found= vop_found; pc->state= state; return END_NOT_FOUND; } static int h263_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size) { ParseContext *pc = s->priv_data; int next; if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { next = buf_size; } else { next= ff_h263_find_frame_end(pc, buf, buf_size); if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { *poutbuf = NULL; *poutbuf_size = 0; return buf_size; } } *poutbuf = buf; *poutbuf_size = buf_size; return next; } AVCodecParser ff_h263_parser = { { CODEC_ID_H263 }, sizeof(ParseContext), NULL, h263_parse, ff_parse_close, };