1/* 2 * VC-1 and WMV3 parser 3 * Copyright (c) 2006-2007 Konstantin Shishkov 4 * Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, 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/** 24 * @file libavcodec/vc1_parser.c 25 * VC-1 and WMV3 parser 26 */ 27 28#include "parser.h" 29#include "vc1.h" 30 31/** 32 * finds the end of the current frame in the bitstream. 33 * @return the position of the first byte of the next frame, or -1 34 */ 35static int vc1_find_frame_end(ParseContext *pc, const uint8_t *buf, 36 int buf_size) { 37 int pic_found, i; 38 uint32_t state; 39 40 pic_found= pc->frame_start_found; 41 state= pc->state; 42 43 i=0; 44 if(!pic_found){ 45 for(i=0; i<buf_size; i++){ 46 state= (state<<8) | buf[i]; 47 if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){ 48 i++; 49 pic_found=1; 50 break; 51 } 52 } 53 } 54 55 if(pic_found){ 56 /* EOF considered as end of frame */ 57 if (buf_size == 0) 58 return 0; 59 for(; i<buf_size; i++){ 60 state= (state<<8) | buf[i]; 61 if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){ 62 pc->frame_start_found=0; 63 pc->state=-1; 64 return i-3; 65 } 66 } 67 } 68 pc->frame_start_found= pic_found; 69 pc->state= state; 70 return END_NOT_FOUND; 71} 72 73static int vc1_parse(AVCodecParserContext *s, 74 AVCodecContext *avctx, 75 const uint8_t **poutbuf, int *poutbuf_size, 76 const uint8_t *buf, int buf_size) 77{ 78 ParseContext *pc = s->priv_data; 79 int next; 80 81 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){ 82 next= buf_size; 83 }else{ 84 next= vc1_find_frame_end(pc, buf, buf_size); 85 86 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 87 *poutbuf = NULL; 88 *poutbuf_size = 0; 89 return buf_size; 90 } 91 } 92 *poutbuf = buf; 93 *poutbuf_size = buf_size; 94 return next; 95} 96 97static int vc1_split(AVCodecContext *avctx, 98 const uint8_t *buf, int buf_size) 99{ 100 int i; 101 uint32_t state= -1; 102 int charged=0; 103 104 for(i=0; i<buf_size; i++){ 105 state= (state<<8) | buf[i]; 106 if(IS_MARKER(state)){ 107 if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){ 108 charged=1; 109 }else if(charged){ 110 return i-3; 111 } 112 } 113 } 114 return 0; 115} 116 117AVCodecParser vc1_parser = { 118 { CODEC_ID_VC1 }, 119 sizeof(ParseContext1), 120 NULL, 121 vc1_parse, 122 ff_parse1_close, 123 vc1_split, 124}; 125