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 Libav. 7 * 8 * Libav 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 * Libav 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 Libav; 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 25 * VC-1 and WMV3 parser 26 */ 27 28#include "parser.h" 29#include "vc1.h" 30#include "get_bits.h" 31 32typedef struct { 33 ParseContext pc; 34 VC1Context v; 35} VC1ParseContext; 36 37static void vc1_extract_headers(AVCodecParserContext *s, AVCodecContext *avctx, 38 const uint8_t *buf, int buf_size) 39{ 40 VC1ParseContext *vpc = s->priv_data; 41 GetBitContext gb; 42 const uint8_t *start, *end, *next; 43 uint8_t *buf2 = av_mallocz(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); 44 45 vpc->v.s.avctx = avctx; 46 vpc->v.parse_only = 1; 47 next = buf; 48 s->repeat_pict = 0; 49 50 for(start = buf, end = buf + buf_size; next < end; start = next){ 51 int buf2_size, size; 52 53 next = find_next_marker(start + 4, end); 54 size = next - start - 4; 55 buf2_size = vc1_unescape_buffer(start + 4, size, buf2); 56 init_get_bits(&gb, buf2, buf2_size * 8); 57 if(size <= 0) continue; 58 switch(AV_RB32(start)){ 59 case VC1_CODE_SEQHDR: 60 vc1_decode_sequence_header(avctx, &vpc->v, &gb); 61 break; 62 case VC1_CODE_ENTRYPOINT: 63 vc1_decode_entry_point(avctx, &vpc->v, &gb); 64 break; 65 case VC1_CODE_FRAME: 66 if(vpc->v.profile < PROFILE_ADVANCED) 67 vc1_parse_frame_header (&vpc->v, &gb); 68 else 69 vc1_parse_frame_header_adv(&vpc->v, &gb); 70 71 /* keep AV_PICTURE_TYPE_BI internal to VC1 */ 72 if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI) 73 s->pict_type = AV_PICTURE_TYPE_B; 74 else 75 s->pict_type = vpc->v.s.pict_type; 76 77 if (avctx->ticks_per_frame > 1){ 78 // process pulldown flags 79 s->repeat_pict = 1; 80 // Pulldown flags are only valid when 'broadcast' has been set. 81 // So ticks_per_frame will be 2 82 if (vpc->v.rff){ 83 // repeat field 84 s->repeat_pict = 2; 85 }else if (vpc->v.rptfrm){ 86 // repeat frames 87 s->repeat_pict = vpc->v.rptfrm * 2 + 1; 88 } 89 } 90 91 break; 92 } 93 } 94 95 av_free(buf2); 96} 97 98/** 99 * Find the end of the current frame in the bitstream. 100 * @return the position of the first byte of the next frame, or -1 101 */ 102static int vc1_find_frame_end(ParseContext *pc, const uint8_t *buf, 103 int buf_size) { 104 int pic_found, i; 105 uint32_t state; 106 107 pic_found= pc->frame_start_found; 108 state= pc->state; 109 110 i=0; 111 if(!pic_found){ 112 for(i=0; i<buf_size; i++){ 113 state= (state<<8) | buf[i]; 114 if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){ 115 i++; 116 pic_found=1; 117 break; 118 } 119 } 120 } 121 122 if(pic_found){ 123 /* EOF considered as end of frame */ 124 if (buf_size == 0) 125 return 0; 126 for(; i<buf_size; i++){ 127 state= (state<<8) | buf[i]; 128 if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){ 129 pc->frame_start_found=0; 130 pc->state=-1; 131 return i-3; 132 } 133 } 134 } 135 pc->frame_start_found= pic_found; 136 pc->state= state; 137 return END_NOT_FOUND; 138} 139 140static int vc1_parse(AVCodecParserContext *s, 141 AVCodecContext *avctx, 142 const uint8_t **poutbuf, int *poutbuf_size, 143 const uint8_t *buf, int buf_size) 144{ 145 VC1ParseContext *vpc = s->priv_data; 146 int next; 147 148 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){ 149 next= buf_size; 150 }else{ 151 next= vc1_find_frame_end(&vpc->pc, buf, buf_size); 152 153 if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) { 154 *poutbuf = NULL; 155 *poutbuf_size = 0; 156 return buf_size; 157 } 158 } 159 160 vc1_extract_headers(s, avctx, buf, buf_size); 161 162 *poutbuf = buf; 163 *poutbuf_size = buf_size; 164 return next; 165} 166 167static int vc1_split(AVCodecContext *avctx, 168 const uint8_t *buf, int buf_size) 169{ 170 int i; 171 uint32_t state= -1; 172 int charged=0; 173 174 for(i=0; i<buf_size; i++){ 175 state= (state<<8) | buf[i]; 176 if(IS_MARKER(state)){ 177 if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){ 178 charged=1; 179 }else if(charged){ 180 return i-3; 181 } 182 } 183 } 184 return 0; 185} 186 187static int vc1_parse_init(AVCodecParserContext *s) 188{ 189 VC1ParseContext *vpc = s->priv_data; 190 vpc->v.s.slice_context_count = 1; 191 return ff_vc1_init_common(&vpc->v); 192} 193 194AVCodecParser ff_vc1_parser = { 195 .codec_ids = { CODEC_ID_VC1 }, 196 .priv_data_size = sizeof(VC1ParseContext), 197 .parser_init = vc1_parse_init, 198 .parser_parse = vc1_parse, 199 .parser_close = ff_parse1_close, 200 .split = vc1_split, 201}; 202