/* * VC-1 and WMV3 parser * Copyright (c) 2006-2007 Konstantin Shishkov * Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * VC-1 and WMV3 parser */ #include "parser.h" #include "vc1.h" #include "get_bits.h" typedef struct { ParseContext pc; VC1Context v; } VC1ParseContext; static void vc1_extract_headers(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t *buf, int buf_size) { VC1ParseContext *vpc = s->priv_data; GetBitContext gb; const uint8_t *start, *end, *next; uint8_t *buf2 = av_mallocz(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); vpc->v.s.avctx = avctx; vpc->v.parse_only = 1; next = buf; s->repeat_pict = 0; for(start = buf, end = buf + buf_size; next < end; start = next){ int buf2_size, size; next = find_next_marker(start + 4, end); size = next - start - 4; buf2_size = vc1_unescape_buffer(start + 4, size, buf2); init_get_bits(&gb, buf2, buf2_size * 8); if(size <= 0) continue; switch(AV_RB32(start)){ case VC1_CODE_SEQHDR: ff_vc1_decode_sequence_header(avctx, &vpc->v, &gb); break; case VC1_CODE_ENTRYPOINT: ff_vc1_decode_entry_point(avctx, &vpc->v, &gb); break; case VC1_CODE_FRAME: if(vpc->v.profile < PROFILE_ADVANCED) ff_vc1_parse_frame_header (&vpc->v, &gb); else ff_vc1_parse_frame_header_adv(&vpc->v, &gb); /* keep AV_PICTURE_TYPE_BI internal to VC1 */ if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI) s->pict_type = AV_PICTURE_TYPE_B; else s->pict_type = vpc->v.s.pict_type; if (avctx->ticks_per_frame > 1){ // process pulldown flags s->repeat_pict = 1; // Pulldown flags are only valid when 'broadcast' has been set. // So ticks_per_frame will be 2 if (vpc->v.rff){ // repeat field s->repeat_pict = 2; }else if (vpc->v.rptfrm){ // repeat frames s->repeat_pict = vpc->v.rptfrm * 2 + 1; } } break; } } av_free(buf2); } /** * Find the end of the current frame in the bitstream. * @return the position of the first byte of the next frame, or -1 */ static int vc1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size) { int pic_found, i; uint32_t state; pic_found= pc->frame_start_found; state= pc->state; i=0; if(!pic_found){ for(i=0; i<buf_size; i++){ state= (state<<8) | buf[i]; if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){ i++; pic_found=1; break; } } } if(pic_found){ /* EOF considered as end of frame */ if (buf_size == 0) return 0; for(; i<buf_size; i++){ state= (state<<8) | buf[i]; if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){ pc->frame_start_found=0; pc->state=-1; return i-3; } } } pc->frame_start_found= pic_found; pc->state= state; return END_NOT_FOUND; } static int vc1_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size) { VC1ParseContext *vpc = s->priv_data; int next; if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){ next= buf_size; }else{ next= vc1_find_frame_end(&vpc->pc, buf, buf_size); if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) { *poutbuf = NULL; *poutbuf_size = 0; return buf_size; } } vc1_extract_headers(s, avctx, buf, buf_size); *poutbuf = buf; *poutbuf_size = buf_size; return next; } static int vc1_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size) { int i; uint32_t state= -1; int charged=0; for(i=0; i<buf_size; i++){ state= (state<<8) | buf[i]; if(IS_MARKER(state)){ if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){ charged=1; }else if(charged){ return i-3; } } } return 0; } static int vc1_parse_init(AVCodecParserContext *s) { VC1ParseContext *vpc = s->priv_data; vpc->v.s.slice_context_count = 1; return ff_vc1_init_common(&vpc->v); } AVCodecParser ff_vc1_parser = { .codec_ids = { CODEC_ID_VC1 }, .priv_data_size = sizeof(VC1ParseContext), .parser_init = vc1_parse_init, .parser_parse = vc1_parse, .parser_close = ff_parse_close, .split = vc1_split, };