/* * MPEG1 / MPEG2 video parser * Copyright (c) 2000,2001 Fabrice Bellard * 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 */ #include "parser.h" #include "mpeg12.h" #include "internal.h" struct MpvParseContext { ParseContext pc; AVRational frame_rate; int progressive_sequence; int width, height; }; static void mpegvideo_extract_headers(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t *buf, int buf_size) { struct MpvParseContext *pc = s->priv_data; const uint8_t *buf_end = buf + buf_size; uint32_t start_code; int frame_rate_index, ext_type, bytes_left; int frame_rate_ext_n, frame_rate_ext_d; int top_field_first, repeat_first_field, progressive_frame; int horiz_size_ext, vert_size_ext, bit_rate_ext; int did_set_size=0; int bit_rate = 0; int vbv_delay = 0; //FIXME replace the crap with get_bits() s->repeat_pict = 0; while (buf < buf_end) { start_code= -1; buf= avpriv_find_start_code(buf, buf_end, &start_code); bytes_left = buf_end - buf; switch(start_code) { case PICTURE_START_CODE: if (bytes_left >= 2) { s->pict_type = (buf[1] >> 3) & 7; if (bytes_left >= 4) vbv_delay = ((buf[1] & 0x07) << 13) | (buf[2] << 5) | (buf[3] >> 3); } break; case SEQ_START_CODE: if (bytes_left >= 7) { pc->width = (buf[0] << 4) | (buf[1] >> 4); pc->height = ((buf[1] & 0x0f) << 8) | buf[2]; if(!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height){ ff_set_dimensions(avctx, pc->width, pc->height); did_set_size=1; } frame_rate_index = buf[3] & 0xf; pc->frame_rate.den = avctx->time_base.den = ff_mpeg12_frame_rate_tab[frame_rate_index].num; pc->frame_rate.num = avctx->time_base.num = ff_mpeg12_frame_rate_tab[frame_rate_index].den; bit_rate = (buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6); avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO; } break; case EXT_START_CODE: if (bytes_left >= 1) { ext_type = (buf[0] >> 4); switch(ext_type) { case 0x1: /* sequence extension */ if (bytes_left >= 6) { horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7); vert_size_ext = (buf[2] >> 5) & 3; bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1); frame_rate_ext_n = (buf[5] >> 5) & 3; frame_rate_ext_d = (buf[5] & 0x1f); pc->progressive_sequence = buf[1] & (1 << 3); avctx->has_b_frames= !(buf[5] >> 7); pc->width |=(horiz_size_ext << 12); pc->height |=( vert_size_ext << 12); bit_rate = (bit_rate&0x3FFFF) | (bit_rate_ext << 18); if(did_set_size) ff_set_dimensions(avctx, pc->width, pc->height); avctx->time_base.den = pc->frame_rate.den * (frame_rate_ext_n + 1) * 2; avctx->time_base.num = pc->frame_rate.num * (frame_rate_ext_d + 1); avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO; } break; case 0x8: /* picture coding extension */ if (bytes_left >= 5) { top_field_first = buf[3] & (1 << 7); repeat_first_field = buf[3] & (1 << 1); progressive_frame = buf[4] & (1 << 7); /* check if we must repeat the frame */ s->repeat_pict = 1; if (repeat_first_field) { if (pc->progressive_sequence) { if (top_field_first) s->repeat_pict = 5; else s->repeat_pict = 3; } else if (progressive_frame) { s->repeat_pict = 2; } } if (!pc->progressive_sequence) { if (top_field_first) s->field_order = AV_FIELD_TT; else s->field_order = AV_FIELD_BB; } else s->field_order = AV_FIELD_PROGRESSIVE; } break; } } break; case -1: goto the_end; default: /* we stop parsing when we encounter a slice. It ensures that this function takes a negligible amount of time */ if (start_code >= SLICE_MIN_START_CODE && start_code <= SLICE_MAX_START_CODE) goto the_end; break; } } the_end: ; if (avctx->codec_id == AV_CODEC_ID_MPEG2VIDEO && bit_rate) { avctx->rc_max_rate = 400*bit_rate; } else if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO && bit_rate && (bit_rate != 0x3FFFF || vbv_delay != 0xFFFF)) { avctx->bit_rate = 400*bit_rate; } } static int mpegvideo_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size) { struct MpvParseContext *pc1 = s->priv_data; ParseContext *pc= &pc1->pc; int next; if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){ next= buf_size; }else{ next= ff_mpeg1_find_frame_end(pc, buf, buf_size, s); if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { *poutbuf = NULL; *poutbuf_size = 0; return buf_size; } } /* we have a full frame : we just parse the first few MPEG headers to have the full timing information. The time take by this function should be negligible for uncorrupted streams */ mpegvideo_extract_headers(s, avctx, buf, buf_size); av_dlog(NULL, "pict_type=%d frame_rate=%0.3f repeat_pict=%d\n", s->pict_type, (double)avctx->time_base.den / avctx->time_base.num, s->repeat_pict); *poutbuf = buf; *poutbuf_size = buf_size; return next; } static int mpegvideo_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size) { int i; uint32_t state= -1; int found=0; for(i=0; i<buf_size; i++){ state= (state<<8) | buf[i]; if(state == 0x1B3){ found=1; }else if(found && state != 0x1B5 && state < 0x200 && state >= 0x100) return i-3; } return 0; } static int mpegvideo_parse_init(AVCodecParserContext *s) { s->pict_type = AV_PICTURE_TYPE_NONE; // first frame might be partial return 0; } AVCodecParser ff_mpegvideo_parser = { .codec_ids = { AV_CODEC_ID_MPEG1VIDEO, AV_CODEC_ID_MPEG2VIDEO }, .priv_data_size = sizeof(struct MpvParseContext), .parser_init = mpegvideo_parse_init, .parser_parse = mpegvideo_parse, .parser_close = ff_parse_close, .split = mpegvideo_split, };