| /* | |
| * Canopus common routines | |
| * Copyright (c) 2015 Vittorio Giovara <[email protected]> | |
| * | |
| * 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 | |
| */ | |
| int ff_canopus_parse_info_tag(AVCodecContext *avctx, | |
| const uint8_t *src, size_t size) | |
| { | |
| GetByteContext gbc; | |
| int par_x, par_y, field_order; | |
| bytestream2_init(&gbc, src, size); | |
| /* Parse aspect ratio. */ | |
| bytestream2_skip(&gbc, 8); // unknown, 16 bits 1 | |
| par_x = bytestream2_get_le32(&gbc); | |
| par_y = bytestream2_get_le32(&gbc); | |
| if (par_x && par_y) | |
| av_reduce(&avctx->sample_aspect_ratio.num, | |
| &avctx->sample_aspect_ratio.den, | |
| par_x, par_y, 255); | |
| /* Short INFO tag (used in CLLC) has only AR data. */ | |
| if (size == 0x18) | |
| return 0; | |
| bytestream2_skip(&gbc, 16); // unknown RDRT tag | |
| /* Parse FIEL tag. */ | |
| bytestream2_skip(&gbc, 8); // 'FIEL' and 4 bytes 0 | |
| field_order = bytestream2_get_le32(&gbc); | |
| switch (field_order) { | |
| case 0: avctx->field_order = AV_FIELD_TT; break; | |
| case 1: avctx->field_order = AV_FIELD_BB; break; | |
| case 2: avctx->field_order = AV_FIELD_PROGRESSIVE; break; | |
| } | |
| return 0; | |
| } | |