blob: ea6cc647d3791df5fdba67f1da6f0dc488e86b96
| 1 | /* |
| 2 | * Canopus common routines |
| 3 | * Copyright (c) 2015 Vittorio Giovara <vittorio.giovara@gmail.com> |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | #include <stdint.h> |
| 23 | |
| 24 | #include "libavutil/rational.h" |
| 25 | |
| 26 | #include "avcodec.h" |
| 27 | #include "bytestream.h" |
| 28 | #include "canopus.h" |
| 29 | |
| 30 | int ff_canopus_parse_info_tag(AVCodecContext *avctx, |
| 31 | const uint8_t *src, size_t size) |
| 32 | { |
| 33 | GetByteContext gbc; |
| 34 | int par_x, par_y, field_order; |
| 35 | |
| 36 | bytestream2_init(&gbc, src, size); |
| 37 | |
| 38 | /* Parse aspect ratio. */ |
| 39 | bytestream2_skip(&gbc, 8); // unknown, 16 bits 1 |
| 40 | par_x = bytestream2_get_le32(&gbc); |
| 41 | par_y = bytestream2_get_le32(&gbc); |
| 42 | if (par_x && par_y) |
| 43 | av_reduce(&avctx->sample_aspect_ratio.num, |
| 44 | &avctx->sample_aspect_ratio.den, |
| 45 | par_x, par_y, 255); |
| 46 | |
| 47 | /* Short INFO tag (used in CLLC) has only AR data. */ |
| 48 | if (size == 0x18) |
| 49 | return 0; |
| 50 | |
| 51 | bytestream2_skip(&gbc, 16); // unknown RDRT tag |
| 52 | |
| 53 | /* Parse FIEL tag. */ |
| 54 | bytestream2_skip(&gbc, 8); // 'FIEL' and 4 bytes 0 |
| 55 | field_order = bytestream2_get_le32(&gbc); |
| 56 | switch (field_order) { |
| 57 | case 0: avctx->field_order = AV_FIELD_TT; break; |
| 58 | case 1: avctx->field_order = AV_FIELD_BB; break; |
| 59 | case 2: avctx->field_order = AV_FIELD_PROGRESSIVE; break; |
| 60 | } |
| 61 | |
| 62 | return 0; |
| 63 | } |
| 64 |