/* * Canopus common routines * Copyright (c) 2015 Vittorio Giovara <vittorio.giovara@gmail.com> * * 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 <stdint.h> #include "libavutil/rational.h" #include "avcodec.h"#include "bytestream.h"#include "canopus.h" 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;}