From e6fb844f7b736e72da364032d251283bce9e63ad Mon Sep 17 00:00:00 2001 From: Vittorio Giovara Date: Thu, 9 Apr 2015 18:11:10 +0200 Subject: Implement shared parsing of INFO tag in Canopus family Add some bounds checking to CLLC; reduce HQX variable scoping, add an error message. --- libavcodec/canopus.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 libavcodec/canopus.c (limited to 'libavcodec/canopus.c') diff --git a/libavcodec/canopus.c b/libavcodec/canopus.c new file mode 100644 index 0000000000..729e7ef876 --- /dev/null +++ b/libavcodec/canopus.c @@ -0,0 +1,63 @@ +/* + * Canopus common routines + * Copyright (c) 2015 Vittorio Giovara + * + * 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 + */ + +#include + +#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; +} -- cgit v1.2.3