filter_transpose.cpp

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/*
 *  Copyright (C) 2004-2025 Savoir-faire Linux Inc.
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program. If not, see <https://www.gnu.org/licenses/>.
 */
 
#include "filter_transpose.h"
#include "logger.h"
 
namespace jami {
namespace video {
 
std::unique_ptr<MediaFilter>
getTransposeFilter(
    int rotation, std::string inputName, int width, int height, int format, bool rescale)
{
    JAMI_WARN("Rotation set to %d", rotation);
    if (rotation == 0) {
        return {};
    }
 
    std::stringstream ss;
    ss << "[" << inputName << "] ";
 
    switch (rotation) {
    case 90:
    case -270:
        ss << "transpose=2";
        if (rescale) {
            if (width > height)
                ss << ", scale=w=-1:h=" << height << ", pad=" << width << ":" << height
                   << ":(ow-iw)/2";
            else
                ss << ", scale=w=" << width << ":h=-1"
                   << ", pad=" << width << ":" << height << ":0:(oh-ih)/2";
        }
        break;
    case 180:
    case -180:
        ss << "transpose=1, transpose=1";
        break;
    case 270:
    case -90:
        ss << "transpose=1";
        if (rescale) {
            if (width > height)
                ss << ", scale=w=-1:h=" << height << ", pad=" << width << ":" << height
                   << ":(ow-iw)/2";
            else
                ss << ", scale=w=" << width << ":h=-1"
                   << ", pad=" << width << ":" << height << ":0:(oh-ih)/2";
        }
        break;
    default:
        return {};
    }
 
    constexpr auto one = rational<int>(1);
    std::vector<MediaStream> msv;
    msv.emplace_back(inputName, format, one, width, height, 0, one);
 
    std::unique_ptr<MediaFilter> filter(new MediaFilter);
    auto ret = filter->initialize(ss.str(), msv);
    if (ret < 0) {
        JAMI_ERR() << "filter init fail";
        return {};
    }
    return filter;
}
 
} // namespace video
} // namespace jami