Deinterlace.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Deinterlace.h"
#include "Exceptions.h"
#include <omp.h>
 
using namespace openshot;
 
Deinterlace::Deinterlace() : isOdd(true)
{
    // Init effect properties
    init_effect_details();
}
 
// Default constructor
Deinterlace::Deinterlace(bool UseOddLines) : isOdd(UseOddLines)
{
    // Init effect properties
    init_effect_details();
}
 
// Init effect settings
void Deinterlace::init_effect_details()
{
    InitEffectInfo();
 
    info.class_name = "Deinterlace";
    info.name = "Deinterlace";
    info.description = "Remove interlacing from a video (i.e. even or odd horizontal lines)";
    info.has_audio = false;
    info.has_video = true;
}
 
// This method is required for all derived classes of EffectBase, and returns a
// modified openshot::Frame object
std::shared_ptr<openshot::Frame> Deinterlace::GetFrame(std::shared_ptr<openshot::Frame> frame, int64_t frame_number)
{
    // Get original size of frame's image
    int original_width = frame->GetImage()->width();
    int original_height = frame->GetImage()->height();
 
    // Access the current QImage and its raw pixel data
    auto image           = frame->GetImage();
    const unsigned char* pixels = image->bits();
    int line_bytes       = image->bytesPerLine();
 
    // Decide whether to copy even lines (start = 0) or odd lines (start = 1)
    int start = isOdd ? 1 : 0;
 
    // Compute how many rows we will end up copying
    // If start = 0, rows_to_copy = ceil(original_height / 2.0)
    // If start = 1, rows_to_copy = floor(original_height / 2.0)
    int rows_to_copy = (original_height - start + 1) / 2;
 
    // Create a new image with exactly 'rows_to_copy' scanlines
    QImage deinterlaced_image(
        original_width,
        rows_to_copy,
        QImage::Format_RGBA8888_Premultiplied
    );
    unsigned char* deinterlaced_pixels = deinterlaced_image.bits();
 
    // Copy every other row from the source into the new image
    // Parallelize over 'i' so each thread writes to a distinct slice of memory
#pragma omp parallel for
    for (int i = 0; i < rows_to_copy; i++) {
        int row = start + 2 * i;
        const unsigned char* src = pixels + (row * line_bytes);
        unsigned char* dst       = deinterlaced_pixels + (i * line_bytes);
        memcpy(dst, src, line_bytes);
    }
 
    // Resize deinterlaced image back to original size, and update frame's image
    image = std::make_shared<QImage>(deinterlaced_image.scaled(
        original_width, original_height,
        Qt::IgnoreAspectRatio, Qt::FastTransformation));
 
    // Update image on frame
    frame->AddImage(image);
 
    // return the modified frame
    return frame;
}
 
// Generate JSON string of this object
std::string Deinterlace::Json() const {
 
    // Return formatted string
    return JsonValue().toStyledString();
}
 
// Generate Json::Value for this object
Json::Value Deinterlace::JsonValue() const {
 
    // Create root json object
    Json::Value root = EffectBase::JsonValue(); // get parent properties
    root["type"] = info.class_name;
    root["isOdd"] = isOdd;
 
    // return JsonValue
    return root;
}
 
// Load JSON string into this object
void Deinterlace::SetJson(const std::string value) {
 
    // Parse JSON string into JSON objects
    try
    {
        const Json::Value root = openshot::stringToJson(value);
        // Set all values that match
        SetJsonValue(root);
    }
    catch (const std::exception& e)
    {
        // Error parsing JSON (or missing keys)
        throw InvalidJSON("JSON is invalid (missing keys or invalid data types)");
    }
}
 
// Load Json::Value into this object
void Deinterlace::SetJsonValue(const Json::Value root) {
 
    // Set parent data
    EffectBase::SetJsonValue(root);
 
    // Set data from Json (if key is found)
    if (!root["isOdd"].isNull())
        isOdd = root["isOdd"].asBool();
}
 
// Get all properties for a specific frame
std::string Deinterlace::PropertiesJSON(int64_t requested_frame) const {
 
    // Generate JSON properties list
    Json::Value root = BasePropertiesJSON(requested_frame);
 
    // Add Is Odd Frame choices (dropdown style)
    root["isOdd"] = add_property_json("Is Odd Frame", isOdd, "bool", "", NULL, 0, 1, false, requested_frame);
    root["isOdd"]["choices"].append(add_property_choice_json("Yes", true, isOdd));
    root["isOdd"]["choices"].append(add_property_choice_json("No", false, isOdd));
 
    // Return formatted string
    return root.toStyledString();
}