CreateImportVideo Class

Member Function Documentation

CreateImportVideo::CreateImportVideo(const QString &videoPath, const QString &exportPath, const QStringList &codecs, QObject *parent = nullptr)

Creates a CreateImportVideo object to be used in a different thread. A videoPath and a exportPath are needed for convertion.

CreateImportVideo::CreateImportVideo(QObject *parent = nullptr)

This constructor is only needed for calling qRegisterMetaType on CreateImportVideo to register the enums.

qRegisterMetaType<CreateImportVideo::ImportVideoState>("CreateImportVideo::ImportVideoState");

[slot] bool CreateImportVideo::createWallpaperGifPreview()

Starts ffmpeg and tries to covert the given video to a 5 second preview gif.

//[...]
args.append("-filter_complex");
args.append("[0:v] fps=12,scale=w=480:h=-1,split [a][b];[a] palettegen=stats_mode=single [p];[b][p] paletteuse=new=1");
args.append(m_exportPath + "/preview.gif");

Returns false if :

• Cannot convert the video
• Generally broken.

[slot] bool CreateImportVideo::createWallpaperImagePreview()

.

[slot] bool CreateImportVideo::createWallpaperImageThumbnailPreview()

Starts ffmpeg and tries to covert the given video to a image preview. Returns false if :

• Cannot convert the video
• Generally broken.

[slot] bool CreateImportVideo::createWallpaperInfo()

Starts ffprobe and tries to parse the resulting json. Returns false if :

• Parsing the output json of ffprobe fails.
• Has no video.
• Cannot parse number of frames.
• Is a wrong file format or generally broken.

[slot] bool CreateImportVideo::createWallpaperVideo(const QString &codec)

Starts ffmpeg and tries to covert the given video to a webm video.

//[...]
args.append("-c:v");
args.append("libvpx-vp8");
args.append("-crf");
args.append("30");
args.append("-pix_fmt");
args.append("yuv420p");
args.append("-b:v");
args.append("0");

Returns false if :

• Cannot convert the video
• Generally broken.

[slot] bool CreateImportVideo::createWallpaperVideoPreview()

Starts ffmpeg and tries to covert the given video to a five second preview.

//[...]
args.append("-vf");
// We allways want to have a 5 second clip via 24fps -> 120 frames
// Divided by the number of frames we can skip (timeInSeconds * Framrate)
// scale & crop parameter: https://unix.stackexchange.com/a/284731
args.append("select='not(mod(n," + QString::number((m_length / 5)) + "))',setpts=N/FRAME_RATE/TB,crop=in_h*16/9:in_h,scale=-2:400");
// Disable audio
args.append("-an");
args.append(m_exportPath + "/preview.webm");

Returns false if :

• Cannot convert the video
• Generally broken.

[slot] bool CreateImportVideo::extractWallpaperAudio()

Starts ffmpeg and tries to covert the given audio into a seperate mp3.

//[...]
args.append("mp3");
args.append("-ab");
args.append("192000");
args.append("-vn");
args.append(m_exportPath + "/audio.mp3");

Returns false if :

• Cannot convert the audio
• Generally broken.

[slot] void CreateImportVideo::process()

Processes the multiple steps of creating a wallpaper.

1. createWallpaperInfo()
2. createWallpaperImagePreview()
3. createWallpaperVideoPreview()
4. createWallpaperGifPreview()
5. createWallpaperVideo() - skiped if already a webm
6. extractWallpaperAudio() - skiped if no audio
7. emit createWallpaperStateChanged(ImportVideoState::Finished);