CreateImportVideo Class

Member Function Documentation

CreateImportVideo::CreateImportVideo(const QString &videoPath, const QString &exportPath, const QString &codec, const int quality, 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. If the video is a container that not contains the video length like webm or mkv we need to count the frames ourself. We then call analyzeWebmReadFrames or analyzeVideo to parse the output. 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()

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);