Getting Started — VapourSynth R72 documentation

# Getting Started

So you managed to install VapourSynth. Now what?

If you don’t know the basics of Python, you may want to check out a tutorial.

You can “play around” in the python interpreter if you want, but that’s not how most scripts are created.

## Example Script

It all starts with a .vpy script. Here’s a sample script to be inspired by, it assumes that BestSource is installed and auto-loaded.

    from vapoursynth import core                     # Get an instance of the core
    clip = core.bs.VideoSource(source='filename.mkv')  # Load a video track in mkv file
    clip = core.std.FlipHorizontal(clip)             # Flip the video clip in the horizontal direction
    clip.set_output()                                # Set the video clip to be accessible for output

Audio is also supported, use BestSource to load your audio file.

    from vapoursynth import core                     # Get an instance of the core
    clip = core.bs.AudioSource(source='filename.mkv')    # Load an audio track in mkv file
    clip = core.std.AudioGain(clip,gain=2.0)         # Gain all channels 2x
    clip.set_output()                                # Set the audio clip to be accessible for output

You can combine 2 operations in one script.

    from vapoursynth import core
    video = core.bs.VideoSource(source='filename.mkv')
    audio = core.bs.AudioSource(source='filename.mkv')
    video = core.std.FlipHorizontal(video)
    audio = core.std.AudioGain(audio,gain=2.0)
    video.set_output(index=0)
    audio.set_output(index=1)

Remember that most VapourSynth objects have a quite nice string representation in Python, so if you want to know more about an instance just call `print()`.

## Preview

It’s possible to directly open the script in VapourSynth Editor or VirtualDub FilterMod for previewing.

## Output with VSPipe

VSPipe is very useful to pipe the output to various applications, for example x264 and flac for encoding.

Here are some examples of command lines that automatically pass on most video and audio attributes.

For x264:

    vspipe -c y4m script.vpy - | x264 --demuxer y4m - --output encoded.264

For flac:

    vspipe -c wav script.vpy - | flac - -o encoded.flac

For FFmpeg:

    vspipe -c y4m script.vpy - | ffmpeg -i - encoded.mkv

For mpv:

    vspipe -c y4m script.vpy - | mpv -
    vspipe -c wav script.vpy - | mpv -