Display Video Vectorscope and Waveform in FFplay

This article explains how to display real-time video analysis tools, specifically the waveform monitor and vectorscope, during video playback using FFplay. You will learn the exact FFmpeg video filter (-vf) commands required to render these scopes either by themselves or side-by-side with your playing video.

Displaying the Waveform Monitor

The waveform monitor measures the luminance (brightness) or chrominance levels of your video. You can view this in FFplay using the waveform filter.

Waveform Only

To replace the video playback entirely with a live waveform monitor, use the following command:

ffplay -i input.mp4 -vf "waveform"

Video and Waveform Side-by-Side

To view your original video and the waveform monitor side-by-side, you need to split the video stream, apply the filter to one stream, and stack them horizontally:

ffplay -i input.mp4 -vf "split=2[original][stream2]; [stream2]waveform[wave]; [original][wave]hstack"

Displaying the Vectorscope

The vectorscope monitors the color information (chrominance) of your video, mapping hue and saturation onto a circular grid.

Vectorscope Only

To view only the vectorscope during playback, use the vectorscope filter:

ffplay -i input.mp4 -vf "vectorscope"

Video and Vectorscope Side-by-Side

Because the vectorscope has a fixed default output size (usually 256x256), stacking it next to a high-definition video requires scaling the vectorscope to match the height of your video:

ffplay -i input.mp4 -vf "split=2[original][stream2]; [stream2]vectorscope=m=color3,scale=-1:ih[vector]; [original][vector]hstack"

Note: scale=-1:ih automatically scales the vectorscope to match the input height (ih) of the video while maintaining its aspect ratio.

Displaying Both Waveform and Vectorscope with Video

If you want a complete monitoring layout, you can split the video into three streams to display the video, the waveform, and the vectorscope all in a single window:

ffplay -i input.mp4 -vf "split=3[original][stream2][stream3]; [stream2]waveform[wave]; [stream3]vectorscope=m=color3,scale=-1:ih[vector]; [original][wave][vector]hstack=inputs=3"