CODEWITHSUNDEEP
gstreamer
Piotr Pradzynski
Piotr Pradzynski

Reputation: 4535

Straightforward way to downscale too large video with GStreamer

I'm using GStreamer to process videos in my project. The input videos can have various formats (both resolutions and aspect-ratio). It can be for example 400x300, 1080p, 4K, 2000x1000, etc.

I would like to downscale videos automatically which are larger than 1080p. So if video is in 4K it should be downscaled to 1080p but if it is in 400x300 format it should be kept in original format.

I've found videoscale pipeline plugin but it does not work as I would like. It is changing scale up and down without any distinctions. Also it is not changing sizes proportionally when only width or height is provided.

Do you know any straightforward way in GStreamer to downscale resolutions automatically to desired size?

Upvotes: 1

Views: 3998

Answers (1)

Florian Zwoch
Florian Zwoch

Reputation: 7373

GStreamer's caps allow ranges. So I believe you are looking for something like this:

video/x-raw,width=[1,1920],height=[1,1080],pixel-aspect-ratio=1/1

This will keep the same aspect ratio but scales down in case it is required to fit into 1920x1080.

E.g.

gst-launch-1.0 videotestsrc ! video/x-raw,width=4000,height=2000 ! videoscale ! video/x-raw,width=[1,1920],height=[1,1080],pixel-aspect-ratio=1/1 ! autovideosink

Will be scaled down to 1920x960.

And:

gst-launch-1.0 videotestsrc ! video/x-raw,width=400,height=200 ! videoscale ! video/x-raw,width=[1,1920],height=[1,1080],pixel-aspect-ratio=1/1 ! autovideosink

Will stay at 400x200.

Upvotes: 7

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