Bug Report Retro Deinterlace Not Working with Cropping

[tikevin83]

When cropping using the Transform options, the Deinterlace->Retro filter appears to stop working properly. I'm using OBS Studio 17.0.2. The video feed is 240P60 coming in off of an Avermedia C027 over S-Video from my Gamecube's GameBoy Player, using the GBI software to output 240 progressive lines over the S-Video connection instead of 480 interlaced lines (this is why the retro deinterlace filter is essential).

The pictures without retro deinterlace or with cropping enabled all have a slight blur compared to the uncropped image with Retro deinterlace enabled.

http://imgur.com/a/ay71u

 

[Suslik V]

How you playback (view) the cropped image?

What exact values you are using for crop feature and what size of the interlaced source? What size of output video?

 

[tikevin83]

The source is 480x720 being scaled to 1440x2160. The source is actually 240 progressive lines but the Avermedia C027 capcard interprets that as 480i and thus the Retro filter is needed to double the scanlines and recreate a 480p source. I used the preview feature to project the image to a monitor so I could screenshot the issue.

Any value of crop causes the blur, the test here used -1 from the left side.

 

[Suslik V]

You mean Fullscreen Projector (Source)? If yes, try Fullccreen Projector (Preview) - right click at preview window to be able to choose this option.

 

[tikevin83]

I'm quite sure that's what I was doing already as you can see that the Retro deinterlace is being properly applied in the last picture. I will double check though and see if there is an image quality difference between the preview and source projector

 

[tikevin83]

Yes I've confirmed the screenshotted behavior is of the fullscreen projector (preview). The Retro filter is definitely not being disabled, just some sort of sharpness degradation when a crop is applied. I've confirmed that the degradation also happens when no scaling is applied to the source, so the unscaled 480x720 image with retro deinterlace also becomes blurred when cropped.

 

[tikevin83]

I've also confirmed that the image quality degrades heavily in a cropped source with Yadif x2 applied compared to an uncropped source with Yadif x2.

 

[Suslik V]

I cannot replicate this issue on my side (with 'Media Source' and interlaced video sample). Either you are using wrong viewer or I miss something. As far as I know, the deinterlacing filter is applied first, so no influence on other filters. Any filtering (point, bilinear, bicubic, lanczos) applied to your sources? If not then use "point" - it close to doubling pixels as "retro" do (so scaling up will become almost unnoticeable).