Can an OSSC (original or Pro) pillarbox 4:3 content on a 16:9 TV?

[parbake]

Can an OSSC (original or Pro) convert a 240p 4:3 RGB signal to display correctly on a 480p 16:9 TV?

Unfortunately the TV doesn’t have a 4:3 display option. I need a device that can both line-double and also horizontally shrink the 240p picture (into the center of the raster) to counteract the TV stretching it to fill a 16:9 screen.

Is that something that an OSSC can do? Or is there another low-lag device which can help? Thanks!

[parbake]

Looking at this again, it seems selectable aspect ratio is available on scalers but not line multipliers, although I don’t think there’s a fundamental reason that a line multiplier couldn’t support selectable width.

Specifically, it looks like it’s available on the OSSC Pro in scaler mode, but not line-multiplier mode nor on the original OSSC. Similarly, it’s an option on RetroTINK-5X Pro but not the 2X Pro.

So it seems I can convert 240p 4:3 to 480p 4:3-inside-16:9 if I order an OSSC Pro, but not with an original OSSC. Can anyone confirm?

[marqs]

I suppose it’s a flat screen TV and not CRT? For CRT it’d be relatively easy to add a new aspect-corrected mode where horizontal sampling timings are multiplied by 4 except active which is multiplied by 3. However, the resulting super resolution mode would not work on a flat screen which instead would require resampling line buffer contents.

A memory organization has been done for the next firmware which among other improvements frees up enough RAM to make it possible to read 2 samples from line buffer for each output pixel. That would allow linear interpolation horizontally and thus freeform scaling in X-axis. However, FW development for OSSC Classic is no more done actively so I can’t promise that feature gets implemented in near future or at all.

[parbake]

Thanks for your reply!

I suppose it’s a flat screen TV and not CRT? For CRT it’d be relatively easy to add a new aspect-corrected mode where horizontal sampling timings are multiplied by 4 except active which is multiplied by 3.

It is a CRT! A widescreen one similar to this Grundig or this Loewe. It accepts 480p via VGA but always displays the picture across the entire 16:9 screen, there’s no way to reduce the width to 4:3. Unfortunately here, these 16:9 480p TVs are much more readily-available than 4:3 480p models.

However, the resulting super resolution mode would not work on a flat screen which instead would require resampling line buffer contents.

A memory organization has been done for the next firmware which among other improvements frees up enough RAM to make it possible to read 2 samples from line buffer for each output pixel. That would allow linear interpolation horizontally and thus freeform scaling in X-axis.

While it sounds like it wouldn’t be necessary in my situation, freeform X-scaling would be a more flexible solution. I’ve read that there are flat-panel displays that would also benefit from 4:3 inside 16:9, and it would also provide more fine-grained control over aspect ratio.

FW development for OSSC Classic is no more done actively so I can’t promise that feature gets implemented in near future or at all.

No worries. Is either solution supported (or likely to be in the future) by the OSSC Pro in line-multiplier mode? I assume freeform scaling is already possible in scaler mode, but with higher latency.

[marqs]

If the freeform horizontal scaling in LM modes gets implemented, it will be included in both Classic and Pro. The other option would be easiest added for Pro A-LM as a new 480p_CRT preset.

[Zo]

Hello,

I am interrested also in this topic. I have a Loewe Xelos TV with a VGA input card and the 4:3 480p pictures are streched to fit 16:9. Is there a way to know if a solution for this situation is or will be implemented ? It doesn’t require something really advanced. I found a trick on the GBS-C that maybe exists on the OSSC Pro : To reduce the horizontal scale and add vertical borders to hide the artefacts on the side. Is something like that possible ?

Thanks

[marqs]

So that is another TV which does not have aspect ratio control? Since the new firmware is going into testing very soon, I could still try to include the super resolution mode for 480p which was mentioned previously. This would at least solve the issue for such analog 480p widescreen displays. For digital flat panels with similar limitation, the best way would be adjusting VIC or M[1:0] Picture Aspect Ratio metadata and hoping they read and act on it. The highest compatible but worst quality option would be the interpolation method, but that would take much more effort to implement.

[Zo]

Thank you !

I think all of the Loewe 100Hz 16:9 TVs with a Q23, Q24, Q25M and Q25H chassis are concerned

Here’s a non exhaustive listing :

• Aventos 3981ZW
• Ergo 6681ZP
• Xelos 5281ZW
• Xelos 5381ZW

This is only for the VGA input

• This reply was modified 1 week, 2 days ago by Zo.

[marqs]

It’s now included in the USB Blaster programmable beta version.

[Zo]

So fast ! That’s great. Thanks !

[Author]

Posts