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High quality Dreamcast captures

category: general [glöplog]
When ps requested a videocapture of a Dreamcast demo (Sanitized by MoonHazard), I decided to try to get a high quality capture as possible. I didn't stop there though. So far I have captured four demos which either had no capture or a low quality one:

The capture setup uses the VGA output from the Dreamcast (720x480), converted and upscaled to 1440x960 using the OSSC and then captured with an Elgato HD60 Pro. The upscaling in the OSSC is done to avoid chroma subsampling by the Elgato card, which seems to happen even if I use RGB.

The Dreamcast only uses 640 of the 720 pixels per line. I assume that the correct aspect ratio for the 640x480 picture is 4:3 (square pixels). Sanitied, Wobble and Reverie are cropped to 1280x960 and black bars added on the top and bottom to get a 1280x1080 video (to avoid resampling by youtube). Delicious uses 640x352, so this demo was upscaled using nearest neighbor to 1920x1056 and then padded on the top and bottom to 1920x1080 for the same reason.

The result is quite nice:
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(The dithering is as far as I know just how the Dreamcast works)

All four demos run in 60 hz, which obviously work just fine on my NTSC Dreamcast. I have tried some PAL demos and they seem to work, but capturing them is a bit tricky. The mode switch from 60 hz to 50 hz right as the demos start means that a few seconds is missing while the capture card tries to sync (I'm trying to get my hands on a PAL Dreamcast). The S-video output on PAL demos does not work (the output is black & white).

If you know of any other Dreamcast demos (only 60 hz for the moment) that need a new capture just reply here.

(I may also try to capture Playstation demos later (I have a modded PAL PS1 which works fine with the OSSC)).
added on the 2019-02-12 22:36:58 by neon neon
Very nice!
thank you!!! <3
added on the 2019-02-13 10:00:43 by psenough psenough
Nice work! If the source is 640x480 you can also opt to go for 1920x1440. A bit awkward as far as displays go but full integer scaling and more YouTube bandwidth. The derivatives (1080p/720p/etc) YouTube creates aren't too bad either.
added on the 2019-02-19 12:05:32 by Rawit Rawit
Amazing, thank you! This demo could use a slightly better capture although I can't remember if it ran in pal60. Possibly as it was coded by Shadez who also did Sanitized by Moonhazard

We are going to KILJU by jumalauta
added on the 2019-02-19 12:33:59 by dodke dodke
According to the comments, We are going to KILJU is PAL and does not support VGA output.

Fortunately the Dreamcast does actually support 576p50 on the VGA output. It took a few hours, but after some tweaking with the OSSC I've managed to make pixel-perfect captures of two 50 hz-only demos. The visible area is still 640x480, so I've cropped and scaled both demos the same way as with the previous ones.

There are still some sync issues when switching from 60 to 50 hz (the Speckdrumm demo is missing a few seconds of the loading-screen).
added on the 2019-02-20 00:41:30 by neon neon


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