Type: Decimate. Sharp, jaggy and shimmer for non-integer upscaled 2D games
Setup required: Flash with compatible firmware with downscaling feature via a PC. Enable downscaling in OSD menu
Cost and availability: Moderate cost to benefit, currently available at RetroTINK
Mike Chi’s RetroTink 5x is one of the most full featured and lowest lag downscalers (3msec!). It requires an HDMI to component DAC for the input in order to downscale 720p, and another DAC to output to a CRT. The RetroTink 5x is first and foremost an upscaler, and downscaling to 15KHz is an advanced and unsupported feature, so the simple decimating approach to downscaling must be taken for what it is. For games that were drawn in a 240p resolution and integer upscaled, the original resolution can be ‘restored’ back to native 240p. The downsides to line-decimating will become apparent when downscaling 3D games with simplistic geometric shapes; causing jagged outlines and shimmer on reoccurring patterns like floor tiles. 2D games that were drawn in 720p can also result in stretch-interpolation artefacts when downscaled:
Stretching a 16:9 image to fill the 4:3 height prior to line decimating unfortunately results in disproportionate sprites. In the above image from Super Mario Maker on the Nintendo WiiU (a 720p game), the left Mario sprite has a larger than normal nose. By using the RetroTink 5x to shift the image vertically by 1 pixel, interpolation applies to the next set of lines, where Mario’s nose on the right now looks closer to his original sprite on the NES. But… shifting the images has only shifted the interpolated lines, giving Mario overgrown hands and a stretched hat, which splay into the sky and his forehead. The same applies to the blocks next to Mario, which will harshly shimmer when the screen scrolls vertically. In essence, you cannot perfectly downscale these games by line decimation.
I MUST make a special mention and apology to Mike and anyone who has watched the RetroTink 5x episode of the Downscaling Chronicles. My error when downscaling the Analogue Pocket via the official Dock was not setting the HDMI output to Integer, resulting in uneven vertical scaling and shimmer. An addendum was made when scoring the RetroTink 5x in Episode 8: The Downscaler Wars.
The OSSC Pro is similar in price and supersedes the RetroTink 5x in some aspects of downscaling. Though if you require a relatively easy to use and high quality upscaler, along with the ability to downscale to 15KHz in 3msec (for most scenario’s), the RetroTink 5x is a fantastic option.
Verdict: Recommended