The Kramer VP725DS and VP-747 are switchable scalers that can be programmed with custom resolutions. Reports on the Shumps forum suggested they can downscale to 240p, but not without quirks.
Top row: Kramer VP-725DS. Bottom row: Kramer VP-747
Switching and Scaling
Credit to Kumulus 28 for discovering 240p output on the VP-725DS
The VP-725DS is part switcher, part scaler in a 3RU metal case. It accepts composite, S-video, component, RGBs/RGBHV, and HDMI (via DVI). Each signal format has its own dedicated Preview Out for pure passthrough with zero processing. There are also Scaled outputs via HD15, BNC, and DVI which are simultaneously active, and will require external HV sync combining for CRT’s that use RGBs
3 User Mode Settings are available as ‘Groups’, which let you program progressive 15KHz, but not interlaced. Although the vertical frequency was set to 60Hz, it was labile and dropped to 58Hz when adjusting other sync timings; causing frequent frame skips. External equipment like the OSSC Pro help to read the actual vertical frequency when adjusting the timings to ensure the frame rate is output as the user intends. These were my video timings that achieved 240p@60Hz full screen for 480p and 720p input:
Within the Graphics Menu is a Vertical Position option which can help align assets to perfectly average duplicate lines to restore 240p upscaled games from a 480p/720p source. 1080p inputs were overscanned, so unless one can make 1080p-optimised User Mode Settings, consider the VP-725DS capped at 720p input for downscaling to 240p. H/V adjustments are confined to a pre-defined window that are dictated by the sync timings, which does not help the 1080p overscan. Auto Image somewhat centers the output, except when HDMI is fed via DVI as this is not a selectable option. Using a DAC to input VGA reactivates this option, which conveniently allows audio extraction, since this model is video-only.
Lag
Latency across progressive inputs (VGA, DVI, component) rapidly rolls between 1–2 frames. For some reason, only 480i input as component rolled at 2-3 frames.
Composite Decoding: Taste the Rainbow
The Preview output is pure passthrough so 240p is preserved without any processing, but there is no transcoding. However, the Scaler can mix and match signal formats, meaning it can decode composite video and output RGB. Unfortunately there is no up-side to this, as it must run through the scaler which entails lag, incorrect processing of 240p input as 480i, and chroma crosstalk; resulting in rainbow artefact of white objects.
VP-747: More Functions, More Lag
Credit to Harb1911 for discovering 240p output on the VP-747
The VP-747 is another scaler that was reported to output 240p. This has a re-worked OSD, adds a fourth User Resolution slot and image rotation. Programming 240p output was much the same process, but there was a whopping >6 frames of lag(!) for progressive inputs, rolling from anywhere between 77msec to 102msec. I did not test the VP-747 after discovering this as it excludes it as a downscaler for the purpose of gaming.
Final Verdict
The VP-725DS is a limited downscaler with some redeeming features. This might be ideal for anyone looking for a 2-in1 video switcher and scaler, with an array of inputs and 3 simultaneously scaled outputs. If this appeals to you, then try to find an ‘A’ variants with audio. Taking into account no scaled 480i, 1-2 frames of lag, the blind wandering vertical frequency, and image controls that do not correct 1080p overscan, I score the Kramer VP-725DS 6.3/10. If looking for a Kramer Switcher/Scaler for downscaling to a CRT, ensure it is in the same family as the VP-725DS by potentially consulting the user manual and seeing if the OSD is a match.
Although the VP-747 has an extra custom resolution slot and image rotation, 6 frames of lag firmly declares it as not suitable for gaming. If the OSD looks the same as the VP-747, I would recommend to steer clear for scaling video games.