Reply To: Tips & Tweaks: Lx3, Lx4, Lx5 modes

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#25482
Voland
Participant

The result of further testing OSSC + retrocomputer Soyuz-Neon. Immediately make a reservation: the experiments showed that in the existing software of this computer, all 300 lines are actively used for graphics !!!

I have the usual 22-inch widescreen Dell 1920*1080, on which I began to conduct experiments.
Having tried all the combinations of parameters, I selected the optimal (V.Active = 297, V.backporch = 6, V.synclen = 4) at which the topmost (first) line of the Soyuz-Neon computer image coincides with the top line of the monitor matrix, and the screen displays 297 lines of the original image of the computer Soyuz-Neon: https://ibb.co/W5KCw04
At the same time, in the menu of the monitor, the current resolution is displayed as 710×594. Accordingly, the 3 lower lines of the original signal are lost, and when trying to increase V.Active = 297 -> 298 and higher, the image disappears for good, because the monitor cannot enter this mode.

Earlier, as an alternative to a PVM TV, I purchased a Sony LMD-1510W monitor, which turned up useless in terms of trying to connect to it the RGBS signal of any retro console. Unexpectedly, the HDMI input of this monitor opened up unprecedented multi-format capabilities, starting with the fact that the HDMI output of the OSSC, brought to it, was recognized as 576i and ending with the fact that the video stream of 301 lines, processed inside OSSC using a 3x multiplier, was recognized on my monitor as the resolution 1NNNx903 – This is despite the fact that the limit resolution of the monitor is 1366×768. NNN in this case changes arbitrarily in direct proportion to the value of the parameter H.samplerate set in OSSC, and, according to my observations, H.samplerate does not significantly affect the final result. For Lx3 mode, the output format was 16: 9, which was interpreted by the multiplier as 1280×288, where 301 multiplied by 3 was used as 288 lines.
Thus, by setting the parameters (V.Active = 301, V.backporch = 6, V.synclen = 4) + Lx3 (16:9) I received all 300 lines of the Soyuz-Neon computer image on the Sony LMD-1510W monitor: https://ibb.co/84KKK4N

Findings:
1). OSSC is a very, very interesting product, I hope the firmware will still be actively developed.
2). Since OSSC, unlike framemeister, is a multiplier, not a scaler, in order to provide better image clarity, you need to use the highest multiplication factor (Lx3, Lx4, Lx5). Accordingly, to use at least Lx4 mode, you will need a monitor that can display 1200 lines vertically. When complying with the FullHD / IPS criteria, the cheapest option is Iiyama ProLite XU2395WSU-1
3). The selected monitor should be as flexible as possible in terms of multi-format signal, otherwise it simply does not recognize most of the modes issued by OSSC.

Resume: I leave to myself OSSC, because besides the framemeister, this is the only decent and versatile upscaler that can also be bought 2 times cheaper.

My questions:
– Is there complete documentation for OSSC, which describes the purpose of each parameter, as well as a list of supported output resolutions for each of the Lx2 .. Lx5 multipliers?
– What affects the parameter H.samplerate and on the basis of which is the value calculated in which it should be set?
– What monitor needs to be purchased so that 300 lines of the original image fit on it when using the Lx5 multiplier? The fact is that I have enough of the image clarity that the Lx4 mode gives.