Difference between revisions of "DScaler"

Latest revision as of 21:31, 4 October 2009

Overview

DScaler is an amazing piece of software. There are still many people who will refuse to buy a capture card that does not support it, as most cards come with terrible drivers and software. DScaler talks directly to the hardware without using drivers and displays the video using hardware overlay. Not only do you not have to put up with poorly written drivers and programs, this method is MUCH, MUCH faster. You can enjoy virtually lagless play while capturing and record good video that would otherwise be an unwatchable mess in other software like VirtualDub. If you want, you can also tweak all sorts of previously unavailable internal card settings to achieve the best picture or performance possible. DScaler will commonly be the difference between thinking your capture card is great, or a piece of crap.

A brief note about capture cards. You can get very good quality from a cheap card, even in the $10-$15 range. Even low-end cards can support s-video input and line-in for stereo audio, so make sure to check before you buy some card that only supports composite or mono. Audio input is nice and often included, but not necessary; without it, you can just send the audio from your console directly to your sound card and use it to record the audio. If your capture card or sound card doesn't take in RCA inputs, you can get a very cheap RCA to headphone jack cable, or your capture card may already come with one for the line-in.

Caveats

The biggest caveat is support. Since DScaler talks directly to the capture card, support for each chipset needs to be individually added. Otherwise, you will have to resort to the slow, generic driver-based DShow mode that other programs use. Fortunately, most cards use the same chips. Generally, if you have a low or mid-end PCI card, which will almost always use either the bt8x8, cx2388x, or saa713x chipsets, it will be supported. USB cards and PVR cards with built-in hardware encoding are generally not supported, and they also tend to have a great deal of lag. If you are unsure if your card is supported, you can find the chipset on Google or just ask. You could also try running DScaler and see if it works without selecting DShow.

DScaler requires hardware overlay to minimize latency, and only one process may use this at a time. This means if you are already using hardware overlay in another program (maybe it's turned on in your media player as well), it will give an error upon loading. Close the other program and try again.

Since DScaler uses ring 0 for highest-level control to interact directly with the hardware, this means that if it crashes, it could take down your entire system and force you to reboot. I've never had it crash, but I guess this is still a consideration.

Setup

Go to the download page and get whatever the newest release is. It should be stable even if it's not listed as a "stable" version. Run the installer. Upon running the program, it should bring up a dialog box asking you for your card. You can try the auto-detect if you don't know or if it's not listed. Many cards are similar so it can still work even if the name isn't the same. Then there should be a dialog box for performance settings. You should select all the highest quality settings: Above 1 GHz, Best picture quality, DScaler alone. If your card has a TV tuner and you care at all about watching TV, the next thing to do is scan for channels just like you would with a stand-alone TV: Channels/Setup. If your card came with a remote control, you can use software like EventGhost to control DScaler.

At this point, you can play around in the menus for a bit to set some of the countless options how you like. The included help is very useful, or you can ask for help in fine-tuning settings. Pixel width should be set the same as or a multiple of the source: 640 for NTSC console output, 768 for PAL, 720 for TV or DVD material. Audio input should be either Tuner for TV or Stereo for console output; you should check pin 1 if it's there. Similarly, go to Settings/Audio Mixer setup and disable the hardware mute. Then go into Settings/Advanced Settings and click on the first row, for your card chipset. If the options are there, I find the best picture is achieved by turning on AGC (including crush), comb, full luma range, and leaving everything else unchecked.

If you really want to reduce lag, besides common-sense stuff like not opening 50 other programs or turning on every filter, there are a couple Advanced Settings to get the latency all the way down. Turn Aspect Ratio/Defer Setting Overlay off, Wait for Vertical Blank off, Field Timing/Maximum Shift to 0, Decoding/Hurry When Late on, Wait for Flip off, Threads to high, Overlay/Back Buffers to 1. Also turn off Capture VBI in Datacasting.

Watching

Use Video Input to switch between TV tuner, composite, s-video, etc. To change channels, hit page up/down to go up or down by one channel, or just type the number of the channel.

The two most important menus for picture quality and performance are Deinterlace and Filters. First, uncheck Automatic Detection and JudderTerminator. The next thing you will want to do is select the general deinterlacer you like the best. I recommend Greedy High Motion, but you can also try TomsMoComp or MoComp2. Click on Show UI and check Horizontal and Vertical Sharpness. I keep Auto Pull-Down (acts like Automatic Detection), In-Between Frames (acts like JudderTerminator), and Median Filter (acts like Noise Reduction, but adds a bit of lag) unchecked. Next you can see what filters you want to use. I personally have them all turned off, but these can be useful if they improve your picture: Temporal Comb, Adaptive Noise Reduction, Chroma. If you can't really tell a difference or know why you would want any of these, just leave them all off.

If your source is an old console (PS1, N64, Saturn, or older), you can try the Old Game deinterlacer; if you are playing via RF or composite, check the composite box in the Old Game settings. Otherwise (TV, DVD, newer console), stick to Greedy High Motion. If you are using RF or composite, you will also want to turn on the Temporal Comb filter to stop dot crawl and rainbowing.

Recording

To take a screenshot, just hit L. You can change the options in the settings, like format (lossy jpeg or lossless tiff that you will want to compress with OptiPNG), compression, location to save, periodic screenshots, preview mode, etc.

To record a quick clip for YouTube or personal use, here is the easiest and fastest way. Set pixel width to 320 for NTSC or 384 for PAL. Go to Actions/Recording/Options and select a lossy codec like Xvid or x264 under Compression Options. Select No Limit, averaged 1/2-height, and YUY2. Now, whenever you want to record, hit Shift-R to record and Shift-S to stop. If your video is jerky, you should try recording with a lossless codec and converting to a lossy format after editing with something like AviSynth, VirtualDub, MeGUI, or Batch Encoding.

If you're recording for SDA, you will obviously want a high quality end video. This means that you will want to capture the picture as purely as possible, so that any touches can be made later. So turn off all filters and select Simple Weave (essentially a dummy deinterlacer). Make sure pixel width is 640 for NTSC or 768 for PAL. DScaler produces video at your monitor refresh rate to maintain smoothness, so to record at 29.97 fps for NTSC, set your refresh rate to 59.94. You can use your video card drivers, but they often round, so in that case use PowerStrip to set it exactly, then select View/Switch Resolution in Full Screen/Use PowerStrip. Go to Actions/Recording/Options and select a lossless codec under Compression Options. Select No Limit, Full Height, and YUY2. Whenever you are ready to record, hit Shift-R to record and Shift-S to stop. You can take the resulting video and encode it yourself to SDA guidelines, using one of the methods above, or you can make your job simpler by using Anri-chan.