User talk:Tmorton166
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[edit] Slam Nation
Slam Nation article was in trouble for copyright. I did not delete it there was nothing there to begin with. I was the one how started it.
[edit] Video Scaler Definition
Hello,
I was just shown the definition of Video Scaler on Wiki, and noted that there are some fundamental short-comings in the definition.
As background, I'm the Senior Test Engineer at Anchor Bay Technologies, Inc. (the makers of the DVDO branded line of video processors for Home Theater, and the ABTxxxx “VRS” line of Scaler ASICs).
To start - it may not be wise to break into the topic of resolutions right off the bat unless there is an alternate link to a resolution "backgrounder" to explain why this “video scaling” even takes place (I used to do Tech Support here and I know there is a great mass of people out there - let alone consumers, who don't even know why they should care about this topic). The definition we present for “Scaling” on our website (www.dvdo.com/faq/glossary.php?searchletter=S) is:
"Scaling: The reformatting of video or digital pictures to occupy a different number of scan lines or a different horizontal or vertical pixel count. Also referred to as "resampling". This is done to zoom an image on the screen without spreading out the existing scan lines, or to change the video from one format to another, for example HDTV to NTSC or NTSC to SECAM."
Again there are a lot of words in there that don't really lend themselves to "ease of understanding" unless one happens to be thoroughly going through our web-glossary. Also, it’s more correct to call the scaler the actual chip which does the scaling. While many products are available with analog or digital inputs and outputs, the device that ultimately does the scaling is in fact digital – and it may not only do scaling, thus it is referred to as an “external/stand-alone video processor”.
“Arbitrary resolutions” is not an accurate way to describe the source and output signals that are involved with scaling. Scaling is a more general concept than just video – even a normal copy of Adobe Photoshop or Jasc Paint Shop Pro will do scaling on static images. To put it simply:
The intention behind Video Scaling is to preserve as much of the original signal information/quality while migrating the information conveyed in one signal format/resolution to another different signal format/resolution. It works either in “upscaling” or “downscaling”.
With digital video on the rise – accurate scaling is more important than it was when the majority of displays on the market were CRTs. With CRTs – there would be scan-lines that represent a signal that was received by the display. The simplest way to scale an image to fit a larger display was to de-focus the electron beam so that it would light more phosphors so that it would occupy more surface area on the display. The problem with this method though is that, as the electron beam sweeps across the phosphors on the screen, the video signal is still changing - thus it will blur the detail for a given line in the image. Inexpensive digital video “up-scalers” do basically the same thing with simple multiplier scaling (i.e. in 2:1 scaling ratio, 1 pixel-in becomes a 2x2 pixel-output [four copies of the original] to increase the size of the final signal).
The results of this scaling method are unfortunately about the same as defocusing the electron beam in a CRT (somewhat blurry – and at a rather substantial loss of visible detail for the same amount of area). The detail in a video signal is a high-frequency (or fast changing) band of the signal (in order to get from white to black from one pixel to the next, the signal needs to change in value a very large amount in a very short time). By simply multiplying the size of a pixel - one is (theoretically) dividing the output detail level by the same multiplier for a given signal. The most difficult conditions for scaling occur when there are values below the decimal point (i.e. 1.7778:1 for horizontal 480p to 720p upscaling). In this case there is no simple answer for what the new pixel should look like – and in many low-cost scaling chips like are found in <$60 DVD players, the new pixel will become literally a mix of the pixels on two adjacent lines of image data and in others it will skip adding lines every so often so that the numerical count is correct (again at the cost of accurate geometry and fine detail). This lends to a further reduction in output resolution, due to the mixing of the high frequency components (everything just blends together – which gives a “soft” look to fine detail). With a digital display like an LCD or plasma – there is a fixed number of available pixels to display video information. This means that the signal received by the display must be fitted to the screen so that there are no blank/black spots around the screen (this is not directly related to displaying a 2.35:1 “cinemascope” movie on a 16:9/1.78:1 Plasma or LCD). Since a digital display has specific “addresses” for pixels and they can’t be moved by changing where an electron beam lands on a phosphor mesh – the image must be corrected before it is given to the display’s glass.
Today’s higher-quality video scalers use some form of interpolation that does not expand the higher-frequency component down to a lower (softer) component, but rather preserves the original detail by ensuring that the original detail is a portion of the final output. There are generally three accepted stand-alone scaler chip manufacturers in the market today: Silicon Optix (www.siliconoptix.com) with the “HQV” line of chips, Gennum (www.gennum.com) with the “VXP” line of chips, and Anchor Bay (www.anchorbaytech.com) with the “VRS” line of chips. Other device manufacturers like Sony, Pioneer, Lumagen, Gefen, and Key Digital have there own proprietary scaling methods – but they do not currently produce chips for other manufacturers. Then there are other manufacturers who use less expensive/complicated scaling methods which can degrade the final video output of a given device – and are integrated with other technologies like MPEG decoding, audio decoding (Dolby Digital, DTS), servo controllers, and HDMI transmitters/receivers which reduce the cost for main-stream devices like inexpensive DVD players (these are at the heart of “upconverting DVD players”), Cable and Satellite boxes, and low cost digital video displays (LCDs). Manufacturers include LSI Logic (www.lsilogic.com), MediaTek (www.mtk.com.tw), Sigma Designs (www.sigmadesigns.com), and Zoran (www.zoran.com).
I would also recommend (as a personal note/opinion) that you should remove the commentary about “highly overpriced upconverters” – this is an opinion by the author, and is not being presented as such. It’s also indicative of ignorance of the reasons behind the purpose of these devices (and in the UK could expose the author to a slander lawsuit). As an example, the Startech DVI Upconverter listed at the bottom of the page is fairly limited in its uses and capabilities (only a few input resolutions over DVI, and a few output resolutions over DVI). The devices that are listed for the DVDO and Lumagen are in fact quite a bit more than just simple scalers – they perform true de-interlacing (not just BOB or Weave – and a completely separate process from scaling) and several other functions like video input and output level calibration, switching from different sources (not just one input type and one output type), color-space transcoding, audio routing, etc.
I would also suggest that the link to: “What is an HD Upconverter?”, be removed as they have seriously missed the mark on the purpose and use of scaling (it’s again “uninformed” and contains a lot of “fluff” with no real technical data backing up the opinion expressed by its author - basically it's a buy recomendation for new DVD players over old ones).
Deinterlacing (listed on this page as “interlacing”) should not be listed on this page. Period. It’s already presented in fairly accurate detail on Wikipedia under “deinterlacing”. The interlacing information is very wrong (it’s not used to increase the resolution – it’s intended to reduce the bandwidth required to convey a frequently refreshed image over a transmission medium). Deinterlacing should only be a link to the deinterlacing definition as it is but a side-note as an unrelated yet often paired-with technology of scaling (and is just about always included in a stand-alone scaler).
Please let me know if I can provide you with any further information relating to this topic.
Cheers!
Tim Strommen mailto:tim@dvdo.com
[edit] Photo
Hey man you probly dont even remember me but you said I could come to you if I needed help well I do. I made this article on one of my fav new(well new ot me anyway) mangas Diabolo(See Diabolo (manga)) and I would like a photo on it perfuribly this one http://img176.imageshack.us/img176/5549/1sdiabolo2tp9.jpg I was wondering if you could teach me how to put a photo on thier or perhaps do it for me. Thanks.
[edit] Video Scaler: The Difference Between Scaling in TVs and DVD Players
I think a stub should be created as a marker for someone to answer this question.
Basically, if I feed an SDTV/EDTV/HDTV (720p or 1080p) an SDTV or EDTV signal, it will display on all these TVs. So there is some sort of video scaling going on in the TV itself.
That being the case, what is the difference in the scaling done by the TV and that done by an upconverting DVD player?
