Recent content by aths

I also have a 2-bit TC for alpha channel. 6 bit average alpha value, 2 bits multiplicator. The 4x4 tile is devided into 8 subtiles of 2x1 texels each. For each subtile we use 3 bits. These 3 bits allow some modulation: higher, lower, more alpha, less alpha. Those modulation is multiplied with...

[]Reply to a strange general S3TC explanation[] There is actually only one real S3TC algorithm with some additional variations or extra alpha channel compression. ATI's 3Dc uses two of those alpha channel compression approaches to encode a 2-channel texture/map. I am currently only examine the...

I hope it's ok I use a second post instead of adding to the previous to improve the clear view. For 4x1 predefined waveform it is obvious that we need these three pieces. (L = lower brightness, H = higher brightness.) L L L B L L B B L B B B And all the way back B L L L B B L L B B B L We...

Yes because I have no idea how to compress with references to neighbour tiles colors. This would include some re-encoding of existing tiles to get an optimal result. In my opinion, cubic interpolations raises more issues than it solves; but I have to admit that some of my "philosophical"...

One of the 2-bit PVRTC modes is just decreased spatial resolution. You could use 4-bit TC and stretch a smaller texture over the same area to get "2-bit" with downscaling each texture dimension by factor 1.414. The other one uses only two brightness levels (or different colors) for a 4x4 tile...

This is not finished work, but I think I finally found an approach. 4-bit TC delivers very good quality. Due to the 2^n addressing scheme, the next step must be 2-bit. Previous 2-bit techniques (I read the work of Simon Fenney) either reduce the number of used color gradients per tile from...

As far as I recognized, LP (half speed, in PAL regions; however the final LP tape speed is comparable to NTSC EP/SLP tape speed) delivers full resolution indeed; however the noise is much stronger while the contrast is much worser. It would be interesting how LP (or SLP) performs with an S-VHS-tape.

Because the phyical resolution of my Philips 9020 TV is much higher than the VHS resolution, I don't need a fully analog monitor without pixels. I never detected more aliasing in a VHS image than on the TV. (Certain structures and textures show moire on the normal TV picture.) Regarding filter...

Since you cannot have infinite detail with a bandwidth-limited signal, "resolution" applies. Also a form of "pixels". Lets assume we have a maximum of 160 periods per scanline, meaning 160 times SIN(0..2PI), or SIN(0..320PI). Then it looks somewhat like 320 pixels (since we have a...

That is (of course) true. However I don't managed it to connect my Laptop to my VCR. Then I would just record some pictures with different line densitiy. Due to some filters inside the VHS recorder, you should get no aliasing, but a blurry image if you get over the limit frequency.

I done it and got to a number of about 288 (while I expected 240 at that time) which looks to be close to the real number. Overscan can be incorporated with assuming of having 7% overscan. To hide some geometry issues, I configured my TV picture to have a bit more overscan, though. You...

I don't want you to count your tv's picture elements but the VHS's freeze image number of luminance details per scanline. Since VHS's horizontal resolution is much lower even than common CRT's resolution, that task is actually possible. Analog PAL does not have 768 pixels per scanline. Since it...

We could *discuss* on and on ... or somebody just counts the number of "pixels" (luminance details) of a scanline. I already did but I want to get a confirmation about my figures.

Please forget wikipedia, because if it comes to AV technologoy, wikipedia often cites sources which I believe are misinterpreted. This is especially true if it comes to the resolution of analogue video images (and also is valid for the english as well as the german edition of wikipedia.) Since...

Anyone with a video recorder and a bit of time, please do me a favour. Get a freeze image and count its "pixels" (distinctive different luminance elements). Because to do so for an entire scanline would be tedious, it is best to encapsule a small portion of the image, such as a TV logo or part...