[MPlayer-users] crt v. lcd

[Phil Rhodes]

> Video that looks spectacular on my crt, most often looks terrible on my
> laptop lcd (tons of macroblock artifacts).

Are you using the same equipment (in terms of both hardware and software) to 
decode it in each case? Playback can include techniques for minimising the 
visbility of macroblocks; decoding this stuff, as well as encoding it, is 
not an absolute, and is dependent on both opinion and equipment performance.

If you are using the same gear, I'd probably assume it's to do with the 
massively larger contrast of which the CRT is capable, or just a difference 
in gamma possibly burying artifacts in black shadows or reducing local 
contrast to the point where the problem is less visible. No display is 
entirely linear, either by default or by design intention, which means that 
a pixel value of 100 isn't necessarily (or even often) twice as bright as a 
value of 50. Encoding and playback software, including things like mplayer 
and ffmpeg, tries to make sensible decisions regarding this, but it's rarely 
a precision operation (which is why, in industry, people go to great lengths 
calibrating displays with hardware probes and adjustment gear). CRT and LCD 
differ wildly in this regard, even when both are really supposed to be sRGB 
devices.

The fullscreen issue may be scaling, as a previous poster mentioned, and his 
suggestions are worthwhile - although most default settings will give you 
the same code that more or less every video player (and 3D video game) uses 
to make images bigger, which is what most of the world is looking at. This 
may minimise aliasing but it shouldn't have an enormous effect on blocking.

If you are encoding stuff yourself then the answer is fairly 
straightforward - don't use compression, use lossless compression, or use 
light compression, use only I-frame compression (such as MPEG-4 with all I 
frames, or MJPEG, or a wavelet codec, or DV, or DVCPRO-100 if it's HD stuff 
as and when the ffmpeg boys get around to putting it into the code). This is 
how industry does it, and it's becoming increasingly easy to do it on home 
equipment, since computers advance far faster than broadcast video 
technology.

ffmpeg is capable of extremely good results with h.264 encoding, though - 
look into that.

P

 Would someone be willing to touch
> on a few of the reasons for this? I've tried to answer it for myself, but
> can't really put it all together. Another question I had concerns watching
> the video at it native resolution vs. fullscreen. Fullscreen you see a lot
> more artifacting and while I understand why this happens, I don't know how
> (if it's possible) to encode, for watching fullscreen.
>
> I'm guessing both questions hit upon some pretty wide subjects, I'm just
> trying to find a starting point.
>
> Thanks,
> Steven
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> MPlayer-users at mplayerhq.hu
> https://lists.mplayerhq.hu/mailman/listinfo/mplayer-users


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