[vlc] Re: HDTV Transport Streams (.ts) and Performance

[Galen]

> 1. The compressed bitrate is quite large, and laptop discs are quite 
> slow.
> If I was you, I'd check that my disk is not the limiting factor. 
> You'll need
> sustainable read rates of >> 3MB/s. Also try increasing the file-cache
> option in vlc preferences.

My disk is able to sustain 10-20 MB/sec read. The OS X GUI seems to 
lack any cache options, although I could have missed it with the many 
many modules present.

> 2. The raw video bandwith (decompressed) is about 100MB/s. This could 
> perhaps
> max out memory (at least if you need to do real time processing on such
> amounts of data). Also laptops tend to have quite limited cache on the 
> cpu,
> which could impact processing of huge amounts of data like this.

I have PC2700 (DDR) RAM in my machine. I hope this is fast enough.  My 
CPU has 512 KB of L2 cache.

> 3. I don't think OS X exports chroma conversion and scaling of the 
> video
> card through any api. So only apple dvd player can use that. 
> Furthermore the
> video card perhaps had IDCT acceleration as well, but vlc don't use 
> that
> anywhere. Rumor say that the opengl system in in osx can convert YUY2 
> to
> RGB, and do scaling, so using the opengl module will only require vlc 
> to do
> YV12->YUY2 conversion (which is cheap in comparison), and graphics 
> card will
> do the rest. This should give a noticeable speedup.

This sounds like the sticky point for why I frustratingly can't get 
these streams to play.

> Then for your comfort I can inform you that my 2.0GHz P4 laptop are no 
> where
> close to playing HDTV in realtime (though my videocard suck in 
> comparison to
> yours), in linux.

That does make me feel just a little better. :)

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