Quicktime 7

[laurent.g]

I like the step where quicktime is going. The new encoding/decoding of H.234 is much promising. But, yes there's always a 'but', I'm wondering how playing such H.264 (encoded) files will be. As a picture quality point of view I think it is going to be like a well encoded DivX. Apple say you can resize the movie while playing. The main question is, will all this goodies (smooth playing, small, full screen, live-resizing) work on a modest Mac? An iBook G3/600 for example.
I don't know if someone could check this up somewhere.

thx.

 

[fryke]

Basically, 'better codecs' do higher compression while losing less data. As the codecs become more advanced, the computing power needed to _decode_ the data increases. There are certain tricks a developer (in this case Apple) can do to improve the playability of such codecs on older hardware, but I guess if you're unlucky with the support of MPEG-4 (and Xvid and DivX and 3ivx etc.) on an iBook G3/600 (and I _wasn't_ quite happy with that back on my iBook G3/800), you'll not be happy with H.264 on that iBook, either. To some degree, H.264 overcomes these issues. Yes, the codec is very scalable, which means you can generate H.264 movie files that look good on even a mobile handset and you can generate H.264 movie files that look very good on HDTV or higher resolution hardware and everything inbetween. The _problem_ is: You'll need separate files for different hardware, AFAIK. That high definition encoded movie file will still take up a few hundred megabytes (or even GB, depending on quality and movie-length, of course). And the iBook would, although _playing_ the movie at a lower resolution, have to handle too much data at the same time, which will result in skipping frames, choppy sound etc. - just like it does with MPEG-4 (and derivates) type files above a certain data-throughput.

 

[fryke]

So the question really is whether you're talking about playing files other people have encoded or playing files you yourself intend to encode, I now realise. If this is about you creating an iMovie and exporting to H.264, you'll have all the controls you need in order to create a file that 'fits' your playing hardware. You can control data throughput (just like you can with MPEG-4 now) etc. Chances are, that this way, you'll get _better_ results than with MPEG-4 or Xvid or DivX (or any other codec available today for that matter).

 

[laurent.g]

By the way, I was more of less thinking of the playability of movies that have a width of about 500 - 600 pixels. (just like viewing online movie trailers when you selected the 'large' option button). I don't know if there's a demo movie included in any Tiger build to test out how well it plays on the installed hardware? And, does the graphic card has anything to de with it? I don't know if someone ever tested those things out?
And besides, would quicktime itself benefit from any of the advantages of recompiling in gcc 4.0 ?
And, do you think Altivec would improve decoding H.264 ?

I olso have an iMac G4/700. That's why I would like to know some answers in this particular area. It could be an usefull insight for a lot of other people too I think.