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H.264 and HD on the Mac

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Dale Launer
H.264 and HD on the Mac
on May 6, 2005 at 12:00:33 am

I've been looking forward to this - what with all the hoopla. But I haven't been having much success doing 1920x1080 encodes. I start with Cinewave Targa HD material - and so far it takes forever, looks too bright, has some odd artifacting (I have some quick fade to black transitions with white titles), and has a stuttery playback (like 12fps).

I've converted/compressed the same material to DVC PRO HD 1080 without problems - and it plays back just find, no weird artifacts, no cranked up brightness, no problems actually.

But h.264 - so far, no good. I have a few more variables to tweak, but so far it seems like it just ain't working right.

I'm going to keep trying 'til the sucker looks good. But even looking crappy the file size is about 90% of the DVC PRO file size.

Wonder if anyone else is compressing HD and what the results are.

Dale Launer
writer.filmmaker
G5 Cinewave HD Huge


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Ben Waggoner
Re: H.264 and HD on the Mac
on May 6, 2005 at 3:11:28 am

A full 1920x1080 24p really need a fast G5 for playback - what were you testing on? The 12-fps is a classic sign that B-frames are getting dropped due to high CPU load. A lower data rate can often help there as well. 90% of DVCPRO-HD is 90 Mbps! Try 9 Mbps and see if that works any better for you.


My Book: http://www.benwaggoner.com/books.htm
Squeeze and ProCoder tutorials: http://www.classondemand.net/benwaggoner/
Compression Class at Stanford: http://www.digitalmediaacademy.org/compression.html


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Dale Launer
Re: H.264 and HD on the Mac
on May 6, 2005 at 4:19:51 am

Ben asked...

- what were you testing on?

2x2Ghz G5 and a 2x2.5Ghz G5.

I'll give the 9 Mbps a try, but keep in mind the DVC PRO HD codec works just fine.

I've been setting the rare window to automatic.



Dale Launer
writer.filmmaker
G5 Cinewave HD Huge


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Ben Waggoner
Re: H.264 and HD on the Mac
on May 11, 2005 at 12:14:29 am

For playback? a 2x2.5 G5 and a 1.33 PB.

Automatic should be fine. Your problem is that you're using an insanely high data rate for H.264 (which compresses to about 1/10th the size of DVC Pro HD at the same quality level).


My Book: http://www.benwaggoner.com/books.htm
Squeeze and ProCoder tutorials: http://www.classondemand.net/benwaggoner/
Compression Class at Stanford: http://www.digitalmediaacademy.org/compression.html


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