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2 Pass VBR Best is the Worst

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John Dehn
2 Pass VBR Best is the Worst
on Sep 22, 2010 at 6:57:24 pm

Hey there.

I started to notice something about a year ago in Compressor 2. When I used the VBR Best setting for compressing longer programs the image would start to pulse and get pixelated, usually around 20-25 minutes into the program. It would last for 30 seconds or a minute and then get better. I eventually found that changing to 1 Pass VBR fixed the problem. I was hopeful that maybe things would be better with Compressor 3. But this time I had an hour long doc that went nuts at 48 minutes in. Again, things look better with 1 Pass and with CBR.

I've looked around for other posts and have found a few people with the same issue, but have never seen any sort of fix or even an explanation for that matter.

Anyone have any thoughts on this. It kills me to not use what is supposed to be the best setting but I don't trust it any further than I can throw my Mac Pro.

Anyway, thanks for the help and here's the specs on my setup.

Mac Pro 2 X 2.26 Quad Core
12 gig of Ram
Snow Leopard
FCP 7.0.3


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Rich Rubasch
Re: 2 Pass VBR Best is the Worst
on Sep 24, 2010 at 2:07:56 am

Ever since DVD Studio Pro came Apple we have used CBR 6.3 mbps for anything that we encode in compressor. We bought BitVice to save us on a couple long encodes, but CBR in Compressor has been our friend.

CBR is easier on playback for DVD players so discs won't skip. Same with AC3 audio...it is the native chipset in DVD players so it streams thru the player effortlessly. Feed a DVD player PCM audio and it has to run it through a different audio circuit making it prone to freezes.

Noe, on long encodes we sometimes just feed a video signal to a Sony DVD recorder and put it on a longer encode setting and let 'er rip. We get acceptable encodes this way and it is a no fuss way to make the encode...we then use MPEG streamclip to demux the M2v and AC3 from the disc for authoring.

Good luck.

Rich Rubasch
Tilt Media Inc.
Video Production and Post
Owner/President/Editor/Designer/Animator
http://www.tiltmedia.com


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eric pautsch
Re: 2 Pass VBR Best is the Worst
on Sep 26, 2010 at 3:52:42 am

Just a couple corrections:

CBR vs VBR has nothing to do with discs skipping. If your bitrates are low enough and you avoid those bitrate spikes that VBR introduces you're fine either way.

Also...ALL players are required to support AC3 and PCM audio. Again, this will not effect playablity unless PCM audio sends you over the top as I explained above.

so the type of compression parameters or audio has nothing to do will making the player feel better...its all about overall bitrates


And...BTW....Compressor is a crappy MPEG 2 encoder :)



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John Dehn
Re: 2 Pass VBR Best is the Worst
on Sep 27, 2010 at 6:46:24 pm

What do you recommend for an mpeg2 encoder?



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Alan Langdon
Re: 2 Pass VBR Best is the Worst
on Jan 20, 2011 at 1:48:24 am

I have noticed the same thing, and it drove me to purchase BITVICE 2.9.7... I am testing it still, but it is pretty nice. Although I still want to see it beat the basic compression that Toast does. Toast encodes pretty darn well, although it makes everything 29.97 even if you feed it 23.98 footage.



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