Blocky Compressor Renders

[David Bogie]

> I’m getting the dreaded blocky renders out of Compressor. The images break up at random times, mostly during dissolves. This was a problem a while ago, and I thought it had been corrected. I’m rendering 90minute Best Quality (2pass vbr) from a self-contained DV Quicktime. < "The dreaded" implies that we all see this from time to time and we don't. Blocky dissolves are caused by encoding settings. "Random times," are you sure? Do you mean they occur randomly during playback of the compressed file or they play back at the same place but the artifact is apparently created at random during the compression run? Random is rare. "Random" implies a drive or bus issue not a media issue. A media issu would mean you get the same artifacts in the same place with every compression run regardless of your settings. "Thought it had been corrected" by whom? Apple? bogiesan This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”

[Bob Pierce]

I call it dreaded because this used to happen all the time with 2 pass vbr encodes from Compressor. Apple, I thought fixed it. It is a random occuring artifact in the encoded Mpeg (it plays back consistently in the same places). And to be clear, it’s not in the original media – only in the mpeg.

In some shots it appears as a kind of pulsing in and out of blockiness in the more complex areas of the image. Other places is happens in the middle of a dissolve. Some shots just fall apart all together.

I’ve reencoded with compressor “fast 90 minute” and the problem is gone. I’ve always assumed that 2 pass made for better quality encodes, but I’m not sure.

Thank you,
Bob

Mac Pro 2.66 – 8GB memory – Mac OS 10.5.2 – Quicktime 7.4.5 –
Mac Book Pro 2.33 Duo –
FC Studio 2 (Final Cut 6.0.3) – Kona Lhe
Adobe Production Suite CS3 –
Sony Multiformat 14″ – Panasonic 42″ Plasma –
Ikegami HLDV7 – PVW EX-1

[Chris Borjis]

Hi bob, there is a bug in compressor with 2-pass vbr that causes this.

You need to switch to single pass CBR to get rid of it completely…for now.

The only time you really need variable bit rate encoding is
to cram as much content as possible on a disc.

[Bob Pierce]

Thanks, Guys for your help. I thought that this problem had been corrected (haven’t seen it in a while). It’s good to know that the single pass quality is still good.
Take care,
Bob

Mac Pro 2.66 – 8GB memory – Mac OS 10.5.2 – Quicktime 7.4.5 –
Mac Book Pro 2.33 Duo –
FC Studio 2 (Final Cut 6.0.3) – Kona Lhe
Adobe Production Suite CS3 –
Sony Multiformat 14″ – Panasonic 42″ Plasma –
Ikegami HLDV7 – PVW EX-1