GH3 to iMovie to iDVD - black stage curtain macro blocks

sigamy

Mu-43 Regular
Joined
Dec 4, 2012
Messages
148
I am creating DVDs for my child's elementary school. I shot ceremony in the gym/auditorm with teachers speaking at podium in front of a black stage curtain. No stage lighting. On the final DVD the black curtain is a mess of dancing macro blocks.

Shot with GH3 in MOV format, 72Mbps. I'm editing in iMovie. Footage looks fine in iMovie. I have exported as 1080p from iMovie. After creating a DVD with iDVD, the black curtain is basically a big macro block.

I know I'm using consumer tools but I can't understand why these black curtains are getting so crushed. The rest of the frame looks fine--teacher at podium, students, etc.

Is there anything I can do to get a better encode? Would compressor do a better job?
 

benhecht

Mu-43 Rookie
Joined
Aug 25, 2014
Messages
14
Not sure what you mean by big macro block, but I use Compressor to make files for DVD (out of Final Cut Pro). There are assorted presets you can use in Compressor for DVD, I use the 90 minute best quality settings if it less than 90 minutes.
 

sigamy

Mu-43 Regular
Joined
Dec 4, 2012
Messages
148
Thanks for taking the time to do that search. I appreciate you taking the time.

Unfortunately that's not really the issue. The issue was that one specific element in a scene or frame is suffering from compression artifacts--not the entire frame on the entire DVD just one particular element in a scene.

In my case it was a black stage curtain. The kids moving along the stage were fine, the teacher standing on the stage/-perfect. Everything else looks great--nice DVD quality. But the black stage curtain really suffered in MPEG2 compression.
 

kinlau

Mu-43 Top Veteran
Joined
Feb 29, 2012
Messages
952
Your software is prioritizing compression for areas with more detail. You could either completely crush the black curtains so that there's no detail left, or lighten them up or even add noise so that your software won't try to compress them as much.
 

sigamy

Mu-43 Regular
Joined
Dec 4, 2012
Messages
148
Your software is prioritizing compression for areas with more detail. You could either completely crush the black curtains so that there's no detail left, or lighten them up or even add noise so that your software won't try to compress them as much.
Thank you. That is a great explanation. For this project, I have to live with the artifacts. I will keep this in mind for future projects. But I really think this is my last DVD delivery...it really hurts to take 1080p down to 480 MPEG2.
 
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