HDV to SD - Quality Issue Redux

bsuratt wrote on 9/12/2008, 9:23 AM
While trying to get a better (clean) render of an HDV to SD project I ran across a setting I had overlooked before and I believe it helps.

To begin with, my current PQ is very good and quite acceptable for SD. But, I kept noticing a slight degree of "frizz" on fast moving background objects. Slight, but noticeable and this in addition to the normal expected 60hz /120hz issue with LCD's!

On the Render tab, Advanced Video there is a checkbox "Allow field based motion compensation" and it is checked by default.

The help file states: "Allow field-based motion compensation
Select this check box if you want to use field- and frame-based motion prediction when predicting frames. When the check box is cleared, only frame-based motion prediction is used.

We recommend that you clear this check box if you’re creating MPEG files for NTSC or PAL DVDs or SVCDs"


Note this last paragraph... it would appear that the default checked condition is not correct for DVD production.

I unchecked the box, did a two pass encode and I believe the video looks cleaner. Not dramatically, but anything is good!

Comments

Robert W wrote on 9/12/2008, 4:47 PM
Hmmm... Another little option to ponder over. I would guess if you were going from 1080i50 to NTSC you might want to leave the option on as field based prediction would be useful.

But what exactly is it doing with the option unflagged? Why should it make a difference if you are not changing frame rates?

It is slightly confusing.
Robert W wrote on 10/9/2008, 8:47 AM
Thought I'd bump this to see if anybody has any further information on this clause yet.

I suspect it may be beneficial left on when converting from HD resolutions down to PAL and NTSC even when they have an equal number of fields. My guess is that it is only worth turning off when the source and target render format are the same and there is no frame cropping or panning in the project, but I could be wrong.
johnmeyer wrote on 10/9/2008, 9:11 AM
PLEASE, please use the search function in this forum. This has been covered before.

Link 1

Link 2

Link 3

There are many others ...

The answer to your question, from Sony, is in one of those links ...