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Ken7
06-25-2009, 09:11 PM
When shooting at 720p indoors and watching the clips on my computer monitor, I notice a rhythmic, almost pulsing of the video. It's almost as if the autofocus is pulsing, but in a VERY consistent, rhythmic way...about 2 pulses a second. The video looks like it's slightly in & out of focus with this pulsing.

Now when I watch this same video on my Pioneer Kuro, I get nothing like that. The focus is stable and there's none of that pulsing! Put the SDHC card back in my computer and the pulsing is back. Although sometimes, the first play will look normal on the computer, but not always.

Weird eh?

John Caballero
06-25-2009, 09:27 PM
What does that tell you really? Playback in your computer having trouble maybe?

J Davis
06-25-2009, 09:47 PM
That makes sense actually.
AVCHD is a container for h264 which uses long GOP compression.
There is one I frame (real frame) followed by fourteen B & P frames. The B & P frames are really text data describing how groups of pixels from the I frame are moved about. so in effect you are really only recording two real frames of pixels per second.

Try transcoding to a normal editing codec and check focus then. BTW - never edit in h264 aka AVCHD, its a recipe for disaster.

sdhurley
06-26-2009, 05:22 AM
n[/I]ever edit in h264 aka AVCHD, its a recipe for disaster.


what about CS4 with its native AVCHD handling? Is that still problematic? I was hoping to use Premiere CS4 to edit these files straight from my SDHC cards. Is that a bad plan?

Martti Ekstrand
06-26-2009, 05:32 AM
If works I'd use it for a rough selection cut and then render that out to something more solid for final edits and CC.

nathankw
06-26-2009, 06:42 AM
I noticed exactly the same when I first played back my footage using the bundled software. It's not in the footage, it's just down to the way its played back.

When I transcoded the footage and played it back it didn't have that pulsing.

You've got to remember there are now 3 things (at least) the determine the picture you actually see:
What image the sensor captures
How that image is encoded
How that image is decoded.

mhood
06-26-2009, 06:54 AM
If works I'd use it for a rough selection cut and then render that out to something more solid for final edits and CC.

I've got to ask if something like Premiere Elements might do for making a rough cut? I'm still hoping for a way to edit AVCHD on my tired old Premiere Pro V7.0. :)

Ian-T
06-26-2009, 07:10 AM
When shooting at 720p indoors and watching the clips on my computer monitor, I notice a rhythmic, almost pulsing of the video. It's almost as if the autofocus is pulsing, but in a VERY consistent, rhythmic way...about 2 pulses a second.

I've been seeing this same thing in a number of videos I've downloaded. I'm glad someone has finally mentioned this because it has really been bothering me. It's a consistent pulsating that happens throughout the video. Very annoying.

J Davis
06-26-2009, 07:49 AM
It doesn't matter what NLE you are editing with, its a bad codec to edit because of the B & P frames. Editing should be done in a codec where every frame is an I frame. Even if your computer is fast enough you can still get errors and weird artifacts, especially with disolve transitions. The errors don't always show up immediately but sometimes show up later when you transcode to mpeg or flv.

I don't work on a PC but for Mac users - transcode to prores. Because AVCHD is 8bit transcoding to proresHQ is unnecessary unless you want to take it to color or AE.