Why is Smart resample ruining my footage? at DVinfo.net

Dave Pearce · April 30th, 2009, 03:02 AM

I thought i was getting the hang of Vegas 8c but it seems not.
Im trying to edit some footage shot on a Panasonic TZ7 (ZS3). Its AVCHD lite and so far its working fine, or so i thought.
Last night i noticed the output had a lot of ghosting in it. After a long search i found that i needed to turn off smart resample in the clips properties. No problem and it fixed it but i'd like to find out why this happened.

The files are 1280x720 50P and i have my project set for this. Under the preview window its showing the above settings so i know thats right.
But its when i go to render i can only get it to 25P (its just for web based viewing). Is this the cause of the problem? Should i be outputting at 50P? Im using the Sony AVC codec and ive created a pre set at 1280 x720 progressive.
This is the first clip ive actually had trouble with, all the others seem fine.

Any help or guidance will be much appreciated. Im pretty new to all this and while i can find my way around Vegas in not really sure on the more technical things like frame rates etc.

Cheers.

Dave.

Gints Klimanis · April 30th, 2009, 12:10 PM

I'd really like to understand what Vegas is doing during Smart Resample. I'm seeing similar ghosting when converting 720p60 to p30 or p24. For p30, even an average of two p60 frames shouldn't result in such a large wash of motion.

Dave Pearce · April 30th, 2009, 12:15 PM

Well i dont know why its doing it but at least i know now to turn it off.

David Esp · May 28th, 2009, 01:23 PM

I get similar and related problem when using 50p source media. Test media have included EX3 native 720 50p and DV-derived 50p (derived using AviSynth TDeint(mode=1) ).

When submitted to a Vegas project for 25p, the result (for default settings) both in the Preview window and in renders has ghosting, as if Vegas is combining pairs of 50p progressive frames together rather than just dropping alternate ones. This is what initially drew my attention to this problem (in a real project). Maybe some of the people complaining of "blurry" SD from HD are victims to this issue.

Vegas has workarounds for this, such as disabling resampling or dropping the sampling rate to 0.5 However these workarounds also have the side effect of reducing smoothness when time-stretching.

April 30th, 2009, 03:02 AM	#1
Dave Pearce Regular Crew Join Date: May 2008 Location: London, UK. Posts: 43	Why is Smart resample ruining my footage? I thought i was getting the hang of Vegas 8c but it seems not. Im trying to edit some footage shot on a Panasonic TZ7 (ZS3). Its AVCHD lite and so far its working fine, or so i thought. Last night i noticed the output had a lot of ghosting in it. After a long search i found that i needed to turn off smart resample in the clips properties. No problem and it fixed it but i'd like to find out why this happened. The files are 1280x720 50P and i have my project set for this. Under the preview window its showing the above settings so i know thats right. But its when i go to render i can only get it to 25P (its just for web based viewing). Is this the cause of the problem? Should i be outputting at 50P? Im using the Sony AVC codec and ive created a pre set at 1280 x720 progressive. This is the first clip ive actually had trouble with, all the others seem fine. Any help or guidance will be much appreciated. Im pretty new to all this and while i can find my way around Vegas in not really sure on the more technical things like frame rates etc. Cheers. Dave. Last edited by Dave Pearce; April 30th, 2009 at 12:16 PM.

May 28th, 2009, 01:23 PM	#4
David Esp Regular Crew Join Date: Apr 2007 Location: Alton in Hants and Swanage in Dorset, UK Posts: 45	50p->25p ghosting & workarounds I get similar and related problem when using 50p source media. Test media have included EX3 native 720 50p and DV-derived 50p (derived using AviSynth TDeint(mode=1) ). When submitted to a Vegas project for 25p, the result (for default settings) both in the Preview window and in renders has ghosting, as if Vegas is combining pairs of 50p progressive frames together rather than just dropping alternate ones. This is what initially drew my attention to this problem (in a real project). Maybe some of the people complaining of "blurry" SD from HD are victims to this issue. Vegas has workarounds for this, such as disabling resampling or dropping the sampling rate to 0.5 However these workarounds also have the side effect of reducing smoothness when time-stretching.

April 30th, 2009, 12:10 PM	#2
Gints Klimanis Inner Circle Join Date: Jun 2003 Location: San Jose, CA Posts: 2,222	I'd really like to understand what Vegas is doing during Smart Resample. I'm seeing similar ghosting when converting 720p60 to p30 or p24. For p30, even an average of two p60 frames shouldn't result in such a large wash of motion.

April 30th, 2009, 12:15 PM	#3
Dave Pearce Regular Crew Join Date: May 2008 Location: London, UK. Posts: 43	Well i dont know why its doing it but at least i know now to turn it off.