Codecs and compression at DVinfo.net

Go Back   DV Info Net > High Definition Video Acquisition > General HD (720 / 1080) Acquisition

General HD (720 / 1080) Acquisition
Topics about HD production.


Reply
 
Thread Tools Search this Thread
Old May 18th, 2008, 05:38 AM   #1
Inner Circle
 
Join Date: Apr 2006
Location: Wales
Posts: 2,130
Codecs and compression

Trying to figure something out. Take a camera that can record 1080P and 720P. Say it's got a codec with a 50mb/sec data rate. If you're shooting a moving subject, or panning or have a scene with a lot of moving details, would you get a better result recording at 720 because the codec is having to process a lot less info and so has less break-up? So it'd be better to shoot 720/25P than 1080/25P in some situations?
Steve
Steve Phillipps is offline   Reply With Quote
Old May 18th, 2008, 10:16 AM   #2
Major Player
 
Join Date: Jan 2007
Location: Pinellas Park
Posts: 232
Quote:
Originally Posted by Steve Phillipps View Post
Trying to figure something out. Take a camera that can record 1080P and 720P. Say it's got a codec with a 50mb/sec data rate. If you're shooting a moving subject, or panning or have a scene with a lot of moving details, would you get a better result recording at 720 because the codec is having to process a lot less info and so has less break-up? So it'd be better to shoot 720/25P than 1080/25P in some situations?
Steve
I think the 720p would handle the motion a bit better but not so much more than to give up the extra resolution. I would have to see both videos side by side, but maybe it would be better to shoot in 720p, considering that scenario. But then again if the codec is efficient enough like AVC-intra, I don't think you will see any percieved motion artifacts shooting in either, 1080p or 720p, so I guess I would stick with 1080p.
John Bosco Jr. is offline   Reply With Quote
Old June 4th, 2008, 10:12 PM   #3
Major Player
 
Join Date: Mar 2005
Location: Neenah, WI
Posts: 547
Quote:
Originally Posted by Steve Phillipps View Post
Take a camera that can record 1080P and 720P. Say it's got a codec with a 50mb/sec data rate. If you're shooting a moving subject, or panning or have a scene with a lot of moving details, would you get a better result recording at 720 because the codec is having to process a lot less info and so has less break-up?
Since you point out that both choices are progressive, the only way that a codec would influence how motion is preserved in the image would be if it was working as temporal compression...like long GOP MPEG or Windows Media. If you had an I-frame codec (no temporal compression), then how motion is captured will have more to do with the camera (aperture, shutter speed, etc...) than the compression.

Now...that's not to say that the choice of framesize has no affect on -overall- image 'quality'...with a fixed data rate, as you point out, the fewer pixels you're handling, the better the image 'quality' (meaning really 'accuracy' I suppose). However motion specifically won't be affected by framesize choice.
__________________
TimK
Kolb Productions
Tim Kolb is offline   Reply With Quote
Old June 4th, 2008, 11:01 PM   #4
Trustee
 
Join Date: May 2004
Location: Knoxville, Tennessee
Posts: 1,666
I interpreted the OP as refering to a situation where high motion in the scene was leading to compression artifacts. In that case, for a given bitrate yes 720P25 will definitely have less artifacting than 1080P25 option.

If the 1080 is interlaced, the answer is less clearcut, although on balance I would anticipate the 720P would still be preferable.
Graham Hickling is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > High Definition Video Acquisition > General HD (720 / 1080) Acquisition

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 08:43 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network