Please Clarify & Help My Brain Regarding HD at DVinfo.net

Barry Rivadue · April 4th, 2010, 12:41 PM

I have a Canon Powershot; it shoots sublime 720p HD. I use a program called Prism Video Converter that reformats it from a mov.file to mpg. I open it in Vegas, and everything is right with the world. A snap!

I also have a HMC150 that I have yet to use, and recently ordered a mega-computer to process ACHDV, which seems more demanding for editing purposes. I also have Cineform waiting in the wings.

Now, what should I expect with ACHDV that makes it more complex? Why is the HD I use with the Powershot so effortless to convert and edit?

Thanks (I should know the answers to all this but admit defeat)

Shaun Roemich · April 4th, 2010, 01:26 PM

Quote:

Originally Posted by Barry Rivadue

Now, what should I expect with ACHDV that makes it more complex?

AVCHD uses a long GOP MPEG compression to achieve the results it does at the bitrates it records at. This requires the MPEG stream to be "unpacked" during playback and modification (editing, effects) as only every keyframe (or "I" frame) contains ALL the information required to make a full frame. This requires a lot of computation, especially given that AVCHD is a "next gen" codec - 5 years from now we will look back and laugh that Long GOP codecs crippled computers but for now, we need raw computing "horsepower" for real time performance.

Barry Rivadue · April 4th, 2010, 02:41 PM

Thanks; I'm glad I ordered that computer.

Dave Blackhurst · April 7th, 2010, 02:01 PM

1280x720=921,600 pixels per frame
1920x1080=2,073,600 pixels per frame

Right there you have over 2x the amount of data crunching. I've got a couple little P&S cameras that shoot pretty nice 720p video as well, but it's not as sharp as a camera shooting 1080, just aren't as many pixels dancing around!

April 4th, 2010, 12:41 PM	#1
Barry Rivadue Major Player Join Date: Jun 2002 Posts: 508	Please Clarify & Help My Brain Regarding HD I have a Canon Powershot; it shoots sublime 720p HD. I use a program called Prism Video Converter that reformats it from a mov.file to mpg. I open it in Vegas, and everything is right with the world. A snap! I also have a HMC150 that I have yet to use, and recently ordered a mega-computer to process ACHDV, which seems more demanding for editing purposes. I also have Cineform waiting in the wings. Now, what should I expect with ACHDV that makes it more complex? Why is the HD I use with the Powershot so effortless to convert and edit? Thanks (I should know the answers to all this but admit defeat) Last edited by Barry Rivadue; April 4th, 2010 at 01:22 PM.

April 4th, 2010, 02:41 PM	#3
Barry Rivadue Major Player Join Date: Jun 2002 Posts: 508	Thanks; I'm glad I ordered that computer.

April 7th, 2010, 02:01 PM	#4
Dave Blackhurst Inner Circle Join Date: Feb 2007 Location: Apple Valley CA Posts: 4,874	1280x720=921,600 pixels per frame 1920x1080=2,073,600 pixels per frame Right there you have over 2x the amount of data crunching. I've got a couple little P&S cameras that shoot pretty nice 720p video as well, but it's not as sharp as a camera shooting 1080, just aren't as many pixels dancing around!