Logic Behind Rendering Full Uncompressed Files

busterkeaton wrote on 4/12/2008, 9:21 PM

AVCHD is not an example of an uncompressed file, fully or not.

The logic is in the way that compression works. One of the things that gets compressed is color.

Do an internet search for 4:1:1 or 4:2:2 color and it will go into depth on this. Look up "lossless vs lossy video codecs" while you're at it.

However, if you add effects to your video, Vegas does its internal calculations uncompressed and if you render to uncompressed you can retain all that color information. This is often done, if you are taking your video into another software package. For example, if you want to create a piece in Adobe After Effects and then edit that into a longer video in Sony Vegas, you may want After Effects to render it to uncompressed so that Vegas has access to all the color information.

For your home videos it probably would never make sense to use uncompressed.

Bit Of Byte wrote on 4/12/2008, 9:43 PM

Thanks Buster,

Have a look at 2nd last post (from "Blink3Times") in this thread
http://www.sonycreativesoftware.com/forums/ShowMessage.asp?MessageID=588393&Replies=12for import to Ulead

"...The final file on output to disk is avchd, just short of an hour at roughly 7 gigs...." (referring to his 625GB fully uncompressed file being rendered for Ulead)...

This is waht I am curous about...

Thoughts?

Bit

NickHope wrote on 4/12/2008, 10:14 PM

I guess Blink is using uncompressed to go from Vegas to Ulead because he can. He's got the disk space and he's later going to delete the file, so why not? That way he's sure not to lose any quality by compressing to an intermediate codec like Cineform or SonyYUV. There is a very tiny quality loss with those because they're not lossless. I bet you couldn't see the difference from uncompressed but there is a difference.

I guess he could have used a lossless codec like Huffyuv or Lagarith, which in theory wouldn't cost him quality. But maybe Ulead doesn't like those. And again, why bother when he's got the system to do uncompressed.

busterkeaton wrote on 4/12/2008, 10:40 PM

The output from Vegas to Ulead is uncompressed and it's 625 gigs.
The final output from Ulead is avchd and it's 7 gigs.
So the AVCHD file is much smaller and it's highly compressed.

What are you curious about?

This is what I talked about before. The intermediate render is uncompressed because it's going into another piece of software (Ulead) for the final render which is compressed using the AVCHD format.

Bit Of Byte wrote on 4/12/2008, 10:43 PM

Fascinating - thanks Nick / Buster.

Amazing how a file can be that compressed!

Thanks

Bit

John_Cline wrote on 4/13/2008, 12:04 AM

"Amazing how a file can be that compressed!"

It's not amazing if you understand how it's done.

rmack350 wrote on 4/13/2008, 12:29 AM

I can think of two reasons why you'd render an uncompressed file:

You've created a short motion graphic that you want to keep in pristine condition.

That graphic has transparency in it.

Why? graphics (rolling tumbling text, for instance) can really show compression, and uncompressed is one of the few codecs that supports transparency.

I wouldn't use it for camera footage but it's a tool you might use when compositing.

Rob Mack

ken c wrote on 4/13/2008, 9:35 AM

I keep everything uncompressed til final render for speed of-re-edits (in AE/V8) and quality ... outputting to uncomp. avi... also makes things fast to work with.. then when ready to do final renders (either dropping footage into DVDA for DVDs, or Flixpro for flvs) it's easy to keep highest quality without multiple compressions

-k

Bit Of Byte wrote on 4/13/2008, 4:37 PM

I luv this idea and will elect to do the same.

What is your hardware configuration to make this happen?

Bit

Rory Cooper wrote on 4/14/2008, 12:18 AM

I am also doing the same but have to rethink my methods when working with hdv which i have only recently started
what do you do about the large file sizes of uncompressed hd avi's
its becoming a problem so i do not want to drop quality for convenience
the emotional content or wow factor of hdv and flie size r in conflict so what is an acceptable solution?

Bit Of Byte wrote on 4/14/2008, 1:04 AM

It seems you have to acquire 1 or 2 TB HDD's/... with all the quad chips to boot.. I think.. ?

Bit

Rory Cooper wrote on 4/14/2008, 4:39 AM

i have my operating system on 1
then i am rendering to my 2nd
and my cach files are on a third with all my library's
and a quad core

i produce animations. Light weight 3d stuff and heavy weigt compositing mainly ads for the ad industry but am slowly adding video to my cv
there is just so much to learn and its important to get it right in the begining rather than relearning. i have always worked in avi uncompressed but with hdv the file sizes are getting bigger so where to from here? the USA sets the trends and we al follow, its just a matter of time so the quicker i get with the programme the better so mabey the anser is just simply bigger hard drives?