Welcome to our community

Be a part of something great, join today!

Log in
  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

4:4:4 Avi

Justin Kirchhoff

Justin Kirchhoff

Well-known member
Joined
Dec 28, 2006
Messages
1,730
Reaction score
0
Points
0
Location
Austin, TX
Website
www.digitalshakedown.com
Question guys,

I have a project coming up that needs to be finished as an uncompressed 4:4:4 avi file. I have After Effects and Compressor, but neither can export AVI files with 4:4:4 (or atleast that I can find).

How would one go about doing this? I can export 4:4:4 quicktime, import it back into after effects and then export and AVI?

Let me know.
 
VirtualDub (tm)?

VirtualDub (tm)?

Justin_Kirch said:
Question guys,

I have a project coming up that needs to be finished as an uncompressed 4:4:4 avi file. I have After Effects and Compressor, but neither can export AVI files with 4:4:4 (or atleast that I can find).

How would one go about doing this? I can export 4:4:4 quicktime, import it back into after effects and then export and AVI?

Let me know.
Click to expand...

I have used VirtualDub (tm) to make uncompressed AVI, you bring in your color corrected video gamma 2.2 BMP frames and the WAV file for the sound and it does a great job of making an uncompressed AVI.

Its hard to play back uncompressed AVI on a PC higher than 720x480, but you can send the uncompressed AVI into other programs that read them to make a DVD or something. VirtualDub seems to be a free download, try google to find it... There also seem to be more than code version, so look for the one you like?

If you have some files other than BMP for your frames like DPX or TIF you might try XnView (tm) or IrfanView (tm) to convert those into BMP.

Uncompressed AVI is much better than a MPEG2 playing back on the screen, very obvious if you are using uncompressed source frames like 3K film scans.
 
I noticed that MPEG StreamClip (free for Windows/Mac) was showing me all codecs available for export to an AVI file that are available during Quicktime conversion. I was surprised, since I thought AVI has restrictions on what can go into its wrapper.

Anyways try that and see if it works.
 
CODEC "none "produces a file that has not been compressed.

Both Quicktime and AVI file formats are "wrappers" that can use a variety of encoding and compression schemes -or CODECs -although, they don't have to.

Typically, an uncompressed QT or AVI is encoded using the full bandwidth of 4bits (1024 levels) per pixel-per R,G & B channels. (*edit* - thus deriving the fabled 4:4:4 color sampling regime)

There are also some CODECs (such as CINEFORM) that preserve the full 4:4:4 color profile of an image.

YUV and YCbCr are sampling (or subsampling) methods that allow for encoding RGB color and luminance data of the pixels using "difference" arithmetic that can reduce the bandwidth required to store and move the data, but also reduces the amount of information describing the original image. I believe there is a YUV 4:4:4 option with some systems but it's more common YUV to be produced using 4:2:2 samping.

These are my findings and Im sure someone may find points that can be further refined or corrected.

Adam
BOXXlabs
 
Bits per pixel?

Bits per pixel?

BOXXLabs said:
CODEC "none "produces a file that has not been compressed.

Both Quicktime and AVI file formats are "wrappers" that can use a variety of encoding and compression schemes -or CODECs -although, they don't have to.

Typically, an uncompressed QT or AVI is encoded using the full bandwidth of 4bits (1024 levels) per pixel-per R,G & B channels. (*edit* - thus deriving the fabled 4:4:4 color sampling regime)

There are also some CODECs (such as CINEFORM) that preserve the full 4:4:4 color profile of an image.

YUV and YCbCr are sampling (or subsampling) methods that allow for encoding RGB color and luminance data of the pixels using "difference" arithmetic that can reduce the bandwidth required to store and move the data, but also reduces the amount of information describing the original image. I believe there is a YUV 4:4:4 option with some systems but it's more common YUV to be produced using 4:2:2 samping.

These are my findings and Im sure someone may find points that can be further refined or corrected.

Adam
BOXXlabs
Click to expand...

The RGB uncompressed AVI I have seen are 8 bits per color RGB or 24bpp (bits per pixel), same as a 24bpp BMP file. 8 bits is 0 to 255 values of R, G, and B. 4 bits is 0 to 15. In YUV files the Y can have more bits and or samples than the U and V, but in RGB they are normally equal(?).

You can look at this link,

http://en.wikipedia.org/wiki/Chroma_subsampling

The numbers 4:2:2 seem to refer to the number of samples of pixel size and not the data depth of the samples, that is you could have 16 bits in a 4:4:4 sample, or 8 bits or maybe 12 bits(?).

Maybe someone with a video compression background could add something more on what uncompressed AVI normally means, I thought it would be RGB since that is how I make them... some programs list RGB in the codec list,

http://www.fourcc.org/
 
The word uncompressed can be ambiguous since it can refer to 4:2:2Y'CbCr or 4:4:4R'G'B' (or maybe 4:4:4Y'CbCr... but probably not). The common formats have the same bit depth for the RGB or Y'CbCr components... so it's not like Y' will be 10bit while Cb and Cr are 8-bit.

If it's AVI, uncompressed would *probably* mean RGB since the other "uncompressed" formats usually won't appear in an AVI / there aren't widely-used AVI codecs for those formats. You can always ask what format they expect, or send the other side a test file (with bars probably and some picture to check that the levels look right).
 
You must log in or register to reply here.
Back
Top