DV capture, convert to HuffYUV in vdub, DOUBLED my file size!

[rcwalters]

What's the deal here? This is my first time trying HuffYUV, I want to archive my original DV-quality files so I figured a lossless compression was the way to go. But, my 6.9GB DV captured file went to over 12GB with HuffYUV. Default settings on Huff.

I do like the 45fps though.

[edDV]

Why are you converting DV to Huffyuv?

DV will not improve by the conversion and it will take higher bitrate to maintain close to the quality of the original file. DV is fine as DV for archive.

The reason you would convert DV to raw YUV or Huffyuv (compressed) is if you wanted to edit or filter in a program that did not support DV format directly. The conversion would be somewhat lossy in UV space but not major.

Many Virtual dub filters will convert YUV to RGB. This can be done with low loss or moderate loss depending on the competance of the filter designer.

If you are working with high quality DV material and want the most transparent processing, better to use a native YUV program like Premiere Pro. For most of us, other issues swamp color space conversion loss.

[mike909]

Yep, what Ed said.
This is currently the ONLY reason I am looking forward to Blue Ray. Digitally archive project files...including a dv tape in its native format.

[rcwalters]

I guess I don't get it. What's the point of a "compression" codec that only enlarges? I don't see the point of converting an already high-lossy file like a DivX or an MPEG to HuffYUV lossless. Seems to me that you'd want to be compressing the original capture, not something that's already been run through the wringer.

So is HuffYUV not actually a compression codec, but actually more of a "conversion" codec? Just so we can have yet another format and codec to install to decode it?

Maybe this question will slap me down into the newbie convert forum.

[Cornucopia]

Not sure what your knowledge level is here, so I'll just clarify something:

"Losslessly Compressed" means losslessly compressed from (and compared to) an UNCOMPRESSED version, NOT from an ALREADY compressed file.
It's not the same as a Zip archive. Even if it were, it probably would right around the same size (give or take), not much less. The ENTROPY has already pretty much been taken out of it.

Scott

[mike909]

What's the point of a "compression" codec that only enlarges?

The point would be so you can edit it (in premier for example) Divx and other formats can not directly be edited in many NLE's.

Seems to me that you'd want to be compressing the original capture, not something that's already been run through the wringer.

this is true. DV has not been 'run through the ringer', so the point of compressing DV would be for either 1. archiving 2. burning to DVD 3. Editing in a program that can not directly support DV (as Ed pointed out 4. any other number of reasons
HuffYUV is a lossless compression format (unlike mpeg2, mpeg4/divx etc.)
EDIT: to clarify, mpeg2 and the like use compression to reduce file size, where HuffYUV does not.

[Cornucopia]

What are LOSSLESSLY compressed good for you ask?

Well, for those who want to capture the highest quality from their Analog sources (not talking digital transfer of DV, as it's already been digitized and compressed within the camera), you don't want any compression artifacts. You want 4:4:4 RGB, or (more commonly) YUV 4:2:2. So standard NTSC SD material (with 8bit/colorprimary sampling) gives you at least 158Mbps!
At that rate, your 33 minute program, which worked out to 6.9GB as DV compressed and 12GB with HuffYUV, would become 39GB. So HuffYUV is actually compressing well--it's only 1/3 of the uncompressed. 8) (And it, unlike DV, is identical to the original, quality-wise)

Scott

[edDV]

Lets assume you have a great 8bit SD video camera
(The truely great ones will be 10bit or more but set that aside).

If you capture that to 720x480/576 4:4:4 RGB or YUV you will have data rates ~ 240Mb/s not counting audio.

If you sample to 4:2:2 YUV (visually lossless but machines can tell the difference), then you cut data rate 1/3 to ~ 160 Mb/s.*

Huffyuv will apply lossless compression to that, and after using all the lossless tricks will get that down to 27-50Mb/s but at the cost of CPU activity to compress and decompress the file (i.e. wait). Huffyuv is for storage and must be decompressed for playback.

DV format will cut chroma sampling further to 4:1:1 or 4:2:0 to get ~120 Mb/s and then apply DCT intraframe compression (similar to jpeg) of about 5x to get to 25 Mb/s. DV maintains entact frames to facilitate optimal editing.

Next you can apply MPeg2 compression to DV which adds more intraframe compression plus interframe compression (motion through frames) to get to DVD (4-9Mb/s rates). Now we are at the consumer gold standard and can further compress that to divx, wmv, xvid, and so on.**


* SMPTE 259M/C adds to this 10 bits, audio and metadata for a 270 Mb/s "SDI" stream which is standard for SDTV broadcast production.

** Actually you will get much better quality if you compress divx, xvid, wmv, etc. from a 4:2:2 SDI master and that is why "their" compression looks better than yours at similar bitrates.

[Cornucopia]

Very good, edDV. Sorry I forgot to add on size requirements for audio.

Boy, modern digital video guys sure are good at squeezing blood out of a turnip!

-or-

Reminds me of those vaccuum shrink bags for your linens, etc. You can only go so small before you're up against diminishing returns for geometrically expanding effort.

Scott