Re: Testing with lossless codecs
Re: Testing with lossless codecs
- Subject: Re: Testing with lossless codecs
- From: Dan DiPaola <email@hidden>
- Date: Tue, 11 Aug 2009 14:04:03 -0700
best,
Dan DiPaola
Co-Founder
HD-encoding.com
818.859.7700 office
818.823.5500 cell
email@hidden
QualityNotQuantity
On Aug 11, 2009, at 12:23 PM, Andreas Wittenstein wrote:
Dan and anyone else who wants 16-bit real-time lossless video,
What are your specific 16-bit needs:
90% of the time we are receiving as 16 bit TIFF image sequence files.
Very few are still delivering as DPX or Cineon. We had issues of
different applications having their own meanings for the the same term.
• RGB, Y'CbCr, or monochrome?
RGB
• Progressive or interlaced?
Mostly Progressive
• With or without alpha?
On occasion w/alpha to be used for Grain or other artifact removal
from under trailer's title graphics
• Full-range or video-range?
Full Range. When possible we do not deal with any color space
compression algorithms prior to our encoding
• Integer or floating-point ('half')?
I believe floating point in most cases
Andreas Wittenstein
Founder, BitJazz Inc.
http://www.bitjazz.com/
On 2009 Aug 11, at 10:34 , Dan DiPaola wrote:
Team,
What if we would like to try and stay in a 16 bit world?
best,
Dan DiPaola
Co-Founder
HD-encoding.com
818.859.7700 office
818.823.5500 cell
email@hidden
QualityNotQuantity
On Aug 10, 2009, at 8:37 PM, Andreas Wittenstein wrote:
Brian,
Animation and None are 8-bit RGB[A] codecs. If you need an RGB[A]
QuickTime codec with 10 bits of precision per channel, try Sheer
RGB[A] 10bf.
http://www.bitjazz.com/sheervideo/
It's only free for the first 20 days of use, but it's truly
lossless, it's really fast, and it's cross-platform.
Andreas Wittenstein
BitJazz Inc.
http://www.bitjazz.com/
On 2009 Aug 10, at 12:44 , Brian Gardner wrote:
Thanks, Darrin.
There appears to be no way to test my plugins using
a lossless QuickTime codec.
I tried the Difference matte technique you suggested to test a
number of QuickTime codecs, including the Animation codec.
None of them were lossless. Actually, it's kind of scary
that QuickTime does not have a single codec that is completely
lossless...
even the "uncompressed" were lossy.
I used a 10 bit DPX 1920x1080p 24.0 fps sequence as source footage,
which I've just received from a recent music video shoot, shot on
a stage.
The goal is to convert it into a single QuickTime ".mov" file,
with lossless compression (or even no compression). I couldn't
achieve that goal.
Here are the codecs that I tested:
Animation (at best setting) - truncates off the bottom 2 bits (10
bit - > 8 bit), which is lossy.
None - Exact same results as Animation. 8-bit only. truncated
bottom 2 bits. Lossy.
(Differencing the Animation and None codecs to each other gives
0's-- exact match.)
FCP Uncompressed 422 10 bit - differences at all edges (to be
expected, 444->422 issue)
DNxHD 10 bit 709 - Noisiest of these codecs. (Noisy into top 8
bits.) Blocking artifacts,
especially in the vertically oriented direction.
Lossy.
Apple Pro Res HQ - slightly noisier than FCP Uncompressed 422,
but similar 444->422 lossy results.
Apple Pro Res 4444 codec - least lossy of the codecs I tested.
Appears to have saved full 10 bits.
(Did not just truncate down to 8. Possibly can do
16->16 bit?) Noisy in bottom bits, though. Lossy.
NOTE: The Apple Pro Res 4444 codec has a bug, in that it does not
appear to do
the right thing if it is given an image that does not have an
alpha channel.
And there is no option in the codec UI to automatically add a
fully opaque alpha channel.
(It would be very nice to have that option.)
When I layer two copies of the SAME resulting ProRes 4444 video
on top of each other,
and toggle visibility of the top layer On & Off -- they do not
match!
There is a brightness/contrast difference, which appears to be
stemming from the alpha.
For my 10 bit 444 source video, Pro Res 4444 was less lossy than
"Uncompressed", "None", and "Animation".
"Lossless" QT codecs appear to only be lossless for 8 bit video,
not anything above 8 bits.
Ditto for 444 video ... where even "Uncompressed" is quite lossy.
Both were rather jarring surprises.
-- Brian
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