Aliasing Artifacts

Ted Ramasola · September 7th, 2009, 03:52 AM

Chris,

Thanks for the reply. Its interesting to note the alias smoothing that cineform seem to apply based on your samples. I'm especially curious to know what it does to the streaks of water and the railings since being in different angles of the diagonal exhibit the stairstepping prominently. Can you post again exact same frames for better comparision?

It would be nice if you can find that same frame which you used for the 720 resolution, that moment when water splash from the rocks is at its longest.

Thanks for doing this tests.

Ted

Chris Barcellos · September 8th, 2009, 01:46 PM

I am posting two new sets just, in which I tried to be sure I was getting same frame.

I am not sure I am seeing that much difference in group.

Ted Ramasola · September 8th, 2009, 01:53 PM

Chris,

The 1080 samples are both ok to my eye, its easy to tell because theyre from the same frame. I think you may have moved a frame in the 720 samples. check again.

Ted

Ted Ramasola · September 8th, 2009, 02:22 PM

Chris,

I'm interested in your tests because,

1. I do my edits on a 720 24p timeline. easier on my hardware, and because i shoot a lot of 60p slomo stuff.

2. I also use a similar intermediate codec only mine is HQ. So i'm making comparisons.

Thanks in advance.

Ted

Xavier Plagaro · September 8th, 2009, 02:39 PM

Of course if you pixel-peep you will find defects with any camcorder. Even on the 100.000$ one!!! If I shoot moving water with my HDV cams I get nothing but low-level youtube quality. Just the fact that the AVCHD of the 7D can cope with moving water and not break away is good news (at least to me!).

Canon should decide to either build the ultimate full-frame 1920x1080 CMOS (who said night-vision?) or to upgrade their scaling algorithms. The 7D has a couple of processors, maybe they can do better than read one line of every three...

Ted Ramasola · September 8th, 2009, 05:12 PM

Hello Xavier,

I wasnt much into pixel peeping but more into the codecs for editing. You see, HQ only runs on Edius. Its similar to Cineform but I abandoned it when prempro 2 came out and was to heavy for the processors at that time. Now that processors are faster I might see if Prem with cineform can do the task. Its integration with after effects is a plus.

But then if its just the same or only slight difference, I'll stick with edius and HQ.

Ted

Xavier Plagaro · September 9th, 2009, 02:04 PM

We need to have 2000 thousands things under-control!

Mayer Chalom · September 9th, 2009, 05:42 PM

Guys are you serious. By inspecting every little pixel, artifact it takes away from the purpose of the 7d. The 7d is truly amazing camera for 1900 bucks (with standard lens 28-135). It offers multiple framerates, fixed the audio to 16 bit from the crappy 12bit of the 5d. Not to mention the obvious shallow dof, amazing low light, and full manual control. The 7d can beat cameras that are 10 times as expensive in alot of areas, just like little canon hv30's and hfs100's beat prosumer cams in the 2k-5k range (pq wise the hv30/hfs100 beats the crap out of the dvx). I have an xl1s and went to an hfs100 and i am amazed by its results. It can match the sharpness of the xh a1 and other cams easily. Anyway i may want to add the canon 7d for its much much much better low light than my hfs100 (which honestly is mediocre but for the price of 900 dollars an amazing cam), and much much shallower dof. I also love the colors from the 7d (at my work we use the 5d mark II and luv it but couldn't really afford it). Hopefully the 7d price will go down in the next 3-6 months. Remember you don't need a 100,000 dollar camera to do quality work. Ppl have done amazing things with little hv30's and hfs100's, 5d mark II etc. A little compression issue that is honestly not visible at all is not going to hinder your creativity.

Jon Fairhurst · September 9th, 2009, 09:18 PM

Quote:

Originally Posted by Mayer Chalom

...fixed the audio to 16 bit from the crappy 12bit of the 5d...

The 5D2 is 16bits at 44.1kHz. Right now the 5D2 is superior for audio because of Magic Lantern. Once Magic Lantern is ported to the 7D, the 7D will have a small edge with 48 kHz, but that's a very small edge indeed.

Personally, I compose film music, like most composers who can't afford a live orchestra, with a sampler. 99 percent of sample libraries use 44.1 kHz audio. Because of that I do all my post work at 44.1 kHz at 24 bits. At the end I resample the whole thing to 48 kHz and dither to 16 bits for the final product. For me 44.1kHz is actually superior in this regard, but I won't complain about 48 kHz.

Ian G. Thompson · September 10th, 2009, 06:21 PM

I think the old DAT recorders used to record to 48 KHz.

Ben Syverson · September 10th, 2009, 10:33 PM

Let's keep things in perspective... It's a consumer camera with a 1/8" microphone jack and questionable A/D. 44k vs 48k is really meaningless in that context. If you want quality, the answer is of course to record on a real audio deck.

Bob Hart · September 10th, 2009, 10:49 PM

Chris.

We have had a bit of a play with the Galbraith footage over here and attempted to convert the 30P to 25P by retiming the playback slower so that the render (hopefully) remains frame-by-frame. We found that if you do not select frame blend "off" in Premiere Pro, that a stutter developed in the playback and it did not look quite as good. This is offtopic for what you were doing but it might be worth checking anyway.

Ian.

My 1993 Sony DAT recorder still records in 48K and quite nicely but then I am also a bit of a technological luddite. I would probably be still recording to transcription disks with a Neumann cutter if people of my ilk were allowed to have their way.

Thank goodness for innovation and progress. Whatever their limitations may be these cameras remain game changers and they are only first generation of their concept. The future is indeed interesting.

Jon Fairhurst · September 11th, 2009, 12:35 AM

Quote:

Originally Posted by Ben Syverson

Let's keep things in perspective... It's a consumer camera with a 1/8" microphone jack and questionable A/D. 44k vs 48k is really meaningless in that context. If you want quality, the answer is of course to record on a real audio deck.

You might be surprised. If you provide the camera a clean, hot signal and turn the gain down, the result is VERY clean, and the sound quality quite good. In my tests, recording with the juicedLink into the 5D with Magic Lantern is noticeably cleaner than I could get with the H4n. At our recent 48 Hour showing, our result was nice and clean, even at theater levels.

I'm not saying it's audiophile quality. The audio is absolutely crisp and detailed, but slightly crunchy. I believe that the filter isn't cutting all of the aliasing. I should buy or design/build a good passive filter and see if that makes a difference.

As long as the 1/8" cable is short and driven hard, the results are surprisingly good.

You can see/hear my reviews here: 1. Canon 5D Mark II Audio Exposed - Boom Mic (juicedLink, Zoom H4n, Microtrack II, BeachTek) on Vimeo

Ian G. Thompson · September 11th, 2009, 08:31 AM

Quote:

Originally Posted by Bob Hart

Thank goodness for innovation and progress. Whatever their limitations may be these cameras remain game changers and they are only first generation of their concept. The future is indeed interesting.

Agreed...amen to dat...I meant.... "that." :)

September 7th, 2009, 03:52 AM	#16
Ted Ramasola Trustee Join Date: May 2005 Location: Allen, Texas U.S.A Posts: 1,117	Chris, Thanks for the reply. Its interesting to note the alias smoothing that cineform seem to apply based on your samples. I'm especially curious to know what it does to the streaks of water and the railings since being in different angles of the diagonal exhibit the stairstepping prominently. Can you post again exact same frames for better comparision? It would be nice if you can find that same frame which you used for the 720 resolution, that moment when water splash from the rocks is at its longest. Thanks for doing this tests. Ted Last edited by Ted Ramasola; September 7th, 2009 at 04:04 AM. Reason: typo

September 8th, 2009, 01:46 PM	#17
Chris Barcellos Inner Circle Join Date: Nov 2005 Location: Elk Grove CA Posts: 6,838	I am posting two new sets just, in which I tried to be sure I was getting same frame. I am not sure I am seeing that much difference in group. Attached Thumbnails __________________ Chris J. Barcellos

September 9th, 2009, 05:42 PM	#23
Mayer Chalom Regular Crew Join Date: Jul 2009 Location: New Jersey United States Posts: 29	C'mon aren't u guys being a little harsh. Guys are you serious. By inspecting every little pixel, artifact it takes away from the purpose of the 7d. The 7d is truly amazing camera for 1900 bucks (with standard lens 28-135). It offers multiple framerates, fixed the audio to 16 bit from the crappy 12bit of the 5d. Not to mention the obvious shallow dof, amazing low light, and full manual control. The 7d can beat cameras that are 10 times as expensive in alot of areas, just like little canon hv30's and hfs100's beat prosumer cams in the 2k-5k range (pq wise the hv30/hfs100 beats the crap out of the dvx). I have an xl1s and went to an hfs100 and i am amazed by its results. It can match the sharpness of the xh a1 and other cams easily. Anyway i may want to add the canon 7d for its much much much better low light than my hfs100 (which honestly is mediocre but for the price of 900 dollars an amazing cam), and much much shallower dof. I also love the colors from the 7d (at my work we use the 5d mark II and luv it but couldn't really afford it). Hopefully the 7d price will go down in the next 3-6 months. Remember you don't need a 100,000 dollar camera to do quality work. Ppl have done amazing things with little hv30's and hfs100's, 5d mark II etc. A little compression issue that is honestly not visible at all is not going to hinder your creativity.

September 10th, 2009, 10:49 PM	#27
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	Chris. We have had a bit of a play with the Galbraith footage over here and attempted to convert the 30P to 25P by retiming the playback slower so that the render (hopefully) remains frame-by-frame. We found that if you do not select frame blend "off" in Premiere Pro, that a stutter developed in the playback and it did not look quite as good. This is offtopic for what you were doing but it might be worth checking anyway. Ian. My 1993 Sony DAT recorder still records in 48K and quite nicely but then I am also a bit of a technological luddite. I would probably be still recording to transcription disks with a Neumann cutter if people of my ilk were allowed to have their way. Thank goodness for innovation and progress. Whatever their limitations may be these cameras remain game changers and they are only first generation of their concept. The future is indeed interesting. Last edited by Bob Hart; September 10th, 2009 at 10:58 PM. Reason: error

September 8th, 2009, 01:53 PM	#18
Ted Ramasola Trustee Join Date: May 2005 Location: Allen, Texas U.S.A Posts: 1,117	Chris, The 1080 samples are both ok to my eye, its easy to tell because theyre from the same frame. I think you may have moved a frame in the 720 samples. check again. Ted

September 8th, 2009, 02:22 PM	#19
Ted Ramasola Trustee Join Date: May 2005 Location: Allen, Texas U.S.A Posts: 1,117	Chris, I'm interested in your tests because, 1. I do my edits on a 720 24p timeline. easier on my hardware, and because i shoot a lot of 60p slomo stuff. 2. I also use a similar intermediate codec only mine is HQ. So i'm making comparisons. Thanks in advance. Ted

September 8th, 2009, 02:39 PM	#20
Xavier Plagaro Regular Crew Join Date: Mar 2009 Location: Rome, Italy Posts: 90	Of course if you pixel-peep you will find defects with any camcorder. Even on the 100.000$ one!!! If I shoot moving water with my HDV cams I get nothing but low-level youtube quality. Just the fact that the AVCHD of the 7D can cope with moving water and not break away is good news (at least to me!). Canon should decide to either build the ultimate full-frame 1920x1080 CMOS (who said night-vision?) or to upgrade their scaling algorithms. The 7D has a couple of processors, maybe they can do better than read one line of every three...

September 8th, 2009, 05:12 PM	#21
Ted Ramasola Trustee Join Date: May 2005 Location: Allen, Texas U.S.A Posts: 1,117	Hello Xavier, I wasnt much into pixel peeping but more into the codecs for editing. You see, HQ only runs on Edius. Its similar to Cineform but I abandoned it when prempro 2 came out and was to heavy for the processors at that time. Now that processors are faster I might see if Prem with cineform can do the task. Its integration with after effects is a plus. But then if its just the same or only slight difference, I'll stick with edius and HQ. Ted

September 9th, 2009, 02:04 PM	#22
Xavier Plagaro Regular Crew Join Date: Mar 2009 Location: Rome, Italy Posts: 90	We need to have 2000 thousands things under-control!

September 10th, 2009, 06:21 PM	#25
Ian G. Thompson Major Player Join Date: Jan 2007 Location: Rockledge, Florida Posts: 351	I think the old DAT recorders used to record to 48 KHz.

September 10th, 2009, 10:33 PM	#26
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	Let's keep things in perspective... It's a consumer camera with a 1/8" microphone jack and questionable A/D. 44k vs 48k is really meaningless in that context. If you want quality, the answer is of course to record on a real audio deck.