Aliasing in 720p

Tim Polster · November 19th, 2011, 02:56 PM

Hello,

I am getting used to the XF300 and am very happy with the image. But I noticed this from a shot today and wanted to see if this had ever been solved or addressed.

The image has been adjusted in Photoshop to try and get the gamma correct as this is a frame from Edius and the YUV to RGB conversion always kills the image.

The lines on the track are showing horrible aliasing. This looks like a poor downconvert. I did not check this in 1080 as I do not film much at lower framerates but it makes me wonder if the 720p mode is hampered by a less than optimal hardware downconvert from 1080p?

Anyway, thanks for your input and I will contact Canon on Monday.

Pavel Sedlak · November 20th, 2011, 10:07 AM

Yes, XF300 has a great mode 1080/50i, 720/50p mode is very bad.

http://thebrownings.name/WHP034/pdf/..._XF300-305.pdf

Ray Pegram · November 22nd, 2011, 04:30 PM

Hi Tim,
So is there any update from Canon? I use 720 50p almost all the time to take advantage of the great slo-mos that can be achieved in post.

Now with this aliasing issue I may have to go back to 1080 25p

Tim Polster · November 22nd, 2011, 07:56 PM

I have been in contact with Canon and they are checking into it. They had me play the clip straight from the camera to my production monitor just to rule out any NLE issues.

I will keep you updated on all of the gory details!

Tim Polster · December 4th, 2011, 08:47 AM

A little update: I sent the original footage to Canon last week and have not heard back from them yet. I will follow up next week.

Tim Polster · December 13th, 2011, 02:53 PM

Still have not been contacted by a Canon tech to talk about my footage...

Tim Polster · December 29th, 2011, 12:50 PM

Update:

I called Canon again and finally got a higher level tech to look at my footage. They see the problem and are sending to engineering.

Please see my other post regarding reporting aliasing to Canon as they told me this issue is NOT on their radar.

Graham Bernard · December 30th, 2011, 01:13 AM

Quote:

Originally Posted by Tim Polster

....this issue is NOT on their radar.

And what is supposed to be our interpretation of that euphemism? That they need a more powerful RADAR scanner or that this is an issue of less than identifiable importance?

I'm going to the London show at Earls Court in February and more than willing to have them review their "concerns".

Luving this camera!

Grazie

Tim Polster · December 30th, 2011, 11:44 AM

Hello Graham,

Please talk to as many folks as you can. In speaking with the level II tech yesterday I got the impression they had never heard of 720p aliasing issues. He hinted that no reports from the call volume meant a low chance of anything being done about it.

I just does not make sense to me if the chipset is progressive how this could be introduced when downsampling to 720p. Maybe the chipset is not progressive or maybe the aliasing happens in 1080p as well. I only shot in 720p60 that day.

I would be happy to test more but to be honest, I only want to put the effort out there if Canon is willing to work to fix the problem. No point in going to great lengths only to get a "sorry" at the end of the road.

Graham Bernard · December 30th, 2011, 12:29 PM

Quote:

Originally Posted by Tim Polster

No point in going to great lengths only to get a "sorry" at the end of the road.

And now it's below your RADAR. Now, don't you feel better?

G

Tim Polster · December 30th, 2011, 12:56 PM

Graham,

I don't quite understand your point. Please clarify.

Graham Bernard · December 30th, 2011, 01:40 PM

Oh, simple really.

Your resignation to what might be a phyric victory might not be worth the effort you might expend, and that Canon would also not pursue this further either. As you say, you were told it wasn't on their RADAR and as a result, my understanding, it might not now be on yours either. And my point was that to stop now would be a better use of your efforts, rather than pursuing what could be a fruitless mission.

Cheers

Grazie

Tim Polster · December 30th, 2011, 02:08 PM

I agree, all of the testing on a user end can not make the company take any action. I want to hope that the mission as it is will not be fruitless. I told the Canon employee that in my opinion, this situation turns into an issue of integrity for the company. They made the camera and labeled it professional. It has a large flaw, at least my camera in its present state. I asked them for a dialogue and time will tell if they are going to participate.

As far as being on my RADAR, it will remain as I mainly shoot in 720p60.

Mikko Topponen · January 9th, 2012, 02:44 AM

One thing that helps a lot is increasing the noise reduction. This happens before scaling and if you take it to 10 the 720p will be pretty clean.

Tim Bakland · January 9th, 2012, 08:22 PM

Pyrrhic Victory. You don't hear that one every day on this forum!

November 19th, 2011, 02:56 PM	#1
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Aliasing in 720p - XF300 Hello, I am getting used to the XF300 and am very happy with the image. But I noticed this from a shot today and wanted to see if this had ever been solved or addressed. The image has been adjusted in Photoshop to try and get the gamma correct as this is a frame from Edius and the YUV to RGB conversion always kills the image. The lines on the track are showing horrible aliasing. This looks like a poor downconvert. I did not check this in 1080 as I do not film much at lower framerates but it makes me wonder if the 720p mode is hampered by a less than optimal hardware downconvert from 1080p? Anyway, thanks for your input and I will contact Canon on Monday. Attached Thumbnails

November 20th, 2011, 10:07 AM	#2
Pavel Sedlak Major Player Join Date: Feb 2007 Location: Prague Czech Republic Posts: 263	Re: Aliasing in 720p - XF300 Yes, XF300 has a great mode 1080/50i, 720/50p mode is very bad. http://thebrownings.name/WHP034/pdf/..._XF300-305.pdf

November 22nd, 2011, 04:30 PM	#3
Ray Pegram Regular Crew Join Date: Oct 2010 Location: Ulladulla - Australia Posts: 56	Re: Aliasing in 720p - XF300 Hi Tim, So is there any update from Canon? I use 720 50p almost all the time to take advantage of the great slo-mos that can be achieved in post. Now with this aliasing issue I may have to go back to 1080 25p __________________ Ray www.coastalweddingvideos.com.au

November 22nd, 2011, 07:56 PM	#4
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Re: Aliasing in 720p - XF300 I have been in contact with Canon and they are checking into it. They had me play the clip straight from the camera to my production monitor just to rule out any NLE issues. I will keep you updated on all of the gory details!

December 4th, 2011, 08:47 AM	#5
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Re: Aliasing in 720p - XF300 A little update: I sent the original footage to Canon last week and have not heard back from them yet. I will follow up next week.

December 13th, 2011, 02:53 PM	#6
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Re: Aliasing in 720p - XF300 Still have not been contacted by a Canon tech to talk about my footage...

December 29th, 2011, 12:50 PM	#7
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Re: Aliasing in 720p - XF300 Update: I called Canon again and finally got a higher level tech to look at my footage. They see the problem and are sending to engineering. Please see my other post regarding reporting aliasing to Canon as they told me this issue is NOT on their radar.

December 30th, 2011, 11:44 AM	#9
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Re: Aliasing in 720p - XF300 Hello Graham, Please talk to as many folks as you can. In speaking with the level II tech yesterday I got the impression they had never heard of 720p aliasing issues. He hinted that no reports from the call volume meant a low chance of anything being done about it. I just does not make sense to me if the chipset is progressive how this could be introduced when downsampling to 720p. Maybe the chipset is not progressive or maybe the aliasing happens in 1080p as well. I only shot in 720p60 that day. I would be happy to test more but to be honest, I only want to put the effort out there if Canon is willing to work to fix the problem. No point in going to great lengths only to get a "sorry" at the end of the road.

December 30th, 2011, 12:56 PM	#11
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Re: Aliasing in 720p - XF300 Graham, I don't quite understand your point. Please clarify.

December 30th, 2011, 01:40 PM	#12
Graham Bernard Old Boot Join Date: Aug 2002 Location: London UK Posts: 3,633	Re: Aliasing in 720p - XF300 Oh, simple really. Your resignation to what might be a phyric victory might not be worth the effort you might expend, and that Canon would also not pursue this further either. As you say, you were told it wasn't on their RADAR and as a result, my understanding, it might not now be on yours either. And my point was that to stop now would be a better use of your efforts, rather than pursuing what could be a fruitless mission. Cheers Grazie

December 30th, 2011, 02:08 PM	#13
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Re: Aliasing in 720p - XF300 I agree, all of the testing on a user end can not make the company take any action. I want to hope that the mission as it is will not be fruitless. I told the Canon employee that in my opinion, this situation turns into an issue of integrity for the company. They made the camera and labeled it professional. It has a large flaw, at least my camera in its present state. I asked them for a dialogue and time will tell if they are going to participate. As far as being on my RADAR, it will remain as I mainly shoot in 720p60.

January 9th, 2012, 02:44 AM	#14
Mikko Topponen Regular Crew Join Date: Oct 2009 Location: helsinki Posts: 104	Re: Aliasing in 720p - XF300 One thing that helps a lot is increasing the noise reduction. This happens before scaling and if you take it to 10 the 720p will be pretty clean.

January 9th, 2012, 08:22 PM	#15
Tim Bakland Major Player Join Date: Aug 2010 Location: Beverly, MA Posts: 512	Re: Aliasing in 720p - XF300 Pyrrhic Victory. You don't hear that one every day on this forum! __________________ Event Videography, New England www.timothybakland.com