Colour bleed

Andre De Clercq · March 19th, 2004, 05:00 PM

Bernd, the color bleed in vertical direction is inherent to Pal decoder systems wereby in addition to that color downshift, also the vertical color resolution is halved in the Pal decoder. That's one of the reasons why components is better.... If the whole video chain (camera+ display)is OK, then the horizontal bleeding should be perfectly symmetrical

Howard Meyer · March 19th, 2004, 06:02 PM

Just came across this issue of color bleeding- thank goodness. I thought mine was the only one with this problem. My GL2, purchased in December of 2003, bleeds to the right as you view the image on the screen. It also has halos around objects of different brightnesses. It has been to the factory once and returned with a note saying it is within specs. Fortunately, there was a follow-up customer survey sent by Canon. After checking 0 in all of the boxes, I received a call from Canon Customer Service. A test tape in now in the hands of their repair department and I received a phone call saying something is wrong. They have already sent me a prepaid mailer to return the GL2, again, and I am just waiting for the go ahead. Hopefully, the problem is correctable although my 30 years as a Ford engineer make me a little cautious. We have had problems with some products that just could not be fixed- and we spent millions trying.

Andre De Clercq · March 21st, 2004, 09:15 AM

Color bleeding in general is defined (limited) by the system (DV...PAL, NTSC..) and can't be reduced with camera settings or design tradeoffs.. Horizontal bleeding symmetry however is a very well known and understood issue by color encoder/decoder designers. It's been defined as the Y/C delay matching and is allmost allways selectable in the encoders as well as in the decoder(monitor or tv). In some cases it's user selectable even in consumer units. In modern TV design several kinds of color transient improvers are being used (CTI...) wereby the system limited color transient values get artificial enhancement resulting in allmost no bleeding for saturated color transients. If you want to (subjectively) verify your video chain (camcorder+display), just shoot a white paper with a red piece of tape from top to bottom and see on your screen if the bleeding is simular on both side of the tape image.

Howard Meyer · March 22nd, 2004, 03:53 PM

Andre
I photographed a red, green and blue tape against a white background and although all showed some bleeding, the red was the worst. And there was a difference from one side of the tape compared to the other. As viewed on the TV screen, the left side of the tape had a very bright fringe or halo with a reddish tint. The right side of the tape had a smeared reddish cast in its halo against the white background but lacked the brightness apparent in the left side.
Canon has had my GL2 and after returning it ask me to send in another tape showing my complaint again. Their reply was "it is within factory specs" (which is what the first reply said).
Because the GL2 has had good write-ups, I can only conclude the quality of the GL2 camcorders runs from excellant to mediocre. I hope potential GL2 purchasers buy the camera from a store that allows a return- not just an exchange. I you get a lemon as I did, the factory warrenty is vaporware.

Bernd Binder · March 24th, 2004, 03:47 AM

Here are the promised frames showing the colour bleed on my XM2.
Please follow the link http://temp.projektstudio.com/
As I have already mentioned, it’s the same on TV and computer monitor.

Howard Meyer · March 24th, 2004, 10:44 AM

Bernd
I wish the guys at Canon had eyesight as good as we do! Yes, I see your bleeding problem and my 70 year old wife with thick glasses also sees it. Very similiar to what I get on my GL2. Fortunately, Canon agreed to revisit my GL2 problem, so I am returning it to the factory for the second time. I seem to have gotten every excuse under the sun for what I see. My fear is they do not know how to fix it.
I wish other GL2 or XM2 owners who DO NOT have bleeding would respond to let us know if the problem is isolated to a few cameras. Better yet, a response from owners who HAVE bleeding problem would also be welcome. If it a universal problem we may just have to bite the bullet and live with it.
Oh, by the way, I saw a few halos in your photos in addition to the bleeding.
Howard

Steve Hancock · March 24th, 2004, 02:13 PM

I've had a GL2 for ~2 years - the first was was returned after a couple of months because of tape noise (while discussing it at my camera shop I was I was standing beside the Canaon rep - he authorized an immediate replacement). Most of the work I do is for sports videos (football) - bright colors and strong sunshine. Both cameras exhibited the bleeding/halo problems talked about here and elsewhere. I've used all the camera adjustments and filters discussed, with reasonable results. But as before, the tape playback looks good, it's OK on the computer, halos etc. visibile on a TV, and a copy to a VHS tape was terrible.

Over the last few months I've been making DVD's. Everything that looked terrble on a VHS tape is almost perfect on a DVD. So while we probably agree that the GL2 (and other digicams) have issues with bright colours (reds especially), I'm wondering if a major part of the problem is converting the digital signal to analog for playback on TV or VHS. Any comments from those electronically inclined (I'm a petroleum engineer, and didn't do well in electricity)?

David Deehan · March 24th, 2004, 03:09 PM

As the thread starter I think it’s about time I rejoined this discussion. It is probably more accurate to call the problem chroma shift than colour bleed; i.e. colours are shifted left and down. The vertical downward shift seems to be strictly confined to Pal users only (not an NTSC GL2 problem). I have had a number of emails from XM2 owners whose cameras exhibit this phenomenon.

I can concur with Steve Hancock’s finding that encoding to DVD and playback on television (using RGB input) reduces (but does not eliminate) the leftward colour shift. It does not however reduce the vertical shift. Again, this vertical shift is an XM2 problem and will not be evident on NTSC GL2’s.

Recently I got my hands on a digital projector. This was connected to my DVD player using component inputs/outputs. The shift was still evident.

Last November I sent my XM2 to Canon for inspection. The following is their reply:
“No fault found. Examined customers tape with complaint. This was found to be within specification. All camcorders will experience some bleeding, even broadcast.”
In my covering letter to Canon I did not mention bleed – all references were to colour shift.

I’m convinced this is a generic defect with all XM2’s. Therefore us poor Pal users will probably just have to suffer as its unlikely Canon will come up with any remedy so late in the product cycle.

Howard Meyer · March 24th, 2004, 03:37 PM

David
It may be a chroma shift that's confined to PAL/XM2 cameras but the GL2 has a big problem also, what ever the name. I see color spilling onto the background regardless of whether I am playing the original tape or a DVD made from the tape but my shift is to the right (when viewing the TV).
And by the way, the Canon reply must be canned- I got the same wording when I sent in my GL2. In regard to broadcast cameras having the same problem, give me a break. I have never seen anything on TV that compares to the bleeding on my GL2- not even on America's Funnest Home Videos.
Howard

David Deehan · March 24th, 2004, 04:15 PM

Howard,

I can understand your annoyance. Since the problem you are experiencing is slightly different to that suffered by XM2 users and not having seen much GL2 footage I'm not in a position to make an informed comment. Not many GL2 users have replied to the main thrust of this thread, which may mean that your situation is not symptomatic of GL2 cameras. This could indicate that your problem is fixable. Wait for a while and see if other GL2 users can confirm that their cameras do not exhibit what you are describing. If this is the case then your GL2 is probably defective - it will also strengthen any future argument with Canon.
Our XM2 problem would seem to be generic; therefore no quick fix is available.

regards

David

Cosmin Rotaru · August 5th, 2004, 08:25 AM

the same problem here - XM2 user (just wanted to add me to the list...)

Did someone tried to solve that in post? Maybe in Vegas? (as I use that!) :)

David Deehan · August 5th, 2004, 04:50 PM

Cosmin,

So you suffer the dreaded colour bleed (chroma shift) problem as well. I’m surprised there haven’t been many more XM2 users adding their names to the list. Did you see my recent thread at:

http://www.dvinfo.net/conf/showthrea...threadid=29688

This thread describes another aspect of the chroma shift problem. I had originally thought it was some type of chromatic aberration but Andre de Clerq convinced me otherwise. The thread was started in this group but was quickly moved by Ken to the Open DV Discussion group – you may have missed it.

David

Bob Harotunian · August 6th, 2004, 08:55 AM

Read this post with some interest and decided to look for a red on white example of bleeding with the GL2. This is not scientific, but the example I posted below does not show me any significant bleed and doesn't raise a concern from my perspective at least with the GL2 model.

http://www.beaconvideo.net/temp01.htm

Andre De Clercq · August 7th, 2004, 04:22 AM

Bob, this is indeed a pretty symmetrical bleed which is fully acceptable. The problem often occurs when the bleed is no longer symmetrical due to chroma shift...all the bleed occurs on one side instead of being distributed (and thus halved over the two edges) of a colored object. Playing back in NTSC(PAL) generally adds extra bleed and sometimes Y/C shift too. Some high-end TV's have CTI (color transient improve) circuits implemented which "cut" color bleed.

March 24th, 2004, 03:47 AM	#35
Bernd Binder New Boot Join Date: Mar 2004 Location: Vienna, Austria Posts: 5	Here are the promised frames showing the colour bleed on my XM2. Please follow the link http://temp.projektstudio.com/ As I have already mentioned, it’s the same on TV and computer monitor. __________________ Bernd

August 5th, 2004, 08:25 AM	#41
Cosmin Rotaru Major Player Join Date: Feb 2003 Location: Romania, Timisoara Posts: 453	the same problem here - XM2 user (just wanted to add me to the list...) Did someone tried to solve that in post? Maybe in Vegas? (as I use that!) :) __________________ Cosmin Rotaru

March 19th, 2004, 05:00 PM	#31
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Bernd, the color bleed in vertical direction is inherent to Pal decoder systems wereby in addition to that color downshift, also the vertical color resolution is halved in the Pal decoder. That's one of the reasons why components is better.... If the whole video chain (camera+ display)is OK, then the horizontal bleeding should be perfectly symmetrical

March 19th, 2004, 06:02 PM	#32
Howard Meyer New Boot Join Date: Dec 2003 Location: Plymouth, MI Posts: 22	Just came across this issue of color bleeding- thank goodness. I thought mine was the only one with this problem. My GL2, purchased in December of 2003, bleeds to the right as you view the image on the screen. It also has halos around objects of different brightnesses. It has been to the factory once and returned with a note saying it is within specs. Fortunately, there was a follow-up customer survey sent by Canon. After checking 0 in all of the boxes, I received a call from Canon Customer Service. A test tape in now in the hands of their repair department and I received a phone call saying something is wrong. They have already sent me a prepaid mailer to return the GL2, again, and I am just waiting for the go ahead. Hopefully, the problem is correctable although my 30 years as a Ford engineer make me a little cautious. We have had problems with some products that just could not be fixed- and we spent millions trying.

March 21st, 2004, 09:15 AM	#33
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Color bleeding in general is defined (limited) by the system (DV...PAL, NTSC..) and can't be reduced with camera settings or design tradeoffs.. Horizontal bleeding symmetry however is a very well known and understood issue by color encoder/decoder designers. It's been defined as the Y/C delay matching and is allmost allways selectable in the encoders as well as in the decoder(monitor or tv). In some cases it's user selectable even in consumer units. In modern TV design several kinds of color transient improvers are being used (CTI...) wereby the system limited color transient values get artificial enhancement resulting in allmost no bleeding for saturated color transients. If you want to (subjectively) verify your video chain (camcorder+display), just shoot a white paper with a red piece of tape from top to bottom and see on your screen if the bleeding is simular on both side of the tape image.

March 22nd, 2004, 03:53 PM	#34
Howard Meyer New Boot Join Date: Dec 2003 Location: Plymouth, MI Posts: 22	Andre I photographed a red, green and blue tape against a white background and although all showed some bleeding, the red was the worst. And there was a difference from one side of the tape compared to the other. As viewed on the TV screen, the left side of the tape had a very bright fringe or halo with a reddish tint. The right side of the tape had a smeared reddish cast in its halo against the white background but lacked the brightness apparent in the left side. Canon has had my GL2 and after returning it ask me to send in another tape showing my complaint again. Their reply was "it is within factory specs" (which is what the first reply said). Because the GL2 has had good write-ups, I can only conclude the quality of the GL2 camcorders runs from excellant to mediocre. I hope potential GL2 purchasers buy the camera from a store that allows a return- not just an exchange. I you get a lemon as I did, the factory warrenty is vaporware.

March 24th, 2004, 10:44 AM	#36
Howard Meyer New Boot Join Date: Dec 2003 Location: Plymouth, MI Posts: 22	Bernd I wish the guys at Canon had eyesight as good as we do! Yes, I see your bleeding problem and my 70 year old wife with thick glasses also sees it. Very similiar to what I get on my GL2. Fortunately, Canon agreed to revisit my GL2 problem, so I am returning it to the factory for the second time. I seem to have gotten every excuse under the sun for what I see. My fear is they do not know how to fix it. I wish other GL2 or XM2 owners who DO NOT have bleeding would respond to let us know if the problem is isolated to a few cameras. Better yet, a response from owners who HAVE bleeding problem would also be welcome. If it a universal problem we may just have to bite the bullet and live with it. Oh, by the way, I saw a few halos in your photos in addition to the bleeding. Howard

March 24th, 2004, 02:13 PM	#37
Steve Hancock Tourist Join Date: Feb 2003 Location: Calgary Posts: 4	I've had a GL2 for ~2 years - the first was was returned after a couple of months because of tape noise (while discussing it at my camera shop I was I was standing beside the Canaon rep - he authorized an immediate replacement). Most of the work I do is for sports videos (football) - bright colors and strong sunshine. Both cameras exhibited the bleeding/halo problems talked about here and elsewhere. I've used all the camera adjustments and filters discussed, with reasonable results. But as before, the tape playback looks good, it's OK on the computer, halos etc. visibile on a TV, and a copy to a VHS tape was terrible. Over the last few months I've been making DVD's. Everything that looked terrble on a VHS tape is almost perfect on a DVD. So while we probably agree that the GL2 (and other digicams) have issues with bright colours (reds especially), I'm wondering if a major part of the problem is converting the digital signal to analog for playback on TV or VHS. Any comments from those electronically inclined (I'm a petroleum engineer, and didn't do well in electricity)?

March 24th, 2004, 03:09 PM	#38
David Deehan Regular Crew Join Date: Feb 2003 Location: Belfast (Northern Ireland) Posts: 26	As the thread starter I think it’s about time I rejoined this discussion. It is probably more accurate to call the problem chroma shift than colour bleed; i.e. colours are shifted left and down. The vertical downward shift seems to be strictly confined to Pal users only (not an NTSC GL2 problem). I have had a number of emails from XM2 owners whose cameras exhibit this phenomenon. I can concur with Steve Hancock’s finding that encoding to DVD and playback on television (using RGB input) reduces (but does not eliminate) the leftward colour shift. It does not however reduce the vertical shift. Again, this vertical shift is an XM2 problem and will not be evident on NTSC GL2’s. Recently I got my hands on a digital projector. This was connected to my DVD player using component inputs/outputs. The shift was still evident. Last November I sent my XM2 to Canon for inspection. The following is their reply: “No fault found. Examined customers tape with complaint. This was found to be within specification. All camcorders will experience some bleeding, even broadcast.” In my covering letter to Canon I did not mention bleed – all references were to colour shift. I’m convinced this is a generic defect with all XM2’s. Therefore us poor Pal users will probably just have to suffer as its unlikely Canon will come up with any remedy so late in the product cycle.

March 24th, 2004, 03:37 PM	#39
Howard Meyer New Boot Join Date: Dec 2003 Location: Plymouth, MI Posts: 22	David It may be a chroma shift that's confined to PAL/XM2 cameras but the GL2 has a big problem also, what ever the name. I see color spilling onto the background regardless of whether I am playing the original tape or a DVD made from the tape but my shift is to the right (when viewing the TV). And by the way, the Canon reply must be canned- I got the same wording when I sent in my GL2. In regard to broadcast cameras having the same problem, give me a break. I have never seen anything on TV that compares to the bleeding on my GL2- not even on America's Funnest Home Videos. Howard

March 24th, 2004, 04:15 PM	#40
David Deehan Regular Crew Join Date: Feb 2003 Location: Belfast (Northern Ireland) Posts: 26	Howard, I can understand your annoyance. Since the problem you are experiencing is slightly different to that suffered by XM2 users and not having seen much GL2 footage I'm not in a position to make an informed comment. Not many GL2 users have replied to the main thrust of this thread, which may mean that your situation is not symptomatic of GL2 cameras. This could indicate that your problem is fixable. Wait for a while and see if other GL2 users can confirm that their cameras do not exhibit what you are describing. If this is the case then your GL2 is probably defective - it will also strengthen any future argument with Canon. Our XM2 problem would seem to be generic; therefore no quick fix is available. regards David

August 5th, 2004, 04:50 PM	#42
David Deehan Regular Crew Join Date: Feb 2003 Location: Belfast (Northern Ireland) Posts: 26	Cosmin, So you suffer the dreaded colour bleed (chroma shift) problem as well. I’m surprised there haven’t been many more XM2 users adding their names to the list. Did you see my recent thread at: http://www.dvinfo.net/conf/showthrea...threadid=29688 This thread describes another aspect of the chroma shift problem. I had originally thought it was some type of chromatic aberration but Andre de Clerq convinced me otherwise. The thread was started in this group but was quickly moved by Ken to the Open DV Discussion group – you may have missed it. David

August 6th, 2004, 08:55 AM	#43
Bob Harotunian Major Player Join Date: Mar 2003 Location: Somerville, MA Posts: 360	Read this post with some interest and decided to look for a red on white example of bleeding with the GL2. This is not scientific, but the example I posted below does not show me any significant bleed and doesn't raise a concern from my perspective at least with the GL2 model. http://www.beaconvideo.net/temp01.htm

August 7th, 2004, 04:22 AM	#44
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Bob, this is indeed a pretty symmetrical bleed which is fully acceptable. The problem often occurs when the bleed is no longer symmetrical due to chroma shift...all the bleed occurs on one side instead of being distributed (and thus halved over the two edges) of a colored object. Playing back in NTSC(PAL) generally adds extra bleed and sometimes Y/C shift too. Some high-end TV's have CTI (color transient improve) circuits implemented which "cut" color bleed.