HDV Reds... at DVinfo.net

Charlie Targett-Adams · August 4th, 2008, 10:54 AM

Hi Everyone,

I've been shooting some live acts at the minute in small clubs on my Sony V1E. Most of the venues just stick a red light on stage to get an atmosphere and this seems to make my V1 go a 'little' crazy. Jagged lines seem to appear around the outlines of things such as on the guitarist's shirt and the singer's face. I shot the footage 25p with no filters or other add ons. Does anyone know how to rectify this in FCP or how to prevent it the next time I shoot? Hopefully the screen captures have attached as Picture 1.jpg and Picture 2.jpg.

Thanks in advance,

Charlie.

Dylan Pank · August 4th, 2008, 11:55 AM

These are a result of the HDV codec's colour sampling system, known as 4:2:0, and it will; affect ALL HDV cameras, so it's not a V1 problem. Basically, while the resolution of the image is 1440x1080, only a black and white version of the image is of that resolution. The blue and red channels are only 720x540 px. In most cases this doesn't notice much, but when you have large blocks of one colour or another (as you have in your case) it shows up very clearly.

In FCP You could put a channel blur on the red channel of 1 pixel, but if you lay back to HDV tape or VC1/H.264 you'll just get the problem back again.

Dylan Pank · August 4th, 2008, 12:07 PM

duplicate post deleted

Greg Laves · August 4th, 2008, 01:03 PM

I shot a group in a local club with similar lighting using my V1. I checked the footage that evening and I didn't notice any of those issues. But I mailed the tape to the producer and don't have any way to go back and check it again. He said the footage was good, so I would assume he did not see any problems either. I was using a picture profile from this forum that was recommended for low light. And I shot in 60i but at 1/30th shutter speed to further help the low light level.

Dave Blackhurst · August 4th, 2008, 01:50 PM

I'm seeing what look more like interlace artifacts... which would indicate post processing issues rather than something related to the camera.

How does the footage look when taken direct out of the camera to a big monitor/TV?? Do the jaggies still show up? If they aren't showing there, you'll need to figure out how to reduct interlace artifacts in your post process.

Dylan Pank · August 5th, 2008, 04:09 AM

I'm not sure they're interlacing artefacts as they're not seen in areas of movement, though they could be related, I guess, given that the V1E records 25p to an interlaced stream.

Stephan Stryhanyn · August 9th, 2008, 01:46 AM

Quote:

Originally Posted by Dylan Pank

These are a result of the HDV codec's colour sampling system, known as 4:2:0, and it will; affect ALL HDV cameras, so it's not a V1 problem.

Absolutely, you nailed it.

Charlie, there may be 2 work-around solutions for you:
1) Try using an intermediate-codec based solution, they upsample chroma to 4:2:2. With Adobe Premiere, I believe Cineform has been proven to reduce considerably this red blocks problem that is due to chroma subsampling. I don't know about EDIUS. As you're using FCP, try capturing to Apple ProRes.
2) Get an analog capture card and capture on the component output. I don't know if this works on the V1, but it's been proven on the Z1 which amazingly upsamples chroma on its component outputs, compared to Firewire/HDV.

Mauro Moreira · August 24th, 2008, 08:18 PM

Charlie,

I`ve got the same problem when shooting a band with a red light on them.
But those "lines" didn`t appear in the tv monitor (normal tv screen, not lcd or plasma), and i shoot in dv mode, not in hdv.
This problem appeared with another camera too, the panasonic gs500, but in small amounts.

Stephen Armour · August 28th, 2008, 03:12 PM

Look like MPEG2 compression artifacts to me. HDV is nasty for that, just try doing chromakeys...

Only fix I know for the V1 is to get a BlackMagic Intensity (and something to put it in) and take that signal from the V1 via HDMI BEFORE it's been HDV compressed.

It's a pain, but the gain is real. Alternative is to change cameras to a HD...

August 4th, 2008, 10:54 AM	#1
Charlie Targett-Adams Tourist Join Date: Dec 2006 Location: London & Mexico Posts: 4	HDV Reds... Hi Everyone, I've been shooting some live acts at the minute in small clubs on my Sony V1E. Most of the venues just stick a red light on stage to get an atmosphere and this seems to make my V1 go a 'little' crazy. Jagged lines seem to appear around the outlines of things such as on the guitarist's shirt and the singer's face. I shot the footage 25p with no filters or other add ons. Does anyone know how to rectify this in FCP or how to prevent it the next time I shoot? Hopefully the screen captures have attached as Picture 1.jpg and Picture 2.jpg. Thanks in advance, Charlie. Attached Thumbnails

August 4th, 2008, 12:07 PM	#3
Dylan Pank Major Player Join Date: Nov 2004 Location: Portsmouth, UK Posts: 611	duplicate post deleted Last edited by Dylan Pank; August 5th, 2008 at 03:44 AM. Reason: duplicate post

August 24th, 2008, 08:18 PM	#8
Mauro Moreira New Boot Join Date: Mar 2008 Location: São Paulo SP Posts: 14	Same problem Charlie, I`ve got the same problem when shooting a band with a red light on them. But those "lines" didn`t appear in the tv monitor (normal tv screen, not lcd or plasma), and i shoot in dv mode, not in hdv. This problem appeared with another camera too, the panasonic gs500, but in small amounts.

August 28th, 2008, 03:12 PM	#9
Stephen Armour Major Player Join Date: Dec 2005 Location: Natal, RN, Brasil Posts: 900	Look like MPEG2 compression artifacts to me. HDV is nasty for that, just try doing chromakeys... Only fix I know for the V1 is to get a BlackMagic Intensity (and something to put it in) and take that signal from the V1 via HDMI BEFORE it's been HDV compressed. It's a pain, but the gain is real. Alternative is to change cameras to a HD... __________________ http://lightinaction.org "All in the view of the LION"

August 4th, 2008, 11:55 AM	#2
Dylan Pank Major Player Join Date: Nov 2004 Location: Portsmouth, UK Posts: 611	These are a result of the HDV codec's colour sampling system, known as 4:2:0, and it will; affect ALL HDV cameras, so it's not a V1 problem. Basically, while the resolution of the image is 1440x1080, only a black and white version of the image is of that resolution. The blue and red channels are only 720x540 px. In most cases this doesn't notice much, but when you have large blocks of one colour or another (as you have in your case) it shows up very clearly. In FCP You could put a channel blur on the red channel of 1 pixel, but if you lay back to HDV tape or VC1/H.264 you'll just get the problem back again.

August 4th, 2008, 01:03 PM	#4
Greg Laves Major Player Join Date: Nov 2007 Location: Corpus Christi, TX Posts: 640	I shot a group in a local club with similar lighting using my V1. I checked the footage that evening and I didn't notice any of those issues. But I mailed the tape to the producer and don't have any way to go back and check it again. He said the footage was good, so I would assume he did not see any problems either. I was using a picture profile from this forum that was recommended for low light. And I shot in 60i but at 1/30th shutter speed to further help the low light level.

August 4th, 2008, 01:50 PM	#5
Dave Blackhurst Inner Circle Join Date: Feb 2007 Location: Apple Valley CA Posts: 4,874	I'm seeing what look more like interlace artifacts... which would indicate post processing issues rather than something related to the camera. How does the footage look when taken direct out of the camera to a big monitor/TV?? Do the jaggies still show up? If they aren't showing there, you'll need to figure out how to reduct interlace artifacts in your post process.

August 5th, 2008, 04:09 AM	#6
Dylan Pank Major Player Join Date: Nov 2004 Location: Portsmouth, UK Posts: 611	I'm not sure they're interlacing artefacts as they're not seen in areas of movement, though they could be related, I guess, given that the V1E records 25p to an interlaced stream.