sample/issues of/while musicvideo at DVinfo.net

Dan Franz · October 30th, 2008, 08:57 AM

hey folks - this post took me awhile, but i was carefully reading since i bought my Z7 which is now about 5 month ago!

Since I m getting more and more into the cam - i keep figuring all sorts of pro s and con s out.
I will post a linke where u can see some issues which i can t explain to myself yet:
have a look at the file/sample clip:

http://www.bright-minds.de/filme/sam..._z7_xs.mov.zip

i was shooting a musicvideo.
the camera was set on a tripod, shooting hdv 1080 25p
I am wondering if those problems show up because I forgot to take of the steadyshot, or because of CMOS in terms of not getting warm with to much colour information. Or because of Auto Shutter which i think i might have forgotten to put on manual...

Take ur time and look at the footage, u can see as u go through frame by frame that pixalation and artifacting are appearing, especialy when light changes.

Would be great to find a solution, and I hope it might be a handling problem and not a product problem.

Thx in advance
*Daniel*

Peter Ford · October 30th, 2008, 11:07 AM

welcome to HDV!

All HDV cameras have this to some degree- its not a camera fault, but a drawback of the recording format.

HDV is a big compromise, to fit almost HD footage, on a tape that was only ever designed for SD.

HDV uses long gop compression. Bit complex, but in laymans terms, you'll have frame 1, which is a solid frame- then frames 2, 3 will be interpreted from differences from frame 1. That is, only pixels that are different to frame 1 are recorded, and then a few frames later you'll have another key frame, and it starts all over again. Its a lot more complex that that though.

Normally, you wont notice it, but with fast moving footage, or flashes of light, you end up with 2 frames next to each other, that are very different - i.e, very bright frame and a very black frame. One of these frames will suffer from lots of pixelation, as the frame before will be completely different, and wont have any relevant information to help the quality of the frame after.

I hope that makes sense!

Basically, you can avoid it by using a more expensive camera with a different recording format.

You can make it less noticeable- aggressive grading, or possibly try using something like a quarter black pro mist- its an subtle optical diffuser, and will soften the images slightly, and might reduce artifects a bit. I know the bbc recommend using one for Z1's and the like, if the final format is to be SD

hope that helps

Dan Franz · October 30th, 2008, 11:19 AM

thx peter -

it does make sense - i guess i need to learn much more about HD(V) and that forum is the best thing ever!

I ll try to use that information for my next shoot.
here is the result - and what we did with the footage - all shot on a Z7

MY NEW ZOO - Sometimes on Vimeo

enjoy
*Daniel*

October 30th, 2008, 08:57 AM	#1
Dan Franz Tourist Join Date: Oct 2008 Location: Berlin, Germany Posts: 2	sample/issues of/while musicvideo hey folks - this post took me awhile, but i was carefully reading since i bought my Z7 which is now about 5 month ago! Since I m getting more and more into the cam - i keep figuring all sorts of pro s and con s out. I will post a linke where u can see some issues which i can t explain to myself yet: have a look at the file/sample clip: http://www.bright-minds.de/filme/sam..._z7_xs.mov.zip i was shooting a musicvideo. the camera was set on a tripod, shooting hdv 1080 25p I am wondering if those problems show up because I forgot to take of the steadyshot, or because of CMOS in terms of not getting warm with to much colour information. Or because of Auto Shutter which i think i might have forgotten to put on manual... Take ur time and look at the footage, u can see as u go through frame by frame that pixalation and artifacting are appearing, especialy when light changes. Would be great to find a solution, and I hope it might be a handling problem and not a product problem. Thx in advance Daniel

October 30th, 2008, 11:07 AM	#2
Peter Ford Regular Crew Join Date: Oct 2006 Location: London, uk Posts: 99	welcome to HDV! All HDV cameras have this to some degree- its not a camera fault, but a drawback of the recording format. HDV is a big compromise, to fit almost HD footage, on a tape that was only ever designed for SD. HDV uses long gop compression. Bit complex, but in laymans terms, you'll have frame 1, which is a solid frame- then frames 2, 3 will be interpreted from differences from frame 1. That is, only pixels that are different to frame 1 are recorded, and then a few frames later you'll have another key frame, and it starts all over again. Its a lot more complex that that though. Normally, you wont notice it, but with fast moving footage, or flashes of light, you end up with 2 frames next to each other, that are very different - i.e, very bright frame and a very black frame. One of these frames will suffer from lots of pixelation, as the frame before will be completely different, and wont have any relevant information to help the quality of the frame after. I hope that makes sense! Basically, you can avoid it by using a more expensive camera with a different recording format. You can make it less noticeable- aggressive grading, or possibly try using something like a quarter black pro mist- its an subtle optical diffuser, and will soften the images slightly, and might reduce artifects a bit. I know the bbc recommend using one for Z1's and the like, if the final format is to be SD hope that helps

October 30th, 2008, 11:19 AM	#3
Dan Franz Tourist Join Date: Oct 2008 Location: Berlin, Germany Posts: 2	thx peter - it does make sense - i guess i need to learn much more about HD(V) and that forum is the best thing ever! I ll try to use that information for my next shoot. here is the result - and what we did with the footage - all shot on a Z7 MY NEW ZOO - Sometimes on Vimeo enjoy Daniel