strange rings in video

[danny.l]

I can only make these settings:
640x480 (or 320x240)
Quality : Fine (or standard)
color : (AUTO, BLWWTR <8mtr, BLWWTR>8mtr, GRNWTR<8mtr, GRNWTR>8mtr, manual,.....) I set it to AUTO
White Balans : Auto

That's all.


The DC1000 is first of all to make pictures.
But I was wandererd by the poor quality of a video.
Now I'm figuring out what the reason is.

 

[danny.l]

I send this question to SeaLife.
This is their answer:

Hello Danny
The DC1000 Video uses a compression software which combines neighboring
pixels that have the same color and converts them into one pixel. File
compression software is commonly used to reduce the file size. For
example, if I shoot a video of a blue water background and all of the
pixels are the same blue color, the compression algorithm will combine
many of the blue pixels which reduces the total file size of the video.
If we don't compress the video, it would require about 10X the file
size. Normally, you will never see the effects of compression in the
finished video, however in underwater scenes it is quite common to have
a gradient blue water background (from light blue to darker blue). The
result is that you will see compression rings when shooting open blue
water. You should not see the rings when shooting more complex scene.
Sorry for the lengthy explanation but I hope that helps.


Karl Schuster
Sealife Technician
Pioneer Research
97 Foster Rd, Ste 5
Moorestown, NJ 08057
(856) 866 9191 Ext.136
SeaLife Cameras - Underwater Cameras and Accessories

Now we know !

 

[DandyDon]

Thanks Danny. I see that the DC1000 shoots in AVI @ 30 fps, as compared to my DC500 which shoots in AGA I think. (My camera is no longer described on the site and I don't see a need to find my manual as it doesn't matter anyway for this discussion.) Got a couple of questions...?

Are you shooting in 640 wide or 320? The smaller size will give you about 4 times as much video time on a card, but at a loss of quality.

How long can you shoot per Gb if set at 640 & 30 fps...?

My DC500 shoots an hour of video @ 640 per Gb;
But my old Canon A540 using AVI shoots like 7 minutes per GB @ 640 I think; my newer Canon A2000 is about 8 minutes per Gb in AVI.

 

[Gombessa]

INow we know !

Pretty much every compression algorithm does that. The question is, why does the DC1000 use so aggressive an algorithm that it causes such noticeable artifacting? At this point, it sounds like there's little you can do about it. Sorry to hear that.

 

[highlandfarmwv]

Mine made rings too

 

[DandyDon]

Mine made rings too

Are you shooting in 640 wide or 320? The smaller size will give you about 4 times as much video time on a card, but at a loss of quality.

How long can you shoot per Gb if set at 640 & 30 fps...?

 

[drbill]

Agree with Gombessa... it's like posterization in a still image. Compression artifacts. I had that happen twice... when I had to convert back-and-forth to MOV format for a Mac user and when I set the color levels wrong when exporting edited footage.