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Old October 24th, 2006, 11:14 AM   #1
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Tiny squares in exported avi movie

I am using Adobe Premier Pro 2.0 to edit a movie shot with a Canon XL1. It looks great. But, becuase I defined the project as 16:9 but have 4:3 footage (newbie move) I have to export the footage and import into a new project defined as 4:3.

The problem occurs with the exported footage. I am exporting the edited timeline as a movie in AVI format usine Microsoft DV codec. When I look at the exported DV movie (after importing or in a viewer), I notice that every so often I'll see a frame with let's say 4 or 5 small rectangles of different colors randomly space around the frame that seem arbitrary and don't fit in, like video noise. I am not sure where these are coming from or how to stop them. There are not a lot of these frames but I want to get rid of them. I rexported the timeline but I still get this effect but in different frames. Any ideas?
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Old October 25th, 2006, 11:18 AM   #2
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Found the answer

The problem occurred when I used the Microsoft DV Avi codec. This apparently compresses the file and in compression created the issue. I tried the Microsoft Uncompressed Avi codec and did not have the problem after exporting the timeline as an Avi movie. This did however generate a very large file - 80 GB.
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Old October 30th, 2006, 01:18 PM   #3
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I had a very similar problem. I always thought that AVI is uncompressed format that has maximum resolution. When I transfer 1 hour footage to PC the file size was around 12 gb. But now, I understand that there is the codec isue. 12 gb file used microsoft DV codec.
Using After effects I generated an uncompressed AVI file that is 10 times larger than the one with codec.

Now I suspect that if I had transfered the shootage uncompressed (if such thing is possible) would it be better quality ?

why does it happen with DV codec AVI ?

I will also search the forum to find an answer.
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Old October 30th, 2006, 01:57 PM   #4
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Quote:
Originally Posted by Baris Ustun
I had a very similar problem. I always thought that AVI is uncompressed format that has maximum resolution. When I transfer 1 hour footage to PC the file size was around 12 gb. But now, I understand that there is the codec isue. 12 gb file used microsoft DV codec.
Using After effects I generated an uncompressed AVI file that is 10 times larger than the one with codec.

Now I suspect that if I had transfered the shootage uncompressed (if such thing is possible) would it be better quality ?

why does it happen with DV codec AVI ?

I will also search the forum to find an answer.
My experience is that the Microsoft DV Avi codec put some glitches in the program that the uncompressed avi format did not. This codec appears to do some compression while the Uncompressed AVI codec apparently does not. This seems evident by the vast difference in file size. I eventually ended up exporting movie to DVD and ended up with a manageble file size. So, if your avi file is an intermediate file in your workflow, I would suggest using the uncompressed codec if you have the hard drive space.
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Old October 30th, 2006, 02:03 PM   #5
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AVI (like QuickTime) is what is known as a container format. It does not under-
stand how data is stored (with the exception of uncompressed).

An AVI (or QT) file can hold any data in any format you want as long as you
have a codec to encode / decode. This codec decides the quality of the image
(or audio you are getting).

(Microsoft)DV codec is indeed a DCT based compression codec (1:5) and will
introduce compression artificats (although you should not be able to see much
of them in the first or second generation).

There are a bunch of other codecs to choose from with varying degrees of
compression & quality. You can install new codecs as well to expand the
selection available (like for example DiVX for output).

However, if you truly want to retain quality for intermediate work (ie, not
for final output) then you can indeed select none or uncompressed or a
lossless (like Zip, doesn't loose any bits) codec (like Sheer).

Those files will be (a lot) bigger since it cannot through certain information
away to reduce file sizes.
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Old October 30th, 2006, 02:16 PM   #6
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Rob,

then Microsoft DV codec is not Lossless codec. right?

The AVI files that I transfer from tape to laptop through firewire has DV codec. (when I right-click the file and check proerties, there I see DV codec)
Does that mean that I loose resolution during transfer ?

Thanks
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Old October 30th, 2006, 05:18 PM   #7
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I think you need to check the codec settings.
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Old October 30th, 2006, 10:35 PM   #8
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Quote:
Originally Posted by Baris Ustun
Rob,

then Microsoft DV codec is not Lossless codec. right?

The AVI files that I transfer from tape to laptop through firewire has DV codec. (when I right-click the file and check proerties, there I see DV codec)
Does that mean that I loose resolution during transfer ?

Thanks
When I look at the properties of captured footage, I don't see any reference to a codec. It simply lists the detailed properties of the captured clip. Perhaps you used a different setting to capture the footage and if so maybe when you capture you can change the settings to get what you want. I am not sure whether is compressed your captured footage or not. Wish I could help more!

Are you capturing into Adobe Premier Pro 2.0. If so, did the program recognize your camera when you connected it?
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Old October 31st, 2006, 02:20 AM   #9
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I checked it with 3 different application. Although none of them is Pro software, I don't think that causes the problem.

While capturing I tried to change settings but all 3 software forced me to use DV codec.

1) Is there any way to capture uncompressed avi from tape to computer ?
2) what is the size (MB) of your 1 minute footage ? (just to compare)
3) When I play the original footage (which has DV codec) through win. media player I notice a great deal of pixel movements. It looks not smooth and as if some of data is loss. But I guess it is a player problem rather than actual data loss. Although there may be a small amount of data loss due to encoding it is not noticable.
I believe that if I convert that avi file to DVD format, there will be no annoying pixel movement problem.


Sowtware I used :
Adobe Premiere Standart v7.0
Ulead Video Studio 8
Windows Movie Maker
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Old October 31st, 2006, 06:43 AM   #10
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1. The footage on the tape is already in DV. You are merely downloading it, so you gain nothing in quality by converting it to uncompressed afterwards.

2. 60s x 25Mb/s = 187.5MB. Add codec overhead and you are in the neighborhood of 200MB.

3. Interlacing. Try rendering a DVD and watching on T.V.
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Old October 31st, 2006, 07:33 AM   #11
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Thanks Emre,

I will try it in the evening. (hopefully before the champs leauge match GS vs PSV)
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Old October 31st, 2006, 11:23 AM   #12
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Quote:
Originally Posted by Baris Ustun
Rob,

then Microsoft DV codec is not Lossless codec. right?

The AVI files that I transfer from tape to laptop through firewire has DV codec. (when I right-click the file and check proerties, there I see DV codec)
Does that mean that I loose resolution during transfer ?

Thanks
That is correct, (Microsoft) DV codec is not lossless (does not through data
away). It is a lossy (does through data away) codec.

As Emre correctly said, a DV camera already has a DV codec onboard and
encodes the video into this format before it lays it down to tape. When you
"capture" it you are basically doing a file copy from tape to your computer.
So no extra (re)compression is going on. You are getting the best quality
you can get (with such a camera).

For this reason I really dislike to use the word capture for DV camera's / tape.
Everyone associates capturing an analog signal and (lossy) compressing that.

I'd rather call it a data transfer or something. Too bad the NLE makers didn't
do that. Same goes for P2 media. It's not something you capture. You import
or transfer such data.
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Old March 14th, 2008, 03:32 PM   #13
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This may not have much to do with what you were talking about, but I thought I'd pipe in anyway...

I recently formatted my computer, backing up everything I had, beforehand. Among the files that were backed up were some avi clips that hadn't been edited yet.

Once I reinstalled everything and placed the avi's back onto the harddrive, the "small square" distortion had invaded these unedited avi's, so that now I will be forced to live with them in the final product. Fortunately, these videos were only a part of our home videos, but frustrating, none-the-less.

The files were backed up onto an external drive during format. I'm not sure why this would or could have happened, but it's something I'll be careful about in the future.
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