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Problem with web compression: Horizontal lines distorting image across several formats

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Greg Harriott
Problem with web compression: Horizontal lines distorting image across several formats
on Feb 20, 2010 at 2:34:39 pm

Hello,
I have been trying to compress some footage that has a good deal of movement in it for the web, and am getting horizontal lines of distortion occurring whenever there is movement in a close up. Here are my specs:

Macbook Pro 2.53 GHz Intel Core 2 Duo with 4GB memory running Mac OS X Version 10.5.8

Editing in Final Cut Pro 7.0 and have started compressing in Quicktime Pro 7.6.2 but also have tried out Compressor, Sorenson Squeeze, MPEG Streamclip, Adobe Media Encoder, and Episode with no luck in any of the programs.

The footage is coming from an HVX200 shooting at 720P 30P and staying in the DVCPRO HD codec into FCP. I have tried exporting the footage as x.264 and h.264 wrapped in either a mp4 or .mov container and am streaming it through flowplayer online.

Here is a link to a compression test page where you can see my problem in test 32 and then the subsequent tests after that:

http://www.audiorecordingheaven.com/testpage

What is weird is that this is not in the raw files or the compressed files when I play them on my computer. I only get the lines of distortion when I view it online. I know that when compressing for web movement in the frame is bad news, but is there any possible way to compress this without all the distortion? Here are my current settings that I have been using in QT Pro:

Program Used: Quicktime Pro
Final Format: .mov
File Size: 8.7 MB

Video
File Format: .mov
Compression Type: x264
Frame Rate: Current
Key Frames: 30
Frame Reordering: Yes
Encoding: Best Quality Multi-pass
Data Rate: 600 kbits/sec
Size: 800x448
Preserve Aspect Ratio Using: fit within size

Audio
Format: AAC
Channels: Stereo (L R)
Rate: 48.000 kHz
Quality: Normal
Target Bit Rate: 128 kbps

Prepare for internet streaming: Fast Start

I have also tried altering the keyframe rate, the bit rate, trying to force key frames through FCP, using a variable bit rate, and am running out of things to try. Any help would be really appreciated because I got this same problem in some footage before and couldn't figure out how to compress it cleanly.

Thanks!
-Greg


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Chris Blair
Re: Problem with web compression: Horizontal lines distorting image across several formats
on Feb 20, 2010 at 5:48:45 pm

I don't think it's the compression but the flash player you're using. I tried viewing your test page on 3 different computers using 3 different browsers (IE, Firefox and Chrome) and it crashed or locked up the browser every single time (6 tries in all). Chrome and Firefox both gave error messages (after I had to end the process) that the "Flash plug-in has crashed." Each computer I used has the latest Flash plug-in and each plays HD videos from Hulu, YouTube, Vimeo and other sites without issues...other than occasionally buffering.

So I think there's something seriously wrong with the programming in the Flash Player you're using. Is it a third party player? A custom programmed one? Or...if you're using javascript to control the flash player, then the javascript programming is messed up too.

The video actually looked ok as it stuttered and jumped along...although it never played smoothly before the page crashed.

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com


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Greg Harriott
Re: Problem with web compression: Horizontal lines distorting image across several formats
on Feb 22, 2010 at 5:05:54 pm

That's really strange I am using a player called flowplayer I honestly don't know too much about it except that it is a pretty common one. I updated the link, could you try again and see if you are getting the same problems?
-Thanks


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Daniel Low
Re: Problem with web compression: Horizontal lines distorting image across several formats
on Feb 20, 2010 at 6:09:09 pm

The only problems I see are jerky frame rates. Nothing crashes and I see no lines.

Can you take a screen shot of the lines you are seeing?

__________________________________________________________________
Sent from my iPad Nano.


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Greg Harriott
Re: Problem with web compression: Horizontal lines distorting image across several formats
on Feb 22, 2010 at 5:14:49 pm

Thanks for checking it out. I tried taking some screen shots, but when I do it pauses the playback and the problem fixes itself. I unfortunately think there is just too much movement in the frame for this to compress and stream properly.

I am interested in the jerky frame rates you are seeing. Is there anything you can think of that would be causing this?


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Daniel Low
Re: Problem with web compression: Horizontal lines distorting image across several formats
on Feb 22, 2010 at 7:01:52 pm

Jerky frame rates are even worse now.

The links to Amazon media play fine.

Why are you resizing at the player end?

You should transcode to the size you will be playing back at, never let the player resize for you.

Also, pick a frame size that is equally divisible by 16, or 8. 800x450 doesn't work.

__________________________________________________________________
Sent from my iPad Nano.


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Greg Harriott
Re: Problem with web compression: Horizontal lines distorting image across several formats
on Feb 24, 2010 at 7:35:44 am

Thanks. I think you are right looks like a problem with the player.

In regards to the frame size, I heard that keeping it divisible by 16 is a good idea. Are you suggesting that I make the player dimensions divisible by 16 and then transcode the video to that size when compressing?


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Daniel Low
Re: Problem with web compression: Horizontal lines distorting image across several formats
on Feb 24, 2010 at 10:30:07 am

[Greg Harriott] "I heard that keeping it divisible by 16 is a good idea"

That's exactly what I said in my previous post to you!

[Greg Harriott] "Are you suggesting that I make the player dimensions divisible by 16 and then transcode the video to that size when compressing?"

Yes. But 16 can be very limiting. Go for div 8 if if not.



__________________________________________________________________
Sent from my iPad Nano.


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