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Compression Confusion

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Andrew Crittenden
Compression Confusion
on Nov 7, 2009 at 6:29:54 am

Is there a place anybody knows where I can study up on everything about video compression?

I'm constantly baffled. For instance, I just exported from a QT movie to FLV. The first movie was compressed at 400kbps (medium quality) The second at 700kpbs (high quality). The final file size for the 400kbps was bigger than the 700!

Does this make sense to anybody?

Thanks,

Andy

Andy


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Daniel Low
Re: Compression Confusion
on Nov 7, 2009 at 9:47:36 am

Are they both the same length?

__________________________________________________________________
"There's no chance that the iPhone is going to get any significant market share. No chance."
Steve Ballmer To USA Today: 30 April 2007

"We and Apple are neck and neck and we're chasing the two
other players,"
Steve Ballmer, referring to Nokia and Research in Motion. October 6th 2009


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Andrew Crittenden
Re: Compression Confusion
on Nov 7, 2009 at 9:36:56 pm

Yes exact same video...

Andy


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Daniel Low
Re: Compression Confusion
on Nov 7, 2009 at 9:44:15 pm

Please detail the exact settings for both.

__________________________________________________________________
"There's no chance that the iPhone is going to get any significant market share. No chance."
Steve Ballmer To USA Today: 30 April 2007

"We and Apple are neck and neck and we're chasing the two
other players,"
Steve Ballmer, referring to Nokia and Research in Motion. October 6th 2009


Return to posts index

Andrew Crittenden
Re: Compression Confusion
on Nov 8, 2009 at 1:11:48 am


Original File:
QT Movie 641.8 mb
Dimension 1280 x 720
Codecs Animation, Integer
Duration 00:27
Total bit rate: 196,072

export Movie to Flash Video
Flash 8 Medium Quality 400kbps
Video On2 VP6 at 400
Audio MPEG layer III MP3 at 96kbps stereo converts to 2.2 mb FLV

export Movie to Flash Video
Flash 8 High Quality 700kbps
Video On2 VP6 at 700
Audio MPEG layer III MP3 at 128kbps stereo converts to 3.1 mb FLV

Thanks


Andy


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Daniel Low
Re: Compression Confusion
on Nov 8, 2009 at 9:57:24 am

I thought you said the 400kbs clip had a bigger file size?

__________________________________________________________________
"There's no chance that the iPhone is going to get any significant market share. No chance."
Steve Ballmer To USA Today: 30 April 2007

"We and Apple are neck and neck and we're chasing the two
other players,"
Steve Ballmer, referring to Nokia and Research in Motion. October 6th 2009


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Chris Blair
Re: Compression Confusion
on Nov 8, 2009 at 5:11:11 pm

Here are some past threads with great links to information about encoding:

http://forums.creativecow.net/readpost/20/863282

http://forums.creativecow.net/thread/20/863293#863294

If you do further google searches you can likely find even more info, although those two links provide pages of information from some of the most knowledgeable people in the insdustry. You could also do a search for onine articles by a guy named Jan Ozer, who conducts all sorts of tests on codecs and encoding software, and writes and lectures about it extensively.

But....even after reading all of that...(and I have several times over), you'll still occasionally end up having to experiment with settings depending on your source material and it's codec/format. There are literally thousands of format/codec combinations out there and each one has its own quirks, which makes it dicey to apply them globally to all video sources. Generally, the higher quality and resolution your source footage is, the better your compressed footage is going to look.

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


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Andrew Crittenden
Re: Compression Confusion
on Nov 8, 2009 at 11:20:13 pm

yes, i inadvertently flopped the two.
It's not a huge difference, but still....



Andy


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Daniel Low
Re: Compression Confusion
on Nov 8, 2009 at 11:53:04 pm

What are you using to to the compression step for you?

__________________________________________________________________
"There's no chance that the iPhone is going to get any significant market share. No chance."
Steve Ballmer To USA Today: 30 April 2007

"We and Apple are neck and neck and we're chasing the two
other players,"
Steve Ballmer, referring to Nokia and Research in Motion. October 6th 2009


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Andrew Crittenden
Re: Compression Confusion
on Nov 8, 2009 at 11:59:33 pm

Not sure what you are looking for. Taking a641 mb QT movie > File > Export > Movie to FLV

My computer specs follow:

Model Name: Mac Pro Mac OSX version 10.5.8 Memory 6GB 1066 MHz DDR3

Model Identifier: MacPro4,1
Processor Name: Quad-Core Intel Xeon
Processor Speed: 2.26 GHz
Number Of Processors: 2
Total Number Of Cores: 8
L2 Cache (per core): 256 KB
L3 Cache (per processor): 8 MB
Memory: 6 GB
Processor Interconnect Speed: 5.86 GT/s
Boot ROM Version: MP41.0081.B04
SMC Version (system): 1.39f5
SMC Version (processor tray): 1.39f5


Andy


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Daniel Low
Re: Compression Confusion
on Nov 9, 2009 at 12:04:07 am

Quicktime is crap at doing any kind of encoding. You really need to use dedicated software like Apple compressor or Telestream Episode. You'll never get consistent results exporting from QT player.

__________________________________________________________________
"There's no chance that the iPhone is going to get any significant market share. No chance."
Steve Ballmer To USA Today: 30 April 2007

"We and Apple are neck and neck and we're chasing the two
other players,"
Steve Ballmer, referring to Nokia and Research in Motion. October 6th 2009


Return to posts index

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