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David Bark
Video For Web
on Dec 29, 2009 at 5:59:28 am

Rather than streaming from Vimeo or YouTube, I've been converting my web videos to Flash using Adobe Media Encoder and loading them on my server. (I'm at lightshineproductions.com).

Anyway, I've got a couple of wedding trailers and a promo video (around 3 - 4 minutes) and I'm doing 520/370 or 420/315 depending on the ratio, using On2 VP6, around 800kbps bitrate, one pass, mono and 64? audio bitrate. The frame rate doesn't seem to effect file size, so I leave it at 30 or 24. My files have been hovering around 20 mb.

Now, I've got a 6 minute video that's coming out as a 39mb Flash file. Is that way too much? I don't have any trouble seeing the videos on the site, and no one else seems to, but I haven't checked on a slower connection.

What happens if I lower the audio bitrate? I guess I'm just looking for tweaks that will make my files smaller without sacrificing too much in the way of quality. Any help will be appreciated.

Thanks,

David


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Chris Blair
Re: Video For Web
on Dec 29, 2009 at 3:39:14 pm

David Bark: I'm doing 520/370 or 420/315...using On2 VP6, 800kbps bitrate, mono and 64? audio bitrate...I've got a 6 minute video that's coming out as a 39mb Flash file. Is that way too much? What happens if I lower the audio bitrate?

Nothing much wrong with your sizes. 800kbps isn't a huge problem but people with slower connections will likely have problems playing back the files without some pausing and buffering. The solution there would be to program in a buffer time within the flash player. What this does is requires X number of seconds of CONTENT to download before playback starts. It doesn't mean the user will have to wait for that amount of time because theoretically the video loads in less time. A good place to start would be to set the buffer at 5 seconds. You can do this within the Flash Player coding or using javascript along with your player. Some people refer to this as AJAX (asynchronous javascript & XML), which in simple terms, just means writing very simple text based code within the HTML page to control your Flash Player.

On the compression...you could probably go down to around 512kb/sec on the video without seeing a huge hit in quality, and lowering the audio bitrate to say 48kb/sec would help a little.

The best way to get the file size down would be to use an H264 codec instead of On2 VP6. You could probably cut the size by 40% without changing any of the pixel sizes or bit rates.

The downside to using H264 is it requires the end-user to have more computer horsepower. As an example, I keep a 12 year old Windows 98 computer as a test computer for websites and video. It will play a video encoded with On2 VP6 without problems. It cannot play an H264 video from the web...it just stutters and freezes. In fact, it can't play an H264 video from the hard drive smoothly and cleanly!

That's how much more complex the H264 codec is than the On2 codec. That said, we use H264 for almost all of the stuff we encode for ourselves and clients because just about any computer made in the last 6-8 years CAN play H264 files without issue.

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


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David Bark
Re: Video For Web
on Dec 29, 2009 at 5:00:26 pm

Thanks Chris.

I actually played around in Media Encoder a bit, and when I used the H264 export format, the lowest I could get the estimated size was 135MB, when I achieved 39 with FLV. That said, I'll have to see what pops out on the other end when I use H264. I'm thinking, though, that that isn't even going to be a Flash file.

I definitely appreciate the heads up on the buffer idea. Never even heard of it. I've been dropping the files into Dreamweaver (which has pretty much allowed me to focus on learning other software and avoiding code), but I guess it's time to dig into HTML a little bit.

Playing around with Export Setting while I'm writing this, and while I seem to have figured out how to get the H264 Format at level 2.2 to drop the size, I'll have to go ahead and encode to see what comes out. (And I'll have to figure out how to drop QT into Dreamweaver.) Thanks again!


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Craig Seeman
Re: Video For Web
on Dec 29, 2009 at 5:52:49 pm

The concept of data rate vs file size is so fundamental and so "in your face simple" I can't understand how people can't see it.

k bits per second is going to yield a number of bits over a number of seconds. Sorry if this offends but it's such as "duh" concept.

Data rate over time is going to result in a given size. More data in the same time is going to be a larger file. Same data over more time is going to be a larger file.

There's no tricky part to this. The very name of the data rate gives you the formula. The math part may involve converting bits to bytes and that in Kilo or Mega.

1000kbits a second for 30 seconds is going to be 30,000kbits. That's going to be roughly 30MB (I'll avoid decimal vs binary measures to keep it simple).

_____
Other settings as well as the information in the source file can cause the data rate to over or undershoot depending on the codec or encoder software used but generally you should get fairly close.

What impacts quality is another set of issues but this is a BASIC discussion of FIILE SIZE.



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David Bark
Re: Video For Web
on Dec 29, 2009 at 6:57:32 pm

Thanks, and no offense taken. Sometimes I can't see the trees because that whole forest thing is in the way!


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Craig Seeman
Re: Video For Web
on Dec 29, 2009 at 8:39:24 pm

[David Bark] "Thanks, and no offense taken. Sometimes I can't see the trees because that whole forest thing is in the way!"

Uh oh, this could head into fractal math!
BTW just remember moss grows on the north side of trees and you should be able to find your way out.



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Craig Seeman
Re: Video For Web
on Dec 29, 2009 at 8:37:03 pm

[Craig Seeman] "1000kbits a second for 30 seconds is going to be 30,000kbits. That's going to be roughly 30MB (I'll avoid decimal vs binary measures to keep it simple). "

Even I can get the math wrong. Oops!. Forget to convert bits to bytes properly. 30,000kbits is about 3.6MB (megabytes).

8 bits equals 1 byte.

and 2 bits is 25ยข so 8 bits will also give you a Buck ($1).
The "pirates" had this stuff down when they were talking about pieces of eight.
http://en.wikipedia.org/wiki/Spanish_dollar
The Spanish dollar (also known as the piece of eight, the real de a ocho or the eight-real coin) is a silver coin, worth eight reales,

So if you watch some of those old pirate movies you can learn the basics of file size math.

Hmm, I wonder if this also gives clues on how to charge for compression jobs .



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Daniel Low
Re: Video For Web
on Jan 3, 2010 at 11:20:09 pm

Sorry, but even setting a data rate of 'x' is not ever going to equal 'x' multiplied by time, as even a CBR rate control will vary that rate over time, then there's VBR.

We all know that setting a data rate of say 1Mb/s sec for a simple scene of 10 seconds at a standard frame size will come out much less that your calculation illustrates.

__________________________________________________________________
"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


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Craig Seeman
Re: Video For Web
on Jan 3, 2010 at 11:43:08 pm

[Daniel Low] "Sorry, but even setting a data rate of 'x' is not ever going to equal 'x' multiplied by time, as even a CBR rate control will vary that rate over time, then there's VBR.

We all know that setting a data rate of say 1Mb/s sec for a simple scene of 10 seconds at a standard frame size will come out much less that your calculation illustrates. "


I noted this on my post. Perhaps you did not read it.

[Craig Seeman] "Other settings as well as the information in the source file can cause the data rate to over or undershoot depending on the codec or encoder software used but generally you should get fairly close.

What impacts quality is another set of issues but this is a BASIC discussion of FIILE SIZE. "


First step . . . BASIC step is to grasp the fundamental relationship between data rate and size. As people grasp that they can explore why over/undershoot happens relating to source content, settings and even different encoding apps as they handle those variations.

If one's objective is to truly baffle a newbie, give them the same source (30 second spot with slate and black) and DGFastchannel Chicago HD specs (uses Quicktime/Compressor) and match those settings as closely as possible in Episode or Quicktime with Matrox CompressHD MAX and so how widely different the file sizes and encoded data rates are

. . . but first people should learn the fundamentals before they learn all the variations and exceptions.




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Daniel Low
Re: Video For Web
on Jan 3, 2010 at 11:56:11 pm

[Craig Seeman] "I noted this on my post. Perhaps you did not read it."

I didn't. Apologies.

[Craig Seeman] "DGFastchannel Chicago HD specs"

Over here, we are thankfully saved from such grief ;-)


__________________________________________________________________
"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


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Craig Seeman
Re: Video For Web
on Jan 4, 2010 at 12:05:31 am

[Daniel Low] "[Craig Seeman] "DGFastchannel Chicago HD specs"

Over here, we are thankfully saved from such grief ;-) "


No dominant FTP spot delivery service there?

BTW the answer is that the largest file would be the one for QuickTime/Compressor. It doesn't seem to lower the data rate for the slate for example, where there's virtually no change from frame to frame. Both Telestream Episode and Matrox Max don't waste bits where they're not needed. It's another good example of what's wrong with Apple's H.264 implementation.





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Daniel Low
Re: Video For Web
on Jan 4, 2010 at 12:10:00 am

[Craig Seeman] "No dominant FTP spot delivery service there?"

Content is distributed as either 50Mb/s I-frame MXF or 15Mb/s LongGOP MPEG-2, delivered via Signiant or Aspera, nothing too picky after that.



__________________________________________________________________
"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


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Craig Seeman
Re: Video For Web
on Jan 4, 2010 at 12:44:15 am

The problem on this end is that while DGFastchannel has a national Standard Def spec, they don't have an HD method of delivery. DGFastchannel's Chicago office has their own spec which is tied to Apple's H.264 codec (YUCK!).



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Craig Seeman
Re: Video For Web
on Dec 29, 2009 at 6:00:37 pm

[David Bark] "I actually played around in Media Encoder a bit, and when I used the H264 export format, the lowest I could get the estimated size was 135MB, when I achieved 39 with FLV."

The codec has virtually nothing to do with the file size. Your data rate settings are the critical factor. Certainly some encoders can over or undershoot based on the settings available for the codec but the disparity shouldn't be very large.

[David Bark] "That said, I'll have to see what pops out on the other end when I use H264."
Pops out? You need to make settings to target the size you want.

[David Bark] "'m thinking, though, that that isn't even going to be a Flash file. "
Thinking base on . . .?

H.264, generally regardless of the extension (.mov, f4v, mp4, etc) IS Flash compatible and has been so since Adobe's December 2007 Player update 2 years ago.
http://labs.adobe.com/wiki/index.php/Flash_Player:9:Update:H.264

[David Bark] " I seem to have figured out how to get the H264 Format at level 2.2 to drop the size"
H.264 Levels and their ranges
http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels

[David Bark] "And I'll have to figure out how to drop QT into Dreamweaver"
Assuming you've updated your software H.264 .mov works fine in Flash. It goes in a SWF wrapper (player interface) just like FLV.




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