Target file size?

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ejtttje
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Target file size?

Postby ejtttje » Fri Jan 27, 2012 6:36 am

I would think this has been noted before, but I can't find it...

The nightlies have dropped the "Target File Size" (aka -S,--size CLI options). This was very handy when I want to target a specific disk size (i.e. fit a couple movies to fill a USB drive or such) Sure I can take each movie duration, compute the time in seconds, divide by my target size, subtract the audio bit rate, pass that along to -b... but that's annoying, why do I have to compute this manually now?

Thanks!

TedJ
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Re: Target file size?

Postby TedJ » Fri Jan 27, 2012 7:07 am

It was dropped because it was becoming increasingly inaccurate and would cause issues with future development goals, such as VBR audio. You'd be amazed how many people would register on the forums to complain of a 1.5% error in their desired target size.

ejtttje
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Re: Target file size?

Postby ejtttje » Fri Jan 27, 2012 7:23 am

I'm not sure the solution to people complaining about inaccurate target sizing is to eliminate target sizing... kind of throwing the baby out with the bathwater there, you might be setting up for even more complaints if people were that reliant on using target size.

If I might suggest, perhaps target size could be made mutually exclusive with VBR audio or other future features, or simply consider it a documentation issue to display a warning that HandBrake can't precisely hit a target size, so the user should leave some headroom... *shrug*

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Rodeo
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Re: Target file size?

Postby Rodeo » Fri Jan 27, 2012 2:14 pm

It also had become a pain to maintain (update it to work with other changes in HandBrake). None of the developers wanted to deal with it anymore, so it was axed…

musicvid
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Re: Target file size?

Postby musicvid » Fri Jan 27, 2012 5:09 pm

There are many free bitrate calculators on the internet, or simply calculate it yourself.

Time (seconds) x Total Average Bitrate (Mbps) x .125 = File Size (MB)

Note that audio bitrate is included in total ABR ;?)

ejtttje
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Re: Target file size?

Postby ejtttje » Sat Jan 28, 2012 6:35 am

Time (seconds) x Total Average Bitrate (Mbps) x .125 = File Size (MB)


Which I guess is my point, HandBrake already knows the duration of the video, and it lets me specify an average bitrate, so it seems trivial to just let me enter the size instead and have it divide to find the bitrate. Otherwise making the user look up the duration, launch another program, type in the duration, and then copy the bitrate back to HandBrake... isn't rocket science, but it does seem a pointless exercise.

musicvid
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Re: Target file size?

Postby musicvid » Sat Jan 28, 2012 6:50 am

Best way to start appreciating the things Handbrake does, is to believe what the developers (who are professionals that volunteer their time) say.
They are trying to juggle several discontinuous libs into a manageable package, and have said over and over that the updates to those libs and the shift to quality-leveled rather than bitrate-leveled encoding makes that minor feature (which you can calculate yourself in a simple excel file) impractical to chase through every incarnation of the software.

TedJ wrote:You'd be amazed how many people would register on the forums to complain of a 1.5% error in their desired target size.
Actually the simple formula I gave is only accurate within about 5% at predicting file size in the real world of long-GOP interframe compression, maybe even a bit less accurate with some high profile compression schemes. As usual, I ran my own tests. I'm sure the developers here are less interested in writing predictive regression algorithms than in improving the software itself, and understandably so.

But if you are convinced it is as easy as you say, ejtttje, I (and many others here) eagerly await your code submission.
;?)
Last edited by musicvid on Sat Jan 28, 2012 7:38 am, edited 3 times in total.

ejtttje
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Re: Target file size?

Postby ejtttje » Sat Jan 28, 2012 7:12 am

musicvid wrote:But if you are convinced it is as easy as you say, I (and many others here) eagerly await your code submission.


Well, you were the one saying I could just divide to find the bitrate... if you think this is something an end user could compute, then HandBrake could just do it for them. But If it's too difficult for HandBrake to compute, then the end user probably won't be able to do it either, so don't suggest some random internet bitrate calculator is going to do the job.

I was already buying the earlier implied argument that with stream overhead and metadata and perhaps not always using the full bitrate and so on, that it's hard to hit a target size. (Although I do wonder if would it be easier to respect a maximum size limit vs. calling it a 'target' size? It seems bit rates tend to provide a similar upper limit to support this usage, but you imply bit rates in general are being phased out which would make it moot.)

musicvid
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Re: Target file size?

Postby musicvid » Sat Jan 28, 2012 7:18 am

Oh, excuse me. If you want to find the APPROXIMATE average bitrate, use the formula or a bitrate calculator. If you want to learn more, read up. But please don't say ridiculous things or second-guess the developers unless you're prepared to back it up with hard solutions. They don't deserve it and have better things to do with their time. Even my $600 nonlinear editing suite doesn't predict file sizes for me, even for something as simple as rendering an MPEG-2 project to fit on a DVD. Maybe there are some reasons for that?

Smithcraft
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Re: Target file size?

Postby Smithcraft » Sat Jan 28, 2012 11:55 am

Play nice!

SC

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Rodeo
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Re: Target file size?

Postby Rodeo » Sat Jan 28, 2012 1:39 pm

Enough. Target size is gone and not coming back, sorry.

Locking.


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