Client wants to export based on file size

Hi all,

I have a client with compressor who wants to export to as close to 100 Meg as possible. She basically wants to set a target file size, possibly a canvass size and have compressor (or another application) take care of the rest.

I have always manually created preset and have never used this approach and am having difficultly answering her as to if it's possible and if not why not. Any suggestions?

Yes, but you'll have to experiment with frame size, frame rate, codec. There is no magic "make it all 100 MB" button.

I'd question where she got 100 MB from, and explain to her all files, depending on frame size/rate, codec, duration, and pixel complexity (how much movement the video contains) will cause variations of video files. Not all will look the same quality if they are all at 100 MB.

I've never had such a request.

But if they are all the same frame specs and duration and codecs and such, one preset should pretty much do it all.

Thanks for the reply, Ben. In principle I agree with you but I'll play devil's advocate:

If options exist to restrict compression datarate to a certain Kb/s (which they do) then surely it would simply be a matter of compressor calculating the maximum datarate allowed based on duration, together with the specified frame rate and canvass size. That wouldn't require a "magic" button, just a regular button

This may sometimes yield a less than stella looking encode, but shouldn't "Maximum quality encode based on final file size" be an option for those who require it?

The background is this client of mine in turn has a client that she is going to be delivering edits to on an ongoing basis. That client has specified 720p mp4 files up to but not exceeding 100MB.

The only way to do it is to encode it in some form of fixed bitrate codec and then do the math based on the length of the video... x megabits per second times y seconds = total number of megabits... convert megabits to megabytes... done. You can do it with VBR codecs as well, but the result will be somewhat, well... variable.

Sorenson Squeeze has a feature that is supposed to allow you to set a target file size and it will figure out the appropriate bitrate, but I have found that it never works very well... especially when targeting absurdly small target file sizes.

Thanks SMG669.

In all I agree that the best approach for ideal results would be to manually tweak all settings. However, I do think there is some value in an option (at least for fixed bitrate codecs) for compressor to optimise for output using your basic formula " x megabits per second times y seconds = total number of megabits... convert megabits to megabytes..."

Unless your codec uses an averaged bit rate algorithm, such as H.264 which is not a fixed rate codec.

And remember that Compressor gives you an estimated file size in the Summary tab of the Inspector.

But to get serious for a moment, the first question is, what specific codec does the client need?

Unless your codec uses an averaged bit rate algorithm, such as H.264 which is not a fixed rate codec.

Agreed - that's why i specified "at least for fixed bit rate codecs"

what specific codec does the client need?

It's web delivery. An H.264 MOV seems appropriate.

H.264 is a variable bit rate codec deep down, and the "bit rate" you set is only an average. In Compressor's Settings section of the Inspector, you should see an estimated file size there for your export.

H.264 is a variable bit rate codec deep down, and the "bit rate" you set is only an average.

If you create an H.264 Mov it states in the compressor options that you can set a bit rate limit (using the Restrict to" option)

www.fcptalent.com/uploads/limit.png

If you can restrict the bit rate, and if final final size is simply bitrate*time then you should conceivably be able to limit the final file size. And if you can do that, I see no reason why it isn't an option.