[FFmpeg-user] formula for transcoding to ogv, shrinking an mkv

[James Miller]

On Fri, 18 Jan 2013, Tom Evans wrote:

> You've been fooled, this is not ffmpeg, it is a fork of ffmpeg, and
> you're unlikely to get support for it on here. The fault is your
> distributor, who decided to switch to the fork. It is very easy to
> build the latest ffmpeg from source, which is what is supported on
> this mailing list.

Thank you for your reply, Tom. I have only recently become aware that 
Ubuntu is using a fork: I found that information when, on getting certain 
error messages that direct me to use avconv, I attempted to find out what 
this avconv is. I really don't like the direction in which the Ubuntu 
project is moving these days--for reasons other than their use of the fork 
in preference to ffmpeg--so next time I upgrade my system, I'm likely to 
go with some other distro. Meantime, I'll look into compiling ffmpeg: I 
suppose it's available through git?

> If you aren't trying to maximise the available space, eg by ensuring
> that you use every single byte available on a DVD, a target bitrate is
> not really worth it, and hence by extension, 2 pass is not worth it.

As stated in my initial posting, I need to upload my screencasts to a site 
that has fairly low upload limits. So my files need to be around 100 MB, 
give or take. This is the reason why I am trying to transcode and shrink 
the lossless screencast files I record. The upload site seems to deal best 
with .ogv files.

> Experiment with the crf option until you find a quality level you are
> happy with. A higher crf will result in a lower quality, lower bitrate
> file, a lower crf will increase the quality and bitrate.

Now I'm getting confused: someone else seemed to be saying (if I 
understood him correctly) that I should not be using the -crf option when 
I transcode.

James