Re: [gentoo-user] Video editing advice on formats and size of file

[Michael Mol <mikemol@gmail.com>]

Dale wrote:
> Howdy,
>
> I been trying to get this to work right for a goooooood while now. I'm
> confused here. I have some videos that I download that are split up.
> Some have two or three parts and a few 4 or 5. What I can't get is this,
> I can't seem to take say two 250Mb videos and make it come anywhere near
> 500Mbs when spliced together. They usually end up being 1.5Gb and
> sometimes much more. I use Kdenlive to do this with. I have tried every
> setting that I can find. I have used exiftool to try to match the
> encoding and rates and all that with no improvement or very little
> improvement.
>
> Is there some secret spice that I am missing or something? Why can't I
> take two videos and splice them together and it be something close to
> the two file sizes added together? I'm not asking for a perfect fit but
> at least something close. If I can get 2 250Mb videos to splice together
> and be 600Mbs, that would be good enough.

You're probably re-encoding, rather than simply splicing the existing 
streams. The resulting size will necessarily have some quality loss, and 
the resulting file size will depend greatly on the quality of your 
encoder, not just on your settings for codec choice and options.

What you really want to do is repackage the audio and video streams from 
all your files into a single container file.

Back when I was poking "simple" things like this, I used 'avidemux'. 
That was ages ago, and on Ubuntu, but it might work for you. You'd want 
to use 'copy' for your audio and video selection, to avoid any transcoding.

On Ubuntu, I usually had difficulties(read: crashes) with avidemux when 
some tool or library it wanted wasn't installed--it wasn't smart enough 
to remove those options from its menus if those options weren't present. 
I haven't tried it on gentoo; it's plausible someone fixed that either 
upstream or as part of some USE flag awareness in the past couple years.

I expect there are ways to do the exact same thing on the command line 
using ffmpeg, but I'm less familiar with that tool.