[mythtv-users] Best way to export to mp4 in .24-fixes

Lawrence Rust lvr at softsystem.co.uk
Mon Mar 5 09:54:18 UTC 2012


On Sun, 2012-03-04 at 18:06 -0500, Michelle Dupuis wrote:
> I'm looking to export recordings to a format compatible with a
> Playbook (hopefully mp4).  I've done research but I'm stuck at:
>  
> mythexport - seems to be missing, and according to mythbuntu wiki is
> depricated
> nuvexport - the mp4 option is disabled and I can't find out why
> customer - I found a bunch of custom scripts but they seem like a lot
> of work for something that should be simple
>  
> I'm using .24 fixes, is there is BEST way to export to mp4 files?

I transcode most of my recordings to mp4 using this script:
http://www.softsystem.co.uk/download/mythtv/myth_shrink

It was derived from this wiki article:
www.mythtv.org/wiki/Example_Script_using_mythtranscode_in_fifodir_mode

It uses mythtranscode to pipe the TS to ffmpeg, which then re-encodes
using libx264.

To run this as a user job, goto mythtv_setup / general / job queue and
enter the following:
myth_shrink -j %JOBID% -l -Q 22.5 -R

The -l option honours the cutlist
The -Q option sets constant ratefactor.  I've found values from 20 to 23
acceptable
The -R option replaces the original recording in the dbase

The script defaults to using the ffmpeg 'hq' preset.  This is somewhat
slower than 'medium' but IMHO produces better motion.  I see a reduction
in size to about 20..25% of original using these settings.  There are a
number of other presets; list them with:
find /usr/share/ffmpeg/ -name \*libx264-\*.ffpreset

You can also use the script from the command line:
myth_shrink -i input -o output

HTH

-- 
Lawrence


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