[mythtv-users] Lossless transcode for MPEG4 recordings?

Peter Bennett pb.mythtv at gmail.com
Sun Nov 4 15:48:26 UTC 2018



On 11/4/18 7:50 AM, Richard Shaw wrote:
> Years ago I used to do lossless transcoding on all my ATSC recordings. 
> They took up less space when $/GB was higher...
>
> Fast-forward to today. I have both ATSC and CC HDHR tuners and Plex on 
> all my TVs that don't connect directly to a FE.
>
> Most things work OK but Plex has problems with the audio getting 
> massively out of sync on some channels. There are a few recordings I 
> saved and I used Avidemux to convert the container to MKV but left the 
> video and audio streams alone. These playback just fine in Plex.
>
> So the questions are...
>
> 1. Is there a lossless transcode equivalent in Mythtv?
> 2. Can I convert the recordings to MKV containers?
>
> I found this thread but I'm not worried about cutpoints, just a fix to 
> the audio sync...
>
> http://lists.mythtv.org/pipermail/mythtv-users/2017-June/391873.html
>
> Per this:
>
> https://www.mythtv.org/wiki/Lossless_Cut
>
> It looks like the answer to #2 is yes, but it doesn't look like the 
> code has been touched since 2013...
>
> Is there an "official" way to handle this within MythTV?
>
> Thanks,
> Richard
>

Here is a script I used for that purpose. It does not take account of 
cutpoints. It converts the file from .ts to mkv format with no 
transcoding. The file will be the same size but players like kodi are 
able to better handle audio sync and subtitles.

It runs very quickly, takes a few minutes to run for a recording, less 
if you leave out the subtitle stuff.

I ran this as a user job after recording. You may have to change it for 
your environment, it has some out of date things and some things 
specific to my setup.

https://github.com/bennettpeter/mythscripts/blob/master/install/opt/mythtv/bin/userjob_mkv.sh 


Peter


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