[mythtv-users] hd-pvr and mytharchive: cutting commercials before re-encoding?

[Will Dormann]

Hi all,

I've been playing around with mytharchive on my new mythtv system.  I've
already gathered that one of the current weaknesses with the ion
platform is that mythcommflag and mytharchive (ffmpeg) won't leverage
vdpau for decoding hd-pvr content.  In testing mytharchive, I tried a
10-second long cutlist from a recording so that I don't have to wait a
day for each test!

The problem I am running into is that the commercial cutting appears to
happen *after* the transcoding from mpeg4 into mpeg2.  This appears to
be the case regardless of whether the mytharchive option to use
mythtranscode or projectx is selected.

Wouldn't it make sense to cut commercials *before* re-encoding the
video?  This would be a nice performance gain for us low-power backend
folks, but I would think that it would also "clean up" video streams
before encoding.   The test I ran last night stopped with the following
ffmpeg errors in mythburn.log:  "error, non monotone timestamps" and
immediately following: "av_interleaved_write_frame(): Operation not
permitted".   I assume that this is some sort of glitch in the
recording, which happens to play back just fine.

I'm not sure about using mythtranscode with mpeg4 source, but from what
I've read, ProjectX handles h.264 ts files just fine.


Thoughts?


Thanks
-WD