[mythtv-users] Compressing PVR-x50 SD video using Handbrake---any advice?

Gordon McCrae gordon.mccrae at gmail.com
Wed May 1 08:08:11 UTC 2013


On 01/05/13 08:29, f-myth-users at media.mit.edu wrote:
> If anyone has a known-working toolchain for compressing SD video
> from PVR-x50 devices using Handbrake, I'd love to know about it.
> I'm basically trying to turn MPEG-2 into H.264 of any flavor.
>
> I recently had occasion to try this, discovered it failed badly, and
> the top hit of the first search I did turned up [1]--which turns out
> to be -my own question- about how to do this from 2.5 years ago.  That
> thread sorta petered out, and even with a release that's several years
> later by now, my attempts just now have failed to find a working
> toolchain that would accomplish this, despite the fact that it seems
> simple.  Using Handbrake directly got zillions of errors and produced
> a tiny file that mplayer couldn't swallow; using ProjectX to
> preprocess and demux left me with files that I wasn't sure how to
> remux correctly, given that ffmpeg's args seem to change every other
> week and that it's now being deprecated in place of avconv.  Maybe I
> just haven't been persistent enough in figuring out the ffmpeg/avconv
> args and that's all I need.
>
> [One rather alarming feature of this process is that the two resulting
> streams claim to differ in duration by about 15 minutes on a 2.5-hour
> test file I tried.  Yet the original plays perfectly fine as MPEG-2
> and does not have any sync problems.  When I noticed the mismatch in
> durations, I decided I was probably doing it wrong---and both ffmpeg
> and avconv simply -hung- at some point during the remux, burning 100%
> CPU but not making the output file any larger after several minutes
> in this state.  So rather than trying to debug my existing process,
> maybe it's better to see if someone has an already-working one.
> Note that the source material for my test was a cable box producing
> S-Video, so it's very unlikely that there's any significant corruption
> in the input signal; certainly nothing observable just by watching it.]
>
> For the sake of argument, I'm trying to do this at the moment under
> Ubuntu 12.04, and I'm doing it on isolated recordings---not something
> I'm trying to get Myth to understand post-compression.  (Though any
> advice on that would be perfectly welcome, too---I presume it's
> basically run it as a transcode job and if necessary rebuild the
> seektable---but I first need to get something that isn't garbage,
> and some of these want to happen with files Myth has never seen.)
>
> Thanks!
>
> [1] http://www.mythtv.org/pipermail/mythtv-users/2010-November/303827.html
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HandBrakeCLI -i "InpitFile.mpg"  --preset="Normal" -o "OutpufFile.mp4"

Cheers
Gordon


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