[mythtv-users] Transcoding for best audio

[John Pilkington]

On 07/07/13 21:26, Michael Stucky wrote:
> On Sat, Jul 6, 2013 at 2:52 AM, Brenden Conte <brenden at thecontes.info
> <mailto:brenden at thecontes.info>> wrote:
>
>     Thank you everyone for your feedback; it has been quite useful!
>
>     Specifically about the --audiotrack argument, i was unable to get it
>     to (seemingly) do anything, or find any examples of its usage in the
>     wild.  From what i can tell, its looking for a number of the
>     audiotrack to use (either as the primary or only, its not clear).
>       But no matter what i specify for an argument, it always creates
>     the same mpeg.
>
>     Any extra info about that argument would be welcome.
>
>     -B
>
>
>
> The --audiotrack argument appears to be part of the --fifodir mode of
> mythtranscode. I too was unable to get it to do anything useful in any
> other context. The --fifodir mode looks interesting because it outputs
> one audio and one video track each to a pipe that can be used by ffmpeg
> (and maybe other programs?) as input, it will --honorcutlist and cleanup
> damaged frames. So it could be used as a replacement for Projectx in
> John's MythDVBcut script except that the video is output in "rawvideo"
> format so it must be encoded/compressed into a usable format (xvid,
> x264, etc.). On my BE with an Intel i7 quad core processor a 1 hour
> recording took about 3 hours to transcode!! This would only be of value
> for something that I knew I wanted to keep and wanted to take advantage
> of mythtranscode's frame accurate cutting.
>
> All of this is somewhat frustrating! Mythtranscode should be the best
> option because it is built into MythTV but it messes with the order of
> audio tracks making it troublesome to use with external players with no
> option that I can find to remove unwanted audio tracks without
> re-encoding the recordings. MythDVBcut does its cutting and repair at
> keyframes so recordings with lots of damaged frames can be somewhat
> choppy but it is fast and reliable for "clean" recordings and allows me
> to select audio tracks without re-encoding.
>
> Mike
>

I used to use the mencoder-based script that I posted earlier as a 
preprocessor to get rid of the problematical extra streams that probably 
still come and go in DVB-T recordings.  I used mythtranscode --mpeg2 
--honorcutlist on the output, usually without problems, with MythArchive 
  with no cutlists and no transcoding then usually able to create a 
full-sized 4.3 GiB DVD image in less than 30 min.  Each stage of the 
process could be checked, but inexplicable failures still happened.

For several years now I've been using ProjectX within scripts to do the 
job instead; currently mythDVBcut.  It's a hands-on process, but I can't 
really see it being anything else. Failures are rare, and rarer than 
before.  There are still niggly inconveniences, but the biggest worry is 
that changes introduced into master, or the underlying tools, will bring 
new problems when a new version of  -fixes makes its appearance. :-)

John