[mythtv-users] Transcode:Keeping AC3

Mitch Gore mitchell.gore at gmail.com
Thu Mar 27 15:31:14 UTC 2008


On Thu, Mar 27, 2008 at 10:01 AM, Kevin Kuphal <kkuphal at gmail.com> wrote:

> On Wed, Mar 26, 2008 at 7:39 PM, Mitch Gore <mitchell.gore at gmail.com>
> wrote:
>
> > I want to save space with my HD recordings.  I want to transcode them
> > but keep the AC3 audio.  I did some searches and I found that it is not
> > possible.  These posts were older so i am wondering what the status in .21
> > is.  I couldnt find the option myself.
> >
> > Also what is the differance between Uncompressed and MP3.  It still
> > makes it 2-channel so the AC3 is being removed.
>
>
> You can, but not using mythtranscode.  If you transcode using something
> like mencoder or other tools you can direct them to retain the AC3 tracks.
> Try searching the archives for "AC3 mencoder" and see what you find.
>
> Kevin
>
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>


I found this script which seems close to what i need:

#!/bin/sh
# Transcode mythtv video down to a reasonable resolution, preserving AC3
audio

if mencoder -o /dev/null $1 2>/dev/null | egrep -q 'fps:(59|60)'; then
# progressive
OFPS="30000/1001"
FPS="60"
FILTER="tinterlace=4,scale=720:360:1,expand=:480"
else
# interlaced
OFPS="30000/1001"
FPS=$OFPS
FILTER="scale=720:360:1,expand=:480"
fi

nice mencoder -of mpeg -mpegopts format=mpeg2:vbitrate=2000 -oac copy
-ovc lavc -lavcopts vcodec=mpeg2video:vbitrate=2000:keyint=18:aspect=16/9
-vf $FILTER -fps $FPS -ofps $OFPS -vc mpeg12 -o /var/video/$1.tmp
/var/video/$1 && chown mythtv /var/video/$1.tmp && mv /var/video/$1.tmp
/var/video/$1


ERROR=$?
if [ $ERROR -eq 0 ]; then
# Fix the database entry for the file
cat << EOF | mysql --user=mythtv --password=mythtv mythconverg
UPDATE
recorded
SET
filesize = $(ls -l /var/video/$1 | awk '{print $5}')
WHERE
basename = '$1';
EOF
fi

nice mythtranscode --buildindex --infile $1

I see a couple of issues.
1.  This wont work with storage groups will it.
2.  I would like to create a userjob for this so i can easily queue up a
job, what do i need to do for that to work?
3.  if i am reading this correctly it appears as its dumping a mpeg2 file.
How do i make it X.264?  Also, where is the res set?

Thanks,
Mitchell
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