[mythtv-users] Very low audio level after transcoding

f-myth-users at media.mit.edu f-myth-users at media.mit.edu
Wed Dec 7 02:06:39 EST 2005

In 0.18.1:

I'm experimenting with transcoding from MPEG2 to MPEG4, and have
discovered that the transcoded files have very low audio levels;
I'd guess on the order of 6-9dB down from the source, at least.

Where are these levels specified?  I'm quite surprised that they're
affected at all.

I'm using all the defaults (as far as I know) except that I changed
the transcoding dimensions from 480x480 to 720x480 to match the
original from the PVR-250.

I can verify absolutely that it's the transcoding process that's doing
this, because I'm saving the originals.  If I play the transcoded
file, and then rename that file to some temporary name and rename the
.nuv.old file in place of the original and play -that-, audio is back
at its normal level.  If I undo the renaming, audio is again quiet.
This is true for transcodings from 5 different channels.

According to ps, the actual transcoding process was something like:

mythtranscode -V 4099 -c 1002 -s 2005-12-06T21:35:00 -p autodetect -d

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