[mythtv-users] Transcode Issues in v0.26

[Rich Freeman]

On Mon, Feb 25, 2013 at 10:10 PM, Rich Freeman
<r-mythtv at thefreemanclan.net> wrote:
> Usually things transcode fine.  However, sometimes I'll get a show
> that transcodes down to a REALLY low bitrate - maybe 100-300 kbps.
> The result is a highly pixelated video.  I haven't been able to
> discern any pattern and it can happen from either video source.

Ok, I've gotten a little further here.  I configured mythtv to keep
the original video around and I found some videos I can consistently
transcode incorrectly.

It turns out the issue isn't actually bitrate, but resolution.  I have
my transcode settings set to configure a vertical resolution and to
scale the horizontal resolution automatically (that way I can use the
same settings for HD vs SD).

It looks like that isn't working correctly.  Videos which transcode
fine have the horizontal resolution you'd expect.  Ones which do not
have a very small horizontal resolution.  For example, one show gets
transcoded from 1920x1080 to 160x480.  Obviously that has a fairly
adverse effect on video quality.

I added some debugging code to mythtranscode.cpp, and I've determined
that the width of 160 is obtained by:
            newWidth = get_int_option(profile, "width");

Looking in the codecparams table I do not have any widths set to 160 -
I just have them set to auto (which is a value of 0 in that table I
believe).

So, the question is where that value of 160 is coming from...  I'll
keep looking but suggestions are welcome.

Rich