[mythtv-users] HDHR Prime recordings of Discovery HD - particularly bad?

Taylor Ralph taylor.ralph at gmail.com
Wed Nov 2 17:47:29 UTC 2011

On Mon, Oct 24, 2011 at 2:51 PM, Ronald Frazier <ron at ronfrazier.net> wrote:
> On Mon, Oct 24, 2011 at 10:10 AM, Robert Kulagowski <rkulagow at gmail.com> wrote:
>> Is anyone else finding that their recordings of Discovery Channel HD
>> are corrupted?  They are playable in MythTV and in mplayer, but at
>> least on my system there's something wrong with the headers, because
>> the built-in lossless transcode fails to work, as do external programs
>> such as projectx and gopchop.
>> This occurs on every single program I record on Discovery HD, but not
>> on other channels.
> I haven't tried on Discovery HD, but last month I had a similar
> problem with Science HD (which, coincidentally, is owned by
> Discovery).
> I tried to use mythtranscode to strip commercials with its lossless
> transcode feature, and it failed. I don't recall the specific error I
> got in the log files, but it led me to believe it was something
> unsupported in the file format. I use that feature often on other
> channels and it works perfectly. I've still got the recordings just
> sitting on my hard drive at the moment waiting for me to get around to
> figuring out what the issue was. I haven't yet tried any other
> programs.
> Coincidentally, I've noticed many (perhaps all) of the recordings off
> of Science HD have an incorrect length. Myth (I'm on 0.24) usually
> calculates the file as being 2 to 5 minutes shorter than it actually
> is. Have you noticed any issues like that on Discovery? Could be 2
> symptoms of the same cause.


This is because the code determines the duration by multiplying the
number of frames by the frame duration (1/fps). Unfortunately the
frame duration isn't always constant. In the case you see it shorter
duration, it is probably due to either variable frame rate or frame
repeats (film telecined). I'm working on this now but not sure when
I'll finish given my time constraints.


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