[mythtv] Transcoding of DVB-T recording expands the file

[Geoffrey Hausheer]

On Thu, 20 May 2004 22:31:43 +0200, "Lorenz Hahn"  said:
> Hi,
> 
> I'm using mythtv since three month yet. My old video recorder already
> has a nice dust layer on its keys. Excellent so far.
> 
> When I've created a cutlist and view the video, the parts I've cut off
> are not allways skipped when viewing the recording. When I scedule the
> recording for transcoding, two things are not very well:

You aren't very clear on what you are doing.
Are you transcoding to MPEG4, or are you using the transcoder to cut
frames and trying to keep the stream MPEG2?
What version of Myth are you using?

> - The cutlist can be edited on a by frame base. The transcoded result
>   has been cut by frames that are near to the created marks but don't
>   match them.

Yes.  This is how the MPEG2 transcoder works today (I assume thatis what
you are using).  Getting frame-exact cutting has a few different
solutions, none of which are really MPEG2 compliant.  Basically I never
finished this part of the implementation.

> - The original file was about 2 GByte large, the transcoding result
>   wasted 40 GByte.
it wasted 40GB?  I am confused.  Are you saying that the final result was
40GB?  That is quite odd.

> - The cutlist can't be edited, when the frontend is started on a
>   different host. Just simply nothing happens, when I've selected
>   the edit cutlist menu entry. 

Looking at the cutlist in the mysql DB may be useful here

> 
> Any hint, where and how I've got to touch the setup?
> 
Basically the MPEG2->MPEG2 transcoding stuff is very crude at the moment.
 Since I don't use it, and never have, my work on the project kind of ebb
and flows.  Since myth has been working very well for me for the past 5
months, I haven't had much incentive to work on it.  Also, many of the
MPEG2->MPEG2 transcoding issues should really be fixed in the ffmpeg
library, and I wasn't too keen on spending much effort on it.

I noticed that recently the ffmpeg guys have implemented padding and
better pts/dts code, so either (a) mythtranscode may magically work
better in CVS than it did in .14, or (b) perhaps a bit of coding can make
it do so.

So the answer is that you probably have to live with the first issue for
a while.  the second issue I don't understand, and the third is probably
easily fixable, though it doesn't seem to have anything to do with
transcoding.

.Geoff