[mythtv-users] Varying data formats during digital reception

John Pilkington J.Pilk at tesco.net
Mon Nov 5 17:39:15 UTC 2012

On 05/11/12 17:03, Mike Perkins wrote:
> On 05/11/12 16:00, John Pilkington wrote:
>> On 05/11/12 14:37, Jose Paulo Moitinho de Almeida wrote:
>>> On Saturday 03 November 2012, Mike Perkins wrote:
>>> ....
>>>> The question is: What changes are being made to mythtv to cope with the
>>>> fact that the bitrate, framerate, resolution, etc of any recorded
>>>> file may
>>>> change from instant to instant?
>>> Last Saturday I updated to 0.26 (mythbuntu system with an old nvidia
>>> card ==>
>>> nouveau, opengl, no vdpau) and since then I have been "trying to
>>> understand"
>>> why the frontend sometimes hangs. The files are ok for vlc, but
>>> mplayer does
>>> not like them.
>>> The problem happen when some new programs start and I was ready to
>>> blame the
>>> broadcaster, but reading this information I realised that the problem
>>> seems to
>>> happen exactly when the program changes from wide to 4:3, something that
>>> happened in 0.25 without problem.
>>> Is there a possible relation? I can try to cut a sample with the
>>> problematic
>>> passage.
>> I would think it's very likely.  The various players probably look at
>> different
>> places in the recording to identify the streams that are present.
>> If you can create a series of cutpoints using the MythTV editor you
>> may be able
>> to get a usable version using this.  It needs only a seektable based
>> on valid
>> keyframes.  I haven't had occasion to use it recently and it used
>> mythconfig.txt, which is no more.
>> http://www.mythtv.org/wiki/Mythpycutter
> ...problem is, he has to get the program started before he can use the
> editor to set the cutpoints...

That's why I said If...
> possible if you have sufficient padding before the actual content
> starts, I suppose. But will the editor fail because the format changed,
> even so?

It just cuts and concatenates chunks defined by keyframes - or at least 
that was the intention.  You get to select *which* keyframes,  Your 
guess as to how the result will play is probably as good as mine.

I think it improves on trying to use dd, and the log identifies the 
cutpoints in the output.  I haven't used it much because for SD I prefer 
to use my Project-X based cutter and I rarely feel the need to record 
HD.  But both are command-line tools and require some initial editing.

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