[mythtv-users] Varying data formats during digital reception

Mike Perkins mikep at randomtraveller.org.uk
Tue Nov 6 18:49:39 UTC 2012

On 06/11/12 17:34, Jose Paulo Moitinho de Almeida wrote:
> On Tuesday 06 November 2012, Mark Greenwood wrote:
>> On Tuesday 06 Nov 2012 08:09:25 Gary Buhrmaster wrote:
>>> On Tue, Nov 6, 2012 at 6:29 AM, Mark Greenwood <fatgerman at gmail.com>
>>> wrote: ...
>>>> I have 0.26 (on mythbuntu 12.04) and VDPAU. I tried a few things.
>>>> Plays fine in mythtv (as a Movie, not sure if that matters)
>>>> Plays fine in mplayer when mplayer is set to use vdpau output
>>>> Set mplayer to use xv output and the video stops at the change of
>>>> aspect but the audio carries on. The mplayer output gives you the
>>>> problem:
>>>> [h264 @ 0x7faa4c59e280]Width/height changing with threads is not
>>>> implemented. Update your Libav version to the newest one from Git. If
>>>> the problem still occurs, it means that your file has a feature which
>>>> has not been implemented. [h264 @ 0x7faa4c59e280]decode_slice_header
>>>> error
>>>> [h264 @ 0x7faa4c59e280]no frame!
>>> Note that this has been reported against FFmpeg/Libav recently, so it
>>> is possible that a fix may eventually make it into the codes(*).  When
>>> it does, and the next FFmpeg merge happens, you should get a fix.
>>> Until then, you are probably out of luck if using the software
>>> decoder.  I suppose you could try running without multiple threads
>>> to see if it works.
>> I did try setting the number of threads (using the smplayer GUI) to 1 but
>> it made no difference. I have always had my doubts as to whether that
>> option actually does anything.
>> Mark
>>> Gary
>>> (*) I expect that some rework of the codes is needed to synchronize
>>> the change(s) across the threads working on the stream.  If it would
>>> have been easy, I would expect it would already be in there.
> Multi threading seems to be the problem for rendering
> "ffplay -threads 1 12002_20121104214000.mpg" works, as well as
> "mplayer -lavdopts threads=1 12002_20121104214000.mpg" (though with the sound
> advanced..)
> but neither "ffplay -threads 2 12002_20121104214000.mpg" nor
> "mplayer -lavdopts threads=2 12002_20121104214000.mpg" manage to pass the
> aspect ratio transition.
> I expect that when at home I change my playback profile to be single threaded
> the problems will disappear (under the carpet!). Should be OK as I only play
> SD content.
> If I understand correctly the question initially raised, regarding the effect
> of these changes in Lossless-Cut and (eventually) in some HDHomerun recordings
> is unrelated.
Don't make the mistake that many do which is to equate digital with HD. That 
might be true where you are but it certainly isn't in other parts of the world.

These problems will hit digital SD users like myself just as much as they will 
affect HD users. In the UK, *everything* is now digital.


Mike Perkins

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