[mythtv-users] mythtranscode crashes on a .ts HD file

John Pilkington johnpilk222 at gmail.com
Mon Jan 14 13:04:54 UTC 2019


On 14/01/2019 12:03, Stefan Davids wrote:
> On 14-01-2019 10:43, UB40D wrote:
>> On Sun, 13 Jan 2019 at 17:45, Stefan Davids <mythtv at stefan.davids.uk.net>
>> wrote:
>>
>>>
>>> To use mythtranscode on h264 with a cutlist you need to use it in fifo
>>> mode to output raw video which can then be transcoded by ffmpeg or
>>> similar reading from the fifos.  Or generate the cutlist via mythutil
>>> and just use ffmpeg directly to cut out those bits and concatenate it
>>> together.
>>>
>>
>> Groan.
> 
> It's not too hard when the script is written since it lends itself to
> automation...
> 
>>> If you're familar with perl there's an example I use here at
>>> http://git.netscum.org.uk/stefan/h264_fifo/src/master/transcode_perl or
>>> there are many other examples in shell script or python around (at least
>>> two on the mythtv website).
>>>
>>
>> Thank you. I am not familiar with Perl and would understand more from a
>> shell or Python script. Which ones do you mean? I've done a bit of
>> searching of the website and there's a hodgepodge of scripts at
>> https://www.mythtv.org/wiki/Transcode_Video, none of which says clearly
>> whether it works for HD.
> 
> the ones I was thinking of are:
> 
> https://www.mythtv.org/wiki/H264_commercial_remover_and_remuxer
> 
> which uses a shell script to chop up the file via ffmpeg.  That
> should be completely lossless but putting the bits back together
> possibly isn't.  Also
> 
> https://www.mythtv.org/wiki/Example_Script_using_mythtranscode_in_fifodir_mode 
> 
> 
> shows mythtranscode working in fifo mode.  I remembered it as python
> but it's ruby apparently....
> 
> I'm happier with perl so I reworked those as examples into something
> I use.
> 
>>> It seems almost impossible to get the cutting exactly right though for
>>> h264 though.
>>
>> Pity. If it has to be such a faff I may give up on doing it on Linux and
>> may resort to Premiere, for the few things I really need to export for 
>> work.
> 
> I think there has been Linux video editing software recommended for this
> sort of thing before but I've never used it, can't remember what it's 
> called
> and don't know if it's any better. I think you need to potentially remux
> to move keyframes around to get cutting perfect with h264 which I've never
> worked out if ffmpeg will do.
> 
> Usually I end up doing the cut close to where it should be with my script
> and then edit the new file again in mythtv to remove what remained.
> I'm sure there are better workflows though!
> 
> Stefan

I hadn't seen the script from the mythtv forum, and maybe that will work 
for you.  Last year I tried vidcutter, which has its own editor/viewer, 
but it was unable to handle the non-AV streams in my DVB-T2 recordings. 
Things may have changed since then.

John P




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