[mythtv-users] How to make a clip from a recording

Nick Rout nick.rout at gmail.com
Thu Oct 29 00:05:41 UTC 2009


On Thu, Oct 29, 2009 at 12:42 PM, Jay Foster <jayf0ster at sbcglobal.net> wrote:
>>> >
>>> >  I have some HDHR recordings that I would like to make some short clips
>>> >  from.  I don't want to do any re-encoding, just clip a specified
>>> > portion
>>> >  out.  I tried mencoder with -ss 01:43:00 -endpos 00:01:00 -oac copy
>>> > -ovc
>>> >  copy, but can't get it to work.  After some experimenting, I think it
>>> > is
>>> >  because mencoder can only seek by an amount that will fit in a 32-bit
>>> >  integer.  The file is 2 hours and 14GB in size.  mencoder will work if
>>> > I
>>> >  keep the -ss value small enough, but the part I want is well past
>>> > that.
>>> >
>>> >  Is there some other simple way to do this.  I would like to be able to
>>> >  specify the starting point of the clip (relative to the beginning of
>>> > the
>>> >  program) and how long (or the end point).
>>> >
>>
>> Dunno if it's as "simple" as you may want, necessarily, but I do this
>> fairly
>> regularly with avidemux. I don't know of any means to do up clips in the
>> myth editor...
>>
>> Bob
>
> I've used avidemux with poor results in the past.  avidemux won't do what I
> need (I don't think).  I need to preserve the MPEG TS stream exactly for the
> portion clipped out.  I do not want to reencode the video and/or audio.  The
> purpose of the clips is to give examples of transmission problems/errors,
> and reencoding the video and/or audio can cover these up or change how they
> appear/sound.

avidemux is a little mis-named now, it does more than avi!

You can copy the audio and video streams, and put it in a variety of
containers. The options in the one I have here are avi (4 sorts) ,
mpeg-ts, mpeg-ps mpeg-video, mp4, ogm, psp, flv and mkv.

>
> The video is MPEG2 TS video and the audio is AC3 (DD5.1).  Can avi files
> even contain AC3 DD5.1 audio?

Yes it can, but see above.

However, whatever you do is probably going to remux the video and
audio streams into whatever container you choose. (I think). So if the
error you are wishing to preserve is in the original muxing, I suspect
it will be lost.


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