[mythtv-users] concatenating recordings?

John Pilkington J.Pilk at tesco.net
Fri Oct 28 18:10:38 UTC 2011

On 28/10/11 18:45, Simon Hobson wrote:
> I may be missing something big here, and be on completely the wrong tack ...
> I was under the impression that a recording (at least for those of us
> using DVB) is simply a capture of a broadcast bitstream over a
> period. Thus concatenating two recordings ought to be just a matter
> of joining the two files together :
> cat file1 file2>  bigfile
> I'd imagine worst case is there's something on the front of the file,
> and so you'd have a bit in the middle that wasn't a valid stream.
> Since the decoder has to cope with dropouts and serious errors, it
> ought to be able to cope and pick up at the next key frame - ie it
> would treat the bit at the join as just a burst of transmission noise.
> Or have I missed something ?
I've tried cat approach (for dvb-t) but when I then processed it with 
project-x I got the first part only back because of timestamp 
incompatibility.  Project-x will demux and concatenate properly and I've 
sometimes used a custom-tweaked derivative of mythcutprojectx to do the 
job, and just drop the new file back in place of the first segment. 
That gets the right file size into the DB too.   mythtranscode --mpeg2 
alone doesn't do that; I haven't tried commflag --rebuild recently.  But 
the script does it by direct insertion into the DB; is there a better way?

John P

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