[MPlayer-users] concatenate mpegs

D Richard Felker III dalias at aerifal.cx
Fri Mar 5 00:44:27 CET 2004


On Fri, Mar 05, 2004 at 12:12:25AM +0200, Ville Saari wrote:
> On Thu, Mar 04, 2004 at 11:41:23AM +0100, Michel Bardiaux wrote:
> 
> > Concatenation will only work *well* under 2 conditions:
> ...
> > (2) The timestamps form a coherent sequence.
> 
> Many (or most) DVD:s don't fullfill that condition. To my experience
> only a small minority has a contiguous time code throughout the whole
> movie.
> 
> Ripping Star Trek VI was a real pain because of this. The DVD had
> burned-in subtitles for Klingon language phrases placed on the
> bottom black bar. I didn't want to retain the black bars, so I
> recreated the subtitles as an mpsub file and wanted to render
> them on the picture while transcoding.
> 
> The problem was that mplayer needs a time code to synchronize the
> subtitles with. The mpeg2-stream on DVD was apparently concatenated
> from several dozens of small clips that each had their own time code.
> So the time code was reset to zero every few minutes.
> 
> I tried to solve the problem by first encoding to a fifo with a lossless
> codec and then ancoding this fifo to the final mpeg4 avi adding the
> subtitles in the process. However I couldn't get this to work and I
> had no disk space for actully storing the losslessly compressed temporary
> file so I had to first encode it into an mpeg4 with absurdly high
> quality settings and then re-encode this to the final file with
> subtitles.

It would have been better to leave the subs soft in the final encode,
rather than burning them on (bleh). Then there wouldn't have been any
problem. But I agree, this timestamp reset thing is horrible. G2 will
try to "repair" DVDs by correcting their timestamps from the data in
the .ifo file or whatever.

Rich




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