[mythtv-users] Re: Getting good audio sync in nuvexport/transcodings w/cutlist?

Brad Templeton brad+myth at templetons.com
Thu Jun 2 22:06:02 UTC 2005

On Thu, Jun 02, 2005 at 04:16:29PM -0400, Cory Papenfuss wrote:
> >Worth a try, though I presume one would have to then do some more to be
> >able to export mythtv's cutlist.   The grail, of course, is to take
> >a mythtv recorded program with cutlist, and generate a cut-down mp2 or
> >mp4 with good audio sync which can either be played externally 
> >(mplayer/xine
> >or players on other OSs) or reincorporated back into myth.
> >
> >(Of course, if myth's internal transcode did better on HD files, that
> >would be the easiest way to attain the latter goal.)
> >
> >What will projectX do for me?  It doesn't appear to have editing.
> >Is it just to get the file into a place where avidemux2 can read it
> >without losing audio sync?
> >
> 	It took me awhile to work up the ambition to anally insert Java 
> enough to make ProjectX go.  Once I did, I was surprised at how much 
> functionality it had.  It will do cutting, and when it does so it parses 
> the stream and tries to correct varying A/V offsets after the first cut. 
> Looked really good, but like I said, some folks have been having subtle 
> issues with the sync of cut streams.

Frankly, at this point, I would be happy with a cutting program that was
given the leeway to move cutpoints to nearby I-frames or A/V sync points so
that there is no rebuilding to be done, and no risk of loss of sync.

For a full fledged editing studio, you need to edit to exact frames, but
for elmination of commercials or extra snippets at the start and end of
recordings, a little leeway is fine.

Particularly if, for example, you just have a series of programs that
you will not be watching for several months, programs that have a cutlist
so you won't watch the cut parts if you watch them now, and you just want
to delete the stuff you would not have watched anyway from your disk.

I will check into project X, the web examples did not imply an easy cutting
interface.  Myth has a reasonably decent cutting interface, though if I
were designing it I would add mouse/trackball support to make it really
easy to slide and search through the program for the cutpoints you want.

I can imagine a nice mouse interface that went like this:

    a) Click to start hunting.  Roll mouse, picture zooms by very fast.
       The screen's worth of movement covers the entire video.
       Get close to your cutpoint.  

    b) Click again and now the mouse movement moves more slowly, the full
      screen of movement covers just a minute or two.  Get closer
    c) Click again and the full sweep is now just a few seconds
    d) Click again and the sweep is just 30 frames or so.  Ideally
        the frames are actually displayed as thumbs.  Final double
        click to pick frame.  right click to go back up.

I bet with an interface like this I could move to any frame I wanted
in a little back and forth of the mouse, in very short time.

Beyond what myth needs, though.

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