[mythtv-users] Video Editing HELP! (COMPLETE noobie)

Douglas Wagner douglasw0 at gmail.com
Thu Jun 4 05:20:55 UTC 2009

On Wed, Jun 3, 2009 at 7:21 PM, Nick Rout <nick.rout at gmail.com> wrote:

> On Thu, Jun 4, 2009 at 11:11 AM, belcampo <belcampo at zonnet.nl> wrote:
> > Nick Rout wrote:
> >>
> >> On Thu, Jun 4, 2009 at 12:40 AM, barbex <barbex at gmail.com> wrote:
> >>>>
> >>>> So I loaded avidemux last night and gave IT a shot.  "Better" is a
> >>>> phrase
> >>>> that comes to mind, at least it's easy enough to use.  Getting rid of
> >>>> commercials was pretty easy after indexing, and saving instead of a 12
> -
> >>>> 15
> >>>> hour process was about 30 minutes...
> >>>>
> >>>> That's about as best as I can say.  The video STILL doesn't work, it
> now
> >>>> looks like it's playing on x2 and there's still no sound.  I've tried
> >>>> AVI
> >>>> and mpeg video saving routines, all a no go.
> >>>
> >>> I was going to suggest avidemux as the only program I could find that
> >>> made any sense to me. And I have successfully cut videos from mpeg
> >>> files that mythtv recorded into new mpeg files. I remember that I had
> >>> to pay attention to Transport Stream (TS) versus PS whatever stream
> >>> and it failed on some files because of errors in the recording. There
> >>> is some information here:
> >>>
> >>>
> http://avidemux.org/admWiki/index.php?title=Editing_MPEG_capture_(DVB_or_IVTV)<http://avidemux.org/admWiki/index.php?title=Editing_MPEG_capture_%28DVB_or_IVTV%29>
> >>> about that problem. So far nuv-files have stumped me but only because
> >>> I got scared of ProjectX.
> >>>
> >>> ProjectX seems to be the solution to all and everything when it comes
> >>> to video and repairing them. I am by no means an expert in this but I
> >>> would try that next.
> >>
> >> I find dvbcut http://dvbcut.sourceforge.net/ to be very good at
> >> cutting DVB material frame accurate before encoding with avidemux.
> >
> > Where can I read "frame accurate" cutting ?
> Most editors only cut to the nearest I frame, and doesn't have to
> re-encode anything (as each GOP is maintained).
> DVBCUT is frame accurate and re-encodes enough to make new I-frames at
> the beginning of the new GOP.
> Say you have a sequence of frames that you want to cut out the first
> three frames.
> I B B x P B B P
> Normally you can't do that because the remaining sequence PBBP does
> not start with an I-frame, the P frame needs the frames before it to
> be decoded.
> So dvbcut re-encodes the remaining sequence to create a new GOP
> starting with an I-frame.
> Hence on the web page: "It follows a "keyhole surgery" approach where
> the input video and audio data is mostly kept unchanged, and only very
> few frames at the beginning and/or end of the selected range are
> re-encoded in order to obtain a valid MPEG file."
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Just wanted to post back to the thread to thank everyone for their posts.
I'm learning ALOT here.

Playing with avidemux on a video.  After indexing I notice that AVIDEMUX
detects the frame speed at almost 60 frames / second in the recording
(59.something), which seems strange since NTSC video is 30.

When I play the file I get VERY scratchy sound, in essence it's as if sound
is recorded something like every other frame or some such.  When I decrease
framerate of the video to 30 I get perfect sound, however it is EXTREMELY
out of sync with the video itself.

I did manage to get rid of the double speed video by decreasing the frame
rate to 30, but then of course sound is borked.  Simply playing the
incomming video though avidemux (without doing anyting to it) has sound
issues...I'm using ALSA:default.

With Kino I get almost 30 minutes (29.somethign) into the video and it stops
processing...however when playing the little bit I do get it's got fine
quality sound and is in sync with the video.  Kino doesn't give me
information on the frame rate or such that it's detected.

I'll look at reading the recording back into Myth and trying the transcode
steps listed above and see if I can get things going that way.

Thanks all for the help, keep the information comming.

--Douglas Wagner
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