[MPlayer-users] A-V sync with mencoder/mplayer

[Ken Bass]

Miroslav,

I think your way works - at least it's the best that I have gotten so far.

First, I do believe what Daniel said about the VHS/VCR variable rates. But
VLC didn't resolve anything, other than to confirm that it was the tape (and
VCR) that was causing the problem. Running VLC, either directly from the
capture card, or from a captured video,  VLC kept spitting out errors like:
"audio starved", "video arrived late".

(BTW: this tape was recorded 25 years ago, from another VHS recording. So it
is not the greatest quality to start with.)

I did have some problems running mencoder with your options. First, I was
using OSS, since that seemed to work the best with my capture card. What it
probably was doing was just ignoring errors, and not informing me - I still
had sync problems with it. When I switched to ALSA, I first got a 2 billion
second XRUN that it recovered from (give or take a 0).  I recorded 1 hour+,
then ran mencoder to write out the index. For the full hour (plus about 12
minutes), the audio was pretty much in sync. There is a small, but
noticeable audio delay (maybe 1 sec or so) throughout the entire recording.
But at least it was constant, and not progressive as it had been before.

Couple of questions, though:

Should I ignore the "1 duplicate frame(s) !", and "Skipped 1 frame"
messages? (apparently they didn't have any noticeable effect on the video).
Would the "-noskip", or "-noencodedup", or "-vf harddup" make any difference
(good or bad)?

For the -tv options, I used "immediatemode=0". Is that a problem? or is it
necessary? Also, I am using hardware MJPEG compression, coming out at
704x480 (this is NTSC, not PAL). This usually gave me better video

This method should work using other a/v-codecs. Right?

I know I can't get a digital re-mastered quality video, but are there any
mencoder options (or any other app) to clean up some of the VHS noise? Like
I said, these are old recordings, mostly made by recording from another
recording (VCR to VCR).

Anyway, for now, this method seems to work, so I'll keep with it.

Thank you VERY much.

ken


On Thu, Dec 10, 2009 at 9:12 PM, Miroslav Rovis <m.rovis at inet.hr> wrote:

> > > In short, I am trying to capture video from vhs, via a tv capture card.
>
> > But
> > > the A-V is out of sync - audio lags video. Actually, it becomes
> > > progresssively worse as the recording goes on.
> >
> >   I've tried the same thing - recording from VHS. The problem is that
> > with a bad vhs tape (or a slow motor) you get rather a variable frame
> > rate video than an exact 25 (or 30) fps one.
> >
> >  I've solved this by running VLC as a capture and encoding to mpeg2 ts
> > and using mplayer -dumpstream to record the stream. Both on different
> > computers, to avoid problems with disk buffers, etc..
> >
> >  With mplayer I can not get recorded analog television either, and the
> > signal was better than on vhs.
> >
> >  Daniel
> >
> > But no luck.
> > >
> > > I have been fighting with this for a long time. So any help/pointers
> will
> > be
> > > greatly appreciated.
>
>
> IPls. let me know if vlc+mencoder is a better solution, better quality,
> which I doubt,
> but I can't tell of course...
> Namely, I am not and have not been converting tapes to files since back
> then, so I cannot test,
> but I am curious to know...
> Good luck!
> Miro
>  <http://www.exDeo.com>
>
> I hope this satisfies your curiosity about VLC!