gpg: failed to create temporary file '/var/lib/lurker/.#lk0x57547100.hantslug.org.uk.26042': Permission denied
gpg: keyblock resource '/var/lib/lurker/pubring.gpg': Permission denied
gpg: Signature made Tue Jan 16 13:02:22 2007 GMT
gpg: using DSA key B2C27BC21C335860
gpg: Can't check signature: No public key
On Tue, Jan 16, 2007 at 12:39:44PM +0000, Tony Whitmore wrote:
> On Tue, Jan 16, 2007 at 12:20:39PM +0000, Hugo Mills wrote:
> > When you first load an MPEG2 into avidemux, it indexes it. If you
> > look at the end of the .idx file (with "tail" is probably easiest),
> > the last but one line will read something like:
> >
> > # track 1 PTS : 1485730378 delta=0381 ms
> >
> > The delta is the A/V offset, and can then be corrected for in the
> > box in the left-hand-side toolbar -- set it to the negative of the
> > delta value (so -381 in the example above).
>
> I know you're talking about DVB recordings, but should there be a
> similar eissue with DVD content? Surely there's a much lower error
> rate on a DVD disc and there shouldn't be sync issues?
There's no issue of drifting sync, where errors cause dropped
packets in either audio or video streams. However, the sync is still
offset by some value between the two. In a perfect stream, this value
will remain constant along the whole period of the stream.
There are three main sources of A/V sync issues, and all three have
different symptoms:
1) "Natural" offset -- the offset is constant throughout the recording.
2) Packet loss -- corruption is seen/heard on the recording where
packets are dropped, and the sync shifts in jumps, but otherwise
remains constant between lost packets.
3) Bad audio or video clock -- sync drifts slowly and continuously for
the whole stream. This is usually encountered when the wrong frame
rate is assumed for the source material (typically 30 FPS instead of
29.997 for NTSC material).
(1) can be fixed using the avidemux offset. (2) can be fixed by
chopping the stream up into separate chunks, each with constant
offset, and re-saving each chunk with the relevant fixed offset value.
(3) isn't something I've encountered personally, but I believe is
usually fixed by setting the correct frame rate when first processing
the video.
Hugo.
--
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
PGP key: 1C335860 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
--- The early bird gets the worm, but the second mouse ---
gets the cheese.
