On Wed, 7 Sep 2005, Florin Andrei wrote:
> Actually, I'm concerned with an issue that I've seen before with MPEG2
> streams generated with mpeg2enc and some DVD players that follow the DVD
> standard specifications very literally (e.g. JVC XV-N55) - during some
There are several other likely candidates for where the problem lies.
Sure mpeg2enc could have an issue - BUT if mplex says the .m2v is
OK, and if DVD Studio Pro says the file is OK and if it plays in
all but one player - the the player is suspect and not the tool chain.
Interesting you mention JVC - that's the only player I ever had a
problem with too. Claimed to be able to play VCDs but it did such
a poor job it was replaced with a different brand.
I haven't tried Mpressionist yet as a bitstream verifier (haven't
needed to since no problems have arisen yet). Might be worth giving
http://www.digigami.com/mpressionist/index.php a try one of these
days (the author did express an interest in my seeing if Mpressionist
correctly handled DualPrimeMotionEstimation ;)).
Other problem areas could be: 1) the authoring software, 2) brand
of media (and it DOES make a difference), 3) recording speed (I almost
NEVER run at the fastest speed the media/burner is capable of) - more
reliable (well formed "pits") at 4x than 8 or higher.
> scenes when there's a lot of motion, the image stutters. The parameters
> are normal, 8000kbps, q=6, etc.
That sounds very much like the player is struggling to pull the data
off the recordable media reliably. You say "when there's a lot of
motion" and that's precisely when the bitrate would be up at the
8000 (or slightly more) -exactly where one would expect issues with
reliable reading of data.
Try 7500 for those movies - you probably won't see the difference but
the disc might be more widely playable.
Commercial DVDs don't have the problem because they're stamped out of
more reflective material.
> If the issue is still present, perhaps we can fix it before the release.
Not likely ;)
Two days before release is not the time to raise the issue of
some players having problems with recordable media with high bitrates.
I've said it numerous times - high bitrates with recordable media
have portability problems. Nothing the encoder can do about that.
It isn't necessarily the transport of the player (although that has
happened - company saves a few cents on the transport or electronics
in order to add some other neat feature to the player) but rather
with the lower reflectivity of the recordable media - not all players
are created equal at pulling off the higher bitrate data from
recordable/rewriteable media.
> Let me try it out and I'll tell you what are my findings.
Where have you been all thru the period leading up to RC1, the rather
lengthy RC1 and then RC2 releases? In a couple days 1.8.0 will be
out (hopefully) and you can begin testing towards 1.8.1 - 7 or 8 months
or so should be sufficient time :-)
Cheers,
Steven Schultz
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