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Date:      Thu, 27 Sep 2001 20:55:19 -0400
From:      Randall Hopper <aa8vb@nc.rr.com>
To:        "Steven M. Schultz" <sms@TO.GD-ES.COM>
Cc:        multimedia@FreeBSD.ORG
Subject:   Re: fxtv suggestion
Message-ID:  <20010927205519.A15291@nc.rr.com>
In-Reply-To: <200109051653.f85Grrc07553@wlv.to.gd-es.com>; from sms@TO.GD-ES.COM on Wed, Sep 05, 2001 at 09:53:53AM -0700
References:  <200109051653.f85Grrc07553@wlv.to.gd-es.com>

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Sorry for the long delay on the response.  I'm just now getting to the
bottom of my inbox this month.

Steven M. Schultz:
 |	I've run into a bit of grief creating content destined for hardware
 |	players such as portable DVD/VCD players.  Hardware players demand
 |	the NTSC frame rate of 29.97 fps (frames per sec).  Feeding a
 |	hardware player with 30 fps causes a .1% (30 vs 30000/1001) drift
 |	with the result that the audio starts leading the video and after
 |	about 8 or 9 minutes there's a ~.5 second lag which is very
 |	noticeable.
 |
 |	My temporary solution was to create a small utility to process the
 |	YUV data (I'm using the MJPEG tools from mjpeg.sourceforge.net) and
 |	drop every 1000th frame (which is I'm told is how it's done).   Voila,
 |	sync'd playback all the way thru a VCD!
 |
 |	What I've done, but not tested, is hack fxtv's "-batch" mode to
 |	implement a "-ntsc" option that drops every 1000th  frame (and the
 |	associated audio).   I was wondering if you'd be interested in the
 |	diffs or had other ideas how to generate NTSC compatible (29.97fps)
 |	output in lieu of 30fps.

Yes, definitely!  Send it on and I'll merge it in.

Also, I'd be interested to know how you've got fxtv configured for capture
to get max fps and at what frame resolution.

 |	On another note I've found the mjpegtools from mjpeg.sourceforge.net
 |	to be very good indeed - the video encoder has support for both 
 |	mpeg-1 and mpeg-2 and has been mmx'ified which brings about a 6 or 7x
 |	speed improvement.   Also included is a vastly improved 'mplex' 
 |	program as well as a MP2 audio encoder.   Definitely worth a look at.

Could you give me some tips toward using this (how you're using it for
exampless)?  It sounds like this is a much better encoding option.  Would
also be interested in your DVD workflow ;-)

Randall

-- 
Randall Hopper
aa8vb@nc.rr.com

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