SCOUG-HELP Mailing List Archives

<< Previous Message << >> Next Message >>

Date:	Mon, 28 Jun 2004 15:24:57 PDT7
From:	"J. R. Fox" <jr_fox@pacbell.net >
Reply-To:	scoug-help@scoug.com
To:	scoug-help@scoug.com
Subject:	SCOUG-Help: Re: Supposed OS/2 Port of FFMPEG (?)

Content Type: text/plain

=====================================================
If you are responding to someone asking for help who
may not be a member of this list, be sure to use the
REPLY TO ALL feature of your email program.
=====================================================

Peter Skye wrote:

> Ah, well, apparently the uploader didn't give his name so the Hobbes
> administrator zapped it. It was uploaded to Hobbes on May 24 (I have
> the upload template which shows the missing uploader name).
>
> But the upload template does give a cross-reference for the program:
>
> http://ffmpeg.sourceforge.net/
>
> and the Download link there can give you a .tar.gz which all you have to
> do is run through your compiler.

Oh, so all we need to do is compile the source code . . . . Maybe
something YOU do, but not the sort of thing *I* do.

> > For anyone seeking to attempt conversions between different video file
> > formats, I am still looking for any evidence that such options exist
> > on *our* platform, even in the form of an early beta.
>
> There's a potential double-whammy on the quality of conversions. If the
> source and target files both use lossy compression then the converted
> file will have poorer quality. And if the conversion also changes the
> XY resolution then the converted file will have poorer quality *unless*
> both the X and Y are exact integer multiples of the source file.

I think I had the rough gist of this. There were several adjustable
parameters on the QT Pro conversion, and I'd be the last person to tell you
I chose the optimum ones -- esp. not on a first try. You saw in the demo
the choice between having that QuickTime movie trailer (BHT) looking good,
with NO sound, or with a compromised visual quality and the sound back in,
thanks to the conversion. I will be installing ODIN, in due course, and
we'll see if that does anything about the lack of sound for .MOV files. My
recollection of several messages on the WV Forum board suggests that it will
*not*.

> By the way, 8x8 cosine transform compression (jpeg/mpeg and others) is
> not lossy per se. But to make the compressed file smaller you have to
> throw away some of the higher cosine harmonics which results in a loss
> of quality. How much you throw away is up to you (or the guy who wrote
> the compression program you're using).

Well, then we got the worst of both worlds on that .AVI converted version of
the "Bubba Ho Tep" trailer: the original .MOV file was something like 23
meg. (?), and the .AVI converted version -- which was rather poor in
comparison, visually -- weighed in at around 66 meg.

> As long as I'm yacking, that fantastic surfing video image you played at
> the SCOUG meeting was, iirc, shot as HD video which has a horizontal
> resolution of approximately 2K. An HD direct compression is always
> "cleaner" than a 35mm (or 16mm) film transfer which is then compressed.

That doesn't surprise me. The best looking shot-on-video stuff I've seen
has been HD. (I think those may still be big, bulky, heavy, very expensive
camera rigs, though.) I know that some more budget and mobility-conscious
filmmakers, who had to shoot on video, have used PAL Betacam. The Euro,
PAL-system footage may need some add'l. post-processing, but I think it can
still give noticeably better resolution than we get here with our NTSC.

Jordan

=====================================================

To unsubscribe from this list, send an email message
to "steward@scoug.com". In the body of the message,
put the command "unsubscribe scoug-help".

For problems, contact the list owner at
"rollin@scoug.com".

=====================================================

Return to [ 28 | June | 2004 ]

SCOUG, Warp Expo West, and Warpfest are trademarks of the Southern California OS/2 User Group. OS/2, Workplace Shell, and IBM are registered trademarks of International Business Machines Corporation. All other trademarks remain the property of their respective owners.