Re: mjpegtools 2.0.0 RC1

-------- Original-Nachricht --------
> Datum: Sat, 01 Jan 2011 08:07:50 +0100
> Von: Bernhard Praschinger <[email protected]>
> An: Developer mailing list <[email protected]>
> CC: Linards Ticmanis <[email protected]>
> Betreff: Re: [Mjpeg-developer] mjpegtools 2.0.0 RC1

> > As for remaining problems: mpeg2enc after the last big bunch of
> > patches still has trouble with low-bitrate encodings such as VCD,
> > producing buffer underflows fairly regularly. At least it does in the
> > state the CVS tree was in shortly before Christmas.

> How did you notice ?
> I did a quick check with the current CVS with that commands:
> [...]
> That seems ok to me, but I have to admit that I didn't burn and test a 
> VCD or SVCD for a very long time (2-3 years I guess).

Hello Bernhanrd and all,

I was mostly encoding animated stuff (the last thing I tried was Star Trek: The Animated Series), which I guess is more difficult to get right for rate control code. Also your test video might have been too short, I'd usually get between one and five underflows per full CD.

> BTW: Do you know why the patch for the reduction parameter -4 -2 did not 
> make it into the CVS (You sent it to the developer mailinglist at the 
> 05.09.2010) ?
> The patch lookes ok for me.  If no one objects I will add it to the CVS.

The first patch I sent, which enabled "-4 0" and "-2 0" to work without crashing, actually made signal-to-noise ratio (PSNR) slightly worse on some test encodings (while considerably slowing down encoding), so I myself sent a message suggesting that it should not be applied and instead a short patch which simply exits with an error on these parameter settings should be used. However by now I've learned that PSNR is not really that good a measure of encoding quality. So maybe some other tests would have to be conducted. If you or somebody else on this group could suggest a good mathematical test of encoding quality that detects even relatively small changes, I could do some more tests when I'm home again next week.

> BTW2: Vacation is always good !

Agree very much. :-)

Happy New Year to you and all on this list. 2011 is the Year Of The Rabbit, should be ideal for working on encoding speed. ;-)

-- 
Linards Ticmanis

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