[MPlayer-users] Re: mpeg2video for DVD authoring?

Tobias Diedrich ranma at gmx.at
Thu Sep 18 16:44:19 CEST 2003

Nico wrote:

> Using that cli, do you still experience  blocks in black areas? Using 
> scplx_mask=0.2 and mbd=2  most of them go away for me,
> but some are still left. Maybe tcpl_mask will remove them?
> I'm searching a definitive solution :)

I haven't checked that yet...

> mbd=2  gives me much better quality than vhq, and it also seems to lower
> the bitrate; I wonder why it's not enough emphasized in the
> Finest Manual

I guess it's too new.

> How many fps do you get?

Currently 11fps (Athlon XP 1700+).
I switched to qscale=3 because I couldn't get 2-pass encoding to work
properly it seems too always produce nearly the same filesize regardless
of vbitrate... I'd love to use qscale=2, but with it the bitrate goes
over 10Mbit every now and then and the mplex complains...
It would be nice to be able to use qscale and still cap the maximum

[Oops, I accidently sent this mail only to Nico... Well, while I'm at it
I'll add bit of additional info below]

The cause for the problem I had with the 2-pass code seems to be the
default quantisation matrix in combination with the near noiseless video
and the quantiser decisions for b-frames. In my case it was always using
qscale 1 for I-Frames and qscale 3 for B-Frames, it simply could not get
better than 1.6Mbit with the settings even though I reqested an average
of 4Mbit. It seems that it rounds up the qfactor for B-Frames to 3 because
of the default vb_qoffset and vb_qfactor of 1.25.

I tried specifying quantisation matrices where all values are 4 for the
inter_matrix and 8 for the intra_matrix. With that I got the bitrate up
to near 4Mbit but encoding was also a lot slower.
I even tried an all-ones matrix, but that seems to be a bad idea, it must
be causing overflows or something... :-)

FYI I was testing with the japanese "Cowboy Bebop - Knocking on Heavens Door"
Movie, which has an average bitrate of near 10MBit. :-)
It has a bit of Film noise, which can be nearly completely removed
with hqdn3d.

Tobias						PGP: http://9ac7e0bc.2ya.com
This mail is made of 100% recycled bits
np: KareKano Act 2.0 - 18: KareKano Act 2.0 - Extreme Astonishment [Jap Title: Kyoutendouchi]

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