[x264-devel] Re: no gain in 2PASS for very low bitrates

[Patrick Lefevre]

I have used 10,000 frames content (with bunch of scene changes) @ 30fps
in 2 pass mode. 1080p is still excellent quality down to 2Mb (4Mb peak).
What is considered low bit-rate?]. For playback, I used mplayer,
otherwise the decoding filter appears too slow (?), at least if used
with mediaplayer. [1221 snapshot]
-- Pat.
 

-----Original Message-----
From: x264-devel-bounce at videolan.org
[mailto:x264-devel-bounce at videolan.org] On Behalf Of Guillaume POIRIER
Sent: Thursday, December 22, 2005 12:29 AM
To: x264-devel at videolan.org
Subject: [x264-devel] Re: no gain in 2PASS for very low bitrates

Hi,

On 12/22/05, shauli rozen <shauli.rozen at gmail.com> wrote:

> >How many frames? 2pass doesn't do much on short videos, other than 
> >giving more accurate bitrate. It only matters when there's many 
> >scenes of varying complexity.

> the movie is 300 frames long , maybe that is not big enough for the 
> 2PASS to take effect?

Yes, that's indeed too short. I couldn't tell you precisely around how
many frames 2pass makes a difference (as Loren said, it depends on how
many different scenes you have). It's probably safe to try with several
thousands frames (for instance 5min = 5*60*25 = 7500 frames)

Guillaume
--
Life is pleasant. Death is peaceful. It's the transition that's
troublesome.
    Isaac Asimov (1920 - 1992)

MPlayer's doc is offline. Find some fresh one here:
http://tuxrip.free.fr//MPlayer-DOCS-HTML/en/
http://tuxrip.free.fr//MPlayer-DOCS-HTML/fr/

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