Public bug reported:
Binary package hint: x264
New version of libx264-98 don't seem to respect bitrates when encoding,
and it seems to mess up crf too (far too big sizes for crf=20).
Previous version in Maverick didn't exhibit this problem. I've encoded
about 10 movies in the past few days, and on Friday evening after
updating to the new version, using the same files and encoding options
the resulting video steam was either 6 times too big or far to small (a
few MB) and unplayable.
Results have been reproduced on two computers, one with a C2Q 9550 and
one with an i5 520M; both computers have had a fresh install of Maverick
in the weeks following release, and I never tweaked anything related to
mplayer, mencoder or x264.
It's far easier to spot on long videos, 1h30 videos streams with
bitrates requested to be 1200kbps end up above 6GB instead of the 900MB
they should be, or end up a few MB, and in both cases they're
unplayable. Doesn't seem to be a problem with bites/bytes since it never
end up as a multiple of eight times the size.
Here are some of the command lines used in case you're not used to
mencoder (video.m2v is the original stream, output.264 is the resulting
stream, -x264encopts are options passed to the x264 encoder):
- single pass, simple example:
mencoder video.m2v -nosound -of rawvideo -ovc x264 -x264encopts bitrate=1000
- 2 pass, :
mencoder video.m2v -vf crop=720:544:0:16 -ofps 25 -nosound -of rawvideo -o
output.264 -ovc x264 -x264encopts
threads=6:bitrate=1530:bframes=16:b-adapt=2:ref=3:direct_pred=auto:weight_b:partitions=all:8x8dct:me=umh:me_range=48:subq=9:mixed-refs:trellis=2:no-fast-pskip:no-dct-decimate:nr=0:fps=25:sps-id=1:pass=1:zones=1,720,b=0.2;180151,182851,b=0.5;182852,190272,b=0.25
(change pass=1>pass=2 for second pass)
This problem makes it impossible to encode videos any more, since the
resulting file is either bigger than the original MPEG2 file, or
unplayable. It seems to be better without specifying bitrate or using
crf, but then you don't know what you end up with (crf gave me results
not in line with the size it should really have been, especially with
conservative values between 19 to 23).
I've attached a list of al the packages updated between the time it
worked in Maverick and after - I did encode a video a few hours before
installing those updates without any trouble, and launched another
encode a few hours after the update, which didn't work anymore.
ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: libx264-98 2:0.98.1653+git88b90d9-3ubuntu1
ProcVersionSignature: Ubuntu 2.6.35-23.41-generic-pae 2.6.35.7
Uname: Linux 2.6.35-23-generic-pae i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Tue Dec 14 19:18:23 2010
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
LANG=fr_FR.utf8
SHELL=/bin/bash
SourcePackage: x264
** Affects: x264 (Ubuntu)
Importance: Undecided
Status: New
** Tags: apport-bug i386 maverick regression
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https://bugs.launchpad.net/bugs/690296
Title:
libx264 2:0.98.1653+git88b90d9-3ubuntu1 messes up bitrate when encoding (at
least using mencoder)
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