On Fri, Jan 23, 2015 at 9:28 AM, jb <jb at kdenlive.org> wrote: > Hello, > > > Hi, > > I recently had a major problem after upgrading from 0.9.6 to 0.9.10 using > > Ubuntu 12.04 > > > > I finished up spending about 2 weeks backing up, restoring, changing to > > Ubuntu 14.04 hoping that would solve the problem but it didn't. > > > > What I found was that everything worked fine with 0.9.6 but rendering > small > > clips with 0.9.10 took twice the time. Larger clips just seemed to clog > up > > and die. > > > > After a lot of investigation I found out that it is the MLT rendering > > profiles which are causing the problems. In 0.9.6 the typical profile for > > an MPEG2 file render was :- > > > > > > f=mpeg acodec=mp2 ab=%audiobitrate+'k' ar=48000 vcodec=mpeg2video > minrate=0 > > vb=%bitrate+'k' bf=2 b_strategy=1 trellis=1 aspect=%dar pass=%passesWhere > > in 0.9.10 the number of profiles was significantly reduced and the number > > of parameters has substantially reduced, the main culprit being the > > replacement 0f "f=mpeg" for "properties = MPEG-2" or something like > that, I > > no longer have 0.9.10 loaded having gone back to 0.9.6 so I cant remember > > exactly what the MLT parameters are. > > > > The main problem is that the new profile takes at least twice as long to > > render, but when the script is running it provides an estimated time > > remaing which counts down (slowly) and then seems to stop at just a few > > seconds remaining or 0 remaining where it sits for about the same time > > again as the rendering all ready took. For short clips this is just an > > incovenience but for longer clips it can sit there apparently frozen for > > hours. > > Maintaining profiles for the many file formats supported by Kdenlive is > not an > easy task. So at some point, before the 0.9.10 release, it was decided to > switch to the profiles provided by MLT with some minor customization. > > The MLT presets are simple text files with FFmpeg properties, that are > installed in: > $INSTALL_DIR/share/mlt/presets/consumer/avformat > > I did some tests with the MPEG-2 profile, and you are right, it takes > almost > twice the time to render, compared to the older settings. > > The difference is in some parameters set in the MLT preset: > mbd=rd > cmp=satd > subcmp=satd > > This is probably supposed to enhance quality, but as you noticed, you can > > yes http://www.ffmpeg.org/faq.html#Which-are-good-parameters-for-encoding-high-quality-MPEG_002d1_002fMPEG_002d2_003f
-- +-DRD-+ -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.kde.org/pipermail/kdenlive/attachments/20150123/33e3a8e4/attachment.html>
