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23.976 render pipeline question

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Mon, 02/07/2011 - 06:51
#1
zontar
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23.976 render pipeline question

Hi there,

Wondering if someone can spot me here - new to kdenlive...

I'm starting with 23.976 AVCHD files (from a Panasconic GH2) which I'm knocking down to 740x480 mjpeg for easy
handling on a slow computer (I know there are many options for this, mjpeg works for me right now). The mjpeg
files play perfectly in mplayer, and mplayer identifies the files as 23.976.

I've created a custom project profile using 23.976 as the frame rate, and cut together a sequence using the 23.976 mjpeg clips.
When I try to render using H.264 presets, the resulting file is 24fps according to mplayer. Audio is drifting.

If I copy/edit a render profile using r=23.976, I still get H.264 files which identify themselves as 24fps. And audio is still drifting.
How can I force H.264 encoding to use 23.976? Or should I be correcting to 24 fps prior to kdenlive ingestion?

Thanks!

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Wed, 02/16/2011 - 09:51
#2
ddennedy
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Re: 23.976 render pipeline question

It works for me; I just did a test. So maybe it is due to some version of kdenlive or ffmpeg/x264. I think some recent version of kdenlive changed the project setting dialog's frame rate from floating point to numerator / denominator, and possibly the older floating point version has some bad effect. You can try r=@24000/1001 .

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Thu, 02/17/2011 - 01:27
#3
zontar
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Re: 23.976 render pipeline question

Love to know which versions you're working with so I can use the same -

I'm on Kdenlive 0.7.8, ffmpeg SVN-r25767, x264 20101029. Project setting frame rate 24000/1001.

Render Settings:
f=mp4 hq=1 acodec=aac ab=128k ar=48000 pix_fmt=yuv420p vcodec=libx264 minrate=0 b=1000k b_strategy=1 r=@24000/1001 subcmp=2 cmp=2 coder=1 flags=+loop flags2=dct8x8 qmax=51 subq=7 qmin=10 qcomp=0.6 qdiff=4 trellis=1 aspect=%dar

Mplayer reports rendered video as:

VIDEO: [H264] 1280x720 24bpp 24.000 fps 1044.0 kbps (127.4 kbyte/s)

Thanks again for any insights/info

(In the first post I said 740x480 sizing, meant 1280x720)

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Sun, 02/20/2011 - 01:19
#4
ddennedy
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Re: 23.976 render pipeline question

I tested with x264 0.85.1448+git1a6d32-4 (some circa v85 git snapshot). It is what is on my Ubuntu 10.04-based KXStudio. My libavformat is 0.6.1 - also from 10.04 package.
As a developer, I always run latest git versions of MLT and Kdenlive, and occasionally I test specific things against git versions of ffmpeg and x264.
You need to make sure your mlt was built against the version of ffmpeg that you have installed. Also, ffmpeg needs to be built against the version of x264 installed. You can not independently upgrade components. Sometimes packaging systems get this wrong and not just folks building from source.

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