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Rendering with high bitrate

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peterk
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Rendering with high bitrate

Sat Jun 21, 2014 6:53 pm
Hi,

Firstly I would like to welcome everyone as this is my first post. I'm Kdenlive big fan and user over a year! :-) All questions I have before I could resolv just with reading this forum :-)

But let's talk about the problem.

I do have 4K camera and I'm recording video at MP4 with about 100mbps .
I have created my own profile with correct resolution, frame rate.
The problem is when I try to render my project.
I can render it with 50mbps bitrate, I can render it 70 mbps bitrate but anythin above 80mbps bitrate crashes.
And it doesn crash with any error, Kdenlive says he's finished rendering but rendred file is empty and whole process takes few seconds.

I tryed to render to script and than run script to see if there's any output but no.
Any suggestions? I had errors before so I would recognize them ;-)

I do have Version 0.9.8 64bit, melt 0.9.0.
TheDiveO
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Re: Rendering with high bitrate

Sun Jun 22, 2014 7:02 am
This is probably an upstream issue. Kdenlive doesn't do the rendering and encoding itself but instead relies on mlt, ffmpeg and several encoding libs. So you'll need to report your issue with mlt, ffmpeg, or libx264 (which may be the culprit or not).

On a side note: if I'm reading your settings correctly, why do you need to render with 100MBytes/s? The render dialog of Kdenlive is in kbytes/s to the best of my knowledge. An 802.3 link Fast Ethernet won't be able to carry your video stream and I doubt that there are any displays out there with 4k frame size that can render such enormous bitrates. So I'm curious to learn what your application might be... ???
peterk
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Re: Rendering with high bitrate

Sun Jun 22, 2014 8:39 am
I have high bitrate input material (directly from camera) and I want to modify it without quality loss.
I found that even though I managed to render 80mbps it's corrupted with errors (artefacts?) and it's not playable :(

Any suggestions?
assadaf
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Re: Rendering with high bitrate

Mon Jul 14, 2014 4:09 pm
Hello

I ran into similar problem i.e. high bitrate footage, that my h/w is inadequate for my hacked Lumix GH2 (44mbps, all intra frames). I tried RAID0 (striped) with 2 SATA drives, also a HD buffered with bcache (10gb SSD partition), but found them both still too slow for processing the footage.

I then realised and tested, that if I do:

find . -name "*.MTS" -exec ffmpeg -y -i {} {}.mp4 \;

the files (*.MTS.mp4) resulted are some 2-3% in size of the original footage, but still having very good image quality. All the details are not there, naturally, but good enough to my eye for editing.

I do the editing using these mp4 files - and render them for test purposes as well. Then, when I want the final rendering, I save the render script(s) instead of doing actual rendering, edit the project file(s) replacing the clip file names e.g. filename.MTS.mp4 -> filename.MTS and launch the renderer script from the command line i.e. it then applies all the effects etc. to the original files instead of light weight mp4 clips.

Looked pretty good to me. I could actually do the editing with an ten years old laptop and perform the final rendering using monster rack server at work - no need to listen to the fan going mad at home, just rsynced the footage et al to the server and hey ho, there it roar.

kdenlive <3

Anyone else tried this method?

--Assa
TheDiveO
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Re: Rendering with high bitrate

Mon Jul 14, 2014 5:13 pm
Assa, have you read the manual about "proxy clips"? These are exactly for the purpose of transparently working with lower-bitrate clips while rendering with the original high-bitrate clips.
assadaf
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Re: Rendering with high bitrate

Mon Jul 14, 2014 5:50 pm
Hey

Sorry, did not read this bit of important info. This is exactly what I wanted. Works as fast as with mp4s.

A perfect job once again!

Cheers,
--Assa


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