Kdenlive and MLT nvenc enabled

[Evert Vorster]

This piqued my interest.
Kdenlive does not appear to have a problem with a custom profile that calls
for a hardware encoder.

To create custom render profiles in kdenlive, just hit the "create new
profile" button in the render dialog. (No idea why you can't edit your
render dialogs in the settings menu, but there you go.)

I created a custom profile for hardware hevc encoding:
properties=x265-medium f=matroska vcodec=hevc_nvenc acodec=aac crf=%quality
ab=%audiobitrate+'k'

I had to clear out the speed options box, as the hardware encoder does not
have a concept of speed, and then I get this output in the render dialog:

NVIDIA: no NVIDIA devices found
[hevc_nvenc @ 0x7f265000c5e0] Cannot init CUDA

So, the profile passes along the requested video encoder, but of course I
don't have the right hardware on hand to actually encode anything.

In short, it appears to work without too much modification.
what is '-c:v ' in ffmpeg terms becomes 'vcodec=' in mlt terms, so you will
probably use 'vcodec=h264_nvenc' for hardware h264 video encode.

Tell us how you get on, please?

-Evert Vorster-

On 20 April 2017 at 02:44, Evert Vorster <evorster at gmail.com> wrote:

> Hi there.
>
> I also transcode a lot of older video to x265 on my nVidia GTX 960 using
> nvenc, and using the ffmpeg and the hardware encoder does make about an
> order of magnitude difference on framerate during encoding.
>
> To achieve this on Arch, I had to install ffmpeg-nvenc from aur, and have
> the right hardware, of course.
> I believe that mlt should pass through ffmpeg options, so if ffmpeg
> supports it, mlt should too, without the need to recompile. Unfortunately I
> am now far away from home, and my linux is running in a virtual machine and
> I won't be able to test it for a couple of weeks. In Arch, at least,
> mlt-git optionally depends on ffmpeg-nvenc, so in the worst case you might
> have to recompile that, too.
>
> Once the foundation is in place, it should be simple enough to have
> kdenlive allow libnvenc in the rendering profiles. File a bug report saying
> that kdenlive does not support all the encoders that mlt supports, and
> point to the thread above. Be warned that you will have to do a lot of
> troubleshooting on your own if using libnvenc breaks things for you. You
> can even follow the same actions and generate a script from kdenlive, and
> modify the encoder yourself and see if it works for you.
>
> Kind regards,
> Evert Vorster
>
> On 19 April 2017 at 13:51, ricciolo9 . <luca.ricciolo at gmail.com> wrote:
>
>> Hi guys. I compiled ffmpeg with the nvenc enabled to encode h264 and h265
>> videos using my nvidia gtx 1060 card.
>> I have a huge difference in transcoding 10x more. From 20/22 fps using
>> libx264 I passed to about 220/230 fps using nvenc.
>> Ok my Cpu is only an i5 750 and for my pc the GPU makes the difference.
>> Now I use a profile on kdenlive for transcode and resize the proxy clip
>> using ffmpeg nvenc enable with an improvement of more than 2x vs my CPU
>> with libx264.
>>
>> So I ask at the MLT mailing list if I can use this encoding power in
>> rendering using MLT. Maybe compiling it with the ffmpeg nvenc enabled.
>> And they found this 2015 discussion.
>>
>> https://forum.kde.org/viewtopic.php?f=272&t=125304#p330864
>>
>> It seems that someone compiled MLT with nvenc enabled on ffmpeg and works.
>>  But the render dialogue of the Kdenlive doesn't permit the libnvenc
>> option.
>>
>> They talk about an improvement of 6x on MLT using nvenc. On 2015 doesn't
>> exists my nvidia gtx 1060 and I don't know the CPU and the GPU used on the
>> test but could be always a very good improvement.
>>
>> Someone tried to use a compiled MLT version with nvenc on Kdenlive?
>>
>> Thanks.
>>
>
>
>
> --
> Evert Vorster
> Isometrix Acquistion Superchief
>
>


-- 
Evert Vorster
Isometrix Acquistion Superchief
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