First of all, thanks again for maintaining kdenlive.

I love how expressive and open it is.

The main reason I'm writing is to humbly suggest an improvement.

When asked to render to the .webm format, kdenlive currently passes

    acodec=vorbis
    
to melt.

I saw it in a kind of log file named something like

    <output-file-name>,webm.txt

Maybe the line of kdenlive's source code is

    https://github.com/KDE/kdenlive/blob/640d4467558db92b5d2dbcc0baaf74a4a5f664c2/data/profiles.xml#L6

But but but!

Rendering to .webm, crashes!

My original bug report is at

    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=884268

Why does it crash?

ffmpeg's web site says the vorbis audio encoder 

    a.) is experimental and 

    b.) not recommended.

You can see this is so by searching for 

    "Please note it is not recommended to use the experimental vorbis for Vorbis encoding; use libvorbis instead."

at

    https://trac.ffmpeg.org/wiki/Encode/HighQualityAudio#AudioencodersFFmpegcanuse

I tried it..

I changed line 6 of

    /usr/share/kdenlive/export/profiles.xml

from

   acodec=vorbis

to

   acodec=libvorbis

It worked!

It rendered to .webm!

Maybe you should change it too.

Thanks again,
Kingsley

PS: Someone using the nick name "furq" on freenode's #ffmpeg channel was the source of much of the above info. furq also seemed to think kdenlive really should be using libopus. I tested it. It didn't seg fault. But the video was silent. I didn't try libopus again, but furq suggested changing quality=good and aq=%audioquality, using something like -ab 128k, and said he didn't know what -quality good even does. He'd never heard of it.