I'm a youtuber myself for about 2 years now, and I know that you have to use good professional software, but without the extra cramps that affect the rendering. I often change format, because it affects how fast the video is uploaded to YouTube, and it's important if you release a few videos a day. That's why you can also link to Movavi Video Converter. I already know it and I can say it hasn't let me down yet. In terms of rendering everything is also quite fast with a large number of formats.