[FFmpeg-user] Efficiently creating mp4 files while creating an animation with blender

[tuxic at posteo.de]

Hi,

for the creation of an animation with blender I want to generate
intermediate results more efficiently.

Current way of building the animation is:
Render the animation into separate images, on per frame.
Merge those images into a mp4 files with ffmpeg.
Check the result.
Correct the animation where needed.
Rerender the according range of frames.
Remerge all frames of the complete animation.
Repeat everything from "Check..." to "Repeat..." as necessary.

Since the animation has several thousands frames, the mergeing
of the frames is a task, which I want to optimize.

On the one hand: Is there any way to merge a mp4-video with
single images of frames? How can I do this?

On the other hand: I am using a PC with a Ryzen 5 3600 CPU and
a NVIDIA Corporation TU106 [GeForce RTX 2060 SUPER] graphics
card on a Gentoo Linux system.
Are there any optimisations available to utilize the graphics
card better? Are there any compiler switches, which may be
benefical?

Cheers! Merry Christmas and a happy New Year!
tuxic