Consider moviepy

[rkdarst]

Idea from chat, credit to the author there: https://coderefinery.zulipchat.com/#narrow/stream/141114-help/topic/adding.20an.20intro.20slide.20to.20a.20video/near/274352859

from moviepy.editor import *
clip = VideoFileClip(f_video).subclip(t_start=(0, 6.5))
image_clip = ImageClip(f_image).set_duration(10)
video = concatenate_videoclips([
    image_clip,
    clip
])
video.write_videofile("video_out.mp4", audio_codec="libvorbis")

What we have works, but this might make something more powerful long-term?