I am the author of a couple of Inkscape movies:
Those were recorded with gvidcap. The CPU didn't look quite busy (I noticed having X in Vesa mode is better than running under nv or nvidia, nvidia was too heavy for the CPU, strange...)
I am not happy with audio quality. Many audio frames were lost. I would understand if CPU load was 90%, but it was about 30% only.
I even tried to record the sound separately in another app. Quality was perfect, file a bit larger, except the combinated video+audio went out of sync pretty early :(
Any hope for audio quality improvement?