Analysis of information sources in references of the Wikipedia article "Betamovie" in English language version.
[04:36] [Design meant] [head] drum could be much smaller, and the tape transport could be [shrunk] [but problem is] although the tape is wrapped most of the way around the drum, there is still a gap. The head can't possibly make a seamless video signal
[06:38] Actual distance the head travels along the tape with each sweep is the same as a normal VCR. It will line up perfectly with the head surface once it's inside a full size Beta VCR [..] But that gap means that the head is travelling a longer distance with each rotation [thus] the head itself travels the distance with a tape-to-head speed that's about 20% too fast
[07:32] [Solution to gap is] sampling the picture tube at 625 lines, the gap from the Betamovie head will routinely throw out 100 [leaving] the 525 you need [thus] head's higher speed when recording becomes cancelled out. [Image isn't lost since extra overscan lines] are pretty much just black.
[08:23] [Betamovie's design means that] the gap is only there when recording [and] when the tape is played back on a normal VCR, there are no gaps at all.
[08:42] because the tape-to-head speed is a little bit slower in the VCR, that 18.8 kHz [recorded signal] automatically [becomes a standard] 15.7 kHz signal [on playback]
[09:08] This video trickery enabled the Betamovie to be remarkably small for its time, while producing recordings that were compatible with your favorite Beta VCR [however it also meant that] Betamovie cannot play back its own recordings
[15:36] the only people who could use a Betamovie were the same people who already had a Betamax VCR. This camera is of literally no use [otherwise]
