Translation:After eight hours, he finally stopped watching television.
It's never pronounced /posmi/. Commonly, it's pronounced /poosmi/, there's a weird glide connecting the two /o/'s, and it's very close to /po:smi/. Pronouncing it exactly as /po:smi/ (with a long vowel without the glide) is quite lazy and that's how it sounds here with the current text-to-speech.
Proper/careful pronunciation should be /poʔosmi/ with a glottal stop. A dialectal (common Czech) alternative is /povosmi/. Both /poʔosmi/ and /povosmi/ are more frequent in Bohemia than in Moravia.