IPTV, VoiceOver and spoken subtitles

Just found this Channels thing and it does sure look exciting to try.

But before I do, I have an accessibility (a11y) question to you VoiceOver users.

If I use Channels with my IPTV-provider, will I have the subtitles read out loud on any TV-channel when I use the Channels app and VoiceOver? That's if the TV-channel provides subtitles.