Since the first Mac Pro we've been using Black Magic Design's hardware to add video grabbing in Photoshop. However, we might go for iMacs now, and there are no room for internal cards, so we will have to go for a Thunderbolt solution.
The workflow is pretty simple: We select a video from our play out server, that is routed through SDI to the Mac Pro's BMD card. In Photoshop we have an action that will grab a frame and composite it with an overlay and save it to a playout computer.
Has anyone any ideas if this kind of funcitonality is available in AJA's or Matrox's Thunderbolt offerings? I'm pretty sure BMD has it on their offerings, but I would like to have some options, and from Matrox's site it seems that there is no such possibility on at least those products I've looked through (MXO2).
BTW, we work in SD over SDI with embedded sound, but will upgrade to HD, so it has to be future "proof". But most video is delivered as files, so grabbing video is mostly done through ingest hardware.