I was wanting to get a video card for my computer that has hdmi to hook up to my 720p tv. And was trying to find out what I need to look for in a video card to carry both video and audio
Look for cards that have an S/PDIF input. These cards will come with the loop cable that is necessary. Also, your motherboard has to have an S/PDIF connector also.
NVIDIA: You have to connect the card to an audio source (sound card/motherboard) using a 2-pin SPDIF header. You get all sound formats the SPDIF can carry (2.0 PCM, Dolby Digital, DTS)
ATI: A sound chip is installed on the card. You get all uncompressed sound formats (2.0, 5.1, and 7.1 PCM)