digitalfreaknyc said:

13mbps is MORE than enough to capture broadcast signals. Remember, broadcast is mpeg-2 but it's being re-compressed in AVC, which is MUCH more efficient.

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And, again, the Hauppauge is the only viable and realistic option for getting phenomenal results with 5.1 sound.

The best features of AVC aren't employed by realtime capture devices, since they would require additional processing time and buffering.

There are some other options for 5.1 sound, but I understand why you are saying "realistic".