[mythtv-users] HD PVR: What does "13.5 Mbps" mean?

[Yeechang Lee]

We'd heard back in January that the Hauppauge HD PVR device allegedly
could handle up to 25Mbps and so could encode 1080p (Blu-ray) video.
However, the description now claims "up to 1080i," and in the official
specifications
(<URL:http://www.hauppauge.com/site/products/hd_pvr.html>), we see

# Hardware encoder
    * H.264 AVCHD video encoder
    * Datarates from 1Mbit/sec to 13.5 Mbits/sec

What could these datarates mean in this case? The maximum bitrate of
the component-input video it accepts, or the maximum bitrate of the
h.264 files it spits out? If the former, what does this imply about
the device's ability to properly capture the full breadth of 1080i
19.39Mbps input?[1] If the latter, is a 13.5Mbps h.264 recording
really sufficient to capture the full quality of 19.39Mbps MPEG-2?[2]

[1] I don't have a Blu-ray player so all I need is 1080i.
[2] I am told that h.264's vaunted efficiency versus MPEG-2 is mainly
at lower bitrates, and that the relative efficiency decreases
significantly at higher bitrates, to something like only 25% better.

-- 
Frontend:		P4 3.0GHz, 1.5TB software RAID 5 array
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