Currently live555MediaServer requires CBR or near-CBR files when
streaming from MPEG-TS. The explanation I've read on the list is that
this is because it makes determining the pacing of frame delivery
easier. As I understand it, the server has an internal model of the
video bit rate, and it can get behind if its model differs greatly from
the reality.
The problem, of course, is that VBR is increasingly the rule, and CBR
the exception. VBR better models the nature of video, and newer
encoding technologies are only increasing the variability. H.264 tends
to have longer GOPs and a higher ratio of B pictures than MPEG-2, for
example.
For example, I have here a 1.4 Mbit/s VBR H.264 + AAC TS file that must
be padded out to 3.7 Mbit/s to get it to stream smoothly because it has
peaks to 4.2 Mbit/s. That's 164% overhead.
My question is, couldn't the server's model of the video file's bit rate
be greatly improved by looking at the index file? That implicitly tells
you the video's bit rate at every point.
(Ross, I will be sending you a link to this 1.4 Mbit/s file off-list.)
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