[M4IF Technotes] FGS truncated bitstream

[Lucia]

Good morning everybody,
I've got a question to ask, apologizing in advantage for my mistakes( i'm new
in video coding).
Suppose we are doing video streaming. When using FGS in the encoding process,
it is possible for the server to truncate the enhancement layer in order to
match the outgoing bit-rate with the channel capacity variations.
Now, i wonder how to truncate the bitstream.  I mean, suppose either
1)	 we stored in the server different files, matching different bit-rates
	(i.e. with EL of different lenghts) or
2)	we have a unique file and the server makes a control on the bitstream and
	bit-rate as to truncate the EL at the right point.
In both cases (i think the first is the most realistic, is it?) we  need to
determine the right point to truncate the bitstream: how can we estabilish
 it?
I've read that there is no standardization on how to decode a truncated
bit-stream, but is there a standardization on how to truncate a bitstream
(for example should we transmit all the (RUN,EOP) symbols in a bit-plane, or
we can truncate the stream not only between two bit-planes, but also inside a
single bit-plane)?
Or is the choose on how to truncate the bitstream laying just on the bit-rate
evaluation during the coding phase or the transmission phase?
i mean, if i know a channel capacity of 32Kbps and i have an output frame
rate of 10 Frame/s i know i have to code each frame with an average of 3200
bits......if i impose a rate control on the base layer such that it is coded
with 2000 bits in average, i know i have to cut the FGS-EL after 1200 bits in
average, depending the exact value on the actual number of bits i use, right?
If there is a standardization, is it in the system part? (nothing is said
about in the video part i have......) and where can i download that part of
the standard?
Thanks in advantage.
Lucia Valentini