Hi All,
I need help with the intepretation of a parameter
in the Open Logical Channel structure.
The problem I have is when i read the AnnexF
specification. In the AnnexF chapter 10.1.1.1 there is a layout of the
logical channel structure that shall be used by the SET device for the codecs
G.711 and G.729. In the structure there is a parameter denoted "# samples".
The definition is : For codecs G.711 A law
64 kbit/s, G.711 56 kbit/s u law 64 kbit/s, ulaw 56 kbit/s and G.729
Annex A this component contains the number of samples -1 per audio packet as
defined in H.245.
The problem with this definition is that it is
not specified in that way in H.245. In H.245 it is stated that all saple based
codecs are considered as frame based with a frame length of 1 ms.
So how shall the "#samples " be interpreted
?
If it is actually samples then the maximum
value seems a bit small.
The parameter is 8 bits which gives a maximum of
256 samples. This corresponds to 32 ms in G.711.
A more reasonable interpretation would be to
consider the parameter as "frames" instead. This would then give a more
flexible range of the packet size and it would fit better with the definitions
of H.245.
Any input to clarify would be
appreciated.
Best regards
/Stefan Jung