Hi Paul,
I think the issue you're seeing here is simply the overhead of the IP
(20 bytes) and UDP (8 bytes) headers (plus our 8-byte timestamp/header).
With a frame size of 256 at 48 kHz, you send 188 packets/sec, which
means about 45 kbit/s of header overhead. Depending on how you're
measuring, you may be seeing the Ethernet overhead of something like
that. All I can assure you is that when you ask CELT for 43 bytes, this
is *exactly* what you receive. Does that explain the numbers you have?
Cheers,
Jean-Marc
Paul Sykes a ?crit :> Hi,
>
> The default settings for celtclient are:-
>
> Sampling rate 48000
> Frame size 256
> Packet size 43
>
> According to my calculations this should give a bitrate of 64kbit/sec +
> a little extra for the 32bit time stamp and 4 null byte pseudo header.
>
> Using vnstat I was very surprised to see that it was reporting a bitrate
> usage of around 16kbyte/sec which is 128kbit/sec, double what I was
> expecting.
>
> I then changed packet size to 86 which I expected should give a bitrate
> of 128kbit/sec, vnstat said I was using 24kbyte/sec which is 192kbit/sec
>
> I then changed packet size to 128, I expected to see a bitrate of
> 192kbit/sec, vnstat gave me a bitrate of 32kbyte/sec which is
> 256kbit/sec
>
> Therefore all measurements were 64kbit/sec greater than I anticipated,
> can somebody tell me why, or I have got something wrong here?
>
> thank you,
> Paul.
>
>
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