Hi,
The only rates now supported are 1200. 1500 and 2400bps. The bits per frame
are as follows:
1200 - 48
1400 - 56
2400 - 48
So, the delay per frame would be at least 40ms for 1200 and 1400. 20ms for
2400.
Any look ahead is not handled by codec2 itself, but by whatever transport
is used. However, since the bitrate must be maintained, unless there is
interleaving performed over multiple voice frames, then the delay will not
be increased by any more than the time to transmit that frame. So probably
the same delay again, 40ms or 20ms (total 80ms or 40ms).
If we're talking about FDMDV, David would need to have the final word, but
my understanding is that it actually sends the frames in two blocks of one
half of a frame each. However I expect it has to have an entire frame to
deliver before it can start, but I can't be sure. So, the total delay
should likely be 80ms under perfect circumstances. But, often there will be
some level of buffering in the buffer sent to the sound card. That part we
can't answer I suspect (maybe someone on list does know?)
Hope I've been of some level of help at least.
Peter, M6DGI.
On 22 August 2012 12:30, YO8RNA <[email protected]> wrote:
> Hi,
>
> I am trying to put together some details about Codec2.
> For now I am looking into the delays of the Codec2 per bitrates.
> As far as I understood for bitrates of 1400 &1200, the frame delay is
> 40ms, but I don't know the look-ahead (if any), therefore I can't find the
> total algorithmic delay.
> For 2000bps and above the framedelay is 20ms, but again, I need to figure
> out the total delay.
>
> Can anyone help here?
>
> For those who can read html emails, here is a table:
> Name Bit Rate (bps) FrameDelay (ms) *look-ahead delay (ms)*
> Total Algorithmic delay (ms)
>
> Codec2 2500 bps 20ms? ?
> ??
> Codec2 2400 bps 20ms? ?
> ??
> Codec2
> 2000 bps
> 20ms?
> ?
> ??
> *Codec2* *1500 bps* *40ms* *?
> **??
> * *Codec2* *1400 bps (56bit each 40ms)
> **40ms* *??
> **??
> * *Codec2* *1200 bps* *?
> **??
> **??
> *
>
> 73,
> yo8rna
>
>
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Freetel-codec2 mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/freetel-codec2
>
>
------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions
will include endpoint security, mobile security and the latest in malware
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
Freetel-codec2 mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
