Hello Steve, Over IP you are more likely to get packet errors, i.e. one complete packet will be missing, or arrive too late to be useful.
Is Codec 2 actually of any use to anyone over IP? The RTP/UDP/IP overhead is about 8 kbit/s...... so unless you are trunking multiple channels in one packet you won't save a huge amount of total bandwidth over say g729. - David On Wed, 2012-02-15 at 07:54 -0700, Steve Strobel wrote: > On Tue, Feb 14, 2012 at 8:49 PM, David Rowe <da...@rowetel.com> wrote: > > > > 4/ Write an interleaver to re-arrange bits in a frame using a random > > pattern known to the encoder and decoder. Useful so that a few > > consecutive bit errors are spread randomly over a frame. > > It seems to me that interleaving bits like that would be especially > effective in combination with using gray code to minimize the > magnitude of the error introduced into any field by a single bit > error. Maybe that is SOP for this kind of thing, but the light just > turned on for me :) > > If interleaving the bits adds significant overhead, it might be worth > making it optional or even doing it in a separate layer (possibly > along with FEC) that could be easily disabled. I don't think > interleaving bits (or FEC) will be of any advantage when the codec2 > audio is being transported over IP, as packets with errors are > generally dropped before they ever reach the VoIP application. > > On that subject, does anyone know if packets with errors can be > captured rather than dropped by putting a network interface into > promiscuous mode or something? If so, it might be possible for errors > that are introduced in the last hop of a IP connection (WiFi, 3G) to > be corrected. There probably isn't anything we can do to get routers > to pass corrupted packets, but that might give us a shot at correcting > some errors. > > Steve > > ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
