Transcoding Benchmarks

Abstract

Odin TeleSystems provides boards with pre-installed and pre-configured vocoders. They are also available with the OTX XDM SDK.

RtpBridge Supported Codecs List

• G.711 (a-law, u-law) / G.711.1 / G.711.2
• G.723
• G.726
• G.729
• GSM-FR
• G.722 / G.722.1 / G.722.2 (AMR-WB)
• AMR-NB

Basics of the Transcoding

The RtpBridge supports the transcoding operation (data converting from one codec to another as softswitch) by the following scheme:

CodecA -> linear PCM16 -> CodecB

The RtpBridge allows to implement transcoding operation of the listed above codecs fully. Note that it is possible any combination between these codecs as in RTP channels so in TDM channels.

The transcoding operations are offloaded to powerful C64+ DSP core (4700 MIPS) of the TI DM64XX SoC processors without increasing the load of ARM core. So the total number of transcoding channels can be determined by resource-intensiveness of encoding / decoding algorithms in accordance with the selected pair of codecs. Below are the benchmark results to judge the availability and number of channels and CPU.

Available Voice Codecs benchmarks

• Synthetic testing results of encoding / decoding operations
• Overall testing results with account of incoming and outgoing RTP connections and jitter
• Number of encoding / decoding channels
• TI C64+ DSP Core Load Tests in various Encoding/Decoding Scenarios

So the Alvis powered by the RtpBridge can successfully offload x86 servers increasing the compactness of solution. This makes possible to create low power-consumption devices as a breeze!