> We need to know the processing requirement of CODEC2 because as per our > requirement > we have to complete codec2 processing(encoding and decoding both) within a > given fixed > time interrupt. please provide me some authentic statistics if you have.
The algorithm must process 80 PCM 125 usec time sample frames (10 ms) into a digital form (up to 64 bits) in the same amount of time (10 ms). So, you have an incoming frame, process it inside this frame time, and output a digital word before the next frame time, and new data arrives. Same for output, you must receive a digital word and have the 80 sample PCM ready to go in 10 ms. There is probably some overhead in interpolation of multiple frames, post-analysis, etc, that would subtract from this 10 ms figure. So, 10 ms is worse case, with better than 10 ms being desired. There's probably some profiling data around somewhere, but 10 ms seems like a long time. David has a video that shows the receiver part taking about 50% of the CPU, and he may have optimized that in the many months since it was made: https://www.youtube.com/watch?v=ATqwsYnKdmY&t=98 I think, with the addition of DMA to input/output from/to analog, the CPU would probably be in the sleep mode waiting for the next interrupt :-) Something not possible on a PC, but available on even the cheapest embedded CPU. If you take longer than 10 ms to make the conversion, then you slowly start leaving real time, and the modem will still be outputting data after you release the PTT, or stop talking. ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
