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ECU buffer sizes

What is the smallest buffer size that can be used for samples?    Can a sample size of 1 be used for sample by sample echo removal?   If you can, what are the penalties for such a small buffer?   Most MIPS requirements are given for a 10ms frame.   The platform is C64+.

  • Hi peburrell,

    could you please provide what environment you are using? Which CSS, BIOS, XDCtools, Software development kits, and etc...

    I don't know what you mean with ECU Buffers.

  • The post is for the ECU (echo cancellor unit) located in the VoLIB.

    The environment is 6457, CCS4, SYS/BIOS6, XDC,VoLIB,FaxLIB, etc.

    The ECU is designed to work on a frame and process the samples using a SendIn/ReceiveIn call.   When setting up the ECU, there is a parameter that indicates the number of samples used in the framebuffer processing.   The docs and samples use a 10ms frame as the baseline.   I would like to know how small the frame size can be (maybe down to 1 sample?) and what affects to the system does it have?   One thing I would like to know is how the MIPS count is affected.

    Paul

     

  • Hi,

    The ECU operates on 2.5ms internal frames.  The input frame must be a multiple of this (20 samples). 

    The exception to this is that the ECU also supports 5.5ms frame multiples for AAL2 (multiples of 22 samples)

    Regards,
    Charlie

  • I could not get the EC to work at 2.5ms.   When I executed a ecuOpen with anything less than 5ms, I would get an exception.  

    The exception was type 2,  code 3, length 0,  with the data being 0.   Looking at the exception code, it indicated it was something to do with EXC_DELETE. 

    Can you let me know what the exception code means (a table added to the docs would be really nice).

    Thanks

    Paul

  • Hi Paul,

    Please pardon my poor memory, the ECU requires frames that are a multiple of 5ms (5.5ms for AAL2) up to 20ms (I believe).  The internal 2.5ms segmentation is merely an implementation quality and is not important to the user.

    Please let me know if you are having any other difficulty.

    Regards,
    Charlie