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ps_process_raw() usage

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y_orlov
2011-02-01
2012-09-22
  • y_orlov

    y_orlov - 2011-02-01

    Hi, I am comparing the whole audio utterance decoding and continuous streaming
    mode and have quite different results on the same acoustic, language model and
    decoder.
    In the first case I am using just one call of the ps_process_raw(self, data,
    data_length, no_search, TRUE) method
    In the second case I am calling ps_process_raw(self, shorts, nshorts,
    no_search, FALSE) several times passing pieces of the whole utterance.
    What can be a problem?
    The first case gives me good recognition result and the second gives quite
    poor results, which are not always consistent.

     
  • Nickolay V. Shmyrev

    Hello

    The difference between both types of ps_process is the following. On full
    process it just builds features from the whole utterance and then decodes. On
    partial processing it builds features from the submitted data and remembers
    them for further processing when full processing will be invoked. It might be
    that since the number of samples is not a product of window size it calculates
    features differently. I suggest you to dump features and compare them.

     
  • Pankaj

    Pankaj - 2011-02-18

    Hello,

    Even I have observed the same thing that feature calculation is different in
    whole utterance decoding and continuous streaming mode. While tracing the code
    I observed that by CMN calculation happens differently in the two modes. In
    whole utterance decoding the default CMN mode is CMN_CURRENT while for
    continous streaming mode it is CMN_PRIOR. In CMN_CURRENT mode the mean of the
    entire current utterance is taken for normalization, while in CMN_PRIOR the
    normalization starts with some user defined initial value and is updated at
    the end of every utterance. This updated value then serves as the initial mean
    value for the next utterance. This might be the reason or one of the reasons
    for difference in features

     

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