topic Speech coding sources: filters in Intel® Integrated Performance Primitives

Speech coding sources: filters

ligoban — Mon, 27 Nov 2006 20:54:36 GMT

In the Speech coding source code there is USC_Modes structure defined. This structure has 2 filter on/off flags: high pass filter and post filter. Where can I get more information about this filters (cutoff frequency etc.)? I wish not to read the source very deep.

Thanks.

Re: Speech coding sources: filters

Vyacheslav_Baranniko — Tue, 28 Nov 2006 15:22:41 GMT

USC is a wrapper interface for various speech codecssome of which optionally may dopre- and post- filtering, like for example ITU G729, G723.1codecs.Thesemodes/flags are not USC specific rather a specific flag of the codec underneath and may not be supported by some USC codec.

Re: Speech coding sources: filters

ligoban — Tue, 28 Nov 2006 15:50:45 GMT

Thank you.

The other question: I need to amplify speech frequencies (1 kHz - 3 kHz). Are filters of 729 and 723 vocoders suitable for it? I mean what is the cutoff frequency for vocoders that supports high-pass filtering?

Does the postfiltering operation the same as described in the ITU recomendations?

Re: Speech coding sources: filters

ligoban — Mon, 04 Dec 2006 22:48:04 GMT

Still got no response :(

Re: Speech coding sources: filters

Vyacheslav_Baranniko — Wed, 13 Dec 2006 20:34:40 GMT

The G729high pass filters cutoff =140 Hz for encoder (pre-processing, ITU G.729, 3.1) and 100 Hz for decoder (4.2.5).

G723.1 high pass filtercutoff is small <7 Hz, basicallyDC removal.