Diego Alejandro Parra Guzman
2017-Oct-10 11:10 UTC
[opus] SILK-implementation some questions
Dear all: I want to formulate couple of questions about SILK codec: 1. I've seen the documentation to the SILK codec that is part of the OPUS exactly the paper with title "The opus codec voice coding with opus, and the "RFC 6716 specification of opus" . Well, I detected that in both is defined a High-Pass filter as part of SILK; however in the paper you put the following description: PAPER: " A high-pass (HP) filter with a variable cut frequency between 60 and 100 Hz" while form the other hand in the RFC 6716 is defined as: RFC 6716: "This is a second order Auto Regressive Moving Average (i.e., with poles and zeros) filter with a cut-off frequency around 50 Hz" and actually both of them are implemented one is in the function silk_Encode @enc_API file, and the second is in the function hp_cutoff @opus_encoder file. Therefore I'm right to guess that you are using both ? and what should be the most convenient reference to follow the implementation of OPUS and it is components such as CELT and SILK ? 2. according to and just to clarify : +----------+ +--------+ +---------+ | Sample | | Stereo | | SILK | ------>| Rate |--->| Mixing |--->| Core |----------> Input |Conversion| | | | Encoder | Bitstream +----------+ +--------+ +---------+ Figure 21: SILK Encoder I want to known if effectively the sample rate conversion and stereo mixing have been implemented directly in the SILK core encoder or instead both/or one were implemented independently? and where they are allocated in the code ?. I request for your help since we are working to improve OPUS in such as way that it could be supported in very constrained devices and in low power consumption local networks such as Bluetooth LE. thanks so much Best regards Diego A parra guzman. -- Diego Alejandro Parra Guzmán Estudiante de ingeniería electrónica Universidad distrital FJC -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.xiph.org/pipermail/opus/attachments/20171010/9e30e151/attachment.html>