Opus - SILK vs CELT

Question

Hi, 
 I wish to have a complexity comparison of SILK and CELT (CPU usage and memory footprint) as I have an audio (speech) encoding and decoding application, I think this might be done already for "Smart Remote" Application. 
 Is it possible to use SILK instead of CELT to reduce bit rate along with BLE stack running in an nRF52811 or nRF52832?

Audun · Accepted Answer

No problem! 
 Sadly I don't have any updated metrics for SILK. 
 The only data point I have at hand is from several years ago that showed CPU usage in the range of 40-100% even when using SILK complexity 0. Average bitrate in this case was around 19 kbit/s, but this varies based on the audio contents. 
 Regarding SILK vs CELT for voice, I don't think CELT is a poor choice for voice, but you might be able to get lower bitrate audio with SILK at the same quality as a higher bitrate CELT stream. 
 If you haven't already, I would encourage you to evaluate different bitrate and mode combinations using for example opus-tools ( http://opus-codec.org/downloads/) using relevant audio samples. 
 (Note that opus-tools uses the floating point Opus implementation, while the SR3 implementations uses fixed point) 
 I do have some sample code that loops an audio sample through an Opus encode-decode cycle and measures RAM and CPU usage. This was used for a CELT metrics assessment, but should work for SILK as well. If you think this might be useful, I can send you an email with the code. 
 - Audun

Opus - SILK vs CELT

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