van Bijleveld Christian (ST-CO/ENG1.3)
2012-Nov-28 08:31 UTC
[opus] Hybrid mode and Packet Loss Concealment
Hello, I am testing OPUS via the opus-tools package opus-tools-0.1.5-win32 (command line tool). I have a question regarding hybrid mode: - I am using as input a 48 KHz sampling rate speech file, thus full band speech. I have tested several bitrates and frame sizes. According to the documentation, OPUS codec will work in hybrid mode when frame sizes of 10 or 20 ms are used, and bitrates from 40Kbps and above. However, the configuration info generated by the tool says that packets are coded either in LP mode (SILK) or MDCT mode (CELT), and I cannot see any reference to hybrid mode. Further reading the documentation, it says that the codec mode depends on, among others, the type of signal (speech vs. music) and that currently this parameter needs to be provided to the application (no automatic detection). I understand from this that by default, OPUS works in music mode. But there is no means to set the parameter to speech at least via a command line flag. How can OPUS be configured to work in speech mode for full band audio? I also have a question regarding Packet Loss Concealment in hybrid mode: - the documentation describes (section 4.4) a PLC method for CELT mode and one for SILK mode. What is the PLC algorithm when OPUS works in hybrid mode? Thanks in advance. Met vriendelijke groeten | Best Regards, Christian van Bijleveld Bosch Security Systems BV Bosch Communications Systems, BL Public Address and Conference Systems (ST-CO/ENG1.3) P.O. Box 80 002 5600 JB Eindhoven The Netherlands www.boschsecurity.com<http://www.boschsecurity.com> T. +31 (0)40 257 7076 F. +31 (0)40 257 7091 christian.vanbijleveld at nl.bosch.com<mailto:christian.vanbijleveld at nl.bosch.com> -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/opus/attachments/20121128/9b9bb981/attachment.htm
On 12-11-28 03:31 AM, van Bijleveld Christian (ST-CO/ENG1.3) wrote:> * I am using as input a 48 KHz sampling rate speech file, thus full > band speech. I have tested several bitrates and frame sizes. > According to the documentation, OPUS codec will work in hybrid mode > when frame sizes of 10 or 20 ms are used, and bitrates from 40Kbps > and above. However, the configuration info generated by the tool > says that packets are coded either in LP mode (SILK) or MDCT mode > (CELT), and I cannot see any reference to hybrid mode. Further > reading the documentation, it says that the codec mode depends on, > among others, the type of signal (speech vs. music) and that > currently this parameter needs to be provided to the application (no > automatic detection). I understand from this that by default, OPUS > works in music mode. But there is no means to set the parameter to > speech at least via a command line flag. How can OPUS be configured > to work in speech mode for full band audio?In general, what you probably just want to do is configure your encoder with OPUS_APPLICATION_VOIP. Otherwise, you can be more specific and do: opus_encoder_ctl(encoder_state, OPUS_SET_SIGNAL(OPUS_SIGNAL_VOICE));> I also have a question regarding Packet Loss Concealment in hybrid mode: > > * the documentation describes (section 4.4) a PLC method for CELT mode > and one for SILK mode. What is the PLC algorithm when OPUS works in > hybrid mode?Hybrid PLC :-) Jean-Marc> > Thanks in advance. > > Met vriendelijke groeten | Best Regards, > *Christian van Bijleveld > > *Bosch Security Systems BV > Bosch Communications Systems, BL Public Address and Conference Systems > (ST-CO/ENG1.3) > P.O. Box 80 002 > 5600 JB Eindhoven > The Netherlands > _www.bosch__security.com_ <http://www.boschsecurity.com> > T. +31 (0)40 257 7076 > F. +31 (0)40 257 7091 > _christian.vanbijleveld at nl.bosch.com_ > <mailto:christian.vanbijleveld at nl.bosch.com> > > > > > > _______________________________________________ > opus mailing list > opus at xiph.org > http://lists.xiph.org/mailman/listinfo/opus >