Hi David, Yes, aware of equalizer in Freedv, however I'm just using libcodec2 directly. I can send you A/B samples later, sure. I was used to my voice sounding bad with artefacts on 1400, and was very surprised that 1400 can sound natural and smooth. Much better than Ambe at just 1400 bits.
On September 10, 2019 8:13:42 PM UTC, David Rowe <da...@rowetel.com> wrote: >Hi Adrian, > >Yes quite a few Ham using FreeDV use filtering and EQ to improve the >speech quality, e.g. using external EQ boxes. We also have a >microphone >and speaker equaliser in FreeDV, plus some noise reduction. More >recently, I have been working on automatic equalisation of input speech >to improve vector quantisation of Codec 2 700C: > > http://www.rowetel.com/?p=6860 > >BTW there are many Codec 2 modes, but the ones in widespread use in >FreeDV modes are: > >FreeDV 1600: Codec 2 1300 >FreeDV 700C/700D: Codec 2 700C > >I listened to you sample but am unsure if it was before or after your >processing, Do you have A/B samples to compare? > >Cheers, >David > >On 10/09/19 21:25, Adrian Musceac wrote: >> >> Hi David, >> I think I can slightly improve the quality of playback of Codec2 >> samples with some rather computationally cheap methods. This >might >> be of use to you for FreeDV. >> Please have a listen at the sample attached, which is Codec2 at >1400 >> bits/s. >> Link included in case the attachment doesn't go through: >> http://qradiolink.org/images/codec2_1400.wav >> The trick is a little filtering, emphasis and a little audio >> compression applied. >> I have some pathological Codec2 samples recorded with my voice >that >> are really improved with this method. If you want I can send them >to >> you. >> Noisy samples have a little problem with the compressor driving >too >> early and bringing out the noise, so I think I can still do some >> adjusting there. >> Codec2 700B is different though, I have to adjust the filters and >> emphasis because I get some aliasing of higher frequencies. >> >> Adrian >> >> >> It seems my previous message got stuck because of the attachment, so >I'm >> including just the link to the Codec2 sample. >> >> >> >> >> _______________________________________________ >> Freetel-codec2 mailing list >> Freetel-codec2@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> > > >_______________________________________________ >Freetel-codec2 mailing list >Freetel-codec2@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/freetel-codec2
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