Re: [Freetel-codec2] Improving quality of Codec2 playback
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 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 ___ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
Re: [Freetel-codec2] Improving quality of Codec2 playback
Hello, I'm currently using the following sox equalizing statement (male speech) before feeding freedv_tx on RaspberryPI (cheap dongle soundcards) : [...] compand 0.02,0.20 5:-60,-40,-10 -5 -90 0.1 During preliminary tests made on April 2019 700C and 700D versions, I found a strong improvement of the quality of the transmitted speech. Not verified again on the current freedv flavors. 73, IU1IPB Ugo -Original Message- From: David Rowe Sent: martedì 10 settembre 2019 22:14 To: freetel-codec2@lists.sourceforge.net Subject: Re: [Freetel-codec2] Improving quality of Codec2 playback 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 ___ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
Re: [Freetel-codec2] Improving quality of Codec2 playback
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
Re: [Freetel-codec2] Improving quality of Codec2 playback
Good work Adrian... I have heard that people have used codec2 to go to 450 bits/sec too... That's the reason I praisa David Rowe alot... His open source work has been a gift for many researchers to play their role in innovations.. On Tue, Sep 10, 2019 at 4:56 PM 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
Re: [Freetel-codec2] Improving quality of Codec2 playback
> 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
