Problem with the 'tvconv' opcode DFT mode

Date	2017-07-13 06:45
From	Nathan Holmes
Subject	Problem with the 'tvconv' opcode DFT mode
Attachments	tvconv-output.wav
	Hello, When using the new tvconv opcode, any partition size above 2 gives odd results. With sizes 4-32, there are high frequencies introduced into the output which remind me of aliasing from downsampling; and as partition size continues to increase, the output devolves into a light crackling. I attached some of the output I get from the example file doc/manual/examples/tvconv.csd, which uses a partition size of 256. In contrast, when the partition size is 1 (and thus, using the direct convolution mode instead of the DFT mode), the opcode seems to work as I'd expect. Interestingly, a size of 2 (which I believe uses DFT mode) seems to work pretty well too. It's just above 2 that things get weird. Or is this all expected behavior? I'm using Windows 7 x64 with Csound 6.09.1 Neat opcode, in any case! Nathan Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2017-07-13 10:26
From	Oeyvind Brandtsegg
Subject	Re: Problem with the 'tvconv' opcode DFT mode
	Hi Nathan, There was a bug, but it has recently been fixed in source. It seems the fix narrowly missed this binary release. There is also a related opcode 'liveconv' that allows dynamic updates to the IR and using longer IRs. Both tvconv and liveconv was developed in the context of a research project on crossadaptive modulation http://crossadaptive.hf.ntnu.no/ best Oeyvind 2017-07-13 7:45 GMT+02:00 Nathan Holmes <nholmes.composer@gmail.com>: Hello, When using the new tvconv opcode, any partition size above 2 gives odd results. With sizes 4-32, there are high frequencies introduced into the output which remind me of aliasing from downsampling; and as partition size continues to increase, the output devolves into a light crackling. I attached some of the output I get from the example file doc/manual/examples/tvconv.csd, which uses a partition size of 256. In contrast, when the partition size is 1 (and thus, using the direct convolution mode instead of the DFT mode), the opcode seems to work as I'd expect. Interestingly, a size of 2 (which I believe uses DFT mode) seems to work pretty well too. It's just above 2 that things get weird. Or is this all expected behavior? I'm using Windows 7 x64 with Csound 6.09.1 Neat opcode, in any case! Nathan Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here -- Oeyvind Brandtsegg Professor of Music Technology NTNU 7491 Trondheim Norway Cell: +47 92 203 205 http://www.partikkelaudio.com/ http://crossadaptive.hf.ntnu.no http://gdsp.hf.ntnu.no/ http://soundcloud.com/brandtsegg http://flyndresang.no/ http://soundcloud.com/t-emp Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2017-07-13 10:49
From	Victor Lazzarini
Subject	Re: Problem with the 'tvconv' opcode DFT mode
	It is probably the case that the bug fix did not make it into the Windows version. The issue was exactly as you described. Unfortunately, this means that the fix will need to wait until the next release (unless Mike re-does the package). best regards Victor Lazzarini Dean of Arts, Celtic Studies, and Philosophy Maynooth University Ireland > On 13 Jul 2017, at 06:45, Nathan Holmes wrote: > > Hello, > > When using the new tvconv opcode, any partition size above 2 gives odd results. With sizes 4-32, there are high frequencies introduced into the output which remind me of aliasing from downsampling; and as partition size continues to increase, the output devolves into a light crackling. > > I attached some of the output I get from the example file doc/manual/examples/tvconv.csd, which uses a partition size of 256. > > In contrast, when the partition size is 1 (and thus, using the direct convolution mode instead of the DFT mode), the opcode seems to work as I'd expect. Interestingly, a size of 2 (which I believe uses DFT mode) seems to work pretty well too. It's just above 2 that things get weird. > > Or is this all expected behavior? > > I'm using Windows 7 x64 with Csound 6.09.1 > > Neat opcode, in any case! > > Nathan > Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here > Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2017-07-13 18:45
From	Nathan Holmes
Subject	Re: Problem with the 'tvconv' opcode DFT mode
	Oh, that's good news! Thanks everyone. I really like tvconv, and I'll definitely be doing some experimentation with liveconv in the future too. In fact, some months back, I found myself wanting to modify IR tables in realtime using the older convolution opcodes, but with not-so-great results; so I was excited when I saw that Oeyvind was developing an opcode to do just that. Great work on these, they're much appreciated! I'll do some reading on the cross-adaptive processing site, it seems fascinating. :) -Nathan On Thu, Jul 13, 2017 at 2:49 AM, Victor Lazzarini <Victor.Lazzarini@nuim.ie> wrote: It is probably the case that the bug fix did not make it into the Windows version. The issue was exactly as you described. Unfortunately, this means that the fix will need to wait until the next release (unless Mike re-does the package). best regards Victor Lazzarini Dean of Arts, Celtic Studies, and Philosophy Maynooth University Ireland > On 13 Jul 2017, at 06:45, Nathan Holmes <nholmes.composer@GMAIL.COM> wrote: > > Hello, > > When using the new tvconv opcode, any partition size above 2 gives odd results. With sizes 4-32, there are high frequencies introduced into the output which remind me of aliasing from downsampling; and as partition size continues to increase, the output devolves into a light crackling. > > I attached some of the output I get from the example file doc/manual/examples/tvconv.csd, which uses a partition size of 256. > > In contrast, when the partition size is 1 (and thus, using the direct convolution mode instead of the DFT mode), the opcode seems to work as I'd expect. Interestingly, a size of 2 (which I believe uses DFT mode) seems to work pretty well too. It's just above 2 that things get weird. > > Or is this all expected behavior? > > I'm using Windows 7 x64 with Csound 6.09.1 > > Neat opcode, in any case! > > Nathan > Csound mailing list Csound@listserv.heanet.ie<mailto:Csound@listserv.heanet.ie> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here > <tvconv-output.wav> Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here