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Link to the project

Hey guys. I'm a longtime lurker, and usually like learning about this stuff on my own, but I figured I would see if someone (especially someone involved with the active open source project or its dependencies) would happen to know something I am really curious about.

If you compile the open source project, Audacity, for Windows and export any amount of silence, the resultant Wav has noise in it. By this, I mean (what seems at first glance) to be random noise appears in the resultant file. Everytime. And this noise varies from export to export - which I did by exporting the same content twice in a row without doing anything inbetween.

So far, the only other thing I have tested is Steinberg's Nuendo 4, and the same methodology produces nice, clean Wav files full of 00 every time.

Since this is my first foray into having the awesomeness of an actively maintained project, I figured somebody would have some knowledge about it, or at least let me know where else to post such a question. I am going to crosspost this to the Audacity forums also, and start there.

I managed to get this built in VS2010, and with DirectSound support, so can provide all the information to do so if anyone wants to try it out.

Cheers!

EvilShred666
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  • I cannot seem to be able to post the fix for getting this to compile in MSVC2010, since I exceed character limits and it requires modifying the ny.props file by one set of quotes, and expanding the environment variables in the Pre-Build and Post-Build steps of portaudio-v19 and portmixer. It says I can post an answer to this question in 8 hours, so I will post the code then. I already answered someone's question on how to build in MSVC2010, so my fix is on another thread. – EvilShred666 Aug 01 '13 at 03:08

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The default settings for (export) quality have dithering activated, which adds a little bit of random noise to improve the sound quality of a downconversion to 16bit WAV. If you turn off dithering you get all 0 on an export of total silence, but for real world audio the sound quality is better with dithering on.

I'm running Audacity in German language, so I can't give you the exact menu terms, but you should be able to find it like this:

Open the settings via the Edit/Settings Menu. Quality is in option 4 and there should be a setting for high quality conversion where you can select the kind of dithering you want. Here you can turn it off.

576i
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