Topics

1

Plugin Development / Plugin DLL not recognised by SV on windows

« on: May 02, 2013, 13:26:58 »

Hi Chris and all,

I'm having some trouble with a vamp plugin we've created here especially for a course we're giving on sound analysis. Basically, on some computers, the plugin is simply not recognised by Sonic Visualiser. The computers belong to the university and run windows xp. Importantly, on non-university machines the plugin is recognised correctly.

Whilst this implies that in part the problem has something to do with the configuration of the university computers, other vamp libraries (e.g. the vamp example library, aubio or libextract) are recognised by SV without any problem! This suggests that there is something different about our DLL which prevents the uni machines from recognising it.

Has anyone experienced something like this before? Any idea what could be the reason for this?

Thanks!

Justin

2

Plugin and Host Announcements / MELODIA - Melody Extraction plug-in now available!

« on: October 16, 2012, 12:02:12 »

The MELODIA plug-in automatically estimates the pitch of a song's main melody. More specifically, it implements an algorithm that automatically estimates the fundamental frequency corresponding to the pitch of the predominant melodic line of a piece of polyphonic (or homophonic or monophonic) music.

You can find out more about the plug-in and download it here: http://mtg.upf.edu/technologies/melodia

Cheers,

Justin

3

Plugin Development / Aligning outputs and getting the little info button

« on: July 20, 2012, 10:51:45 »

Hi Chris!

I'm glad to say I already have a very early alpha version of my plugin working. I'll probably have some more questions as I get closer to a proper release, but for now just a couple of small questions:

1) The plug-in has several outputs. Of these, one is a matrix type (with 600 bins) and the other is a single value per frame (in cents). Ideally, I want both to be on the same scale, so the matrix bins represent values 0-5990 cents (i.e. bin*10), and then if the single value output has a value of say 4000 cents, it should appear at the same height as bin 400 (which represents value 400*10 = 4000 cents). In trying to do this I have 2 problems (a) apart from giving the matrix bins names, can I set them to represent numerical values? (b) since the single value has a greater range than the matrix (matrix goes from bin 0 to bin 599, but single value can also have negative values), they are both squeezed to fit on the screen meaning the values are not aligned. Any possible solution?

2) When loading QM plugins, there is a little button at the top right corner of the plugin parameters window with an 'i', which when clicked opens a url (in this case http://vamp-plugins.org/plugin-doc/qm-vamp-plugins.html). Would it be possible to have this 'i' button on my plug-in and direct it to a url of my choice?

Thanks!

justin

4

Plugin Development / Sampling rates, input domain and sonification

« on: July 11, 2012, 15:59:22 »

Hello there,

Newbie to the vamp-world, just about to write my first plug-in and have encountered some doubts I was hoping someone could help me out with:

1) Sampling rate:

Imagine my algorithm requires a fixed sampling rate (e.g. fs = 44100), block size (e.g. 2048 @ fs = 44.1k) and hop size (e.g. 1024 @ fs=44.1kHz). I understand that I can specify a preferred block and hop size, and even return false in the initialization function if the host specifies something else. But, what about the sampling rate? Specifying a required block/hop size (in samples) is not really useful if the sampling rate is not known.

I realise I can save the value of inputSampleRate to a parameter, then check it in the initialization function and return false if it's not 44100, but that would be quite annoying for a user analysing audio with different sampling rates. Is there no way to re-sample the audio before it is chopped into blocks? Re-sampling the audio after it is already chopped into blocks means I have no control over the block/hop size (in terms of their actual duration in seconds).

2) Time-domain filtering:

Is there any way to apply a time domain filter first, and then get the input in the frequency domain? Just hoping to avoid having to compute the DFT inside the plug-in itself.

3) Sonification (sonic visualiser):

In sonic visualiser I see that some output types can be sonified (e.g. clicks at detected onsets). If the output of my plug-in is a continuous per-frame frequency value (in Hz), is there any way to sonify the output in sonic visualiser, e.g. with a sinusoid that follows the frequency of the output?

Thanks!

Justin