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Getting and Using Vamp Plugins / Inconsistencies in QM-plugin output (when invoked using simple-host or SV app)
« on: August 29, 2008, 10:14:08 »
I used the feature extraction functionality of the Sonic Visualiser Queen Mary Plugin which provides some higl-level features very valuable for me. Thanks to the developers for that!!
Using the simple host application (vamp-simple-host.exe) included in the the vamp sdk 1.3 also allows to extract these features on the command line. However I detected some inconsistencies between the plugin's output depending on whether it is invoked by the simple host application or it is invoked by the Sonic Visualiser main application (if the output is exported to a file). E.g. the beat tracker detected some more beats when run using the simple host, although most of the beats are (nearly) identical. Although I didn't expect that, this is not a serious issue for me. (Probably the plugin got different input of two different fft implementations, well I don't know...)
What I'm more worried about is the differences in the chromagram or the constant-q output. If I use the main application I got an output which has 4 frames more. That shouldn't be the case. I used the same sound file and the default parameters, so the number of frames should be equal. (my plugin version: 1.4 but the same problems occur with version 1.0, my Sonic Visualiser main application version: 1.3, my OS: Windows)
Looking at the results more closely I found out that the results do correspond, however the simple host's output misses the first four frames. As if the sound files starts 0.74 seconds later.
Is it a bug? I don't have an explanation for this.
Thanks for any comments,
Hannes
Using the simple host application (vamp-simple-host.exe) included in the the vamp sdk 1.3 also allows to extract these features on the command line. However I detected some inconsistencies between the plugin's output depending on whether it is invoked by the simple host application or it is invoked by the Sonic Visualiser main application (if the output is exported to a file). E.g. the beat tracker detected some more beats when run using the simple host, although most of the beats are (nearly) identical. Although I didn't expect that, this is not a serious issue for me. (Probably the plugin got different input of two different fft implementations, well I don't know...)
What I'm more worried about is the differences in the chromagram or the constant-q output. If I use the main application I got an output which has 4 frames more. That shouldn't be the case. I used the same sound file and the default parameters, so the number of frames should be equal. (my plugin version: 1.4 but the same problems occur with version 1.0, my Sonic Visualiser main application version: 1.3, my OS: Windows)
Looking at the results more closely I found out that the results do correspond, however the simple host's output misses the first four frames. As if the sound files starts 0.74 seconds later.
Is it a bug? I don't have an explanation for this.
Thanks for any comments,
Hannes