Message 3: sf3 bug - sample links are removed

• Sep 9, 2015 - 22:18


As the developer of the software Polyphone, one user asked me to work on the sf3 support. We exchanged a couple of emails and I'm now convinced of its benefits. By dividing by 10 the size of a soundfont and keeping most of its quality, it makes it easy to embed in a lot of applications (video games, mobile applications, ...). The idea is not new in that the format sf2pack (please note the "2") already exists for example, but it is now an open-source format which is promoted by a well-driven software with a pretty big community. Thus, I added the sf3 import / export.

The background being stated, I have several remarks and interrogations (most of them being technical). This message is part of a series comprising other messages.

Message 3: sf3 bug - sample links are removed

(GitHub issue created here )

Sample links are lost while exporting as sf3 (according to the sftools library). Once the sf3 is created, we don't know anymore which samples go together, which one was left and which one was right. This has no impact on the sound (the left and right attributes being just informative), but if we import an sf3 to edit it, precious information is missing. This appears to be done on purpose but I didn't find which one.

If it's related to the idea of compressing both left and right samples together - rendering the attribute left / right useless - I think it's a bad idea since the sf2 format is based on mono samples (sometimes played together but this is 2 distinct mono samples). Sf2 players take thus into account mono samples to play and if samples are merged, developers would be forced to dissociate them first so that the sf3 format can be read. Two parts of a stereo sample, once imported in a soundfont, may be played completely differently depending on what parameter we put.

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