Reading Loop points from WAV file - possible?

[Julian Ray]

Hi,

I have a lot of WAV files with loops (made them for my Kontakt sample libraries), some of which I would like to use for my FS project. I was searching forum on this subject, but no luck.
Can anyone, please clarify if it is possible for FS to recognize WAV Loop points? If not - what would be possible solution?

Thanks!
Ray

[trogluddite]

Assuming the loop points are stored in the standard way for a WAV file, then yes it's possible - but not especially easy.
Ruby can read files as raw bytes, and then decode them into whatever kind of data they represent; so if you know how a file format is laid out, it's possible to decode just about anything.

I have had a play at decoding WAV files in the past, though I didn't gt particularly far. Below is the old project file, which you're free to cherry-pick if its at all useful to you - it'll give you a sense of what you'd be letting yourself in for, at least! From a cursory look, I can't tell exactly which chunks of a wav its able to read - you might get lucky and see your marker/loop data, or you might not - good luck!

WAV File Reader.fsm

(1.28 KiB) Downloaded 865 times

[Julian Ray]

Thank you very much for the explanation and example - I'll definitely study it and see for how deep I can understand it

Cheers!

[tulamide]

There are also two projects from KGisback, one of it specifically a wave file reader, that was quite advanced. But you would need to use the search function (or Google's site search) to find it, because I forgot about the title.

[adamszabo]

its better if you search for "KG_is_back", thats the username

[Julian Ray]

Thanks guys, I'll search it right now

[acg2010]

Not sure if this would be of any use but while researching SDR, I came across this reference to parsing a wav in C.

http://truelogic.org/wordpress/2015/09/ ... file-in-c/

Maybe can glean some helpful hints, or convert code to assembler maybe, idk.

[Spogg]

I don’t know if this could help trog to modify his Ruby code, but I’ve attached a short WAV which does loop nicely, and a screenshot of the Wavosaur properties which show the loop start and end samples.

I imagine agc2010 wants only the loop sample values for a player.

Cheers

Spogg

[trogluddite]

Thanks for the example file, Spogg, and for the code example, agc2010 (I would have included the research links from my old project - but they were all broken!)

Having had a bit more of a look at my old code, I think that extracting the other data "chunks" should be possible by adding their structures to the table at the beginning. I'll need to think a bit more about the parser though, as I don't think it will handle tables nested within tables properly yet; and if I remember the WAV format correctly, loop points require cross-referencing data from two different "chunks". Coincidentally, one of my current projects is a MIDI SysEx decoder which does exactly the same kind of memory-mapped data extraction - it's a similar enough problem that I may well end up with code that can be re-used here.

[guyman]

Can we write Loop points TO a wav file?