Rockbox Technical Forums

Support and General Use => Plugins/Viewers => Topic started by: kfb on April 17, 2008, 03:47:26 PM

Title: MIDI playback error on Sansa e250: "null waveform"
Post by: kfb on April 17, 2008, 03:47:26 PM
I tried playing a MIDI file and no sound comes out, just the message "crap...null waveform..." printed out on the display repeatedly.  I followed the instructions at http://www.rockbox.org/twiki/bin/view/Main/PluginMidiPlay to download and copy over the patchset to .rockbox/patchset and verified that the patch files were in the right location.  I did this twice to make sure.  I also tried several different MIDI files.  However, I still get the same error message each time.  Any ideas?
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: Chronon on April 17, 2008, 04:51:24 PM
I'm not familiar with that error message.  Shouldn't it complain about a missing patchset if that's the problem?  Which revision of Rockbox are you running?

Hmm.. I'm sorry that I can't be of much help here.  For what it's worth, I haven't had any problems playing back MIDI files on my Gigabeat. 
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: nls on April 17, 2008, 05:31:56 PM
Could you make one of these files available somewhere or link to one perhaps so we can take a look?
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: zajacattack on April 17, 2008, 05:58:11 PM
Either way, most MIDI files still won't play on the PortalPlayer targets.
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: Chronon on April 17, 2008, 06:03:58 PM
Have you encountered this particular error, zajacattack?
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: zajacattack on April 17, 2008, 06:11:54 PM
No, I always get the "Buffer miss!" message; however, I believe that his error message most likely has to with the fact that the PortalPlayer targets can't buffer at 22,050 KHz.
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: kfb on April 17, 2008, 06:21:08 PM
I'm running r17068-080410.  I've attached an example midi file to this post.
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: nls on April 19, 2008, 05:50:12 AM
Does any midi files work for you? I tested the track you attached but it plays fine on my h320 and in the simulator...
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: zajacattack on April 19, 2008, 02:52:48 PM
Are you sure you unzipped the patchset right? It plays perfect on my e280R.
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: kfb on April 23, 2008, 12:52:53 PM
Well, I download 3 more midi files from a different source and tried them, and I also tried downloading and copying over the patch set one more time.  No luck at all - still the same error every time.
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: Chronon on April 23, 2008, 01:59:20 PM
There's another Sansa user having MIDI troubles here: http://forums.rockbox.org/index.php?topic=16540.0
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: bascule on April 23, 2008, 04:17:27 PM
Again, your sample 'Love' file works OK for me on an e280.

It seems your file structure is correct, you should have folder:
/.rockbox/patchset

containing files:
*.pat (lots of)
*.cfg (two of)
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: kfb on April 24, 2008, 07:41:10 PM

It seems your file structure is correct, you should have folder:
/.rockbox/patchset

containing files:
*.pat (lots of)
*.cfg (two of)

Yup, I have those files and folders in the location described.
Argh :-\ is there any way to get in touch with the author of the midi plugin and find out more about what the error message "null waveform" is supposed to mean?
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: Chronon on April 24, 2008, 08:04:47 PM
You might try resetting your settings and see if that helps anything.
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: bascule on April 25, 2008, 04:01:43 AM
Well, I've found the error message in the code (http://svn.rockbox.org/viewvc.cgi/trunk/apps/plugins/midi/synth.c?view=markup), but there's no comments that help me understand what's going on here (seeing as I know nothing about MIDI and very, very little about C).

It would seem that you may just be out of luck, as the error only seems to exhibit itself on your device. You may want to hop onto IRC (linked from sidebar) and ask about it there, as that's where most of the actual coders hang out...
Title: Re: MIDI playback error on Sansa e250: "null waveform"
Post by: bascule on April 25, 2008, 04:10:29 AM
I'm locking this, so that discussion on the apparently similar errors encountered with MIDI on PP devices can continue in http://forums.rockbox.org/index.php?topic=16540.0