GL Error: 502 When Recording in Modal View Opened More Than Once

[dyelax]

This may be something I'm doing wrong, but it seems like something going on with the graphics code in the framework (I'm not very familiar with Open GL, so I can't really tell.)

I'm trying to create a recording controller presented in a modal view. While it works perfectly the first time I present the view and record, if I cancel the recording and open it again, when I try to record I get thrown a GL Error: 502 and only the top half of the waveform draws. I've tried destroying every EZAudio property I'm using (AudioPlotGL, Microphone and Recorder) when I dismiss the view and recreating them all in case there's some information hanging around from the first recording that's screwing something up, but I still get the error.

If I stay in the same view and reset everything (The retry button on the top right) It will re-record just fine. The issue is only when I dismiss the view and reopen it.

Video of the problem: http://youtu.be/PtlIa_uM1W4

Link to the Xcode Project: https://www.dropbox.com/sh/kf8cxo3pcsh5u9p/AABk7zpekdVvL2rZrVA40CkZa

[dyelax]

@syedhali: Update: I'm now pretty sure it really is an issue inside the framework, as I tweaked the included "EZAudioRecordExample" project so the recording view controller is presented modally and the same error happens.

[emajcher]

@dyelax Unfortunately I ran into this also ... after spending a night trying to fix it (with little Open GL knowledge) I gave up and wrote my own waveform display with Core Graphics that sort of mimics the audio display of the voice memo app, but instead of a contiguous graph, it just draws straight vertical lines (which was in the original design anyway). I would be happy to share this with you, it was only about 70 lines of code and might be a good starting point for you to write something custom if you need to launch in a modal ... I suspect instead of vertical lines you could modify it to use a connected path, discarding old data points.

[dyelax]

@emajcher Thanks! That would be really helpful. You can email me at matthew_cooper@brown.edu. (Or just post it here if that's possible to help others with the problem until it's resolved.)

[ogoldfinger]

+1 for this. I had the same problem so I tried using just audioplot (not GL) and it worked fine except then I ran into this problem: https://github.com/syedhali/EZAudio/issues/55

But uncommenting that line as suggested in that thread worked for me as well so now I have it working in a modal (albeit not with openGL)

[emajcher]

AHH!! I ran into that issue also (non open GL audio plot) which is why I ended up writing my own waveform display, I hadn't seen the problem/solution #55 which would have saved me some time. Dyelax, you might want to try that option first (use AudioPlot vs. AudioPlotGL) which will use core graphics and adding the fix in #55. My implementation will require you to do some additional work to get a connected graph like audio plot, but I will still send it as a simple reference.

[dyelax]

Thanks a ton guys. I'll try out those two options. Glad I'm not the only one with this issue though -- hopefully it'll get patched up for the openGL plot.

[syedhali]

Know I'm a little late here, but this seems to be an issue with the OpenGL context. I'll look into this a bit, but TBH I'm in the process of writing a new version of EZAudio with a completely new EZAudioPlotGL that's much easier to customize and allows multiple GL plots at once. This probably won't get released until sometime in October, but I figured I'll let you guys know!

[nmcc24]

Some fix on the AudioPlotGL plot would be great, otherwise i'll adopt AudioPlot

[don-inkscreen]

Having this issue as well; have switched to EZAudioPlot in the meantime.