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So, I'm building a threaded IMA ADPCM decoder streaming audio data to OpenAL (see below for short description) but I've run into some trouble.

One of my issues is that sometimes my call to alBufferData:

alBufferData(*bufferID, format, pcmData, sizeInBytes, bitRate);

returns AL_INVALID_VALUE even though, when checking the parameters they look, e.g., like this:

bufferID='109770616', format='AL_FORMAT_STEREO16', dataPtr='109754188', sizeInBytes='8164'

Any clues, anyone? The actual sound being played sort of stutteres when this happens, and the error usually happens ~10 times in a row (on the same sound). It also usually happens when I repeatedly start the same sound (for example when shooting short bursts with an LMG... ;))

Quick simplified tour of the streaming-decoder-module-thing

How a sound gets played:

  1. A sound is triggered to play.
  2. One bufferSize worth of audio is decoded and the rest is queued for further decoding.
  3. OpenAL is triggered to start playing the sound.

The decoding/streaming loop

  1. For each sound queued for decoding, decode bufferSize worth of audio.
  2. The decoded audio is added to an alBuffer (see call above) with the appropriate bufferID.
happytrooper
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  • Does integer to which bufferID points have valid bufffer id? Had it been created with alGenBuffers? – Mārtiņš Možeiko Jun 12 '12 at 17:19
  • bufferID value seems a lot similar to dataPtr value. So more likely it is pointer. Are you printing bufferID or *bufferID ? I'm more interested in *bufferID. – Mārtiņš Možeiko Jun 14 '12 at 08:45
  • Ignore above comment, I was too slow in editing it: Hiya @Mārtiņš! The value of `bufferID` is the value shown above (`'109770616'`). The bufferID is generated and used like this: `alGenBuffers` -> `alBufferData` -> `alSourceQueueBuffers`. I continually check for processed buffers with `alGetSourcei(sID, AL_BUFFERS_PROCESSED, &processedBuffers)` and reuse the processed bufferID by unqueuing it with `alSourceUnqueueBuffers` and refill it with `alBufferData` again. – happytrooper Jun 14 '12 at 08:53
  • Ah, you're right I am printing the pointer - my bad! I'll get back to you when I've tested again .. – happytrooper Jun 14 '12 at 08:54
  • `alBufferData: bufferID='8581768', format='AL_FORMAT_STEREO16', dataPtr='111853112', sizeInBytes='8164', bitRate='44100'`. Error message: Invalid Value – happytrooper Jun 14 '12 at 09:15

2 Answers2

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if it's not too late I'll tell you the similar problems I had with BufferData and here's how I fixed it. Although, keep in mind, I don't know the specifics of your threaded program.

Invalid value is returned for a number of reasons, the ones I know of are...
-Queuing new buffers (to a streaming source) if the source already has a bufferID assigned (because it gets set to static if you set buffer id). If so, remove the ID in the source property.
-Changing the buffer format mid play. You can't change any buffer setting (fmt,samplerate) except for the buffer data itself once a source starts playing, even if it is on another queued one.

It sounds like you might be changing one of these settings in another thread.

Another thing that may cause pops is replaying the sound. Calling play again just stops the source cold, then rewinds the current buffer and starts playing from the beginning. Playing a gun sound like that won't sound like you want it (layered i assume). 2 options, mix the remaining gun sound into the buffer then replay it, but this might not work. another fool proof is just to use multiple sources and rotate which ones get called on each gun fire.

good luck on your project.

extracrispy
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  • Excellent reply, thank you @extracrispy! While I haven't yet had time to continue working on this project (I will in some time though) the reasons you point out do sound valid! As soon as I'm back on this project I will investigate this further and come back with a reply. Until then, as I cannot just upvote your answer (need 15 rep ..) I will mark it as accepted! – happytrooper Jul 16 '12 at 13:00
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Since I stumbled over the same error and this question is the first that appears in search engines, I'd like to quickly post the problem I ran into in hope that it is useful to others. I use stb_vorbis (from https://github.com/nothings/stb) with OpenAL and when I tried to feed the data into OpenAL, I got the same AL_INVALID_VALUE error. It turned out that the buffers have to be a multiple of 4 (at least on the soft_al implementation and with AL_FORMAT_STEREO16 (might be different for other implementations / formats).

bufferSize = stb_vorbis_decode_filename("sound.ogg", &channels, &sampleFrequency, &pcmData);

// Adjust the bufferSize to a multiple of 4
bufferSize = bufferSize - bufferSize%4;

alBufferData(mySoundBuffer, AL_FORMAT_STEREO16, pcmData, bufferSize, sampleFrequency);

I got it working by trial and error, so if you run into this error, you might want to check this as well.

Kind regards, Moritz

Moritz Molch
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