How to get sound samples?

[Vouk]

I am currently writing an Output aex plugin. It already works with outputting videos (AddFrame) but how do i get the sound samples?

A_Err (*AEIO_AddSoundChunk)(

AEIO_BasicData *basic_dataP,

AEIO_OutSpecH outH,

const A_Time *start,

A_u_long num_samplesLu,

const void *dataPV);

How do I get the samples?

Thank you.

P.S.: The function has a different signature in the header file than in the PDF. Am I missing something?

[Vouk]

I bet the sample data is in dataPV. But how in what format / structure? Anybody?

[Guest]

Check the file SDK_Backwards.cpp in the included SDK examples, it is a good starting point on how to check out audio tracks, modify/process them and write them back.

[Vouk]

Thanks, but the thing is that the samples are stored in:

const void *dataPV

is of type "const void*". I need to know what I need to cast it to.

[Guest]

Yes, this area is undocumented and the current headers are inconsistent (e.g. using the undefiend AEIO_SndWorldH handle). You might try just dumping the data and opening it with an audio editor to see if it is always a certain raw format or actually the compressed audio stream according to the project/export settings. Probably only Adobe can help you here...

[Vouk]

Adobe admitted on twitter the documentation needs to be corrected.

I guess the data might be different depending on the number of channels, sample format,... that's why it could be a void*. But it could be just anything. Is it packed or planar?

Yes, only Adobe can help here. Everything else is just guessing.

[Guest]

I assume that the intended method was to provide a handle "AEIO_SndWorldH" in the interface that actually points to a AEIO_SndWorld structure which has more detailed description of the current format, just like with pixel data. However this neither seems to be implemented nor documented (yet).

[jeroyg · Accepted solution]

the sound samples are in "dataPV" and there will be "num_samplesLu" starting at time "start".

you can use AEGP_GetOutSpecSoundSampleSize, AEGP_GetOutSpecSoundChannels, and AEGP_GetOutSpecSoundEncoding with outH to get the bytes per sample, number of channels, and the format the samples are in. the samples will be interleaved.

[Vouk]

I got it working. Thank you.

[AnmolM]

Helpful info. Thanks.