Hi

I am trying to send an array blob from Csound to Python (osc4py3). The blob gets received, but I can’t figure out the format/type.

In osc4py3 the blob comes through as a memoryview object. When I try to access its elements, I only get numbers which are nothing like what I sent, and I am guessing it is some type issue.

I was trying to look into the source code for OSCsend for /array/blob, and int32_t and char are the types I can identify.

Can anyone point me in the right direction for how to approach this?

Best,

Andreas

Thanks for this Eduardo. At the receiving end it looks like 96 chars, which seem to be the same no matter the number of dimensions and size of array I send.

Which is strange if the blob should be able to contain arrays of different sizes and dimensions.

I will ask the guy developing the library if he can explain it to me.

Best, Andreas

An osc blob is just a char buffer. It's up to the receiver to convert it to usable data. The format is "documented" in the source code of OSCsend:

          ar = (ARRAYDAT *) p->arg[i];

          size = 0;

          for(j=0; j < ar->dimensions; j++) {

            size += (int32_t)ar->sizes[j]*sizeof(MYFLT);

          }

          if(buffersize + size + 12 > bsize) {

            aux_realloc(csound, buffersize + size + 128, &p->aux);

            out = (char *) p->aux.auxp;

            bsize = p->aux.size;

          }

          data = size + 8;

          byteswap((char *)&data,4);

          memcpy(out+buffersize,&data,4);

          buffersize += 4;

          memcpy(out+buffersize,&(ar->dimensions),4);

          buffersize += 4;

          memcpy(out+buffersize,&ar->sizes[0],ar->dimensions*4);

          buffersize += ar->dimensions*4;

          memcpy(out+buffersize,ar->data,size);

          buffersize += size;

          break;

From there, the format seems to be:

* Total byte size of the data (int32)
* dimensions (number of dimensions, int32)
* sizes (array of int32 with size given by the dimensions)
* the array data itself, as double (8 bytes per element)

cheers,
Eduardo

Hi

I am trying to send an array blob from Csound to Python (osc4py3). The blob gets received, but I can’t figure out the format/type.

In osc4py3 the blob comes through as a memoryview object. When I try to access its elements, I only get numbers which are nothing like what I sent, and I am guessing it is some type issue.

I was trying to look into the source code for OSCsend for /array/blob, and int32_t and char are the types I can identify.

Can anyone point me in the right direction for how to approach this?

Best,

Andreas

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Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here