[OSC_dev] blob metadata (was: Images ?)

[Stephen Sinclair]

The idea occurred to me once that it certainly would be nice to be
able to send meta data with blobs so that they could be interpreted
correctly.  This could include applications like streaming audio data
-- you would want information about sample rate, compression, etc.
Another use case for meta data would be for sending things like
matrices: row/column information would be necessary.  (Right now I am
sending matrices as lists of 9 or 16 floats)

Well, for the former case (images, sound files), the internet is
fortunately already well-populated with standards for file types:
e.g, http://en.wikipedia.org/wiki/MIME

I suppose you could even just send a message with two blobs: a MIME
header and a file.  Of course, it might not fit in a UDP message, so
you might want to use TCP, and in that case, perhaps you also might as
well be using HTTP instead of OSC... but I digress.

For the problem of sending metadata about vector/matrix formats, I
have no solution except to define application-specific standards.
(i.e., my receiver "knows" that a certain message has a 3x3 matrix as
its 9 arguments.)  Does anyone know if there are any existing metadata
standards for identifying mathematical data structures?


Steve


On Thu, Mar 5, 2009 at 3:07 AM, Gaspard Bucher <gaspard at teti.ch> wrote:
> I am not sure I see any cross-application use case where it would be
> needed to have a common picture format. Most of the cases I see are
> image processing applications in which cases you need a lossless
> compression (not some jpg or png). Personally I could use a special
> compressed blob with some meta-data on the size and number of layers
> (multi-plane matrix).
>
> Gaspard
>
> On Thu, Mar 5, 2009 at 8:37 AM, Xavier Miller <xavier.miller at cauwe.org> wrote:
>> Hello,
>>
>> In our application, we plan to send images in OSC messages. Is already a
>> type tag defined ? I think it should be interesting to define one, which
>> is not "blob".
>>
>> Something like "p" (picture), then the image format (bmp, xpm, png,
>> jpg... / dimensions), then the image blob itself.
>>
>> Kind regards,
>> Xavier Miller.
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