Large chunks of data

[mwilson]

Hi,

I am working on a video service which will transfer image data (>1 MegaPixel) as a return type. I plan to define this as:

interface IMAQ
...

sequence<byte> acquire();

....


Is this the proper way to do this?

Thanks,
Mark

[jaggu]

think so as byte is fastest you can get as is uninterpretted.

[mwilson]

I looked at the "similar threads", and ZeroC indicates that sending data in such big chunks is not efficient.

So, now I'm thinking of defining:

interface IMAQTransferHandler {
imageStart(ImageID);
imageEnd(ImageID);
imageData(ImageID, ByteSeq);
};

And my image acquisition interface becomes:

interface IMAQ {
...
ImageID acquire(IMAQTransferHandler*);
...
};

Opinions are welcome!

Mark

[michi]

If you have sufficient memory to buffer the entire image, you can send it in a single RPC. (You'll have to adjust the value of the Ice.MessageSizeMax property to allow requests larger than a megabyte.) More likely though, you'll have to split the data into chunks and retrieve the chunks. I suggest you have a look at the source for IcePatch2. It does a similar job and should provide some ideas.

Cheers,

Michi.

[mwilson]

Makes sense - let the client do the work. Nice and simple.

[topgun300]

I changed my Ice.MessageSizeMax to something really big, and now I can transfer really big images as parameters. Is there any disadvantage in doing this?

[marc]

Originally Posted by topgun300

I changed my Ice.MessageSizeMax to something really big, and now I can transfer really big images as parameters. Is there any disadvantage in doing this?

Please see this post regarding our new support policy for these forums:

Important note: Change in support policy