piwolf

Any links or info on how to split a data stream value out as two seperate High Byte and Low Byte channels on DMX? Tilt Pan value application with a range of 65535 which I am assuming is the bit depth of the two interleaved 255 values that dmx runs on. 

Using Enttec products. I have all the regular DMX packing well in hand, just dont understand how to order the data from a single value to a split set of values of lower depth.

Any links or info on how to split a data stream value out as two seperate High Byte and Low Byte channels on DMX?  Tilt Pan value application with a range of 65535 which I am assuming is the bit depth of the two interleaved 255 values that dmx runs on. 
Using Enttec products.  I have all the regular DMX packing well in hand, just dont understand how to order the data from a single value to a split set of values of lower depth.


dmx-high-bytelow-byte-coding

> Any links or info on how to split a data stream value out as two 

> seperate High Byte and Low Byte channels on DMX? Tilt Pan value 

> application with a range of 65535 which I am assuming is the bit 

> depth of the two interleaved 255 values that dmx runs on.

> Using Enttec products. I have all the regular DMX packing well in 

> hand, just dont understand how to order the data from a single 

> value to a split set of values of lower depth.

Not sure if I understand you correctly, but I assume you're using two 

On 07-08-26, at 1315, piwolf wrote:
>
> Any links or info on how to split a data stream value out as two  
> seperate High Byte and Low Byte channels on DMX?  Tilt Pan value  
> application with a range of 65535 which I am assuming is the bit  
> depth of the two interleaved 255 values that dmx runs on.
> Using Enttec products.  I have all the regular DMX packing well in  
> hand, just dont understand how to order the data from a single  
> value to a split set of values of lower depth.
>
Not sure if I understand you correctly, but I assume you're using two  
channels to send an unsigned short?

unsigned short pan = whatever;
char channel1 = (pan & 0xff00) >> 8;
char channel2 = (pan & 0xff);

Yes I am sending to two channels each with a range or 0-255. There combination of values creates a range of 65535. The code excerpt you posted is intended for me to implement where? This is something I want to be constantly streaming update data to.

Are 0xff00 and 0xff the hex locations for most and least significant byte? I know char is a data type/object but give me the quick rundown on what type "unsigned short" is?

Yes I am sending to two channels each with a range or 0-255.  There combination of values creates a range of 65535.  The code excerpt you posted is intended for me to implement where?  This is something I want to be constantly streaming update data to.
Are 0xff00 and 0xff the hex locations for most and least significant byte?  I know char is a data type/object but give me the quick rundown on what type "unsigned short" is?

> Yes I am sending to two channels each with a range or 0-255. There 

> combination of values creates a range of 65535. The code excerpt 

> you posted is intended for me to implement where? This is 

> something I want to be constantly streaming update data to.

I don't know what your DMX object looks like, so I have a hard time 

advising here. If you want me to take a look at it you can send it to 

me off-list. The DMX object I have accepts a number of channels at a 

time as a list. I would probably implement the code I pasted upstream 

to my DMX object, since it's specific to one fixture, not the DMX 

object itself. Consider the [expr] object.

> Are 0xff00 and 0xff the hex locations for most and least 

> significant byte? I know char is a data type/object but give me 

> the quick rundown on what type "unsigned short" is?

0xff00 and 0xff are bit masks. I recommend reading up on bit 

http://en.wikipedia.org/wiki/Bitwise_operation#AND

http://en.wikipedia.org/wiki/Bitwise_operation#Shifts_in_C.2C_C.2B.2B.

I also recommend reading up on data types. An unsigned short in most 

languages is an unsigned 16 bit value, giving a maximum of 65535. A 

char is typically 1/2 a short, or 8 bits.

On 07-08-26, at 1353, piwolf wrote:
>
> Yes I am sending to two channels each with a range or 0-255.  There  
> combination of values creates a range of 65535.  The code excerpt  
> you posted is intended for me to implement where?  This is  
> something I want to be constantly streaming update data to.
>
I don't know what your DMX object looks like, so I have a hard time  
advising here. If you want me to take a look at it you can send it to  
me off-list. The DMX object I have accepts a number of channels at a  
time as a list. I would probably implement the code I pasted upstream  
to my DMX object, since it's specific to one fixture, not the DMX  
object itself. Consider the [expr] object.

> Are 0xff00 and 0xff the hex locations for most and least  
> significant byte?  I know char is a data type/object but give me  
> the quick rundown on what type "unsigned short" is?
>
0xff00 and 0xff are bit masks. I recommend reading up on bit  
operations, both masking and shifting.

http://en.wikipedia.org/wiki/Bitwise_operation#AND
http://en.wikipedia.org/wiki/Bitwise_operation#Shifts_in_C.2C_C.2B.2B. 
2C_and_Java

I also recommend reading up on data types. An unsigned short in most  
languages is an unsigned 16 bit value, giving a maximum of 65535. A  
char is typically 1/2 a short, or 8 bits.

So I understand the masking; and the variable types; and mostly the expression object but I am curious if I need to write an external or not. I take in the OSC float value from the lemur; then multiply it to get it into the range for the unsigned short, but Im not declaring an unsigned short, just an int in the range of one; then I tried to use the expression object to perform a masking function but the output I am getting is well beyond the range of an 8 bit value. I can see the problem from the math that I am sending in a higher bit depth variable even though I am in the value range I need to be. Is there a way to implement the masking without writing it in Visual Studio as an external? The only variable types I am familiar with declaring inside of max are the obvious, int,float,and symbol. What would be the cleanest and process friendly way of performing the split? Am I missing an obvious way with the max scripting to declare the bit depth of variables or should I do it in my external compiler? Thanks again!!

So I understand the masking; and the variable types; and mostly the expression object but I am curious if I need to write an external or not.  I take in the OSC float value from the lemur; then multiply it to get it into the range for the unsigned short, but Im not declaring an unsigned short, just an int in the range of one; then I tried to use the expression object to perform a masking function but the output I am getting is well beyond the range of an 8 bit value.  I can see the problem from the math that I am sending in a higher bit depth variable even though I am in the value range I need to be. Is there a way to implement the masking without writing it in Visual Studio as an external?  The only variable types I am familiar with declaring inside of max are the obvious, int,float,and symbol.  What would be the cleanest and process friendly way of performing the split?  Am I missing an obvious way with the max scripting to declare the bit depth of variables or should I do it in my external compiler?  Thanks again!!

> So I understand the masking; and the variable types; and mostly the 

> expression object but I am curious if I need to write an external 

Who knows- we can't read your mind. My guess is that if you can't 

already figure out what to do at this point, then writing an external 

You have a lemur which is giving you a float value with some range 

(input), and you want to convert it to an unsigned short to send over 

DMX (output). This really means you need a high and low byte to send 

So just put the math I replied with previously into an expr and you 

are good to go, no? If not, can you please restate your question in 

such a way that we don't need to assume we know what you are doing.

On 07-09-01, at 1912, piwolf wrote:
>
> So I understand the masking; and the variable types; and mostly the  
> expression object but I am curious if I need to write an external  
> or not.
>
Who knows- we can't read your mind. My guess is that if you can't  
already figure out what to do at this point, then writing an external  
won't help you.

You have a lemur which is giving you a float value with some range  
(input), and you want to convert it to an unsigned short to send over  
DMX (output). This really means you need a high and low byte to send  
over two DMX channels.

So just put the math I replied with previously into an expr and you  
are good to go, no? If not, can you please restate your question in  
such a way that we don't need to assume we know what you are doing.

thanks for posting up that demo patch, massively helpful for me.

DMX High Byte/Low Byte coding