Re: [seq24-users] seq24-0.7.0 (sysex)

[federico <xa...@in...>]

Rob Buse ha scritto:

>>>i was wondering if it is possible to implement System Exclusive MIDI
>>>      
>>>
>>messages(?).
>>    
>>
>
>currently the only thing that seq24 does is act as a thru for incoming
>sysex.
>
>  
>
>>>think that a SysEx message it is like a midi controller message, example:
>>>CC:   0xB# 0xPP 0xVV
>>>SysEx:  0xF0 0x32 0x2# 0xPP 0xVV 0xF7
>>>      
>>>
>
>Well, each device has such a different sysex format, I can not think of
>an easy way to support it.  Where should it go in the midi stream?  How
>should seq24 represent each block of sysex visually?  Does seq24 play
>  
>

i think they are the same as a control change, so they can be 
represented in the sequence data window

>the sysex each time though the loop?  I really can't think of any way
>  
>
yes, it should be played every time, like the midi controller messages

>to implement a sysex editor other than just a hex editor style.
>
>Maybe if the user specifies the sysex pattern ahead of time, and then the
>data editor will modify one byte out of that stream?
>  
>
good! i also think those messages can be put in a new submenu called 
sysex (where the midi controllers are).
the user should be able to put its own messages (even by adding some 
quoted strings and bytes to a C file) with a simple template, ie.:

#define SYSEX_MAX 10

struct sysex_message {
 char name[20];
 unsigned char message[SYSEX_MAX];
 int  offset_channel;
 int offset_param;
 int offset_value;
};

example[] =
{
  { "cutoff", {0xf0, 0x32, 0x31, 0x32, 0x00, 0xf7}, 2, 3, 4 },
  { "resonance", {0xf0, 0x32, 0x31, 0x33, 0x00, 0xf7}, 2, 3, 4 },
  { "lfo3 deep", {0xf0, 0x32, 0x31, 0x34, 0x00, 0xf7}, 2, 3, 4 }
}

we can collect and share all these parameters, so users can find their 
synth's parameters already in.

>And the VAL's can be edited with the mouse?
>  
>
yes! i think they should be act and look like normal controller 
messages, because they do the same function.

>
>  
>
>>what would happen if i load a midi file with sysex data in it? (ps. does
>>seq24 follows some standard for its format?)
>>will seq24 play the sysex strings?
>>    
>>
>
>seq24 uses the midi file standard. It will currently  just throw away
>sysex if found in the file.
>
>rob
>  
>
ouch! i think when defining sysex messages, there should be a 
"reverse-resolution" of the sysex type, so that seq24 could recognize 
that those sysex string is my bass cutoff.

example function:

int match_sysex_data(unsigned char* data)
{
    bool match;
    //cycle through user-defined messages (usermsg[])
    for(int id=0; id<MSG_COUNT; id++) {
       match = true;
       for(int i=0; i<SYSEX_MAX && data[i] != 0xf7; i++) {
          //compare byte-by-byte skipping variable bytes (chan, value)
          if(i != usermsg[id].offset_channel &&
             i != usermsg[id].offset_value) {
                match = match && (usermsg[id].message[i]==data[i]);
          }
       }
       if(match) return id;
    }
    return -1;
}