[openbeos-midi] Re: Midi2 handling of SysEx data

  • From: "Martijn Sipkema" <msipkema@xxxxxxxxxxxxxxxxxxx>
  • To: <openbeos-midi@xxxxxxxxxxxxx>
  • Date: Sun, 1 Feb 2004 14:22:31 +0100

>> I'm working on some SexEx Send/Receive tools, and found out that SysEx
>> data handled by Midi2 gets the first and last bytes stripped off.
> The OpenBeOS Midi2 kit works exactly like the BeOS R5 kit in that regard.
> Which means we can't change that.
> However, you can override the Data() hook to look for a sysex yourself.
> data buffer that is passed to Data() does include the control bytes (at
> least 0xF0, but not necessarily 0xF7). You would do something like this:
> void MyConsumer::Data(.....)
> {
>    if (atomic && data[0] == B_SYS_EX_START)
>    {
>        // do your thing
>    }
>    else
>    {
>        // let superclass handle it
>        BMidiLocalConsumer::Data(.....);
>    }

One thing I never quite understood is the 'atomic' flag. IIRC the MIDI
message callbacks are only called for data with atomic == true, as you
are doing here also. For large SysEx messages it would make sense to
send them non-atomically, but this causes them to be ignored by most
(probably all) applications...


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