Re: [fluid-dev] Fluidsynth Channels

[Pedro Lopez-Cabanillas]

On Wed, Nov 30, 2011 at 3:11 PM, David Henningsson <address@hidden> wrote:
> On 11/30/2011 12:28 PM, Pedro Lopez-Cabanillas wrote:
>>
>> On Wed, Nov 30, 2011 at 8:45 AM, David Henningsson<address@hidden>
>>  wrote:
>>>
>>> On 11/29/2011 09:14 PM, Craig wrote:
>>>>
>>>>
>>>> My question is, gleaning the fluidsynth source and docs it appears that
>>>> fluidsynth can handle midi channels above the 0-15, given that
>>>> information, how does a midi file format hand of a midi event with a
>>>> standard note on ->    144 + midi channel, message1, message2, and time
>>>> stamp.  If I increas the 144 + midi channel, I end up in 160 land which
>>>> is a different midi event.
>>>>
>>>> I am a 50 year old man who write symphonies.  I would love to have
>>>> access to more that 16 channels.  How does fluidsynth do this?
>>>
>>>
>>>
>>> Hi Craig and thanks for your interest in FluidSynth!
>>>
>>> The MIDI file format does not support more than 16 channels - this is a
>>> limitation in the MIDI file format, not FluidSynth. You'll have to use
>>> special API calls in order to make use of more than 16 channels.
>>>
>>> That said; XG level 2 and level 3 seems to support more than 16 channels.
>>> Does anybody know if there is a MIDI file meta event that would switch
>>> "group of MIDI channels for this track" or something? I haven't found
>>> anything myself, but it would be very useful if it existed.
>>
>>
>> Each group of 16 MIDI channels is usually known as a "MIDI port".
>> There is a SMF meta-event to specify a specific port name for each
>> track:
>>
>> http://home.roadrunner.com/~jgglatt/tech/midifile/port.htm
>
>
> Aha, thanks. I also found this:
> http://www.midi.org/techspecs/rp19.php
>
> Unfortunately it does not impose a very good standard for Device names :-(
>
> I had a quick look at timidity source as well, which seems to do something
> similar for "FF 21 01 x" instead, probably as described here:
>
> http://www.omega-art.com/midi/mfiles.html#meta
>
> The code looked a little strange so I'm not completely sure this was it.
>
> // David
>

The "FF 21" (port prefix) meta-event is the old, long time ago
deprecated, numeric version of the "new" Port Name meta-event. The "x"
argument is replaced by a numeric value (range 0-127) representing a
MIDI port ordinal, without any good standard for ordering ports,
either. As this event has been lying around many years, there are some
MIDI files in the wild carrying this one. I have a few myself.

Regards,
Pedro