如何强制 MIDI 设备报告控制状态? [英] How to force a MIDI device to report control status?

问题描述

我正在使用 python-rtmidi 读取带有滑块和旋钮的 MIDI 设备.

I'm using python-rtmidi to read a MIDI device with sliders and knobs.

每当滑块移动或旋钮转动时，我都会收到 CONTROL_CHANGE 事件(这很好用).

I get CONTROL_CHANGE events whenever a slider moves or a knob is turned (this works fine).

但是如何轮询 MIDI 设备以找出程序启动时滑块和旋钮的初始位置?

But how can I poll the MIDI device to find out the initial position of the sliders and knobs when my program starts?

用户没有移动任何东西，所以没有发送 CONTROL_CHANGE 消息.

The user hasn't moved anything, so no CONTROL_CHANGE messages are sent.

(我没有关于 MIDI 设备的任何文档；它是一个 WORLDE Easycontrol 9"；我只是想使用标准的 MIDI 消息.)

(I don't have any documentation for the MIDI device; it's a "WORLDE Easycontrol 9"; I'm just trying to use standard MIDI messages.)

此外 - 虽然我引起了您的注意 - 是否有打开/关闭按钮 LED 的标准命令?我曾尝试向按钮的控制器编号(值 0 和 127)发送 CONTROL_CHANGE 命令，但 LED 仅在手动按下按钮时亮起.

Also - while I have your attention - is there a standard command to turn the button LEDs on/off? I've tried sending CONTROL_CHANGE commands to the button's controller number (values 0 and 127), but the LEDs only light when the buttons are manually pushed.

我现有的代码:

import rtmidi

class Midi:

    CONTROL_CHANGE = 0xB0

    def __init__(self, port=0):
        self.midi_in = rtmidi.MidiIn() # gets BUT DOES NOT OPEN a midi input port
        self.midi_out = rtmidi.MidiOut()

        try:
            self.midi_in.open_port(port)
            self.midi_out.open_port(port)

            self.running = True

        except:
            self.running = False # in case there was no such MIDI port

    def read(self):

        if self.running:
            event = self.midi_in.get_message()

            if event:
                return event[0]

        return None

    def write(self, message):
        if self.running:
            self.midi_out.send_message(message)

推荐答案

官方 MIDI 规范没有定义读取控件当前状态的机制.但是，许多设备都有特定于供应商的命令来启动批量参数转储.

The official MIDI specifications do not define a mechanism to read the current status of a control. However, many device have vendor-specific commands to start a bulk parameter dump.

是否可以从计算机更改控件是特定于设备的.

Whether controls can be changed from the computer is device specific.

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