Midi recording doesn't work

[taherromdhane]

When I try to record midi, the application seemingly crashes and restarts. From what I understood, there's an issue with the midi input logic in the code, I played around with midi settings but it works 1 out of 5 times on a good day.

Installation Method
Project image, latest version (v1.5.1 - Hotfix)

Error Messages
I have this in the logs, I'm actively investigating so will update with more findings

[2024-11-11 17:20:06] Starting webinterface
[2024-11-11 17:20:06] Running disable_ap.sh
[2024-11-11 17:21:31] 'NoneType' object has no attribute 'send'
[2024-11-11 17:21:39] Unhandled Exception: TypeError - list indices must be integers or slices, not str
[2024-11-11 17:21:48] Inport loaded and set to Digital Piano:Digital Piano MIDI 1 20:0
[2024-11-11 17:21:48] Can't load input port: RtMidiOut Client:RtMidi output 130:0
[2024-11-11 17:21:48] hostapd package is installed
[2024-11-11 17:21:50] Starting webinterface
[2024-11-11 17:21:50] Running disable_ap.sh
[2024-11-11 17:23:03] Unhandled Exception: TypeError - 'NoneType' object is not subscriptable
[2024-11-11 17:23:11] Inport loaded and set to Digital Piano:Digital Piano MIDI 1 20:0
[2024-11-11 17:23:11] Can't load input port: RtMidiOut Client:RtMidi output 130:0
[2024-11-11 17:23:12] hostapd package is installed
[2024-11-11 17:23:14] Starting webinterface
[2024-11-11 17:23:14] Running disable_ap.sh
[2024-11-11 17:26:44] Can't load input port: Digital Piano:Digital Piano MIDI 1 20:0
[2024-11-11 17:26:44] Can't load input port: RtMidiOut Client:RtMidi output 130:0
[2024-11-11 17:26:45] hostapd package is installed
[2024-11-11 17:26:48] Starting webinterface
[2024-11-11 17:26:48] Running disable_ap.sh
[2024-11-12 08:40:12] Error while getting ports 'NoneType' object has no attribute 'poll'

Environment

• Python version: 3.9.2
• No LCD screen, I'm using only the web interface

[taherromdhane]

When debugging here's the stack trace of the error:

Exception has occurred: TypeError       (note: full exception trace is shown but execution is paused at: <module>)
'NoneType' object is not subscriptable
  File "D:\Work\Projects\piano led\Piano-LED-Visualizer\lib\savemidi.py", line 50, in add_control_change
    self.messages_to_save["main"].append(["control_change", time_value, status, channel, control, value])
  File "D:\Work\Projects\piano led\Piano-LED-Visualizer\visualizer.py", line 495, in <module> (Current frame)
    saving.add_control_change("control_change", 0, control, value, midiports.last_activity)
TypeError: 'NoneType' object is not subscriptable

[taherromdhane]

Update:

When investigating more I found that it might be a race condition, since the call to

    def add_control_change(self, status, channel, control, value, time_value):
        self.messages_to_save["main"].append(["control_change", time_value, status, channel, control, value])

in main thread was made before the initialization of messages_to_save in the midi controller thread (I assume ?)

def start_recording(self):
        self.is_recording = True
        self.menu.render_message("Recording started", "", 500)
        self.messages_to_save = dict()
        self.messages_to_save["main"] = []
        self.restart_time()
        self.first_note_time = 0

my theory is that the call to MenuLCD.render_message is delaying the midi controlling thread right after we set is_recording to true, thus when the main thread tries to save midi by calling add_control_change the exception is thrown.

[jka-kan]

Does changing the order in start_recording help? Initialize self.messages_to_save before setting self.is_recording = True?
I also noticed that in line 73 self.messages_to_save is initialized as a list. Is this intentional or should it be a dict with key "main" always available in case of something wants to write to it even though it is not expected?

[taherromdhane]

@jka-kan changing the order fixed the problem for me, I might open a pull request for that