More protocol decoding

encoding.py

@@ -0,0 +1,78 @@
+import math
+from typing import Optional, List
+
+import mido
+
+PREFIX = [0x00, 0x20, 0x0D, 0x10]
+SUBID_IN_STATUS = 0
+SUBID_IN_RMS = 1
+SUBID_IN_PEAK = 2
+
+SUBID_OPTIONS = 0
+SUBID_MIXER = 1
+SUBID_LOOPBACK = 2
+SUBID_INPUT_OUTS = 3
+SUBID_GAIN = 4
+
+def decode_message(msg: mido.Message) -> tuple[Optional[int], Optional[List[int]]]:
+    msg_bytes = msg.bytes()
+    if msg_bytes[:5] != [0xF0] + PREFIX:
+        return None, None # noop
+
+    result_words = []
+    try:
+        chunks = zip(*[iter(msg_bytes[6:-1])] * 5, strict=True)
+        for packed in chunks:
+            value = packed[4] << 28 | packed[3] << 21 | packed[2] << 14 | packed[1] << 7 | packed[0]
+            result_words.append(value)
+    except ValueError:
+        pass  # invalid message
+
+    return msg_bytes[5], result_words
+
+
+def encode_message(subid: int, payload: List[int]) -> mido.Message:
+    data = [subid]
+    for word in payload:
+        data += [
+            word & 0x7F,
+            word >> 7 & 0x7F,
+            word >> 14 & 0x7F,
+            word >> 21 & 0x7F,
+            word >> 28 & 0x7F,
+        ]
+
+    return mido.Message('sysex', data=PREFIX + data)
+
+
+def hex_format(msg, width=2):
+    return ' '.join([("{x:0" + str(width) + "x}").format(x=x) for x in msg])
+
+
+def bin_format(msg, width=32):
+    return ' '.join([("{x:0" + str(width) + "b}").format(x=x) for x in msg])
+
+
+def get_bitfield(word, position, length):
+    return (word >> position) & ((1 << length) - 1)
+
+
+def set_bitfield(word, val, position, length):
+    mask = ((1 << length) - 1)
+    val = (val & mask) << position
+    return (word & mask << position) | val
+
+
+def level_to_db(val):
+    return 6 + (val - 0xFF) / 2
+
+
+def fader_to_db(val):
+    return 6 + (abs(val) - 0xFF) / 2
+
+
+def format_db(val, min_db=-120):
+    if math.isnan(val) or val <= min_db:
+        return '∞'
+    else:
+        return format(val, '.1f')