Initial commit: QobuzD - Qobuz Connect renderer for Linux

Rust-based QConnect renderer with:
- QConnect WebSocket protocol (hand-rolled protobuf)
- Audio playback via Symphonia + cpal
- Play, pause, resume, volume, skip support
- Correct BufferState/PlayingState enum values per proto spec
- Server-driven queue management (no local queue)
- Periodic position reporting for track-end detection

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

decode_burp.py

@@ -0,0 +1,172 @@
+#!/usr/bin/env python3
+"""Decode QConnect WebSocket messages from Burp capture."""
+import json, sys
+
+def decode_varint(data, pos):
+    val = 0; shift = 0
+    while pos < len(data):
+        b = data[pos]; pos += 1
+        val |= (b & 0x7F) << shift
+        if not (b & 0x80): return val, pos
+        shift += 7
+    return val, pos
+
+def parse_fields(data):
+    fields = []; pos = 0
+    while pos < len(data):
+        if pos >= len(data): break
+        tag, pos = decode_varint(data, pos)
+        fnum = tag >> 3; wt = tag & 7
+        if wt == 0:
+            val, pos = decode_varint(data, pos)
+            fields.append((fnum, wt, val.to_bytes(8, 'little')))
+        elif wt == 1:
+            fields.append((fnum, wt, data[pos:pos+8])); pos += 8
+        elif wt == 2:
+            ln, pos = decode_varint(data, pos)
+            fields.append((fnum, wt, data[pos:pos+ln])); pos += ln
+        elif wt == 5:
+            fields.append((fnum, wt, data[pos:pos+4])); pos += 4
+        else: break
+    return fields
+
+def get_varint(fields, num):
+    for f, w, d in fields:
+        if f == num and w == 0:
+            return int.from_bytes(d[:8], 'little')
+    return None
+
+def get_bytes(fields, num):
+    for f, w, d in fields:
+        if f == num and w == 2: return d
+    return None
+
+def get_fixed32(fields, num):
+    for f, w, d in fields:
+        if f == num and w == 5: return int.from_bytes(d[:4], 'little')
+    return None
+
+def get_fixed64(fields, num):
+    for f, w, d in fields:
+        if f == num and w == 1: return int.from_bytes(d[:8], 'little')
+    return None
+
+MSG_NAMES = {
+    1: "ERROR", 21: "RNDR_JOIN", 23: "STATE_UPDATED", 25: "VOLUME_CHANGED",
+    28: "QUALITY_CHANGED", 29: "VOLUME_MUTED", 41: "SET_STATE", 42: "SET_VOLUME",
+    43: "SET_ACTIVE", 44: "SET_QUALITY", 45: "SET_LOOP", 46: "SET_SHUFFLE",
+    47: "MUTE_VOLUME", 61: "CTRL_JOIN", 66: "QUEUE_REQ", 67: "QUEUE_REQ2",
+    75: "QUEUE_UPDATE", 76: "SESSION_SETUP", 77: "ACK_JOIN", 79: "TRACK_LIST",
+    82: "SRV_STATE_ECHO", 83: "DEVICE_LIST", 86: "SRV_VOL_ECHO",
+    87: "SRV_VOL_ECHO2", 90: "SRV_QUEUE_INFO", 91: "SRV_QUEUE_RESP",
+    97: "SRV_ACK", 98: "SRV_ACK2", 99: "SRV_QUALITY_ECHO",
+    100: "SRV_QUALITY_INFO", 103: "SRV_TRACKLIST_RESP"
+}
+
+def decode_renderer_state(data):
+    """Decode RendererState proto"""
+    f = parse_fields(data)
+    ps = get_varint(f, 1)
+    bs = get_varint(f, 2)
+    pos_data = get_bytes(f, 3)
+    dur = get_varint(f, 4)
+    qi = get_varint(f, 6)
+    nqi = get_varint(f, 7)
+
+    pos_ms = None; ts = None
+    if pos_data:
+        pf = parse_fields(pos_data)
+        ts = get_fixed64(pf, 1)
+        pos_ms = get_varint(pf, 2)
+
+    return f"playing={ps} buffer={bs} pos={pos_ms}ms dur={dur}ms qi={qi} nqi={nqi}"
+
+def decode_set_state(data):
+    """Decode SET_STATE (type 41) payload"""
+    f = parse_fields(data)
+    ps = get_varint(f, 1)
+    pos = get_varint(f, 2)
+    qv = get_bytes(f, 3)
+    ct = get_bytes(f, 4)
+    nt = get_bytes(f, 5)
+
+    qv_str = ""
+    if qv:
+        qvf = parse_fields(qv)
+        qv_str = f" qver={get_varint(qvf, 1)}.{get_varint(qvf, 2)}"
+
+    ct_str = ""
+    if ct:
+        ctf = parse_fields(ct)
+        ct_str = f" cur_track(qi={get_varint(ctf, 1)} tid={get_fixed32(ctf, 2)})"
+
+    nt_str = ""
+    if nt:
+        ntf = parse_fields(nt)
+        nt_str = f" next_track(qi={get_varint(ntf, 1)} tid={get_fixed32(ntf, 2)})"
+
+    return f"playing_state={'None' if ps is None else ps} pos={pos}{qv_str}{ct_str}{nt_str}"
+
+def process_message(payload_str, direction):
+    data = payload_str.encode('latin-1')
+    if len(data) < 2: return
+
+    # Decode frame layer
+    pos = 0
+    while pos < len(data):
+        if pos >= len(data): break
+        ft = data[pos]; pos += 1
+        flen, pos = decode_varint(data, pos)
+        if pos + flen > len(data): break
+        fbody = data[pos:pos+flen]; pos += flen
+
+        if ft != 6: continue  # only data frames
+
+        # Parse frame body fields
+        ff = parse_fields(fbody)
+        f7 = get_bytes(ff, 7)
+        if not f7: continue
+
+        # Inside f7, field 3 = QConnect message
+        cf = parse_fields(f7)
+        for cfnum, cwt, cdata in cf:
+            if cfnum != 3 or cwt != 2: continue
+            mf = parse_fields(cdata)
+            mt = get_varint(mf, 1)
+            if mt is None: continue
+
+            name = MSG_NAMES.get(mt, f"TYPE_{mt}")
+            payload = get_bytes(mf, mt)
+
+            extra = ""
+            if mt == 23 and payload:  # STATE_UPDATED
+                # Unwrap field 1 (RendererState wrapper)
+                sf = parse_fields(payload)
+                state_data = get_bytes(sf, 1)
+                if state_data:
+                    extra = " " + decode_renderer_state(state_data)
+                else:
+                    extra = " " + decode_renderer_state(payload)
+            elif mt == 41 and payload:  # SET_STATE
+                extra = " " + decode_set_state(payload)
+            elif mt == 82 and payload:  # SRV_STATE_ECHO
+                sf = parse_fields(payload)
+                state_data = get_bytes(sf, 1)
+                if state_data:
+                    extra = " " + decode_renderer_state(state_data)
+
+            arrow = ">>>" if "CLIENT" in direction else "<<<"
+            print(f"  {arrow} {name}({mt}){extra}")
+
+# Read from burp JSON
+import subprocess
+# Just process messages passed on stdin
+for line in sys.stdin:
+    line = line.strip()
+    if not line: continue
+    try:
+        msg = json.loads(line)
+        d = msg.get('direction', '')
+        p = msg.get('payload', '')
+        process_message(p, d)
+    except: pass