ytdl-org/youtube-dl · error · NotImplementedError
Unsupported (void) property %r on %r
Error message
Unsupported (void) property %r on %r
What it means
Error "Unsupported (void) property %r on %r" thrown in ytdl-org/youtube-dl.
Source
Thrown at youtube_dl/swfinterp.py:649
args = list(reversed(
[stack.pop() for _ in range(arg_count)]))
obj = stack.pop()
if isinstance(obj, _AVMClass_Object):
func = self.extract_function(obj.avm_class, mname)
res = func(args)
assert res is undefined
continue
if isinstance(obj, _ScopeDict):
assert mname in obj.avm_class.method_names
func = self.extract_function(obj.avm_class, mname)
res = func(args)
assert res is undefined
continue
if mname == 'reverse':
assert isinstance(obj, list)
obj.reverse()
else:
raise NotImplementedError(
'Unsupported (void) property %r on %r'
% (mname, obj))
elif opcode == 86: # newarray
arg_count = u30()
arr = []
for i in range(arg_count):
arr.append(stack.pop())
arr = arr[::-1]
stack.append(arr)
elif opcode == 93: # findpropstrict
index = u30()
mname = self.multinames[index]
for s in reversed(scopes):
if mname in s:
res = s
break
else:
res = scopes[0]View on GitHub (pinned to 956b8c5855)
Solutions
- Update youtube-dl; the SWF uses an unsupported void property.
When it happens
Trigger: Thrown at youtube_dl/swfinterp.py:649 when the library encounters an invalid state.
Common situations: See trigger scenarios.
AI-assisted analysis of ytdl-org/youtube-dl@956b8c5855 (2026-08-14).
Data as JSON: /api/errors/4d1bf08e1eef183b.
Report an issue: GitHub.