```py
video_ids = []
q = Queue()
# ydl using extract_flat: True
q.put(ydl.extract_info(channel_url))
while not q.empty():
    info = q.get()
    if info['_type'] == 'url':
        if info.get('ie_key') == 'Youtube':
            video_ids.append(info['id'])
        else:
            q.put(ydl.extract_info(info['url']))
    elif info['_type'] == 'playlist':
        for entry in info['entries']:
            q.put(entry)   
print(len(video_ids))
```