When a YouTube playlist or channel listing has more than one page of videos, the continuation URLs specify `youtube.com` instead of `www.youtube.com`. This causes an unnecessary HTTP round-trip for each continuation page the extractor accesses.
**Example**
<code>
youtube-dl -s --print-traffic https://www.youtube.com/channel/UCBR8-60-B28hp2BmDPdntcQ
</code>
**Before**
<code>
GET /playlist?list=UUBR8-60-B28hp2BmDPdntcQ&disable_polymer=true
Host: www.youtube.com
HTTP/1.1 200 OK
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIsEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoOZWdaUVZEcERSMUUlM0Q%253D&disable_polymer=true
Host: youtube.com
HTTP/1.1 301 Moved Permanently
Location: https://www.youtube.com/browse_ajax?action_continuation=1&continuation=4qmFsgIsEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoOZWdaUVZEcERSMUUlM0Q%253D&disable_polymer=true
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIsEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoOZWdaUVZEcERSMUUlM0Q%253D&disable_polymer=true
Host: www.youtube.com
HTTP/1.1 200 OK
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIqEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoMZWdkUVZEcERUV2RD&disable_polymer=true
Host: youtube.com
HTTP/1.1 301 Moved Permanently
Location: https://www.youtube.com/browse_ajax?action_continuation=1&continuation=4qmFsgIqEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoMZWdkUVZEcERUV2RD&disable_polymer=true
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIqEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoMZWdkUVZEcERUV2RD&disable_polymer=true
Host: www.youtube.com
HTTP/1.1 200 OK
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIqEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoMZWdkUVZEcERTM2RE&disable_polymer=true
Host: youtube.com
HTTP/1.1 301 Moved Permanently
Location: https://www.youtube.com/browse_ajax?action_continuation=1&continuation=4qmFsgIqEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoMZWdkUVZEcERTM2RE&disable_polymer=true
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIqEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoMZWdkUVZEcERTM2RE&disable_polymer=true
Host: www.youtube.com
HTTP/1.1 200 OK
</code>
**After**
<code>
GET /playlist?list=UUBR8-60-B28hp2BmDPdntcQ&disable_polymer=true
Host: www.youtube.com
HTTP/1.1 200 OK
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIsEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoOZWdaUVZEcERSMUUlM0Q%253D&disable_polymer=true
Host: www.youtube.com
HTTP/1.1 200 OK
GET /browse_ajax?action_continuation=1&continuation=4qmFsgIqEhpWTFVVQlI4LTYwLUIyOGhwMkJtRFBkbnRjURoMZWdkUVZEcERUV2RD&disable_polymer=true
Host: www.youtube.com
HTTP/1.1 200 OK
</code>
The old code now works again, but it downloads without limit. This is why a limit of 1000 videos is added, it can be overwritten with the `--max-downloads` option - that way, only so many ids will be extracted as videos downloaded
This moves feed extraction from using html content to json metadata. However, loading additional pages no longer works.
The _extract_video_info function also returns a continuation object that contains some metadata that - together with an API key that is in the page source - might be used to request the next page.
