decodebin3: Handle streams without CAPS or TIME segment
decodebin3 will do its best to figure out whether a parsebin is required to process the incoming stream.
The problem is that for push-based stream it could happen that the stream would not provide any caps, resulting in nothing being linked internally.
Furthermore, there is the possibility that a stream with caps would not be using a TIME segment, which is required for multiqueue to properly work.
In order to fix those two issues, we force the usage of parsebin on push-based streams:
- When the pad is linked, if upstream can't provide any caps
- When we get a non-TIME segment
Fixes #2521 (closed)