basesink: Add property to handle seamless-seek by sink
Submitted by Seungha Yang
There seems to no way to set segment.rate immediately in pipeline without flush.
To mimic the feature, there might be 2 options but seems ugly for me.
- Reduce queue size in pipeline as much as possible and use non-flush seek.
- Adjust clock maybe??
Another option is that make use of step event but originally step event is not for this feature. So we need more pretty way to change rate immediately.
One of use case of this rate change is, Youtube rate change which is perfectly seamless.