Get the dts that was before the current byte in the adapter.
When distance is given, the amount of bytes between the dts and the current position is returned.
The dts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when the adapter is first created or when it is cleared. This also means that before the first byte with a dts is removed from the adapter, the dts and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.
| this |
a Adapter |
| distance |
pointer to location for distance, or |
|
The previously seen dts. |