Seek isn't supported for this input

[InkosiZhong]

When I try to use nvc.SeekContext to seek a specified frame from a video encoded by VPF, an error will raise:

Seek isn't supported for this input

However, using set(cv2.CAP_PROP_POS_FRAMES, xxx) of cv2.VideoCapture can successfully seek the frame.
Meanwhile, nvc.SeekContext is able to seek a frame from any video encoded by PyAV or FFmpeg.

encoder | VPF | PyAV/FFmpeg | VPF
decoder | VPF | VPF         | cv2
seek    | ❎  | ✅         | ✅

To sum up, VPF cannot jump to a certain frame of a video encoded with VPF.

[RomanArzumanyan]

Hi @InkosiZhong

VPF produces Annex.B elementary bitstream, you need to put it into container using muxer of choice.
E. g. PyAV will do. Then you can try to seek. Elemetary bitstream doesn't contain timestamps which are used for seek operations.