Question: In the PSS buffering model, what triggers the removal of a video frame from the hypothetical pre-decoder buffer?
Option 1: Expiration of the initial pre-decoder buffering period
Option 2: Receipt of a new SP PLAY request
Option 3: When both the decoding timer reaches the scheduled playback time of the frame and the previous video frame has been totally removed from the pre-decoder buffer
Option 4: Completion of the decoding timer's cycle
Explanation: According to the PSS buffering model, the removal of a video frame from the hypothetical pre-decoder buffer is initiated when two specific conditions are met simultaneously: (1) the decoding timer has reached the scheduled playback time of the frame, and (2) the previous video frame has been completely removed from the pre-decoder buffer. This ensures synchronized playback and prevents buffer overflow or underflow, highlighting the importance of timing and sequence in video streaming over packet-switched networks.