Video Decoder DPB Emptying at CRA Random Access Points

The patent applies preliminary action by setting the no_output_of_prior_pics_flag in advance before decoding random access point pictures (CRA, GRA, GDR). This flag pre-instructs the decoder to empty the DPB of previously-decoded pictures that would otherwise be unavailable for reference, ensuring reference picture availability is maintained while preventing DPB overflow that would disrupt continuous playback.

The patent applies local quality by selectively managing DPB contents based on picture type. Instead of uniformly emptying the entire DPB, the patent uses the no_output_of_prior_pics_flag to selectively remove only those previously-decoded pictures that would cause overflow or are not needed for reference, while preserving pictures that are still useful for decoding future frames. This localized management maintains reference picture availability where needed while preventing overflow.

The patent applies parameter changes by introducing and manipulating the no_output_of_prior_pics_flag parameter in the video bitstream. This syntax element enables dynamic control of DPB management at random access points, allowing the system to optimize between compression efficiency and decoding reliability. By changing this parameter, the system can prevent DPB overflow without requiring additional buffer resources, thus maintaining image quality while managing data size for network transmission.