Patent ID: 7650031

Claim:
A method performed by a device for identifying black frames within a sequence of frames, each frame having blocks, the method comprising: receiving by the device the sequence of frames that includes base frames and non-base frames, a non-base frame being dependent on a decoding of a block of a base frame; decoding by the device the blocks of base frames of the received sequence of frames; for each of the base frames, determining whether each of the decoded blocks of the base frame is black or not black; when a decoded block of the base frame is determined to be non-black, indicating that the base frame is non-black; and when no decoded block of the base frame is determined to be non-black, indicating that the base frame is black; and for each of the non-base frames of the received sequence of frames, for blocks of the non-base frame, decoding by the device the block of the non-base frame; determining whether the decoded block of the non-base frame is black or not black; and when the decoded block of the non-base frame is determined to be non-black, indicating that the non-base frame is non-black and suppressing the decoding of other blocks of the non-base frame; and when no decoded block of the non-base frame is determined to be non-black, indicating that the non-base frame is black.