y, an encoder can be able to use at least half of the DPB capacity specified in Annex A and clauses G.10 and H.10 while allowing the decoder to use the remaining capacity for storage of unfiltered pictures that have been indicated as preferable for display until the output time arrives for those pictures. Rec. ITU-T H.264 (01/2012) dec_frame_buffering_constraint_flag equal to 1 indicates that the use of the frame buffering capacity of the HRD decoded picture buffer (DPB) as specified by max_dec_frame_buffering has been constrained such that the coded video sequence will not require a decoded picture buffer with more than Max( 1, max_dec_frame_buffering) frame buffers to enable the output of the decoded filtered or unfiltered pictures, as indicated by the deblocking filter display preference SEI messages, at the output times specified by the dpb_output_delay of the picture timing SEI messages. dec_frame_buffering_constraint_flag equal to 0 indicates that the use of the frame buffering capacity in the HRD may or may not be constrained in the manner that would be indicated by dec_frame_buffering_constraint_flag equal to 1. For purposes of determining the constraint imposed when lec_frame_buffering_constraint_ flag is equal to 1, the quantity of frame buffering capacity used at any given point in time by each frame buffer of the DPB that contains a picture shall be derived as follows: If both of the following criteria are satisfied for the frame buffer, the frame buffer is considered to use two frame buffers of capacity for its storage. The frame buffer contains a frame or one or more fields that is marked as "used for reference", and The frame buffer contains a picture for which both of the following criteria are fulfilled: The HRD output time of the picture is greater than the given point in time. It has been indicated in a deblocking filter display preference SEI message that the encoder preference for the picture is for the display process to display the cropped result of the picture construction process prior to