The associations responsible for the HD DVD and Blu-ray Disc standards approved the H.264 profile/level High@L4.1 for HD content, and High@L3.1 for SD content. As such, the Cyberlink decoder enforces compliance with the levels.
That has resulted in two implications:
1. H.264 video must comply with the L4.1 and L3.1 limitations for the Decoded Picture Buffer (DPB) size, which limits the video resolution and number of reference frames.
2. H.264 streams must declare L4.1 or L3.1 in the "level_idc" flag (set by --level with x264) in order to achieve smooth DXVA playback.
HD-HQ profile options:
--level 4.1 --ref 4 --mixed-refs --bframes 3 --b-rdo --bime --weightb --direct auto --filter -1:-1 --trellis 2 --partitions p8x8,b8x8,i4x4,i8x8 --8x8dct --vbv-bufsize 50000 --vbv-maxrate 50000 --me umh
SD-HQ profile options:
-level 3.1 --ref 8 --mixed-refs --bframes 3 --b-rdo --bime --weightb --direct auto --filter -1:-1 --trellis 2 --partitions p8x8,b8x8,i4x4,i8x8 --8x8dct --vbv-bufsize 14000 --vbv-maxrate 17500 --me umh