360 Systems MAXX-6T - Manual (Page 111)

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MAXX 6T Owner’s Manual Page 111
APPENDIX B – PROFILES AND GOP STRUCTURES
MPEG-2 Profiles
MPEG-2 accommodates certain sub-set functionality by defining a set of profiles and levels. MAXX
6T supports two of these.
Profile/Level Width Height Color Max. Bit Rate
Main Profile@Main Level 720 576 4:2:0 15 Mb/s
4:2:2 Profile@Main Level 720 576 4:2:2 50 Mb/s
Table 3 - Supported MPEG-2 Profiles
GOP Structure
GOP structure defines the MPEG Group of Pictures coding as combinations of I, P, and B frames.
The allowable combinations are presented in a drop-down list. I-Frame only encoding will produce
the least compressed picture and requires more hard disk space. However, I-frames facilitate frame-
accurate editing. For broadcast-quality resolution, I-frame encoding should be considered at 25
Mb/sec and above. Low bit rates should never be used with I-frame encoding.
Long-GOP video recorded with P and B frames produces superior image quality for a given data
rate, compared to I-frame. Most broadcasters go to air with 8, 10 or 12 Mb/sec content, having long
GOP length.
Image Servers produce and require Closed GOP architecture. Open GOP is not supported.
Encode Mode
MAXX 6Ts employ Variable Bit Rate (VBR) MPEG-2 encoding. For almost all broadcast
applications, VBR encoding produces superior results than its alternative, Constant Bit Rate.