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ADV8003 Latency - Additional Questions and Clarification

Question asked by danngai on Mar 25, 2014
Latest reply on Apr 3, 2014 by GuenterL

Hello Video Experts,



First, Thank you for all of your help and quick responses on previous questions!  Ok, here goes.


1.  ADV8003 HW Manual. Paragraph  and  Normal and Low Latency paragraphs.   Table 24.  For the Interlaced rates  [i.e. 480i/60Hz], the frame latency listed in the 480p/720p/1080p "output" column is 1.1~2.3 frames latency.  In this case of interlaced to progressive conversion, is a frame considered a 1/60 second [progressive] frame or a 1/30 second [interlaced] frame? 1.1 frames latency could mean 1.1 x 16.67ms or 1.1 x 33.33ms and we need to double check. 


2.  From what we’ve seen of other motion-adaptive de-interlacers,  some can perform this function in two lines of latency due to the using of look-back field buffers instead of buffering up one or more full fields prior to the start of outputting the progressive video.  If possible, can you explain the general function of the motion adaptive de-interlacer?


3.  Our requirements are that we have to get from video in to output port in 20ms.  With 2.3 frames of latency, and hoping that a frame in the 480i/60 case is hopefully 16.67ms, we might be able to make adjustments.  However, is there a detailed breakdown of the latencies for the individual processing functional blocks?     The general "total" latency doesn't provide us enough information to inteligently optimize the video processing to meet the our 20ms total latency while providing the video processing functions that the customer requires.  We won't be able to know if we can meet the customer's latency requirement until we manufacture a board.


4. Page 188 of HW Manual. 


          “When crop or album mode is enabled, frame latency will be different from that listed in Table 33”


Then it goes on to say that one can find out the actual latency at run-time using the latency measurement registers.  We will be needing both of these these modes in addition to the others and will need to fit within the 20ms requirement.  What is the "difference" in latency that is expected for crop/album mode?  We need more specific numbers so we can do our latency stack up with our desired features.  Is it possible to get this number?  Is there a range difference that can be expected?  Ball park estimate?


Thank you for your help!