ValkkaFS

Notes on the block and timestamp scheme

• Stream number 0 is always the "leading codec"

    A, a = frames from source A (mayor letter = KEY frame.  Designates time start, i.e. sps packet, etc.)
    B, b = frames from source B
    etc.
    
    Assume that if cameras are on-line, there is a key-frame from each camera in every block
    

                                                                BlockTable
                                                                
                                                                k-max, maximum KEY frame timestamp in block
                                                                max, maximum frame timestamp in block
                                                                
    time ->
                                                                k-max max       block
                                                                
    01 02 03 04 05 06 07 08 09 10 11 12 13 14                   12    14        10
    b  b  d  D  a  A  a  c  c  a  C  B  b  b                    

    15 16 17 18 19 20 21 22 23 24 25 26 27 28                   26    28        11
    a  a  B  c  A  C  b  b  c  b  a  D  d  a 

    29 30 31 32 33 34 35 36 37 38 39 40 41 42                   37    42        12
    A  b  B  c  d  C  d  d  D  a  a  b  c  a

Request time (21, 29) == (seek_time, end_time)

==>

Lower limit: we need that all cameras have stamped a key frame with =< 21. This way we can seek to t = 21.

{ all keyframes <= seek_time, at least if max(all keyframes) <= seek_time }

if any of the cameras has stamped > 21, needs earlier block

--> start from block 10 (search: last block of all blocks that have k-max =< 21)

Higher limit: all cameras have stamped >= 29 for any frame

if any of the cameras has stamped < 29, needs later block

--> last block to include is 12 (search: first block of all blocks that have max >= 29)