[mpeg2-dev] SEQUENCE_MODIFIED and changes in byterate

[Marian Ď. <md...@bt...>]

Hi all,

  I'd like to ask for comments about the following behaviour:

Some DVB-S transpoders are using VBR for all TV stations, and seem to
change maxBps in almost every sequence header (see below).

  With libmpeg2-0.5.1, this triggers SEQUENCE_MODIFIED state, which
invokes player routines for aspect ratio changes etc.

  libmpeg2-0.4.1 was deliberately ignoring changes in maxBps and 
gave SEQUENCE_REPEATED state in such case.

  Should the players now check for this situation, or would it make sense
to put back the previous behaviour - i.e. giving SEQUENCE_REPEATED 
from libmpeg2 even if maxBps was changed?


        Thanks & kind regards,

               M.

  

   ff1fe S- --- --- - SEQUENCE MPEG2 MP@ML 720x576 chroma 360x288 fps 25
maxBps 976100 vbv 229376 picture 720x576 display 720x576 pixel 64x45 guessed
118x81
  1b6266 S- --- --- - SEQUENCE_MODIFIED MPEG2 MP@ML 720x576 chroma 360x288
fps 25 maxBps 976150 vbv 229376 picture 720x576 display 720x576 pixel 64x45
guessed 118x81
  2c16ee S- --- --- - SEQUENCE_MODIFIED MPEG2 MP@ML 720x576 chroma 360x288
fps 25 maxBps 705250 vbv 229376 picture 720x576 display 720x576 pixel 64x45
guessed 118x81
  386cc6 S- --- --- - SEQUENCE_MODIFIED MPEG2 MP@ML 720x576 chroma 360x288
fps 25 maxBps 722800 vbv 229376 picture 720x576 display 720x576 pixel 64x45
guessed 118x81
  4f82ee S- --- --- - SEQUENCE_MODIFIED MPEG2 MP@ML 720x576 chroma 360x288
fps 25 maxBps 976150 vbv 229376 picture 720x576 display 720x576 pixel 64x45
guessed 118x81
  661466 S- --- --- - SEQUENCE_REPEATED MPEG2 MP@ML 720x576 chroma 360x288
fps 25 maxBps 976150 vbv 229376 picture 720x576 display 720x576 pixel 64x45
guessed 118x81
  7813b6 S- --- --- - SEQUENCE_MODIFIED MPEG2 MP@ML 720x576 chroma 360x288
fps 25 maxBps 976100 vbv 229376 picture 720x576 display 720x576 pixel 64x45
guessed 118x81