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• Revision 52256cdbca : Modify static threshold calculation Used 3 * standard_deviation in internal thr

  26 juillet 2013, par Yunqing Wang

  Changed Paths :
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Modify static threshold calculation

  Used 3 * standard_deviation in internal threshold calculation
  instead of fit curve. This actually approached the algorithm
  better.
  For comparison, similar tests were done :
  The overall psnr loss is less than before.
  1. derf set :
  when static-thresh = 1, psnr loss is 0.329% ;
  when static-thresh = 500, psnr loss is 0.970% ;
  2. stdhd set :
  when static-thresh = 1, psnr loss is 0.922% ;
  when static-thresh = 500, psnr loss is 1.307% ;

  Similar speedup is achieved. For example,
  clip bitrate static-thresh psnr time
  akiyo(cif) 500 0 48.952 5.077s(50f)
  akiyo 500 500 48.866 4.169s(50f)

  parkjoy(1080p) 4000 0 30.388 78.20s(30f)
  parkjoy 4000 500 30.367 70.85s(30f)

  sunflower(1080p) 4000 0 44.402 74.55s(30f)
  sunflower 4000 500 44.414 68.69s(30f)

  Change-Id : Ic78833642ce1911dbbd1cb6c899a2d7e2dfcc1f3

• Revision 01a37177d1 : Refactor rd_pick_partition for parameter control This commit changes the partit

  20 août 2013, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_onyx_if.c

  
  
  Refactor rd_pick_partition for parameter control

  This commit changes the partition search order of superblocks from
  SPLIT, NONE, HORZ, VERT to NONE, SPLIT, HORZ, VERT for
  consistency with that of sub8x8 partition search. It enable the use
  of early termination in partition search for all block sizes.

  For ped_area_1080p 50 frames coded at 4000 kbps, it makes the runtime
  goes down from 844305ms -> 818003ms (3% speed-up) at speed 0.

  This will further move towards making the in-search partition types
  configurable, hence unifying various speed-up approaches.

  Some speed 1 and 2 features are turned off during the refactoring
  process, including :
  disable_split_var_thresh
  using_small_partition_info

  Stricter constraints are applied to use_square_partition_only for
  right/bottom boundary blocks. Will bring back/refine these features
  subsequently. At this point, it makes derf set at speed 1 about
  0.45% higher in compression performance, and 9% down in run-time.

  Change-Id : I3db9f9d1d1a0d6cbe2e50e49bd9eda1cf705f37c

• ffmpeg on android : playing MPEG2 TS udp multicast stream

  27 août 2013, par user1513822

  I want to make android media player using ffmpeg.
  (catch MPEG2 TS multicast stream via WIFI network and decode it)
  I checked followings :

  • My iptime AP supports WIFI multicast protocol.
    (send multicast stream in wired PC, and wifi connected PC can receive it)
  • My Android phone can receive multicast stream via WIFI.
    I coded NDK socket programming which is join udp multicast group and receive packets
    (I added multicast access grant to AndroidManifest.xml)
  • FFMPEG library is ported to android and it can play local media file.

  But when I try to open network stream using FFMPEG library, avformat_open_input() function returns fail.

  gFormatCtx = avformat_alloc_context();
  
  av_register_all(); 
  
  avcodec_register_all(); 
  
  avformat_network_init(); 
  
  if(avformat_open_input(&gFormatCtx,"udp://@239.100.100.100:4000",NULL,NULL) != 0)
  
      return -2;

  this code always return "-2".
  If I use "av_dict_set()" api, which option should I use ?

  av_dict_set(&options, "udp_multicast", "mpegtsraw", 0);

  please let me know what should I check for avformat_open_input error ?

  thanks.