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• Measure "delta time" between two simulation conditions

  14 décembre 2017, par mrj

  i understand that to measure BD-BR and BD-PSNR 4 data points are required (4 differents QPs). i want to measure time difference between two simulation conditions and each QP provide me a time.

  should i calculate the time difference between each one of the four QPs and then the average of them all** ? thanks in advance.

  ** as in :

  deltaTimeQP22 = timeSimulation1QP22 - timeSimulation2QP22
  
  deltaTimeQP27 = timeSimulation1QP27 - timeSimulation2QP27
  
  deltaTimeQP32 = timeSimulation1QP32 - timeSimulation2QP32
  
  deltaTimeQP37 = timeSimulation1QP37 - timeSimulation2QP37
  
  deltaTime = (deltaTimeQP22 + deltaTimeQP27 + deltaTimeQP32 + deltaTimeQP37)/4

• Revision 897192be43 : Added one more reference frame LAST2_FRAME Under the experiment CONFIG_MULTI_RE

  21 août 2015, par Zoe Liu

  Changed Paths :
   Modify /configure

  
   Modify /vp9/common/vp9_blockd.h

  
   Modify /vp9/common/vp9_entropymode.c

  
   Modify /vp9/common/vp9_entropymode.h

  
   Modify /vp9/common/vp9_enums.h

  
   Modify /vp9/common/vp9_loopfilter.h

  
   Modify /vp9/common/vp9_onyxc_int.h

  
   Modify /vp9/common/vp9_pred_common.c

  
   Modify /vp9/common/vp9_pred_common.h

  
   Modify /vp9/decoder/vp9_decodeframe.c

  
   Modify /vp9/decoder/vp9_decodemv.c

  
   Modify /vp9/decoder/vp9_decoder.c

  
   Modify /vp9/encoder/vp9_bitstream.c

  
   Modify /vp9/encoder/vp9_denoiser.c

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_encoder.c

  
   Modify /vp9/encoder/vp9_encoder.h

  
   Modify /vp9/encoder/vp9_mcomp.c

  
   Modify /vp9/encoder/vp9_rd.c

  
   Modify /vp9/encoder/vp9_rd.h

  
   Modify /vp9/encoder/vp9_rdopt.c

  
   Modify /vpxenc.c

  
  
  Added one more reference frame LAST2_FRAME

  Under the experiment CONFIG_MULTI_REF. Current version shows
  LAST2 vs base in nextgen on the testset of derflr :

  (1) 8-bit : Average PSNR +0.53%
  (worst : students_cif : -0.247% ; best : mobile_cif : 1.902%)
  (2) 12-bit HBD : Average PSNR +0.63%
  (worst : pamphlet_cif : -0.213%, best : mobile_cif : 2.101%)

  More tuning on the reference frame context design and default
  probs are being conducted. This version does not guarantee to
  work with other experiments in nextgen. A separate CL will address
  the working with all other experiments.

  Change-Id : I7f40d2522517afc26ca389c995bad56989587f65

• x264 encoding taking longer when encoding static frames (than

  14 septembre 2015, par Danilo

  ​Hi,
  I’m using x264 for live video streaming and I’ve noticed that the thread
  responsible for encoding uses ​​more cpu (sometimes 50% more with 1920x1080) when the video stream is frozen (i.e. : camera is sending the same frame over an over again) or when I make it encode the same image over and over again.

  This seems somewhat counter intuitive to me, as I would expect x264 to use
  more processing power when encoding complex scenes other then static ones.

  My encoder settings are the following :

  1280x720 fps=25/1 timebase=0/0 bitdepth=8 cabac=0 ref=1 deblock=1:0:0 analyse=0x3:0x113
  
  me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1
  
  8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=1 lookahead_threads=0
  
  sliced_threads=0 slice_max_size=1190 nr=60 decimate=1 interlaced=0 bluray_compat=0
  
  constrained_intra=0 bframes=0 weightp=0  keyint=1200 keyint_min=120 scenecut=40
  
  intra_refresh=0 rc_lookahead=0 rc=crf mbtree=0 crf=24.0 qcomp=0.60 qpmin=0 qpmax=69
  
  qpstep=4 vbv_maxrate=1024 vbv_bufsize=350 crf_max=35.0 nal_hrd=none

  I created a github gist based on the example.c encoder bundled in x264’s
  source code and tested encoding times with it. (You can find it here :
  https://gist.github.com/danilogr/ab4976ff4e0831ab274b)

  Average encoding time for the static scene is 38% bigger than for a scene
  with movements. (You can find my test case and also the output from my test
  encoder on the link above).

  ​​
  ​I’ve also noticed that by setting ​​scenecut=0, subme=0, trellis=0 and me=dia I can get rid of this problem​, but with noticeable quality​ decrease.

  ​
  ​Could anyone, please, shed some light on the reasons for this odd behavior ?
  ​Also, what can be done in order to avoid this situation without a major decrease in quality ?​