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• 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 ?​

• lavfi/eq : rework expression evaluation

  13 mars 2015, par arwa arif

  lavfi/eq : rework expression evaluation
  In particular, add support for t, pos, n, r parameters, and add an eval
  
  mode option.
  Also, partially reword option documentation.
  With several major edit by Stefano Sabatini.
  Signed-off-by : Stefano Sabatini <stefasab@gmail.com>
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/version.h
  • [DH] libavfilter/vf_eq.c
  • [DH] libavfilter/vf_eq.h

• avfilter/avfiltergraph : Avoid allocation for AVFilterGraphInternal

  10 février 2024, par Andreas Rheinhardt

  avfilter/avfiltergraph : Avoid allocation for AVFilterGraphInternal
  To do this, allocate AVFilterGraphInternal jointly with AVFilterGraph
  
  and rename it to FFFilterGraph in the process (similarly to
  
  AVStream/FFStream).
  
  The AVFilterGraphInternal* will be removed on the next major version
  
  bump.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavfilter/avfilter.c
  • [DH] libavfilter/avfilter_internal.h
  • [DH] libavfilter/avfiltergraph.c
  • [DH] libavfilter/pthread.c