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• Revision eec3def7c5 : Modified no memory rate control. This 2-pass rate control setting allocates bit

  16 octobre 2013, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_onyx_if.c

  
   Modify /vp9/encoder/vp9_onyx_int.h

  
   Modify /vp9/encoder/vp9_ratectrl.c

  
  
  Modified no memory rate control.

  This 2-pass rate control setting allocates bits based
  on first pass stats to each kf group, gf group and individual
  frame but does not correct the bits left and allocation after
  each frame.

  In other words it recommends a bit allocation for each frame
  but does not try and correct any over or under spend on a
  frame over the remainder of the clip. This reduces the accuracy
  of rate control in terms of hitting an average bitrate but prevents
  problems that may arise because early frames either use to many
  or too few bits. This mode is currently more inclined to undershoot
  than overshoot (particularly at higher data rates).

  Also minor changes to rate of adaption when recode loop is not
  enabled.

  This mode is currently enabled by default for VBR.
  It gives the following % performance gains.

  derf +0.467, +1.072
  yt 2.962, 2.645
  stdhd 1.682, 1.595,
  yt-hd 2.3, 2.174

  Change-Id : I3c84a9bf8884e5b345698ff0e19187f792c2f3a0

• Ffmpeg gdigrab records black window when capturing graphics-intensive flight simulator

  23 mars 2021, par iter

  I am trying to capture video from XPlane, a popular flight simulator. I'm running on Windows.

  



  Normally, I can capture individual windows using gdigrab, but when I use it on an XPlane window like so...

  



  ffmpeg -f gdigrab -framerate 30 -i "X-System" -b:v 300K capture.mp4


  



  ...I get a video file that's the right dimensions but is all black. I imagine this may have something to do with how XPlane talks directly to the GPU. I should add that if I capture the entire desktop like so...

  



  ffmpeg -f gdigrab -framerate 30 -i desktop -b:v 300K capture.mp4


  



  ...I get everything including the simulator window, but naturally with unrelated windows in the capture, including windows sitting on top of the simulator window.

  



  Is there a way for gdigrab to capture video this GPU-intensive window alone ? Is there a different tool I can use ?

  


• gstreamer vaapih264enc generated ts segment dont play on AVPlayer

  21 juin 2022, par Guru Govindan

  I have a pipeline that transcodes an rtsp stream into hls segments. The manifest is playable in browsers(with hlsjs) and ffplay and VLC. However when I play the stream or individual ts segments in Quicktime player or my IOS App that uses avplayer, it doesnt work.

  


  This seems to be an issue only with vaapih264enc. When I try the same with software encode like x264enc it works fine.

  


  The following is a simple pipeline where this is reproducible.

  


  GST_DEBUG=3 gst-launch-1.0 rtspsrc location='rtsp://user:pass@10.10.10.12:554/' name=rtpsrc0 \
 rtpsrc0. ! rtph264depay ! queue ! decodebin ! vaapih264enc ! mpegtsmux name=mux ! filesink location=mymux.ts \
 rtpsrc0. ! decodebin ! queue ! fdkaacenc ! mux.


  


  when I run the following command to copy the encoded stream as is from the generated ts segment it works

  


  ffmpeg -i mymux.ts -c copy mymux_ffmpeg.ts


  


  Is the ffmpeg adding some additional header information that the quicktime player is happy with ?

  


  I appreciate any help with this.