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• 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

• MLT melt slideshow on Windows : unable to control output video length and problems with using wildcards

  10 novembre 2020, par Tjk

  I am using the following command within a batch script to, hopefully, eventually programmatically create simple video slideshows with transitions :

  


  melt 131.jpg 132.jpg 133.jpg ttl=75 -attach crop center=1 -filter luma cycle=75 duration=25 -transition mix -consumer avformat:out.mp4 frame_rate_num=30 frame_rate_den=1


  


  Most of this command is an adaptation for Windows of this command on the MLT website blog (with the exception of the part that scales and transforms the image). For some reason when I run this, however, the output video file is 25 minutes long !

  


  I have two main questions :

  


  a. How do I properly control the duration of each image in the video ? I have experimented quite a bit with changing the parameters and I have a semi-decent understanding of what they all mean (I am a newbie to MLT but I figured that there's no way to do something like this easily in FFMPEG alone). The only way I have found to decrease the duration with any amount of control is to increase the output framerate to absurd numbers (which, of course, is not ideal as it's a massive waste of time and energy and still doesn't really solve the issue).

  


  b. How do I use a wildcard to input all the .jpg files in a folder on Windows ? I tried adding *.jpg but that didn't work and I don't know how else to do it within a batch script (I tried using the following code to get the file names as a variable, but I wasn't able to get string concatenation working correctly because it only outputs the final file name)

  


  set files=
for /r %%i in (*.jpg) do (
    echo %%i
    set files=%files% "%%i"
)
echo %files%


  


  Thank you for any suggestions !

  


• avcodec/aacenc : add strict bit rate control option

  25 avril 2023, par Jeremy Wu

  avcodec/aacenc : add strict bit rate control option
  In certain use cases, controlling the maximum frame size is critical. An
  
  example is when transmitting AAC packets over Bluetooth A2DP.
  While the spec allows the packets to be fragmented (but UNRECOMMENDED),
  
  in practice most headsets do not recognize nor reassemble such packets.
  In this patch, we allow setting `bit_rate_tolerance` to 0 to indicate
  
  that the specified bit rate should be treated as an upper bound up to
  
  frame level.
  Signed-off-by : Jeremy Wu <jrwu@chromium.org>
  

  • [DH] libavcodec/aacenc.c
  • [DH] libavcodec/options_table.h