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• recompiling audio from a movie source

  4 novembre 2016, par jkushner

  Is it possible to recompile movie files to re-stream the audio so they all have the same volume level ? We’ve got users submitting videos and to me it seems some are higher in volume whereas others are not, and they all have the same volume level on the controls, and i’d like to standardize this so all movie files have the same volume levels.

  I was thinking of ffmpeg although I only have novice knowledge of this technology and haven’t done my research in it yet.

  Anyway if there’s anything available I’d love to know.

  Thanks !

• avcodec/utvideodec : Avoid qsort when creating Huffman tables

  24 septembre 2020, par Andreas Rheinhardt

  avcodec/utvideodec : Avoid qsort when creating Huffman tables
  The Ut video format uses Huffman trees which are only implicitly coded
  
  in the bitstream : Only the lengths of the codes are coded, the rest has
  
  to be inferred by the decoder according to the rule that the longer
  
  codes are to the left of shorter codes in the tree and on each level the
  
  symbols are descending from left to right.
  Because longer codes are to the left of shorter codes, one needs to know
  
  how many non-leaf nodes there are on each level in order to know the
  
  code of the next left-most leaf (which belongs to the highest symbol on
  
  that level). The current code does this by sorting the entries to be
  
  ascending according to length and (for entries with the same length)
  
  ascending according to their symbols. This array is then traversed in
  
  reverse order, so that the lowest level is dealt with first, so that the
  
  number of non-leaf nodes of the next higher level is known when
  
  processing said level.
  But this can also be calculated without sorting : Simply count how many
  
  leaf nodes there are on each level. Then one can calculate the number of
  
  non-leaf nodes on each level iteratively from the lowest level upwards :
  
  It is just half the number of nodes of the level below.
  This improves performance : For the sample from ticket #4044 the amount
  
  of decicycles for one call to build_huff() decreased from 1055489 to
  
  446310 for Clang 10 and from 1080306 to 535155 for GCC 9.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/utvideo.c
  • [DH] libavcodec/utvideo.h
  • [DH] libavcodec/utvideodec.c

• How to fix FFmpeg crashed in Android 4/5/6 by sws_setColorspaceDetails function ?

  8 février 2023, par hachman

  I have using FFmpeg(ver 4.2) with cocos2dx game engine, and it works well at all iOS version and Android above level 24(include level 24). However, it may be crashed in Android under level 23(Andorid version 6.0.1).

  


  I am using bugly to record this problem, it located at "sws_setColorspaceDetails" function as this :

  


  #00 pc 01297b38 sws_setColorspaceDetails + 2704 [armeabi-v7a]

java:
org.cocos2dx.lib.Cocos2dxRenderer.onDrawFrame(Cocos2dxRenderer.java:94)
android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1535)
android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1240)


  


  So, how can I solve this problem ? This function is in "libswscale/utils.c", and I can't use "try-catch" to get more infomation.