Recherche avancée

Sur d’autres sites (5693)

• avformat/matroskadec : Link to parents in syntax tables

  17 mai 2019, par Andreas Rheinhardt

  avformat/matroskadec : Link to parents in syntax tables
  By linking to the syntax of the parent (i.e. the containing master
  
  element) one can check whether an element is actually part of a higher
  
  level in the EBML hierarchy. Knowing this is important for
  
  unknown-length levels, because they end when an element that doesn't
  
  belong to this, but to a higher hierarchy level is encountered.
  Sometimes there are different syntaxes dealing with the same elements.
  
  In this case it is important to use a parent that contains all the
  
  elements at the parent level ; whether this is the syntax actually used
  
  to enter the child's level is irrelevant. This affects the list of level
  
  1 elements (which has been used as parent for matroska_cluster, too) and
  
  it affects recursive elements (currently only the SimpleTag), where the
  
  non-recursive parent has to be choosen.
  This is in preparation for a patch that redoes level handling.
  Finally, the segment id has been added to ebml_syntax. This will enable
  
  handling of unknown-length EBML headers.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskadec.c

• Acceptable Video Size For Social Network With FFMpeg

  2 août 2022, par John Santos

  I'm building a social network on Android and using FFMPeg to compress the videos before uploading them. Videos will have maximum 1 minute of duration.

  



  The original video for test has 87.74Mb 1080x1920.

  



  Trying to find the middle point between quality and file size I could get to a video size of either 26Mb with an "meh" quality (which I'm not happy with) or 33.06Mb with a good quality (scaling the video to 480x852).

  



  Problems :

  



  1) It's taking an average of 2min 30sec to compress a 1 minute video !

  



  2) Even 25Mb seems to be too much for a 1 minute video for a social network

  



  The ask :

  



  1) Any clue how do Instagram and Facebook do it to compress and upload the same video above within 1 minute !!?? I know they compress it cause the quality is not the same when on Facebook/Instagram but how to they get it done that fast ?

  



  2) What would it be an acceptable file size for a 1 minute video on Facebook/Instagram ? I'm worried about wasting too much storage for 1 minute videos. Does anyone have any idea about it ?

  



  ---

  



  I'm searching a lot about FFMpeg commands to get it better and better but it would be easier if I had in mind what I want to achieve.

  


• Revision 307b6c22a3 : Switch the default 2 pass vbr variant. On balance Deb's modified rate control

  1er mai 2014, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
  
  Switch the default 2 pass vbr variant.

  On balance Deb’s modified rate control for VBR seems
  to be outperforming especially on some low motion YT
  clips so I have switched this to be the default mode for
  now.

  Change-Id : I0713d430cad6425ac5c48fccdf332e12814ee44a