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• SDL_SetVideoMode fails under Android ?

  17 avril 2013, par user1568549

  I am trying to buid a Video Player for android using libsdl for rendering and libav for decoding.

  First, i cross-compiled the sdl library for Android platform.
  Then i ceated the jni layer for my sdl cpp file(already tested under ubuntu)
  but when i test it under Android it fails(with fatal error segv11 signal) exactly at the beginning in the following instruction :

   this->screen = SDL_SetVideoMode(width, height, 0, 0);

  Does anyone know any workaround for this error ?

  Does anyone know how to display video using sdl under android ?
  And is there any instructions or steps that i must follow in order to render SDL gui under android ?

  Thanks in advance !

• Getting the frame number as the filename for an extracted frame in ffmpeg

  7 janvier 2015, par Prashanth

  The following command line extracts the I frames from the video

  ffmpeg -i input.flv -f image2 -vf "select='eq(pict_type,PICT_TYPE_I)'" -vsync vfr thumb%04d.png

  But the frames are sequentially numbered ..like thumb0001,2,3,4,5.... Suppose the 9th frame is an I frame then I want the the extracted frame’s file name as ’thumb9.png’...suppose if 18th frame is the next I frame then the extracted frame’s filename should be ’thumb10.png’ or ’10.png’...

  How to achieve this ? Thanks in advance...

• swscale/aarch64 : add hscale specializations

  26 mai 2022, par Swinney, Jonathan

  swscale/aarch64 : add hscale specializations
  This patch adds code to support specializations of the hscale function
  
  and adds a specialization for filterSize == 4.
  ff_hscale8to15_4_neon is a complete rewrite. Since the main bottleneck
  
  here is loading the data from src, this data is loaded a whole block
  
  ahead and stored back to the stack to be loaded again with ld4. This
  
  arranges the data for most efficient use of the vector instructions and
  
  removes the need for completion adds at the end. The number of
  
  iterations of the C per iteration of the assembly is increased from 4 to
  
  8, but because of the prefetching, there must be a special section
  
  without prefetching when dstW < 16.
  This improves speed on Graviton 2 (Neoverse N1) dramatically in the case
  
  where previously fs=8 would have been required.
  before : hscale_8_to_15__fs_8_dstW_512_neon : 1962.8
  
  after : hscale_8_to_15__fs_4_dstW_512_neon : 1220.9
  Signed-off-by : Jonathan Swinney <jswinney@amazon.com>
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libswscale/aarch64/hscale.S
  • [DH] libswscale/aarch64/swscale.c
  • [DH] libswscale/utils.c