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• x264 library speed - Altivec vs SSE2 -

  25 février 2013, par Omer Merdan

  I have simple cheap dualcore intel-3ghz-debian and access to super-expensive powerPc7-Aix.

  And after few days of strugle, i compiled libx264 and tested it on both computers :

  1. GCC : library x264 on intel (with SSE2 capabilities) and
  2. GCC on 16 core powerPc (with altivec).

  ... and result is that cheap intel is x2 times faster ! (with altivec disabled, intel is 10x times faster)

  My question : is this normal ?
  Does all other powerPC-users have same results ? Can powerPc-altivec-optimisation of x264 library work at same speed with intel... or MMX/SSE optimisation is officially at least 2 times faster for this library ?

  I am not interested in multi-thread options. Number of cores and threads are irrelevant. Just simple one-thread x264 encoding with default "medium preset" using rawvideo as source, sse vs altivec.

  Maybe native Aix XLC compiler provide better results ? (i managed only gcc to work)

  ... mac-powerpc-users maybe know something about this.

  powrPc7-Aix:$ time (cat raw10sec.y4m |x264 --input-res 720x576 --fps 50 -o /dev/null -)
  
  x264: 64-bit XCOFF
  
  x264 [info]: using cpu capabilities: Altivec
  
  time: real 0m33.559s
  
  ---
  
  intelDebian:$ time (cat raw10sec.y4m |x264 --input-res 720x576 --fps 50 -o /dev/null -)
  
  x264: ELF 32-bit LSB executable
  
  x264 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.1 Cache64
  
  time: real 0m16.503s

• How to speed up ffmpeg video conversions [closed]

  24 janvier 2013, par PIKP

  I need to extract the audio as a MP3 file from a given video file. I have selected "ffmpeg" for audio extraction process. with the use of following arguments I have managed to extract the audio as a MP3. this work very well. but it takes about "2 minutes" to extract the audio from "21 minutes" long video file.

  ffmpeg -i source_video.avi -vn -ar 44100 -ac 2 -ab 128k -f mp3 sound.mp3

  for my purpose "2 minutes" for "21 minutes" is a long time. I need to speed up this as much as possible.

  could someone please tell me what are the factors that control the conversion speed ?

  currently I'm using a SATA hard disk with 7500rmp, will it speed up the conversion process if I upgrade my hard disk to SSD ?

  Thank you !

• Revision 5290eeab88 : Speed 2 feature adjustment. With sf->auto_mv_step_size on it is questionable wh

  3 juillet 2013, par Paul Wilkins

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

  
  
  Speed 2 feature adjustment.

  With sf->auto_mv_step_size on it is questionable
  whether sf->reduce_first_step_size is worthwhile.
  At speed 2 it was not having a big impact.

  Even at speed 2 sf->optimize_coefficients = 0 is not
  having a big speed imapct so for now I have moved it
  down into a higher speed setting.

  Change-Id : I8a54de76d486ad37aabce76474889da2768b14c1