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• How to change ffmpeg -threads settings [migrated]

  5 août 2014, par Jacob

  Working on a tube site. I’m running videos through ffmpeg on a linux dedicated server to convert to mp4.

  The server specs :

  Architecture:          x86_64
  
  CPU op-mode(s):        32-bit, 64-bit
  
  Byte Order:            Little Endian
  
  CPU(s):                8
  
  On-line CPU(s) list:   0-7
  
  Thread(s) per core:    2
  
  Core(s) per socket:    4
  
  Socket(s):             1
  
  NUMA node(s):          1
  
  Vendor ID:             GenuineIntel
  
  CPU family:            6
  
  Model:                 60
  
  Stepping:              3
  
  CPU MHz:               3491.749
  
  BogoMIPS:              6983.49
  
  Virtualization:        VT-x
  
  L1d cache:             32K
  
  L1i cache:             32K
  
  L2 cache:              256K
  
  L3 cache:              8192K
  
  NUMA node0 CPU(s):     0-7

  Issue during testing is that even only doing 4-5 at once, the server load skyrockets to an average of around 36. This is just a single person. I imagine when it opens, many people will be uploading at once.

  It seems ffmpeg tries to use all the resources available per conversion.

  I’ve heard there’s a -threads setting you can change, but I cannot find it. I have an 8 cpu server. It’s only used for conversions, so I’ve heard the best setting would be between 2 and 4. I can test it out.

  But how do I change this setting ? Everything I see online discusses this setting, but not the steps to change it.

• arm : Detect 32 bit cpu features on ARMv8 when running on a 64 bit kernel

  23 juin 2014, par Martin Storsjö

  arm : Detect 32 bit cpu features on ARMv8 when running on a 64 bit kernel
  When running on a 64 bit kernel, /proc/cpuinfo lists different
  
  optional features than on 32 bit kernels (because some of them
  
  are mandatory in the 64 bit implemenations).
  The kernel does list the old features properly if they are queried
  
  via /proc/self/auxv though - however this file is not always readable
  
  (e.g. on most android systems). The getauxval function could also
  
  provide the same info as /proc/self/auxv even if this file isn’t
  
  readable, but this function is not always available (and thus would
  
  need to be loaded with dlsym for compatibility with older android
  
  versions).
  The android cpufeatures library does this slightly differently,
  
  by assuming that these are available if the "CPU architecture"
  
  line is >= 8, see [1] for details.
  It has been suggested to include the old, non-optional features in
  
  /proc/cpuinfo as well, but that suggested patch never was merged.
  
  See [2] for the discussion around this suggestion.
  [1] https://android-review.googlesource.com/91380
  
  [2] http://marc.info/?l=linux-arm-kernel&m=139087240101974
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavutil/arm/cpu.c

• arm : Detect 32 bit cpu features on ARMv8 when running on a 64 bit kernel

  23 juin 2014, par Martin Storsjö

  arm : Detect 32 bit cpu features on ARMv8 when running on a 64 bit kernel
  When running on a 64 bit kernel, /proc/cpuinfo lists different
  
  optional features than on 32 bit kernels (because some of them
  
  are mandatory in the 64 bit implemenations).
  The kernel does list the old features properly if they are queried
  
  via /proc/self/auxv though - however this file is not always readable
  
  (e.g. on most android systems). The getauxval function could also
  
  provide the same info as /proc/self/auxv even if this file isn’t
  
  readable, but this function is not always available (and thus would
  
  need to be loaded with dlsym for compatibility with older android
  
  versions).
  The android cpufeatures library does this slightly differently,
  
  by assuming that these are available if the "CPU architecture"
  
  line is >= 8, see [1] for details.
  It has been suggested to include the old, non-optional features in
  
  /proc/cpuinfo as well, but that suggested patch never was merged.
  
  See [2] for the discussion around this suggestion.
  [1] https://android-review.googlesource.com/91380
  
  [2] http://marc.info/?l=linux-arm-kernel&m=139087240101974
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavutil/arm/cpu.c