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• lavfi : generic hardware surface upload and download filters

  25 février 2016, par Mark Thompson

  lavfi : generic hardware surface upload and download filters
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] doc/APIchanges
  • [DBH] libavfilter/Makefile
  • [DBH] libavfilter/allfilters.c
  • [DBH] libavfilter/avfilter.c
  • [DBH] libavfilter/avfilter.h
  • [DBH] libavfilter/version.h
  • [DBH] libavfilter/vf_hwdownload.c
  • [DBH] libavfilter/vf_hwupload.c

• Download multiple files with ffmpeg, keep one stream from each (according to default stream selection), and then mux them into single file ?

  23 août 2021, par Bernard

  With ffmpeg, I can download m3u8 streams with the following command :

  


  ffmpeg -i http://example.com/test.m3u8 -c copy output.mp4


  


  The above command will keep the best quality video and audio (to some definition of 'best').

  


  However, I'm faced with a situation where I have several m3u8 streams, all of them possibly containing zero or more video or audio streams. I would like to take at most one video and audio from each url (according to ffmpeg's definition of 'best'), and mux them together into the final mp4 file.

  


  This is essentially what I want :

  


  ffmpeg -i http://example.com/test0.m3u8 -c copy output0.mp4
ffmpeg -i http://example.com/test1.m3u8 -c copy output1.mp4
ffmpeg -i http://example.com/test2.m3u8 -c copy output2.mp4
ffmpeg -i output0.mp4 -i output1.mp4 -i output2.mp4 -map 0 -map 1 -map 2 -c copy output.mp4


  


  Is there any way to do it without the temporary files ?

  


• FFMpeg sws_scale Static and Shared Huge Performance Difference

  6 novembre 2018, par Ali

  I used swscale in my code as a shared library then managed to compile FFMpeg (4.1) to static libraries with Visual Studio with this command just to get swscale :

  ./configure --toolchain=msvc --arch=x86_32 --disable-everything --disable-programs 

  I have nasm and yasm installed. this my config output :

  install prefix            /usr/local
  
  source path               .
  
  C compiler                cl
  
  C library                 msvcrt
  
  ARCH                      x86 (generic)
  
  big-endian                no
  
  runtime cpu detection     yes
  
  standalone assembly       yes
  
  x86 assembler             nasm
  
  MMX enabled               yes
  
  MMXEXT enabled            yes
  
  3DNow! enabled            yes
  
  3DNow! extended enabled   yes
  
  SSE enabled               yes
  
  SSSE3 enabled             yes
  
  AESNI enabled             yes
  
  AVX enabled               yes
  
  AVX2 enabled              yes
  
  AVX-512 enabled           yes
  
  XOP enabled               yes
  
  FMA3 enabled              yes
  
  FMA4 enabled              yes
  
  i686 features enabled     yes
  
  CMOV is fast              no
  
  EBX available             no
  
  EBP available             no
  
  debug symbols             yes
  
  strip symbols             no
  
  optimize for size         no
  
  optimizations             yes
  
  static                    yes
  
  shared                    no
  
  postprocessing support    no
  
  network support           yes
  
  threading support         w32threads
  
  safe bitstream reader     yes
  
  texi2html enabled         no
  
  perl enabled              no
  
  pod2man enabled           no
  
  makeinfo enabled          no
  
  makeinfo supports HTML    no
  
  
  
  External libraries:
  
  schannel
  
  
  
  External libraries providing hardware acceleration:
  
  d3d11va                    dxva2
  
  
  
  Libraries:
  
  avcodec                    avdevice                   avfilter                   avformat                   avutil                     swresample                 swscale
  
  
  
  Programs:
  
  Enabled decoders:
  
  Enabled encoders:
  
  Enabled hwaccels:
  
  Enabled parsers:
  
  Enabled demuxers:
  
  Enabled muxers:
  
  Enabled protocols:
  
  Enabled filters:
  
  Enabled bsfs:
  
  null
  
  Enabled indevs:
  
  Enabled outdevs:

  This compiled successfully and I replaced the lib files with .a file in QT :

  INCLUDEPATH += $$PWD/ffmpeg/inc/
  
  LIBS += $$files($$PWD/ffmpeg/lib/*.a, true)

  I didn’t change anything else. EXE works correctly without dependency but problem is static swscale is so much slower than the shared one. For 1080p share .DLL takes 2ms to shrink and convert yuv to rgb and static .A takes 6ms to

  I also tried removing --disable-everything --disable-programs but still the same. I want to know if it’s because of the cl compiler or I missed a library or a setting ?

  BTW this my system : Win10/i7 4820K/16GB/GTX970

  EDIT :

  I got this in app output :
  No accelerated colorspace conversion found from yuv420p to bgra.
  Although x86 folder in swscale is compiled, it seems it’s not linked in the output.