Recherche avancée

Sur d’autres sites (8934)

• Adjust —preset slow

  28 juillet 2016, par Henrik Gramner

  Adjust —preset slow
   * Swap —me umh for —trellis 2. They have a similar effect on performance
  
     but the latter gives slightly better results in most cases.
  
   * Change —b-adapt from 2 to 1. Negligible difference in quality since the
  
     b-adapt 1 improvements, but it’s significantly faster.
  Also remove a redundant assignment from veryfast (—me hex is set by default).
  

  • [DH] common/common.c

• swresample : add exact_rational option

  12 juin 2016, par Muhammad Faiz

  swresample : add exact_rational option
  give high quality resampling
  
  as good as with linear_interp=on
  
  as fast as without linear_interp=on
  
  tested visually with ffplay
  
  ffplay -f lavfi "aevalsrc=’sin(10000*t*t)’, aresample=osr=48000, showcqt=gamma=5"
  
  ffplay -f lavfi "aevalsrc=’sin(10000*t*t)’, aresample=osr=48000:linear_interp=on, showcqt=gamma=5"
  
  ffplay -f lavfi "aevalsrc=’sin(10000*t*t)’, aresample=osr=48000:exact_rational=on, showcqt=gamma=5"
  slightly speed improvement
  
  for fair comparison with -cpuflags 0
  
  audio.wav is 1 hour 44100 stereo 16bit wav file
  
  ffmpeg -i audio.wav -af aresample=osr=48000 -f null -
  
          old         new
  
  real    13.498s     13.121s
  
  user    13.364s     12.987s
  
  sys      0.131s      0.129s
  linear_interp=on
  
          old         new
  
  real    23.035s     23.050s
  
  user    22.907s     22.917s
  
  sys      0.119s     0.125s
  exact_rational=on
  
  real    12.418s
  
  user    12.298s
  
  sys      0.114s
  possibility to decrease memory usage if soft compensation is ignored
  Signed-off-by : Muhammad Faiz <mfcc64@gmail.com>
  

  • [DH] libswresample/arm/resample_init.c
  • [DH] libswresample/options.c
  • [DH] libswresample/resample.c
  • [DH] libswresample/resample.h
  • [DH] libswresample/resample_template.c
  • [DH] libswresample/soxr_resample.c
  • [DH] libswresample/swresample.c
  • [DH] libswresample/swresample_internal.h
  • [DH] libswresample/version.h
  • [DH] libswresample/x86/resample_init.c

• arm : vp9 : Add NEON itxfm routines

  8 octobre 2016, par Martin Storsjö

  arm : vp9 : Add NEON itxfm routines
  This work is sponsored by, and copyright, Google.
  For the transforms up to 8x8, we can fit all the data (including
  
  temporaries) in registers and just do a straightforward transform
  
  of all the data. For 16x16, we do a transform of 4x16 pixels in
  
  4 slices, using a temporary buffer. For 32x32, we transform 4x32
  
  pixels at a time, in two steps of 4x16 pixels each.
  Examples of relative speedup compared to the C version, from checkasm :
  
                           Cortex       A7     A8     A9    A53
  
  vp9_inv_adst_adst_4x4_add_neon :     3.39   5.83   4.17   4.01
  
  vp9_inv_adst_adst_8x8_add_neon :     3.79   4.86   4.23   3.98
  
  vp9_inv_adst_adst_16x16_add_neon :   3.33   4.36   4.11   4.16
  
  vp9_inv_dct_dct_4x4_add_neon :       4.06   6.16   4.59   4.46
  
  vp9_inv_dct_dct_8x8_add_neon :       4.61   6.01   4.98   4.86
  
  vp9_inv_dct_dct_16x16_add_neon :     3.35   3.44   3.36   3.79
  
  vp9_inv_dct_dct_32x32_add_neon :     3.89   3.50   3.79   4.42
  
  vp9_inv_wht_wht_4x4_add_neon :       3.22   5.13   3.53   3.77
  Thus, the speedup vs C code is around 3-6x.
  This is mostly marginally faster than the corresponding routines
  
  in libvpx on most cores, tested with their 32x32 idct (compared to
  
  vpx_idct32x32_1024_add_neon). These numbers are slightly in libvpx’s
  
  favour since their version doesn’t clear the input buffer like ours
  
  do (although the effect of that on the total runtime probably is
  
  negligible.)
                             Cortex       A7       A8       A9      A53
  
  vp9_inv_dct_dct_32x32_add_neon :    18436.8  16874.1  14235.1  11988.9
  
  libvpx vpx_idct32x32_1024_add_neon 20789.0  13344.3  15049.9  13030.5
  Only on the Cortex A8, the libvpx function is faster. On the other cores,
  
  ours is slightly faster even though ours has got source block clearing
  
  integrated.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavcodec/arm/Makefile
  • [DBH] libavcodec/arm/vp9dsp_init_arm.c
  • [DBH] libavcodec/arm/vp9itxfm_neon.S