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• aarch64 : vp9 : Implement NEON loop filters

  14 novembre 2016, par Martin Storsjö

  aarch64 : vp9 : Implement NEON loop filters
  This work is sponsored by, and copyright, Google.
  These are ported from the ARM version ; thanks to the larger
  
  amount of registers available, we can do the loop filters with
  
  16 pixels at a time. The implementation is fully templated, with
  
  a single macro which can generate versions for both 8 and
  
  16 pixels wide, for both 4, 8 and 16 pixels loop filters
  
  (and the 4/8 mixed versions as well).
  For the 8 pixel wide versions, it is pretty close in speed (the
  
  v_4_8 and v_8_8 filters are the best examples of this ; the h_4_8
  
  and h_8_8 filters seem to get some gain in the load/transpose/store
  
  part). For the 16 pixels wide ones, we get a speedup of around
  
  1.2-1.4x compared to the 32 bit version.
  Examples of runtimes vs the 32 bit version, on a Cortex A53 :
  
                                         ARM AArch64
  
  vp9_loop_filter_h_4_8_neon :          144.0   127.2
  
  vp9_loop_filter_h_8_8_neon :          207.0   182.5
  
  vp9_loop_filter_h_16_8_neon :         415.0   328.7
  
  vp9_loop_filter_h_16_16_neon :        672.0   558.6
  
  vp9_loop_filter_mix2_h_44_16_neon :   302.0   203.5
  
  vp9_loop_filter_mix2_h_48_16_neon :   365.0   305.2
  
  vp9_loop_filter_mix2_h_84_16_neon :   365.0   305.2
  
  vp9_loop_filter_mix2_h_88_16_neon :   376.0   305.2
  
  vp9_loop_filter_mix2_v_44_16_neon :   193.2   128.2
  
  vp9_loop_filter_mix2_v_48_16_neon :   246.7   218.4
  
  vp9_loop_filter_mix2_v_84_16_neon :   248.0   218.5
  
  vp9_loop_filter_mix2_v_88_16_neon :   302.0   218.2
  
  vp9_loop_filter_v_4_8_neon :           89.0    88.7
  
  vp9_loop_filter_v_8_8_neon :          141.0   137.7
  
  vp9_loop_filter_v_16_8_neon :         295.0   272.7
  
  vp9_loop_filter_v_16_16_neon :        546.0   453.7
  The speedup vs C code in checkasm tests is around 2-7x, which is
  
  pretty much the same as for the 32 bit version. Even if these functions
  
  are faster than their 32 bit equivalent, the C version that we compare
  
  to also became around 1.3-1.7x faster than the C version in 32 bit.
  Based on START_TIMER/STOP_TIMER wrapping around a few individual
  
  functions, the speedup vs C code is around 4-5x.
  Examples of runtimes vs C on a Cortex A57 (for a slightly older version
  
  of the patch) :
  
                           A57 gcc-5.3  neon
  
  loop_filter_h_4_8_neon :        256.6  93.4
  
  loop_filter_h_8_8_neon :        307.3 139.1
  
  loop_filter_h_16_8_neon :       340.1 254.1
  
  loop_filter_h_16_16_neon :      827.0 407.9
  
  loop_filter_mix2_h_44_16_neon : 524.5 155.4
  
  loop_filter_mix2_h_48_16_neon : 644.5 173.3
  
  loop_filter_mix2_h_84_16_neon : 630.5 222.0
  
  loop_filter_mix2_h_88_16_neon : 697.3 222.0
  
  loop_filter_mix2_v_44_16_neon : 598.5 100.6
  
  loop_filter_mix2_v_48_16_neon : 651.5 127.0
  
  loop_filter_mix2_v_84_16_neon : 591.5 167.1
  
  loop_filter_mix2_v_88_16_neon : 855.1 166.7
  
  loop_filter_v_4_8_neon :        271.7  65.3
  
  loop_filter_v_8_8_neon :        312.5 106.9
  
  loop_filter_v_16_8_neon :       473.3 206.5
  
  loop_filter_v_16_16_neon :      976.1 327.8
  The speed-up compared to the C functions is 2.5 to 6 and the cortex-a57
  
  is again 30-50% faster than the cortex-a53.
  This is an adapted cherry-pick from libav commits
  
  9d2afd1eb8c5cc0633062430e66326dbf98c99e0 and
  
  31756abe29eb039a11c59a42cb12e0cc2aef3b97.
  Signed-off-by : Ronald S. Bultje <rsbultje@gmail.com>
  

  • [DH] libavcodec/aarch64/Makefile
  • [DH] libavcodec/aarch64/vp9dsp_init_aarch64.c
  • [DH] libavcodec/aarch64/vp9lpf_neon.S

• Best way to develop a multimedia player [on hold]

  30 décembre 2016, par Martin

  I would like to develop a multimedia player. I should design a structure which describes a collection of video and audio files. It can specify each video stream start and end time (such as different audio streams) and the player should play the collection as it was one stream.

  An example : I want to play 2 minutes from the first video file’s video stream from minute 3, and 3 minutes from the second video file from minute 1, during the 5 minute specified above I want to play a third file’s audio stream.

  I thought about developing it in C (which has the proper memory manipulation possibilities) with the help of ffmpeg library (to be able to support a wide range of media formats) and the SDL library to show the output.
  Have you any thoughts on this which could help me ? (eg. : any pitfalls, other/better ways to solve this problem)

• aarch64 : vp9 : Add NEON itxfm routines

  14 novembre 2016, par Martin Storsjö

  aarch64 : vp9 : Add NEON itxfm routines
  This work is sponsored by, and copyright, Google.
  These are ported from the ARM version ; thanks to the larger
  
  amount of registers available, we can do the 16x16 and 32x32
  
  transforms in slices 8 pixels wide instead of 4. This gives
  
  a speedup of around 1.4x compared to the 32 bit version.
  The fact that aarch64 doesn’t have the same d/q register
  
  aliasing makes some of the macros quite a bit simpler as well.
  Examples of runtimes vs the 32 bit version, on a Cortex A53 :
  
                                         ARM  AArch64
  
  vp9_inv_adst_adst_4x4_add_neon :       90.0     87.7
  
  vp9_inv_adst_adst_8x8_add_neon :      400.0    354.7
  
  vp9_inv_adst_adst_16x16_add_neon :   2526.5   1827.2
  
  vp9_inv_dct_dct_4x4_add_neon :         74.0     72.7
  
  vp9_inv_dct_dct_8x8_add_neon :        271.0    256.7
  
  vp9_inv_dct_dct_16x16_add_neon :     1960.7   1372.7
  
  vp9_inv_dct_dct_32x32_add_neon :    11988.9   8088.3
  
  vp9_inv_wht_wht_4x4_add_neon :         63.0     57.7
  The speedup vs C code (2-4x) is smaller than in the 32 bit case,
  
  mostly because the C code ends up significantly faster (around
  
  1.6x faster, with GCC 5.4) when built for aarch64.
  Examples of runtimes vs C on a Cortex A57 (for a slightly older version
  
  of the patch) :
  
                                  A57 gcc-5.3   neon
  
  vp9_inv_adst_adst_4x4_add_neon :       152.2   60.0
  
  vp9_inv_adst_adst_8x8_add_neon :       948.2  288.0
  
  vp9_inv_adst_adst_16x16_add_neon :    4830.4 1380.5
  
  vp9_inv_dct_dct_4x4_add_neon :         153.0   58.6
  
  vp9_inv_dct_dct_8x8_add_neon :         789.2  180.2
  
  vp9_inv_dct_dct_16x16_add_neon :      3639.6  917.1
  
  vp9_inv_dct_dct_32x32_add_neon :     20462.1 4985.0
  
  vp9_inv_wht_wht_4x4_add_neon :          91.0   49.8
  The asm is around factor 3-4 faster than C on the cortex-a57 and the asm
  
  is around 30-50% faster on the a57 compared to the a53.
  This is an adapted cherry-pick from libav commit
  
  3c9546dfafcdfe8e7860aff9ebbf609318220f29.
  Signed-off-by : Ronald S. Bultje <rsbultje@gmail.com>
  

  • [DH] libavcodec/aarch64/Makefile
  • [DH] libavcodec/aarch64/vp9dsp_init_aarch64.c
  • [DH] libavcodec/aarch64/vp9itxfm_neon.S