libsvtav1 AV1 编码速度比 libaom 大大提升

libaom 编码速度 speed=0.0178x 真的无法忍受这个速度，每秒只能处理 2-3个帧

相比 libaom ，libsvtav1 速度有所提升 speed=0.0966x 差不多提升了 10倍左右

ffmpeg 现在支持 libsvtav1，只有 x64 才能用，x86 不支持

ffmpeg -i D:media	est.mp4 -c:v libsvtav1 -y test-libsvtav1.mp4
ffmpeg version N-99286-gc7867b6ed1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9.3-win32 (GCC) 20200320
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --enable-iconv --enable-zlib --enable-libxml2 --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvmaf --enable-vulkan --enable-libvorbis --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-ffnvcodec --enable-cuda-llvm --enable-libglslang --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libvidstab --disable-libwavpack --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp
  libavutil      56. 59.100 / 56. 59.100
  libavcodec     58.106.100 / 58.106.100
  libavformat    58. 58.100 / 58. 58.100
  libavdevice    58. 11.102 / 58. 11.102
  libavfilter     7. 87.100 /  7. 87.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:media	est.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.35.101
  Duration: 00:00:31.35, start: 0.000000, bitrate: 3127 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 3117 kb/s, 31.18 fps, 60 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> av1 (libsvtav1))
  Stream #0:1 -> #0:1 (mp3 (mp3float) -> aac (native))
Press [q] to stop, [?] for help
-------------------------------------------
SVT [version]:  SVT-AV1 Encoder Lib v0.8.4-123-ge9ffb5ee
SVT [build]  :  GCC 9.3-win32 20200320   64 bit
LIB Build date: Sep 20 2020 01:08:06
-------------------------------------------
Number of logical cores available: 4
Number of PPCS 62
[asm level on system : up to avx2]
[asm level selected : up to avx2]
-------------------------------------------
SVT [config]: Main Profile      Tier (auto)     Level (auto)
SVT [config]: EncoderMode                                                       : 8
SVT [config]: EncoderBitDepth / EncoderColorFormat / CompressedTenBitFormat     : 8 / 1 / 0
SVT [config]: SourceWidth / SourceHeight                                        : 1280 / 720
SVT [config]: Fps_Numerator / Fps_Denominator / Gop Size / IntraRefreshType     : 30 / 1 / 33 / 2
SVT [config]: HierarchicalLevels  / PredStructure               : 4 / 2
SVT [config]: BRC Mode / QP  / LookaheadDistance / SceneChange                  : CQP / 50 / 16 / 0
-------------------------------------------
Output #0, mp4, to 'test-libsvtav1.mp4':B time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.58.100
    Stream #0:0(eng): Video: av1 (libsvtav1) (av01 / 0x31307661), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], q=0-63, 7000 kb/s, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc58.106.100 libsvtav1
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc58.106.100 aac
frame=  904 fps=2.8 q=42.0 Lsize=    2778kB time=00:00:31.32 bitrate= 726.6kbits/s dup=5 drop=21 speed=0.0966x
video:2258kB audio:495kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.932547%
[aac @ 0000016ebfbc8b40] Qavg: 612.859

虽然编码速度不是很快，但是速度快接近 0.1 已经很不错了，希望还能快一些，能达到 1.0 就好了；