ffmpeg.exe -i avisynth.avs -i bbb3d_sunflower_soundtrack_surround.ac3 -c:v libx264 -preset veryslow -profile:v high444 -level 5.2 -crf 16 -c:a copy -y outputbunny_yuv444_veryslow.mp4

ffmpeg version N-69060-gcd960c8 Copyright (c) 2000-2015 the FFmpeg developers
  built on Jan 14 2015 22:02:36 with gcc 4.9.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-lib
modplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrw
b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinge
r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
 --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enab
le-zlib
  libavutil      54. 16.100 / 54. 16.100
  libavcodec     56. 20.100 / 56. 20.100
  libavformat    56. 18.101 / 56. 18.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5.  7.101 /  5.  7.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, avisynth, from 'avisynth.avs':
  Duration: 00:10:34.53, start: 0.000000, bitrate: 0 kb/s
    Stream #0:0: Video: rawvideo (444P / 0x50343434), yuv444p, 3840x2160, 60 fps
, 60 tbr, 60 tbn, 60 tbc
[ac3 @ 02a56060] Estimating duration from bitrate, this may be inaccurate
Input #1, ac3, from 'bbb3d_sunflower_soundtrack_surround.ac3':
  Duration: 00:10:34.14, start: 0.000000, bitrate: 320 kb/s
    Stream #1:0: Audio: ac3, 48000 Hz, 5.1(side), fltp, 320 kb/s
No pixel format specified, yuv444p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 02aff780] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 02aff780] profile High 4:4:4 Predictive, level 5.2, 4:4:4 8-bit
[libx264 @ 02aff780] 264 - core 144 r2525 40bb568 - H.264/MPEG-4 AVC codec - Cop
yleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=5 deb
lock=1:0:0 analyse=0x3:0x133 me=umh subme=10 psy=1 psy_rd=1.00:0.00 mixed_ref=1
me_range=24 chroma_me=1 trellis=2 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chr
oma_qp_offset=4 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1
interlaced=0 bluray_compat=0 constrained_intra=0 bframes=8 b_pyramid=2 b_adapt=2
 b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scene
cut=40 intra_refresh=0 rc_lookahead=60 rc=crf mbtree=1 crf=16.0 qcomp=0.60 qpmin
=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[mp4 @ 02afec60] track 1: codec frame size is not set
Output #0, mp4, to 'outputbunny_yuv444_veryslow.mp4':
  Metadata:
    encoder         : Lavf56.18.101
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv444p, 3840x2
160, q=-1--1, 60 fps, 15360 tbn, 60 tbc
    Metadata:
      encoder         : Lavc56.20.100 libx264
    Stream #0:1: Audio: ac3 ([165][0][0][0] / 0x00A5), 48000 Hz, 5.1(side), 320
kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (copy)
Press [q] to stop, [?] for help
x264 [error]: malloc of size 46718720 failedme=00:00:00.00 bitrate=N/A
Video encoding failed
Conversion failed!