[FFmpeg-user] wrong number of ref frames

Tue Dec 17 19:37:44 CET 2013

I used ffmpeg to encode a video with libx264, using High Profile @ Level 4.1.  So the reference frames should be 9.  But it’s actually using 16.  Can anyone figure out why?  The encode also displays major visual artifacts in QuickTime Player 7 (see attached screenshot), which I’m guessing might be caused by the too many ref frames.  It plays fine in VLC.

Screenshot: https://www.dropbox.com/s/fi8hwrf5u3jrl0r/blocky.jpg

$ ffmpeg -i short\ cut\ 12-16\ lock.mov -pix_fmt yuv420p -vf scale=hd720 -acodec libfdk_aac -b:a 128k -vcodec libx264 -preset veryslow -crf 19 -profile high -level 41 shortCRF19.mov
ffmpeg version N-57394-gea9632b Copyright (c) 2000-2013 the FFmpeg developers
  built on Oct 24 2013 11:58:12 with Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
  configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-static --enable-libass --enable-libbluray --enable-libfdk-aac --enable-libmp3lame --enable-libvpx --enable-libx264 --enable-opencl --enable-libfreetype --disable-shared --enable-libopenjpeg --enable-libvorbis --enable-libtheora
  libavutil      52. 47.101 / 52. 47.101
  libavcodec     55. 38.101 / 55. 38.101
  libavformat    55. 19.104 / 55. 19.104
  libavdevice    55.  5.100 / 55.  5.100
  libavfilter     3. 89.100 /  3. 89.100
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
  libpostproc    52.  3.100 / 52.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'short cut 12-16 lock.mov':
  Metadata:
    major_brand     : qt  
    minor_version   : 537199360
    compatible_brands: qt  
    creation_time   : 2013-12-17 08:50:12
  Duration: 00:05:42.01, start: 0.000000, bitrate: 166700 kb/s
    Stream #0:0(eng): Video: prores (apch / 0x68637061), yuv422p10le, 1920x1080, 165139 kb/s, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 24k tbn, 24k tbc (default)
    Metadata:
      creation_time   : 2013-12-17 08:50:12
      handler_name    : Apple Alias Data Handler
      timecode        : 00:00:03:00
    Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2013-12-17 08:50:12
      handler_name    : Apple Alias Data Handler
      timecode        : 00:00:03:00
    Stream #0:2(eng): Data: none (tmcd / 0x64636D74) (default)
    Metadata:
      creation_time   : 2013-12-17 08:50:12
      handler_name    : Apple Alias Data Handler
      timecode        : 00:00:03:00
Please use -profile:a or -profile:v, -profile is ambiguous
[libx264 @ 0x7ffb41809a00] using SAR=1/1
[libx264 @ 0x7ffb41809a00] DPB size (16 frames, 57600 mbs) > level limit (9 frames, 32768 mbs)
[libx264 @ 0x7ffb41809a00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
[libx264 @ 0x7ffb41809a00] profile High, level 4.1
[libx264 @ 0x7ffb41809a00] 264 - core 138 r2358 9e941d1 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - options: cabac=1 ref=16 deblock=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 chroma_qp_offset=-2 threads=24 lookahead_threads=4 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=23 scenecut=40 intra_refresh=0 rc_lookahead=60 rc=crf mbtree=1 crf=19.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mov, to 'shortCRF19.mov':
  Metadata:
    major_brand     : qt  
    minor_version   : 537199360
    compatible_brands: qt  
    encoder         : Lavf55.19.104
    Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 24k tbn, 23.98 tbc (default)
    Metadata:
      creation_time   : 2013-12-17 08:50:12
      handler_name    : Apple Alias Data Handler
      timecode        : 00:00:03:00
    Stream #0:1(eng): Audio: aac (libfdk_aac) (mp4a / 0x6134706D), 48000 Hz, stereo, s16, 128 kb/s (default)
    Metadata:
      creation_time   : 2013-12-17 08:50:12
      handler_name    : Apple Alias Data Handler
      timecode        : 00:00:03:00
Stream mapping:
  Stream #0:0 -> #0:0 (prores -> libx264)
  Stream #0:1 -> #0:1 (pcm_s16le -> libfdk_aac)
Press [q] to stop, [?] for help
frame= 8200 fps= 15 q=-1.0 Lsize=   66450kB time=00:05:42.01 bitrate=1591.6kbits/s    
video:60883kB audio:5345kB subtitle:0 global headers:0kB muxing overhead 0.335523%
[libx264 @ 0x7ffb41809a00] frame I:62    Avg QP:15.59  size: 76674
[libx264 @ 0x7ffb41809a00] frame P:1804  Avg QP:18.77  size: 17581
[libx264 @ 0x7ffb41809a00] frame B:6334  Avg QP:22.65  size:  4085
[libx264 @ 0x7ffb41809a00] consecutive B-frames:  1.4%  2.0%  7.1% 36.5% 13.2% 30.1%  3.1%  1.8%  4.8%
[libx264 @ 0x7ffb41809a00] mb I  I16..4: 13.1% 68.8% 18.1%
[libx264 @ 0x7ffb41809a00] mb P  I16..4:  1.3%  5.3%  0.7%  P16..4: 42.2% 12.6% 12.0%  0.3%  0.1%    skip:25.6%
[libx264 @ 0x7ffb41809a00] mb B  I16..4:  0.0%  0.4%  0.1%  B16..8: 34.7%  4.1%  0.9%  direct: 1.9%  skip:57.9%  L0:44.1% L1:50.0% BI: 5.9%
[libx264 @ 0x7ffb41809a00] 8x8 transform intra:72.3% inter:71.1%
[libx264 @ 0x7ffb41809a00] direct mvs  spatial:98.8% temporal:1.2%
[libx264 @ 0x7ffb41809a00] coded y,uvDC,uvAC intra: 72.7% 57.0% 23.5% inter: 8.6% 6.4% 0.3%
[libx264 @ 0x7ffb41809a00] i16 v,h,dc,p: 30% 16%  6% 48%
[libx264 @ 0x7ffb41809a00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 14%  8%  6%  9% 12% 13% 12% 13% 12%
[libx264 @ 0x7ffb41809a00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 14%  8%  2% 10% 15% 14% 13% 11% 11%
[libx264 @ 0x7ffb41809a00] i8c dc,h,v,p: 26% 34% 22% 17%
[libx264 @ 0x7ffb41809a00] Weighted P-Frames: Y:5.5% UV:3.8%
[libx264 @ 0x7ffb41809a00] ref P L0: 50.0% 10.9% 14.2%  4.9%  4.1%  3.3%  2.8%  1.4%  1.3%  1.2%  1.1%  1.0%  1.0%  1.0%  1.0%  0.7%
[libx264 @ 0x7ffb41809a00] ref B L0: 79.7%  8.0%  4.0%  1.7%  1.4%  1.2%  1.0%  0.5%  0.5%  0.4%  0.4%  0.4%  0.4%  0.3%  0.2%
[libx264 @ 0x7ffb41809a00] ref B L1: 93.3%  6.7%
[libx264 @ 0x7ffb41809a00] kb/s:1458.30