[FFmpeg-user] Compression is a lot smaller

[Cecil Westerhof]

Through scripts I use ffmpeg for cutting and compressing videos and
sometimes adding a watermark. Nothing fancy, but handy.

In the past the original file was between 4 to 13 times bigger as the
compressed file. Today I compressed a few files again. The compression
was almost non existing to less as three.

454 -> 415
503 -> 230
490 -> 254
462 -> 157
497 -> 197
454 -> 174

Some logging of the worst (the first):
    nice -n 10 ionice -c3 ffmpeg -y -i 00039.MTS -vcodec libx264 -crf 23 -acodec libmp3lame -preset veryfast 00039.mp4
    ffmpeg version 4.1.6-1~deb10u1 Copyright (c) 2000-2020 the FFmpeg developers
      built with gcc 8 (Debian 8.3.0-6)
    .
    .
    .
      libavutil      56. 22.100 / 56. 22.100
      libavcodec     58. 35.100 / 58. 35.100
      libavformat    58. 20.100 / 58. 20.100
      libavdevice    58.  5.100 / 58.  5.100
      libavfilter     7. 40.101 /  7. 40.101
      libavresample   4.  0.  0 /  4.  0.  0
      libswscale      5.  3.100 /  5.  3.100
      libswresample   3.  3.100 /  3.  3.100
      libpostproc    55.  3.100 / 55.  3.100
    Input #0, mpegts, from '00039.MTS':
      Duration: 00:02:49.02, start: 1.040000, bitrate: 22533 kb/s
      Program 1 
        Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(top first), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 50 tbr, 90k tbn, 50 tbc
        Stream #0:1[0x1100]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 256 kb/s
        Stream #0:2[0x1200]: Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090), 1920x1080
    Stream mapping:
      Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
      Stream #0:1 -> #0:1 (ac3 (native) -> mp3 (libmp3lame))
    Press [q] to stop, [?] for help
    [libx264 @ 0x563820eef380] using SAR=1/1
    [libx264 @ 0x563820eef380] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX XOP FMA3 BMI1
    [libx264 @ 0x563820eef380] profile High, level 4.0
    [libx264 @ 0x563820eef380] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=6 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=10 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
    Output #0, mp4, to '00039.mp4':
      Metadata:
        encoder         : Lavf58.20.100
        Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 12800 tbn, 25 tbc
        Metadata:
          encoder         : Lavc58.35.100 libx264
        Side data:
          cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
        Stream #0:1: Audio: mp3 (libmp3lame) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp
        Metadata:
          encoder         : Lavc58.35.100 libmp3lame
    .
    .
    .
    video:421739kB audio:2642kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.027043%
    [libx264 @ 0x563820eef380] frame I:23    Avg QP:24.52  size:417042
    [libx264 @ 0x563820eef380] frame P:1621  Avg QP:26.67  size:165193
    [libx264 @ 0x563820eef380] frame B:2581  Avg QP:30.40  size: 59857
    [libx264 @ 0x563820eef380] consecutive B-frames:  8.0% 29.4%  6.3% 56.2%
    [libx264 @ 0x563820eef380] mb I  I16..4:  3.2% 19.9% 76.8%
    [libx264 @ 0x563820eef380] mb P  I16..4:  1.1%  5.9%  3.6%  P16..4: 45.3% 16.5% 19.4%  0.0%  0.0%    skip: 8.3%
    [libx264 @ 0x563820eef380] mb B  I16..4:  0.2%  0.8%  0.1%  B16..8: 20.0%  9.5%  3.8%  direct:24.2%  skip:41.5%  L0:20.1% L1:34.8% BI:45.1%
    [libx264 @ 0x563820eef380] 8x8 transform intra:54.1% inter:41.3%
    [libx264 @ 0x563820eef380] coded y,uvDC,uvAC intra: 84.1% 74.6% 39.9% inter: 43.9% 18.0% 3.8%
    [libx264 @ 0x563820eef380] i16 v,h,dc,p: 38% 29% 21% 12%
    [libx264 @ 0x563820eef380] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 21% 22% 23%  5%  5%  5%  6%  5%  9%
    [libx264 @ 0x563820eef380] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 10% 36% 14%  5%  6%  5%  8%  5% 11%
    [libx264 @ 0x563820eef380] i8c dc,h,v,p: 45% 25% 19% 12%
    [libx264 @ 0x563820eef380] Weighted P-Frames: Y:5.9% UV:2.7%
    [libx264 @ 0x563820eef380] kb/s:20443.06

What could be happening here?
When I need to provide more information: let me know.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof