[FFmpeg-user] Keep vfr and original pts

[Wolfgang Hugemann]

> Use -vsync 0. No addiitional frames should be added.

Well, this is true, but the video is switched to cfr. As I said, I tried
this too. And usin mkv or webm instead of mp4 make no difference.

ffmpeg -y -i kollision.mp4 -vf boxblur=10:1  -vsync 0 -copyts blur.mp4

gives the output:

ffmpeg version 2021-01-24-git-1775688292-full_build-www.gyan.dev
Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 10.2.0 (Rev6, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static
--disable-w32threads --disable-autodetect --enable-fontconfig
--enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp
--enable-lzma --enable-libsnappy --enable-zlib --enable-libsrt
--enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray
--enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi
--enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264
--enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg
--enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype
--enable-libfribidi --enable-libvidstab --enable-libvmaf
--enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid
--enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va
--enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan
--enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug
--enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame
--enable-libshine --enable-libtheora --enable-libtwolame
--enable-libvo-amrwbenc --enable-libilbc --enable-libgsm
--enable-libopencore-amrnb --enable-libopus --enable-libspeex
--enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite
--enable-libmysofa --enable-librubberband --enable-libsoxr
--enable-chromaprint
  libavutil      56. 63.101 / 56. 63.101
  libavcodec     58.117.101 / 58.117.101
  libavformat    58. 65.101 / 58. 65.101
  libavdevice    58. 11.103 / 58. 11.103
  libavfilter     7. 96.100 /  7. 96.100
  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 'kollision.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:00:02.32, start: 0.000000, bitrate: 908 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661),
yuv420p(tv, bt709), 1280x720, 903 kb/s, SAR 1:1 DAR 16:9, 15.10 fps, 25
tbr, 25641 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 000001e4beec4300] using SAR=1/1
[libx264 @ 000001e4beec4300] using cpu capabilities: MMX2 SSE2Fast SSSE3
SSE4.2 AVX
[libx264 @ 000001e4beec4300] profile High, level 3.1, 4:2:0, 8-bit
[libx264 @ 000001e4beec4300] 264 - core 161 r3033 0d754ec - H.264/MPEG-4
AVC codec - Copyleft 2003-2020 - http://www.videolan.org/x264.html -
options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7
psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1
8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6
lookahead_threads=1 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=2 keyint=250
keyint_min=15 scenecut=40 intra_refresh=0 rc_lookahead=40 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 'blur.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.65.101
    Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p(tv,
bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 15 fps, 15360
tbn (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]
      encoder         : Lavc58.117.101 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
frame=    1 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A
speed=   0x
frame=   35 fps=0.0 q=-1.0 Lsize=      76kB time=00:00:00.00 bitrate=N/A
speed=   0x
video:75kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 1.724296%
[libx264 @ 000001e4beec4300] frame I:1     Avg QP:17.73  size: 31047
[libx264 @ 000001e4beec4300] frame P:9     Avg QP:18.91  size:  2944
[libx264 @ 000001e4beec4300] frame B:25    Avg QP:22.27  size:   728
[libx264 @ 000001e4beec4300] consecutive B-frames:  2.9%  5.7%  0.0% 91.4%
[libx264 @ 000001e4beec4300] mb I  I16..4: 16.4% 76.6%  7.0%
[libx264 @ 000001e4beec4300] mb P  I16..4:  0.3%  1.6%  0.0%  P16..4:
16.6%  3.8%  1.7%  0.0%  0.0%    skip:75.9%
[libx264 @ 000001e4beec4300] mb B  I16..4:  0.0%  0.3%  0.0%  B16..8:
10.6%  0.4%  0.0%  direct: 0.1%  skip:88.5%  L0:47.2% L1:51.5% BI: 1.3%
[libx264 @ 000001e4beec4300] 8x8 transform intra:77.9% inter:95.7%
[libx264 @ 000001e4beec4300] coded y,uvDC,uvAC intra: 74.2% 64.9% 6.5%
inter: 2.1% 2.4% 0.0%
[libx264 @ 000001e4beec4300] i16 v,h,dc,p:  2% 47%  2% 49%
[libx264 @ 000001e4beec4300] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 48%  6%
3%  5%  4%  8%  5%  5%
[libx264 @ 000001e4beec4300] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 31% 42%  5%
2%  6%  4%  6%  2%  2%
[libx264 @ 000001e4beec4300] i8c dc,h,v,p: 39% 36%  9% 15%
[libx264 @ 000001e4beec4300] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 000001e4beec4300] ref P L0: 71.5%  4.0% 18.4%  6.2%
[libx264 @ 000001e4beec4300] ref B L0: 74.8% 23.8%  1.4%
[libx264 @ 000001e4beec4300] ref B L1: 95.9%  4.1%
[libx264 @ 000001e4beec4300] kb/s:259.71