c++ - ffmpeg滤镜图像处理

Question

ffmpeg 在构建视频之前对图像应用一些过滤器。有什么方法可以知道这些过滤器吗？

我正在使用这个命令(所以默认情况下保留每个参数):

ffmpeg -framerate 12 -i frame%02d.jpg out.mp4

一帧示例:

图片文件:

来自视频:

我正在使用 C++ 进行图像处理，我对 ffmpeg 过滤图像的方式很感兴趣

编辑

当我启动命令行时，我在终端中得到的是:

ffmpeg -framerate 5 -i frame%02d.jpg output.mp4


ffmpeg version 2.8.11-0ubuntu0.16.04.1 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  configuration: --prefix=/usr --extra-version=0ubuntu0.16.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
[mjpeg @ 0x23e8600] Changeing bps to 8
Input #0, image2, from 'frame%02d.jpg':
  Duration: 00:01:40.20, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 2576x1456 [SAR 1:1 DAR 23:13], 5 fps, 5 tbr, 5 tbn, 5 tbc
No pixel format specified, yuvj420p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 0x23ec680] using SAR=1/1
[libx264 @ 0x23ec680] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x23ec680] profile High, level 5.0
[libx264 @ 0x23ec680] 264 - core 148 r2643 5c65704 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - 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=12 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=2 keyint=250 keyint_min=5 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 'output.mp4':
  Metadata:
    encoder         : Lavf56.40.101
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuvj420p(pc), 2576x1456 [SAR 1:1 DAR 23:13], q=-1--1, 5 fps, 10240 tbn, 5 tbc
    Metadata:
      encoder         : Lavc56.60.100 libx264
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
Press [q] to stop, [?] for help
frame=  501 fps=3.8 q=-1.0 Lsize=  154288kB time=00:01:39.80 bitrate=12664.6kbits/s    
video:154284kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.002771%
[libx264 @ 0x23ec680] frame I:3     Avg QP:17.31  size:564506
[libx264 @ 0x23ec680] frame P:498   Avg QP:19.27  size:313841
[libx264 @ 0x23ec680] mb I  I16..4:  0.2% 97.1%  2.7%
[libx264 @ 0x23ec680] mb P  I16..4:  0.0% 46.3%  0.5%  P16..4: 12.5% 13.0%  7.7%  0.0%  0.0%    skip:20.1%
[libx264 @ 0x23ec680] 8x8 transform intra:98.9% inter:73.3%
[libx264 @ 0x23ec680] coded y,uvDC,uvAC intra: 99.0% 99.7% 96.0% inter: 52.0% 57.7% 37.0%
[libx264 @ 0x23ec680] i16 v,h,dc,p: 17% 16% 13% 54%
[libx264 @ 0x23ec680] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 10% 12% 33%  6%  7%  6%  8%  7% 10%
[libx264 @ 0x23ec680] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 12% 13% 14% 10% 13%  9% 11%  8% 10%
[libx264 @ 0x23ec680] i8c dc,h,v,p: 66% 14% 14%  5%
[libx264 @ 0x23ec680] Weighted P-Frames: Y:2.0% UV:1.2%
[libx264 @ 0x23ec680] ref P L0: 45.6% 16.0% 20.4% 17.6%  0.5%
[libx264 @ 0x23ec680] kb/s:12613.66

Answer 1

如果输入的像素格式不能应用于输出，ffmpeg 将自动插入一个缩放器来执行转换。

使用日志级别 40 或更高级别运行命令将显示这些自动插入的过滤器的存在。

[graph 0 input from stream 0:0 @ 0000000002bffb40] w:320 h:240 pixfmt:rgb24 tb:1/25 fr:25/1 sar:1/1 sws_param:flags=2
[auto_scaler_0 @ 0000000002bb7f20] w:iw h:ih flags:'bicubic' interl:0
[format @ 0000000002bfe940] auto-inserting filter 'auto_scaler_0' between the filter 'Parsed_null_0' and the filter 'format'
[auto_scaler_0 @ 0000000002bb7f20] w:320 h:240 fmt:rgb24 sar:1/1 -> w:320 h:240 fmt:yuv444p sar:1/1 flags:0x4

类似的适用于音频，例如可以添加自动重采样器。