ffmpeg使用ss与t参数对视频进行剪辑

ffmpeg能够实现对视频进行剪辑操作，ss为指定视频剪切开头的起始时间，t制定视频的总长度，ss与t的单位均为：秒。

ffmpeg -ss 7200 -i 1080p.mp4 -c copy -t 900 1080psrc.mp4

-ss 指定视频剪切起始时间为2:00:00

-i 指定视频源文件

-c 原始编解码数据必须被拷贝，即剪辑前后文件的编码方式保持一致

-t 制定剪取的视频长度

任务执行过程显示：

$ ffmpeg -ss 7200 -i 1080p.mp4 -c copy -t 900 1080psrc.mp4
ffmpeg version 4.1.4-1build2 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.2.1-4ubuntu1)
  configuration: --prefix=/usr --extra-version=1build2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  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, mov,mp4,m4a,3gp,3g2,mj2, from '1080p.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: isommp423gp5
    creation_time   : 2019-07-31T13:32:46.000000Z
    encoder         : My MP4Box GUI 0.6.0.6 <http://my-mp4box-gui.zymichost.com>
  Duration: 03:01:11.42, start: 0.000000, bitrate: 3037 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 2794 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
    Metadata:
      creation_time   : 2019-07-31T13:30:02.000000Z
      handler_name    : 复鲁冒脮脽联脙脣4Ｂ好栒久栔 蓝鹿芒双脳脰幕).Avengers.Endgame.2019.BD-1080p.X264.AAC.CHS.ENG-UUMp4.mp4
      encoder         : AVC Coding
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 238 kb/s (default)
    Metadata:
      creation_time   : 2019-07-31T13:33:09.000000Z
      handler_name    : avengers.endgame.2019.1080p.bluray.x264-sparks.m4a
    Stream #0:2(und): Data: none (mp4s / 0x7334706D), 0 kb/s (default)
    Metadata:
      creation_time   : 2019-07-31T13:33:12.000000Z
      handler_name    : GPAC MPEG-4 OD Handler
    Stream #0:3(und): Data: none (mp4s / 0x7334706D), 0 kb/s (default)
    Metadata:
      creation_time   : 2019-07-31T13:33:12.000000Z
      handler_name    : GPAC MPEG-4 Scene Description Handler
Output #0, mp4, to '1080psrc.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: isommp423gp5
    encoder         : Lavf58.20.100
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 2794 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 24k tbc (default)
    Metadata:
      creation_time   : 2019-07-31T13:30:02.000000Z
      handler_name    : 复鲁冒脮脽联脙脣4Ｂ好栒久栔 蓝鹿芒双脳脰幕).Avengers.Endgame.2019.BD-1080p.X264.AAC.CHS.ENG-UUMp4.mp4
      encoder         : AVC Coding
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 238 kb/s (default)
    Metadata:
      creation_time   : 2019-07-31T13:33:09.000000Z
      handler_name    : avengers.endgame.2019.1080p.bluray.x264-sparks.m4a
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame=21607 fps=0.0 q=-1.0 Lsize=  352596kB time=00:14:59.98 bitrate=3209.4kbits/s speed=1.79e+03x
video:325701kB audio:26302kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.168539%

使用ffprobe查看输出后的1080psrc.mp4文件属性：

$ ffprobe -i 1080psrc.mp4
ffprobe version 4.1.4-1build2 Copyright (c) 2007-2019 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.2.1-4ubuntu1)
  configuration: --prefix=/usr --extra-version=1build2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  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, mov,mp4,m4a,3gp,3g2,mj2, from '1080psrc.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:15:01.21, start: 0.000000, bitrate: 3205 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 2960 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
    Metadata:
      handler_name    : 复鲁冒脮脽联脙脣4Ｂ好栒久栔 蓝鹿芒双脳脰幕).Avengers.Endgame.2019.BD-1080p.X264.AAC.CHS.ENG-UUMp4.mp4
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 239 kb/s (default)
    Metadata:
      handler_name    : avengers.endgame.2019.1080p.bluray.x264-sparks.m4a