时间戳未打印在 FFMPEG 的缩略图上

Posted 2023-03-29

【中文标题】时间戳未打印在 FFMPEG 的缩略图上

【英文标题】：Timestamp not printed on thumbnails with FFMPEG

【发布时间】：2021-08-03 09:59:02

【问题描述】：

我有一个脚本，它使用 FFMPEG 每 45 秒为给定文件夹中的多个视频生成带有平铺缩略图的图像。图像以生成它的视频的名称命名。它为每个视频生成缩略图，但不会在其上打印时间戳。字体文件的路径正确；所以我不知道问题出在哪里。我在 Fedora Linux 中使用该脚本。

这是脚本上的 FFMPEG 命令行代码：

 ffmpeg -ss 00:00:05 -i test.mp4 -loglevel 40 -frames 1 -bt 20M -vf "drawtext=fontfile=/usr/share/fonts/open-sans/OpenSans-Light.ttf:timecode='00\\:00\\:00\\:00':r=30:fontcolor=white:x=220:y=220:box=1:boxcolor=black@0.5,select=not(mod(n\,1350)),scale=200:150,tile=15x48" -n "$name.png"

这是控制台输出

ffmpeg version 4.4 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 11 (GCC)
  configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-***-protection -fcf-protection' --extra-ldflags='-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld ' --extra-cflags=' -I/usr/include/rav1e' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libaom --enable-libdav1d --enable-libass --enable-libbluray --enable-libcdio --enable-libdrm --enable-libjack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librav1e --enable-libsmbclient --enable-version3 --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-version3 --enable-vapoursynth --enable-libvpx --enable-vulkan --enable-libglslang --enable-libx264 --enable-libx265 --enable-libxvid --enable-libxml2 --enable-libzimg --enable-libzvbi --enable-lv2 --enable-avfilter --enable-avresample --enable-libmodplug --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-lto --enable-libmfx --enable-runtime-cpudetect
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
[h264 @ 0x56051b4b3cc0] Reinit context to 1280x720, pix_fmt: yuv420p
[mpegts @ 0x56051b4acc80] max_analyze_duration 5000000 reached at 5000000 microseconds st:0
Input #0, mpegts, from 'test.mp4':
  Duration: 00:04:57.02, start: 1.400000, bitrate: 2853 kb/s
  Program 1 
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
  Stream #0:0[0x100]: Video: h264 (Main), 1 reference frame ([27][0][0][0] / 0x001B), yuv420p(progressive, left), 1280x720 [SAR 1:1 DAR 16:9], 30 fps, 30 tbr, 90k tbn, 60 tbc
  Stream #0:1[0x101]: Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 96 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> png (native))
Press [q] to stop, [?] for help
[h264 @ 0x56051ba69e00] Reinit context to 1280x720, pix_fmt: yuv420p
[Parsed_scale_2 @ 0x56051b5953c0] w:200 h:150 flags:'bicubic' interl:0
[graph 0 input from stream 0:0 @ 0x56051b725ac0] w:1280 h:720 pixfmt:yuv420p tb:1/90000 fr:30/1 sar:1/1
[Parsed_scale_2 @ 0x56051b5953c0] w:1280 h:720 fmt:yuv420p sar:1/1 -> w:200 h:150 fmt:rgb24 sar:4/3 flags:0x4
Output #0, image2, to '.png':
  Metadata:
    encoder         : Lavf58.76.100
  Stream #0:0: Video: png, 1 reference frame, rgb24(pc, progressive, left), 3000x7200 (0x0) [SAR 4:3 DAR 5:9], q=2-31, 200 kb/s, 0.04 fps, 0.04 tbn
    Metadata:
      encoder         : Lavc58.134.100 png
No more output streams to write to, finishing.00.00 bitrate=N/A speed=   0x    
[AVIOContext @ 0x56051b84c8c0] Statistics: 0 seeks, 2 writeouts
frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:24.00 bitrate=N/A speed=0.47x    
video:465kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Input file #0 (test.mp4):
  Input stream #0:0 (video): 8761 packets read (96159422 bytes); 8760 frames decoded; 
  Input stream #0:1 (audio): 0 packets read (0 bytes); 
  Total: 8761 packets (96159422 bytes) demuxed
Output file #0 (.png):
  Output stream #0:0 (video): 1 frames encoded; 1 packets muxed (476224 bytes); 
  Total: 1 packets (476224 bytes) muxed
[AVIOContext @ 0x56051b4b5d00] Statistics: 107090352 bytes read, 18 seeks

【参考方案1】：

时间码可能在那里，但您没有在 drawtext 中应用 fontsize。因此，由于缩小比例，它可能太小而无法看到。试试：

ffmpeg -loglevel 40 -n -ss 00:00:05 -i test.mp4 -vframes 1 -vf "drawtext=fontfile=/usr/share/fonts/open-sans/OpenSans-Light.ttf:timecode='00\\:00\\:00\\:00':r=30:fontcolor=white:fontsize=92:x=220:y=220:box=1:boxcolor=black@0.5,select=not(mod(n\,1350)),scale=200:150,tile=15x48" "$name.png"

或者先缩小尺寸，然后应用drawtext。

见drawtext filter documentation。

【参考方案2】：

感谢 llogan，该脚本现在可以运行。对于任何想要使用该脚本的人，这里是代码：

#!/bin/bash
for i in *mp4,mkv;
    do name=`echo "$i" | cut -d'.' -f1`
    echo "$name"
   ffmpeg -ss 00:00:05 -i "$i" -loglevel 40 -frames 1 -bt 20M -vf "drawtext=fontfile=/usr/share/fonts/open-sans/OpenSans-Light.ttf:timecode='00\\:00\\:00\\:00':r=30:fontsize=92:fontcolor=white:x=220:y=220:box=1:boxcolor=black@0.5,select=not(mod(n\,1350)),scale=200:150,tile=15x48" -n "$name.png"

done

【讨论】：

您应该解释为什么您发布的代码可以解决您最初的问题，以便其他有相同问题的人受益。