我有两个类似的覆盖过滤器用法，使用两个视频作为输入，如果一个视频是主视频，它就可以工作，如果另一个视频是主视频，则覆盖会被隐藏。
表达式一：
ffmpeg.exe -v error -stats -ss 0.40 -i "GH010161.MP4" -ss 0.4 -i "GH010165.MP4" -vframes 1 -filter_complex "[1] scale=400:400 [a];[0] scale=200:200[b];[a][b] overlay=10:10" -y OutFrame_e1.jpg
表达式二（切换了输入文件，因此它是顶部的另一个）：
ffmpeg.exe -v error -stats -ss 0.40 -i "GH010165.MP4" -ss 0.4 -i "GH010161.MP4" -vframes 1 -filter_complex "[1] scale=400:400 [a];[0] scale=200:200[b];[a][b] overlay=10:10" -y OutFrame_e2.jpg
如果我切换过滤器表达式也没有关系，因为只有视频1GH010165.MP4才能在后台/主屏幕上显示。
如果我生成完整视频输出（即 MP4），则两者都可以工作，因此只有在制作帧图像时才会出现问题。
我相信它与值有某种联系-ss，但两个视频都可以使用该时间码分别生成一帧。如果我删除 for -ss，GH010161.MP4它也会起作用。
有什么想法可以解决它吗？
以下是完整报告（不含）-v error：
C:\Users\mmo21\Videos\ffmpeg.exe -ss 0.20 -i "C:\Users\mmo21\Videos\GPRo\GH010161.MP4" -ss 0.20 -i "C:\Users\mmo21\Videos\GPRo\GH010171.MP4" -vframes 1 -filter_complex "[1]scale=400:trunc((400 / iw) * (ih / 2))*2[over];[0][over] overlay =10:10" -y C:\Users\mmo21\Videos\OutFrame.jpg
ffmpeg version N-83657-g7e4f32f Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 6.3.0 (GCC)
configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
libavutil 55. 47.100 / 55. 47.100
libavcodec 57. 81.100 / 57. 81.100
libavformat 57. 66.102 / 57. 66.102
libavdevice 57. 2.100 / 57. 2.100
libavfilter 6. 74.100 / 6. 74.100
libswscale 4. 3.101 / 4. 3.101
libswresample 2. 4.100 / 2. 4.100
libpostproc 54. 2.100 / 54. 2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\Users\mmo21\Videos\GPRo\GH010161.MP4':
Metadata:
major_brand : mp41
minor_version : 538120216
compatible_brands: mp41
creation_time : 2020-07-21T18:06:22.000000Z
firmware : H18.02.02.10.00
Duration: 00:08:22.40, start: 0.000000, bitrate: 40186 kb/s
Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, smpte170m), 1920x1440 [SAR 1:1 DAR 4:3], 40006 kb/s, 49.99 fps, 50 tbr, 90k tbn, 100 tbc (default)
Metadata:
creation_time : 2020-07-21T18:06:22.000000Z
handler_name : GoPro AVC
encoder : GoPro AVC encoder
timecode : 18:06:22:35
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
creation_time : 2020-07-21T18:06:22.000000Z
handler_name : GoPro AAC
timecode : 18:06:22:35
Stream #0:2(eng): Data: none (tmcd / 0x64636D74) (default)
Metadata:
creation_time : 2020-07-21T18:06:22.000000Z
handler_name : GoPro TCD
timecode : 18:06:22:35
Stream #0:3(eng): Data: none (gpmd / 0x646D7067), 28 kb/s (default)
Metadata:
creation_time : 2020-07-21T18:06:22.000000Z
handler_name : GoPro MET
Stream #0:4(eng): Data: none (fdsc / 0x63736466), 12 kb/s (default)
Metadata:
creation_time : 2020-07-21T18:06:22.000000Z
handler_name : GoPro SOS
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\Users\mmo21\Videos\GPRo\GH010171.MP4':
Metadata:
major_brand : mp41
minor_version : 538120216
compatible_brands: mp41
creation_time : 2020-07-29T12:16:22.000000Z
firmware : H18.02.02.10.00
Duration: 00:01:24.20, start: 0.000000, bitrate: 30154 kb/s
Stream #1:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, smpte170m), 1920x1440 [SAR 1:1 DAR 4:3], 30005 kb/s, 25 fps, 25 tbr, 90k tbn, 48 tbc (default)
Metadata:
creation_time : 2020-07-29T12:16:22.000000Z
handler_name : GoPro AVC
encoder : GoPro AVC encoder
timecode : 12:16:22:16
Stream #1:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
creation_time : 2020-07-29T12:16:22.000000Z
handler_name : GoPro AAC
timecode : 12:16:22:16
Stream #1:2(eng): Data: none (tmcd / 0x64636D74) (default)
Metadata:
creation_time : 2020-07-29T12:16:22.000000Z
handler_name : GoPro TCD
timecode : 12:16:22:16
Stream #1:3(eng): Data: none (gpmd / 0x646D7067), 28 kb/s (default)
Metadata:
creation_time : 2020-07-29T12:16:22.000000Z
handler_name : GoPro MET
Stream #1:4(eng): Data: none (fdsc / 0x63736466), 9 kb/s (default)
Metadata:
creation_time : 2020-07-29T12:16:22.000000Z
handler_name : GoPro SOS
[swscaler @ 00000000021fb6a0] deprecated pixel format used, make sure you did set range correctly
Output #0, image2, to 'C:\Users\mmo21\Videos\OutFrame.jpg':
Metadata:
major_brand : mp41
minor_version : 538120216
compatible_brands: mp41
firmware : H18.02.02.10.00
encoder : Lavf57.66.102
Stream #0:0: Video: mjpeg, yuvj420p(pc), 1920x1440 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 50 fps, 50 tbn, 50 tbc (default)
Metadata:
encoder : Lavc57.81.100 mjpeg
Side data:
cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
Stream mapping:
Stream #0:0 (h264) -> overlay:main
Stream #1:0 (h264) -> scale
overlay -> Stream #0:0 (mjpeg)
Press [q] to stop, [?] for help
frame= 1 fps=0.0 q=8.4 Lsize=N/A time=00:00:00.02 bitrate=N/A speed=0.0761x
video:161kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
OutFrame_e1.jpg
OutFrame_e2.jpg
答案1
似乎有必要将两个视频渲染为相同的帧速率。我认为 -ss 参数在某种程度上不稳定，并且并非总是能够根据 -ss 值生成帧图像。如果帧速率相同，上述示例将有效。