我有一系列的帧，我将它们连接起来以创建视频。
在一系列帧上，我想叠加一幅具有不同不透明度的图像（想要产生淡入淡出的动画效果）。
不透明度应该随时间或帧数（）而变化。
尝试使用此命令：
ffmpeg -f concat -i input.txt -i inputImg.jpg -filter_complex "[1]format=argb,geq=r='r(X,Y)':a='T*alpha(X,Y)'[v1];[0][v1]overlay=x=70:y=100" -crf 22 -threads 2 -preset ultrafast output.mp4
输出：
ffmpeg version N-81989-g7845c13 Copyright (c) 2000-2016 the FFmpeg developers
built with gcc 5.4.0 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --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-libschroedinger --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-decklink --enable-zlib
libavutil 55. 32.100 / 55. 32.100
libavcodec 57. 61.103 / 57. 61.103
libavformat 57. 52.100 / 57. 52.100
libavdevice 57. 0.102 / 57. 0.102
libavfilter 6. 64.100 / 6. 64.100
libswscale 4. 1.100 / 4. 1.100
libswresample 2. 2.100 / 2. 2.100
libpostproc 54. 0.100 / 54. 0.100
Input #0, concat, from 'input.txt':
Duration: 00:00:22.01, start: 0.000000, bitrate: 0 kb/s
Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1920x1080 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
Input #1, image2, from 'inputImg.jpg':
Duration: 00:00:00.04, start: 0.000000, bitrate: 545 kb/s
Stream #1:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 396x323 [SAR 1:1 DAR 396:323], 25 tbr, 25 tbn, 25 tbc
File 'output.mp4' already exists. Overwrite ? [y/N] y
[swscaler @ 0000000000c0c820] deprecated pixel format used, make sure you did set range correctly
No pixel format specified, yuvj420p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 0000000000c04f40] using SAR=1/1
[libx264 @ 0000000000c04f40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0000000000c04f40] profile Constrained Baseline, level 4.0
[libx264 @ 0000000000c04f40] 264 - core 148 r2721 72d53ab - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=2 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=22.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, mp4, to 'output.mp4':
Metadata:
encoder : Lavf57.52.100
Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuvj420p(pc), 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
Metadata:
encoder : Lavc57.61.103 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream mapping:
Stream #0:0 (mjpeg) -> overlay:main
Stream #1:0 (mjpeg) -> format
overlay -> Stream #0:0 (libx264)
Press [q] to stop, [?] for help
frame= 599 fps=244 q=-1.0 Lsize= 251kB time=00:00:23.92 bitrate= 86.0kbits/s dup=587 drop=0 speed=9.76x
video:248kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.275079%
[libx264 @ 0000000000c04f40] frame I:3 Avg QP:12.33 size: 38456
[libx264 @ 0000000000c04f40] frame P:596 Avg QP:11.07 size: 232
[libx264 @ 0000000000c04f40] mb I I16..4: 100.0% 0.0% 0.0%
[libx264 @ 0000000000c04f40] mb P I16..4: 0.1% 0.0% 0.0% P16..4: 0.6% 0.0% 0.0% 0.0% 0.0% skip:99.4%
[libx264 @ 0000000000c04f40] coded y,uvDC,uvAC intra: 3.5% 7.1% 6.6% inter: 0.1% 0.3% 0.0%
[libx264 @ 0000000000c04f40] i16 v,h,dc,p: 95% 4% 1% 0%
[libx264 @ 0000000000c04f40] i8c dc,h,v,p: 81% 10% 8% 0%
[libx264 @ 0000000000c04f40] kb/s:84.59
但输出视频不包含叠加图像。
注意：框架尺寸和叠加图像的尺寸不同。