如果我尝试连接两个视频，则会因视频屏幕大小不同而引发错误。我为每两个视频添加了一个setdat = 16/9参数，如描述here。然后我得到了下面的错误。如何连接两个不同屏幕尺寸的视频？
代码：
ffmpeg -i /var/www/html/GetVideo/reklam/muzikli1.mp4 -i /var/www/html/GetVideo/tempvideo/sample.mp4 -filter_complex \ "[0]setdar=16/9[a];[1]setdar=16/9[b]; \ [a][b]concat=n=2:v=1:a=1" /var/www/html/GetVideo/reklam/out.mp4
错误：
pi@raspberrypi:/var/www/html/GetVideo $ ffmpeg -i /var/www/html/GetVideo/reklam/muzikli1.mp4 -i /var/www/html/GetVideo/tempvideo/sample.mp4 -filter_complex \ "[0]setdar=16/9[a];[1]setdar=16/9[b]; \ [a][b]concat=n=2:v=1:a=1" /var/www/html/GetVideo/reklam/out.mp4
ffmpeg version git-2018-05-06-652b857 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 6.3.0 (Raspbian 6.3.0-18+rpi1+deb9u1) 20170516
configuration: --arch=armel --target-os=linux --enable-gpl --enable-libx264 --enable-nonfree
libavutil 56. 18.100 / 56. 18.100
libavcodec 58. 19.101 / 58. 19.101
libavformat 58. 13.101 / 58. 13.101
libavdevice 58. 4.100 / 58. 4.100
libavfilter 7. 21.100 / 7. 21.100
libswscale 5. 2.100 / 5. 2.100
libswresample 3. 2.100 / 3. 2.100
libpostproc 55. 2.100 / 55. 2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/html/GetVideo/reklam/muzikli1.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
Duration: 00:00:13.35, start: 0.000000, bitrate: 244 kb/s
Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 918x512 [SAR 1:1 DAR 459:256], 110 kb/s, 5 fps, 5 tbr, 5k tbn, 10k tbc (default)
Metadata:
handler_name : VideoHandler
encoder : AVC Coding
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 129 kb/s (default)
Metadata:
handler_name : SoundHandler
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/html/GetVideo/tempvideo/sample.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf57.65.100
Duration: 00:00:25.57, start: 0.000000, bitrate: 1015 kb/s
Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 896 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 113 kb/s (default)
Metadata:
handler_name : SoundHandler
[AVFilterGraph @ 0x2fa9a20] No such filter: ' '
Error initializing complex filters.
Invalid argument