我想按顺序播放多个视频，然后应用一些效果。我想gnlcomposition可以帮助我。
官方gnlcomposition documentation真的很小。所以我开始测试一些基于gst-launch的gnlcomposition脚本，我用它来搜索。
如果我跑：
>gst-launch gnlcomposition (^
gnlfilesource name="s1" location="file:///C:/p/test/a.mp4" ^
start=0 duration=240 media-start=0 media-duration=240 ^
gnlfilesource name="s2" location="file:///C:/p/test/b.mp4" ^
start=0 duration=240 media-start=0 media-duration=240 ^
) ! queue ! videorate ! progressreport name="Merging " ! ^
ffmpegcolorspace ! ffenc_mpeg4 ! ffmux_mp4 ! ^
filesink location="C:/p/test/c.mp4"
我明白了：
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
0:00:00.303017000 4052 0204B3E8 ERROR
ffmpeg .:0:: Tag mp4v/0x7634706d incompatible with output codec id '13'
Merging (00:00:00): 0 seconds
ERROR: from element /GstPipeline:pipeline0/ffmux_mp4:ffmux_mp40:
Could not configure supporting library.
0:00:00.305017000 Additional debug info:
..\..\..\..\..\Source\gst-ffmpeg\ext\ffmpeg\gstffmpegmux.c(654):
gst_ffmpegmux_collected (): /GstPipeline:pipeline0/ffmux_mp4:ffmux_mp40:
Failed to write file header - check codec settings
4052 ERROR: pipeline doesn't want to preroll.
0204B3E8 Setting pipeline to NULL ...
ERROR ffmpeg .:0:: Tag mp4v/0x7634706d incompatible with output codec id '13'
Freeing pipeline ...
我正在使用Ossbuild Win64二进制文件：
GStreamer-WinBuilds-GPL-x86-Beta04-0.10.7.msi
您能帮助和/或提供适当的文件吗？