ffmpeg中的Sendcmd

问题描述

为什么 ffmpeg 中的 sendcmd 对 drawtext 有效，但对 scale、rotation 和其他过滤器无效?

示例(此代码有效)

ffmpeg -i testIN.mp4 -filter_complex "[0:v]sendcmd=f=testTXT.cmd,drawtext=fontfile=PF.ttf:text='': fontcolor=white:fontsize=150" testOUT.mp4

testTXT.cmd

0 drawtext reinit 'text=111';1 drawtext reinit 'text=222';2 drawtext reinit 'text=333';

示例(此代码不起作用)

ffmpeg -i testIN.mp4 -filter_complex "[0:v]sendcmd=f=testTXT.cmd,drawbox=x=10:y=10:w=100:h=100" testOUT.mp4

testTXT.cmd

0 drawbox reinit 'x=20:y=20:w=200:h=200';1个拉杆重新初始化'x=30:y=30:w=300:h=300';2 drawbox reinit 'x=40:y=40:w=400:h=400';

解决方案

您遇到了几个问题:

1. 并非所有过滤器都支持 sendcmd.您可以使用 ffmpeg -filters 查看哪些过滤器支持 sendcmd.查找过滤器名称左侧的C".此外，只有某些过滤器选项(又名 sendcmd命令")可以与 sendcmd 一起使用.请参阅FFmpeg 过滤器文档，或参考man ffmpeg-filters，并查看每个过滤器的 Commands 部分下的可用选项.

2. 每个过滤器命令都必须在 sendcmd 文件中声明.文档示例中显示的 reinit 似乎仅限于 drawtext 过滤器，但这在文档中没有解释.

旋转示例

示例 sendcmd 文本文件:

 0 旋转角度 '45*PI/180';1 旋转角度'90*PI/180'；2 旋转角度'180*PI/180'；

示例 ffmpeg 命令:

 ffmpeg -i input.mp4 -filter_complex "[0:v]sendcmd=f=test.cmd,rotate" output.mp4

上面的例子将在持续时间0、1和2上轮换.

叠加示例

示例 sendcmd 文本文件:

0覆盖@1 x 10，覆盖@1 y 10,覆盖@2 x W-w-10，叠加@2 y H-h-10，覆盖@3 x (W-w)/2,覆盖@3 y (H-h)/2;#overlay@1 在此期间不会移动，因此此处不需要新条目2.25覆盖@2 x 10，叠加@2 y H-h-10，覆盖@3 x (W-w)/2,覆盖@3 y H-h-10；

示例 ffmpeg 命令:

ffmpeg -i video.mp4 -i overlay1.png -i overlay2.jpg -i overlay3.png -filter_complex "[0:v]sendcmd=f=test.cmd,nullsink;[0:v][1:v]overlay@1[bg1];[bg1][2:v]overlay@2[bg2];[bg2][3:v]overlay[v]" -map "[v]" -map 0:一个?-c:a 复制 output.mp4

Why sendcmd in ffmpeg works with drawtext, but does not work with scale, rotation and other filters?

Example (this code works)

ffmpeg  -i testIN.mp4 -filter_complex "[0:v]sendcmd=f=testTXT.cmd,drawtext=fontfile=PF.ttf:text='': fontcolor=white:fontsize=150" testOUT.mp4

testTXT.cmd

0 drawtext reinit 'text=111';
1 drawtext reinit 'text=222';
2 drawtext reinit 'text=333';

Example (this code does not work)

ffmpeg -i testIN.mp4 -filter_complex "[0:v]sendcmd=f=testTXT.cmd,drawbox=x=10:y=10:w=100:h=100" testOUT.mp4

testTXT.cmd

0 drawbox reinit 'x=20:y=20:w=200:h=200';
1 drawbox reinit 'x=30:y=30:w=300:h=300';
2 drawbox reinit 'x=40:y=40:w=400:h=400';

解决方案

You are encountering several issues:

1. Not all filters support sendcmd. You can see which filters support sendcmd with ffmpeg -filters. Look for a "C" to the left of the filter name. Additionally, only certain filter options (aka sendcmd "commands") can be used with sendcmd. See the FFmpeg filter documentation, or refer to man ffmpeg-filters, and view the available options under the Commands section for each filter.

2. Each filter command must be declared in the sendcmd file. The reinit shown in the documentation example appears to be limited to the drawtext filter, but this is not explained in the documentation.

rotate example

Example sendcmd text file:

    0 rotate angle '45*PI/180';
    1 rotate angle '90*PI/180';
    2 rotate angle '180*PI/180';

Example ffmpeg command:

    ffmpeg -i input.mp4 -filter_complex "[0:v]sendcmd=f=test.cmd,rotate" output.mp4

The above example will rotate on duration 0, 1, and 2.

overlay example

Example sendcmd text file:

0
overlay@1 x 10,
overlay@1 y 10,
overlay@2 x W-w-10,
overlay@2 y H-h-10,
overlay@3 x (W-w)/2,
overlay@3 y (H-h)/2;

# overlay@1 does not move at this duration so it needs no new entry here
2.25
overlay@2 x 10,
overlay@2 y H-h-10,
overlay@3 x (W-w)/2,
overlay@3 y H-h-10;

Example ffmpeg command:

ffmpeg -i video.mp4 -i overlay1.png -i overlay2.jpg -i overlay3.png -filter_complex "[0:v]sendcmd=f=test.cmd,nullsink;[0:v][1:v]overlay@1[bg1];[bg1][2:v]overlay@2[bg2];[bg2][3:v]overlay[v]" -map "[v]" -map 0:a? -c:a copy output.mp4

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