linux - 提取文本之间

Question

请你帮助我好吗？

frame=48612 fps= 50 q=28.0 size=  113664kB time=00:33:45.42 bitrate= 459.7kbits/s speed=2.09x    
frame=48612 fps= 50 q=28.0 size=  113664kB time=00:33:45.45 bitrate= 459.7kbits/s speed=2.09x    
frame=48613 fps= 51 q=28.0 size=  113664kB time=00:33:45.45 bitrate= 459.7kbits/s speed=2.09x    
frame=48613 fps= 50 q=28.0 size=  113664kB time=00:33:45.47 bitrate= 459.7kbits/s speed=2.09x    
frame=48613 fps= 49 q=28.0 size=  113664kB time=00:33:45.49 bitrate= 459.7kbits/s speed=2.09x    
frame=48614 fps= 50 q=28.0 size=  113664kB time=00:33:45.49 bitrate= 459.7kbits/s speed=2.09x    
frame=48614 fps= 50 q=28.0 size=  113664kB time=00:33:45.51 bitrate= 459.7kbits/s speed=2.09x    
frame=48614 fps= 51 q=28.0 size=  113664kB time=00:33:45.53 bitrate= 459.7kbits/s speed=2.09x    
frame=48615 fps= 50 q=28.0 size=  113664kB time=00:33:45.53 bitrate= 459.7kbits/s speed=2.09x    
frame=48615 fps= 50 q=28.0 size=  113664kB time=00:33:45.55 bitrate= 459.7kbits/s speed=2.09x    
frame=48615 fps= 50 q=28.0 size=  113664kB time=00:33:45.57 bitrate= 459.7kbits/s speed=2.09x    
frame=48616 fps= 52 q=25.0 size=  113664kB time=00:33:45.57 bitrate= 459.7kbits/s speed=2.09x    

您知道是否可以删除除 FPS={num} 之外的所有内容吗？我想输出这样的东西:

50
50
51
50
49
50
...

我试过的:

ffmpeg -i in.mp4 -stats_period 0.0001 out.mp4 | grep -o -P '(?<=fps= ).*(?= q=)'
ffmpeg -i in.mp4 -stats_period 0.0001 out.mp4 | grep fps | awk '{print $2}' | tr -d , 

两者都不起作用!

uname -svr => Linux 4.4.0-210-generic #242-Ubuntu SMP Fri Apr 16 09:57:56 UTC 2021

此外，ffmpeg 每秒返回每一帧，不是静态的 .txt 文件。
谢谢你。

Answer 1

使用进度选项将统计信息传送到标准输出并 grep。ffmpeg -i in.mp4 -stats_period 0.0001 -progress pipe:1 out.mp4 | grep -oP "(?<=fps=)\d+\.\d+"