ffmpeg - 多次写入相同的帧？

Question

使用以下命令：

ffmpeg -i test.mp4 -vf "select='not(mod(n,2000))',setpts=N/3/TB" -r 3 output.gif 

我写1帧，每2000，在3FPS GIF文件。

但是，当我看到FFmpeg的输出也有一些是令人困惑：

speed=0.00997frame= 1 fps=0.7 q=-0.0 size=  1kB time=00:00:00.01 
speed=0.00498frame= 1 fps=0.4 q=-0.0 size=  1kB time=00:00:00.01 
speed=0.00332frame= 2 fps=0.6 q=-0.0 size=  2kB time=00:00:00.34 
speed=0.0847xframe= 2 fps=0.4 q=-0.0 size=  2kB time=00:00:00.34 
speed=0.0678xframe= 2 fps=0.4 q=-0.0 size=  2kB time=00:00:00.34 
speed=0.0565xframe= 2 fps=0.3 q=-0.0 size=  2kB time=00:00:00.34 
speed=0.0968xframe= 3 fps=0.4 q=-0.0 size=  20kB time=00:00:00.68 
speed=0.0847xframe= 3 fps=0.4 q=-0.0 size=  20kB time=00:00:00.68 
speed=0.0753xframe= 3 fps=0.3 q=-0.0 size=  20kB time=00:00:00.68 
speed=0.0678xframe= 4 fps=0.4 q=-0.0 size=  41kB time=00:00:01.01 
speed=0.0915xframe= 4 fps=0.3 q=-0.0 size=  41kB time=00:00:01.01 
speed=0.0839xframe= 4 fps=0.3 q=-0.0 size=  41kB time=00:00:01.01 
speed=0.0774xframe= 4 fps=0.3 q=-0.0 size=  41kB time=00:00:01.01 
speed=0.0954xframe= 5 fps=0.3 q=-0.0 size=  66kB time=00:00:01.34 
speed=0.089x frame= 5 fps=0.3 q=-0.0 size=  66kB time=00:00:01.34 
speed=0.0834xframe= 5 fps=0.3 q=-0.0 size=  66kB time=00:00:01.34 
speed=0.0785xframe= 6 fps=0.3 q=-0.0 size=  90kB time=00:00:01.68 
speed=0.093x frame= 6 fps=0.3 q=-0.0 size=  90kB time=00:00:01.68 
speed=0.0881xframe= 6 fps=0.3 q=-0.0 size=  90kB time=00:00:01.68 
speed=0.0837xframe= 6 fps=0.3 q=-0.0 size=  90kB time=00:00:01.68 

它看起来像每个被重建多次，目标帧。 我希望是这样的：

speed=0.00997frame= 1 fps=0.7 q=-0.0 size=  1kB time=00:00:00.01 
speed=0.00332frame= 2 fps=0.6 q=-0.0 size=  2kB time=00:00:00.34 
speed=0.0968xframe= 3 fps=0.4 q=-0.0 size=  20kB time=00:00:00.68 
speed=0.0678xframe= 4 fps=0.4 q=-0.0 size=  41kB time=00:00:01.01 
speed=0.0954xframe= 5 fps=0.3 q=-0.0 size=  66kB time=00:00:01.34 
speed=0.0785xframe= 6 fps=0.3 q=-0.0 size=  90kB time=00:00:01.68 

我缺少的东西？

（这是从一个ffmpeg - multiple output with thumbnails随访）

Answer 1

这只是进度报告。每次刷新报告时，如果新帧尚未编码，它将显示相同的数字。 fps速度为1.0意味着每帧编码1帧。所以，如果一秒钟内进度报告有两次刷新，第二个将显示相同的帧数。