user18532: According to this ffmpeg documentation, it seems one of the 'native' frame rate for ffmpeg is

'ntsc':   30000/1001

while 30000/1001=29.9700... does not equal to 29.97, I wonder if a Sony Pro camera really means it shots in 29.97, not 30000/1001?
If that Sony camera does shot in exact 29.97fps, I suppose we should keep the 29.97fps, should not change the fps of the video file to 30000/1001?

user1871: 29.97 is shorthand for 30000/1001. There is no 29.970000... frame rate standard. FFmpeg will keep the native framerate (usually), so no need to specify an output -r value.

18532: <p>According to this <a href="https://ffmpeg.org/ffmpeg-utils.html#Video-rate" rel="nofollow noreferrer">ffmpeg documentation</a>, it seems one of the 'native' frame rate for <code>ffmpeg</code> is</p>

<blockquote>
  <p>'ntsc':   30000/1001</p>
</blockquote>

<p>while 30000/1001=29.9700... does not equal to 29.97, I wonder if a Sony Pro camera really means it shots in 29.97, not 30000/1001?</p>

<p>If that Sony camera does shot in exact 29.97fps, I suppose we should keep the 29.97fps, should not change the fps of the video file to 30000/1001?</p>
 1871: <p><code>29.97</code> is shorthand for 30000/1001. There is no <code>29.970000...</code> frame rate standard. FFmpeg will keep the native framerate (usually), so no need to specify an output <code>-r</code> value.</p>
