Converting video files

By Dave Nason, 9 May, 2025

Member of the AppleVis Editorial Team

Forum
macOS and Mac Apps

Hi all,
I did a screen recording using QuickTime on my Mac, which resulted in a large .mov file.
I want to convert this to .m4v or whatever smaller file type. I attempted this using VLC Media Player, selecting the default option of “H264 + mp3 / mp4”.
However the resulting file has video but no sound. I tried again, this time selecting the Customise button first, and audio does appear to be checked, but got the same result.
I’ve tried three times now with the same result. They say trying the same thing over and over again and expecting a different result is the definition of madness, so probably time to try something else!
Can anyone tell me what I’m doing wrong in VLC, or point me to a different tool?
Cheers,
Dave

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Comments

By João Santos on Friday, May 9, 2025 - 15:28

I just do it using ffmpeg from the command-line, usually from inside a Docker container since ffmpeg pulls lots of dependencies that I don't want to clutter my system with.

After installing ffmpeg inside Docker or using your favorite macOS package manager like MacPorts or HomeBrew, encoding a QuickTime video named Input.mov to an Mp4 file named Output.mp4 is just a matter of typing something like:

ffmpeg -i Input.mov  -s 960x540 -r 30 -ac 2 Output.mp4

The above command breaks down to:

  • the -i switch specifies the input file (Input.mov);
  • The -s switch specifies the output resolution (960x540);
  • The -r switch specifies the output frame-rate (30);
  • The -ac switch specifies the number of output audio channels (2);
  • The remaining argument specifies the output file (Output.mp4).

Notice that the 960x540 resolution in my example above is actually quite low. If you want regular text to be readable and relatively crisp to sighted people you should aim at least to half your screen's horizontal and vertical pixel resolution.