ffmpeg .mov to .mp4 results in big file size decrease

[TailG8R]

So I converted a 30.2 GB .mov file to a .mp4 file with ffmpeg. This resulting .mp4 file was only 2.71 GB. Does that sound right?

[video.baba]

Why would it not?

[jagabo]

If you just remuxed there should be very little difference in file size. If you re-compressed anything is possible.

[TailG8R]

I used ffmpeg, the command prompt command line utility. https://ffmpeg.zeranoe.com/builds/

ffmpeg -i myvideo.mov myvodeo.mp4

[jagabo]

Then you re-compressed the video. If you just wanted to remux (copy) from move to mp4 add "-vcodec copy -acodec copy" to your command line:

ffmpeg -i myvideo.mov -vcodec copy -acodec copy myvodeo.mp4

Why do you want an mp4 file? Are you looking for a smaller file or to just re-wrap the existing audio and video in an mp4 container?

[theewizard]

use 'mediaInfo' on the source file and they output file
this will tell you the codec info and bitrate etc.. of each file
what you did was a 10x reduction, thats a lot of compression
but IF you went raw video to h264, its possible
how does the new file compare to the source when playing

[TailG8R]

Then you re-compressed the video. If you just wanted to remux (copy) from move to mp4 add "-vcodec copy -acodec copy" to your command line:

ffmpeg -i myvideo.mov -vcodec copy -acodec copy myvodeo.mp4

Why do you want an mp4 file? Are you looking for a smaller file or to just re-wrap the existing audio and video in an mp4 container?

I want MP4 because Amazon Video Direct requires the .mp4 container for movies using the H264 codec. They don't accept .mov containers. Unfortunately Final Cut Pro's QuickTime conversion renders a .mov file for H264.

I tried to use that "-vcodec copy acodec copy" but got an error message "unable to find a suitable output format for acodec"

I see that you can also specify output rate. For example:
"ffmpeg -i infile.mov -b:v 3750k -b:a 192k outfile.mp4"

Or you can do it like this:
-i infile.mov -crf 0 quality outfile.mp4

[jagabo]

There's an endless variety of ways you can get what you need. If your video is already encoded with an acceptable codec you will only degrade it by reencoding it. It sounds like you just need to convert the audio.

[TailG8R]

Again I'm only converting to .mp4 because Amazon requires it.

[videobruger]

I tried to use that "-vcodec copy acodec copy"

Needs a hyphen (-copy acodec)

[pandy]

To be precise you need something like bellow to fully copy file with ffmpeg:

@ffmpeg -i %1 -map 0 -c copy -movflags faststart %~n1.mp4