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Hi, I just used iMovie to rotate a video made with a smatphone in mp4 format, the result is a video in .mov format, the video size is now 240MB instead of the original 32MB.
Question, does this change the quality of the video or does it stay intact?
Thanks in advance.
Windows, Windows 10
No, not necessarily. The .mov format is a container that can hold different codecs, so that not all .mov is alike. For example, one can render a .mov file in H.264 (like Mp4) or pro res422. When the .mov format is encoded with pro res422 it is very uncompressed and therefor larger than the more compressed Mp4 file. Thus pro res422 is an editing format, suitable for precise professional editing. However, the Mp4 format is very high quality delivery format designed for viewing. It can be edited as well. You won't notice any quality drop off by using it. Your iPhone .mov file probably is not a pro res422 file. If you open your .mov file with QuickTimePlayer and do a Window/Show Movie inspector,likely it will be an H.264 file just like the Mp4 file.
Quality is determined by things like the resolution, compression rate, and frame rate. Those can vary with pro res or Mp4 or .mov. If the .mov file looks good to you, then go with it. The quality will be intact.
-- Rich
No, not necessarily. The .mov format is a container that can hold different codecs, so that not all .mov is alike. For example, one can render a .mov file in H.264 (like Mp4) or pro res422. When the .mov format is encoded with pro res422 it is very uncompressed and therefor larger than the more compressed Mp4 file. Thus pro res422 is an editing format, suitable for precise professional editing. However, the Mp4 format is very high quality delivery format designed for viewing. It can be edited as well. You won't notice any quality drop off by using it. Your iPhone .mov file probably is not a pro res422 file. If you open your .mov file with QuickTimePlayer and do a Window/Show Movie inspector,likely it will be an H.264 file just like the Mp4 file.
Quality is determined by things like the resolution, compression rate, and frame rate. Those can vary with pro res or Mp4 or .mov. If the .mov file looks good to you, then go with it. The quality will be intact.
-- Rich
The quality would stay intact.
For clarity, as I understand it you created an Mp4 movie with your smart phone that you exported into iMovie for Mac, and when you go to export it from iMovie Mac you find that you get a .mov file that is much larger than your original Mp4 file. Correct?
Assuming that you are now working in Mac iMovie, if the movie is now in .mov format that means you have chosen Best Quality (pro res) as an export option. That would result in a .mov file that usually is about 4x larger than an Mp4 file that is highly compressed. If that's the case, chose Good Quality instead of Best Quality and that will give you an Mp4 file that is much smaller than your .mov file. There really is no reason to be using the Best Quality (pro res) format unless you are doing some very exacting professional quality editing. Unless you are expanding and examining by pixels, or displaying on a theater sized screen, there would be no difference to the human eye.
-- Rich
Hi Rich! first of all Thanks for the help!
Since I didn't get any answers in the "iMovie for IOS" section, I posted my question here in the "iMovie for Mac" section.
My post is "true" except that I did the rotation on the iPhone and not on the Mac (I don't have a Mac).
On iMovie for IOS, however, I cannot choose the quality, it exports it in .mov format, without giving the option to changes.
Ii is not a problem if it has become bigger, what interests me is that it does not lose quality (nothing professional but it is a family video that I care a lot), because I also happen to see it on a 24 "monitor.
So I understand that a .MOV is lossless quality while a .MP4 is lossy compression (about 4 times as opposed to a .MOV), right?
1000 Thanks!
Perfect, you clarified several concepts to me, thank you very much!
In fact, analyzing the video .mov tells me: Video: MPEG4 Video (H264) 1280x720 30fps 10432kbps [V: Core Media Video (h264 main L3.1, yuv420p, 1280x720, 10432 kb / s)].
I ask you one last thing, is there a way to always put a preview to the video without lowering the quality? in the sense that the original video from Windows Explorer, I see it with a thumbnail, a image of the video, while the one I rotated no, I only see the icon of the program with which I open it.
1000 Thanks again.
If by "preview" you mean adding a thumbnail to the icon of the movie, there will be no quality change. Is that what you are referring to?
If so, iMovie randomly adds as a thumbnail the frame that is in the middle of the movie. iMovie doesn't have a feature that lets one change the thumbnail.
Once the movie's icon is on your desktop, you can change or insert a thumbnail by control-clicking on the icon and selecting Get Info. In the Get Info box that appears there is a thumbnail icon at the top of the box. You can select the thumbnail and then open and copy/paste any photo or screen shot into it to change the thumbnail that displays. However, this does not change the metadata of the video so the thumbnail change will not carry over to other non-apple apps that are not on your computer.
If you are talking about adding some kind of trailer to the beginning of the movie, that shouldn't change the quality either, assuming that you are using the same codec and settings as you used for the main movie.
-- Rich
Rotate video
