I have digitized my Standard Definition DV tapes for iMovie 10 editing. I exported (shared) a section of a video in Low, Med, High, ProRes and at first glance, they all look the same. Indistinguishable from each other. For standard def video, does it matter what setting I choose to export? I know disk space is cheap, but if choosing the higher setting isn't buying me any quality savings then I'll save the disk space. Thoughts?
iMac Line (2012 and Later)
Usually upscaling to a higher resolution than the original media yields unsatisfactory results. You can't turn standard media into hi res.
Pro Res renders a .mov file with a much higher bitrate and thus file size is 4x. If they all look the same to you I would go with High Quality Mp4 out of iMovie. Mp4 is the most globally compatible format. Unless you select Pro Res everything shared out from iMovie will be Mp4.
Sometimes it depends on the use you intend to make of the video. If you are going to project it on a big screen, maybe you could tell the difference between Best Quality pro res and High quality Mp4. For TV or computer viewing I doubt it would make a difference. If you were going to post it on the internet you wouldn't want the large file size of pro res.
So, it really is your call.
-- Rich
Usually upscaling to a higher resolution than the original media yields unsatisfactory results. You can't turn standard media into hi res.
Pro Res renders a .mov file with a much higher bitrate and thus file size is 4x. If they all look the same to you I would go with High Quality Mp4 out of iMovie. Mp4 is the most globally compatible format. Unless you select Pro Res everything shared out from iMovie will be Mp4.
Sometimes it depends on the use you intend to make of the video. If you are going to project it on a big screen, maybe you could tell the difference between Best Quality pro res and High quality Mp4. For TV or computer viewing I doubt it would make a difference. If you were going to post it on the internet you wouldn't want the large file size of pro res.
So, it really is your call.
-- Rich
I am not an expert on the technicalities of bitrates and compression methods. These would depend upon the codec and settings being used. I believe that the difference between low, medium, and high quality would depend upon compression rate, method of compression, resolution, and bit rate, and whether the latter is variable or average. Frame rate may also come into play. So there is no one factor. You could find out the data rate by opening the clip in Quicktime and selecting Window/Show Movie Inspector. DV footage has low compression. Mp4 has more compression. In iMovie you have either Mp4 or pro res. If you export with the options High quality and Better Quality compression, with a resolution no more than one notch higher than the original, you should be fine.
-- Rich
Thanks so much Rich. Looking at some other SD DV clips shared in the low, med, High, Prores options, there does seem to be a bit (slightly) of a difference. Files size, massive difference between the Mp4 and ProRes. Looking at the files on the computer, I also noticed the ProRes file is interlaced which I'm assuming is more of an exact copy of what the original interlaced footage is. Mp4 seems to deinterlace the footage. These are home movies that I'm diving into which probably will be viewed either on i devices or televisions in the future and more then likely not re-edited for quality. But in the mean time, I'll take your advise and go with Mp4 'high' quality which I'm sure will be good enough for future viewing.
Lastly, Is it a good assumption the difference between low, med, high quality is due to different bitrates? Is it possible to find out what the bitrate is on the original DV footage and if you want an Mp4 equivalent, that's the bitrate you pick?
Again, thanks so much for your expertise on this.
iMovie 10.1 sharing setting for SD video
