Video Bitrate in Imovie

Blu-ray players actually have both a blue and red laser so it can switch off per the type of disk detected.

But yes, the software should have a way to change the encoding bit rate. Normally, there are two settings. A high and low so you can set a higher DVD bit rate of about 20 for higher quality, but also a lower of say, 15, so if a drive is having trouble keeping up with decoding 20 it can switch to the lower bit rate (and somewhat lower quality) version.

I dropped my Adobe CC subscription down to Photoshop only a year ago or so. I'm now using the free version of DaVinci Resolve. In Adobe Premiere Pro / Media Encoder, you have sliders to set the high and low bit rate. In DaVinci, it's a bit more simplified under Encoding Profile where you can choose Auto, High, Main, or Base.

I downloaded and used iMovie for a small sample video so we're looking at the same settings. There aren't a lot of choices, which isn't unusual for an app meant for novices.

The ProRes choice only succeeds in creating an .mp4 ten times the size of the settings above with almost no visual difference in quality.

The default under Custom is 20. Since there is no actual VIDEO_TS folder to output for burning a movie DVD, then there is also no secondary lower bit rate. The presumption of iMovie is you're going to output a final video file for anything other than a true movie DVD.

So, if you set the custom rate to the max of 26.667 Mbps, a set top player may not be able to decode that from the .mp4 you burn to a data disk DVD fast enough. This is the kind of thing where I use a rewritable DVD so I can experiment with what does or doesn't work, and not make one coaster after another in the process.

The difference is the laser. Small clip of tech specs from a web site: While a DVD uses a 650 nm red laser, Blu-ray Disc uses a 405 nm "blue" laser diode.

Blu-ray disks normally have much higher bit rates than DVDs. But when you go too high on a DVD, the red laser can't read the data fast enough, and it fails. The USB (I presume saved as an .mp4) works since the transfer rate is much faster than a DVD can produce.

It takes a while to get used to the much greater number of editing choices in DaVinci Resolve. Coming from Premier Pro, it wasn't too bad for me. More a matter of finding the same tools in different places.

I still think it's incredible they make DaVinci available for free, considering all it does. But they make their money on the true pros who spring for the extra features in the paid Pro version of the software, and/or the editing hardware.

For myself, I've learned a lot about video editing over the years, but I would still barely rate myself any higher than apprentice.

You're welcome. And have fun working on those family videos. 🙂