Best way to deal with .webm clips?

For minimum generation loss convert with ffmpeg to some ProRes flavor and PCM audio with something like:

ffmpeg -i input.webm -c:v prores_ks -profile:v 3 -timecode 00:00:00:00 -c:a pcm_s16le output.mov

There are pre-built binaries for ffmpeg you can download. However on MacOS I prefer using the Homebrew package manager which gives you access to many hundred useful utilities you can easily build from source code on your own machine. It requires no software development knowledge. I use ffmpeg I built for Apple Silicon using Homebrew.

Re webm, Shutter Encoder handles that, including hardware decode acceleration.

Internally webm uses the VP9 codec. Neither Premiere Pro nor FCP supports webm. Resolve does but Resolve internally uses ffmpeg for many non-professional, less-standardized codecs. That's how it achieved the "Swiss Army Knife" capability -- not because they natively wrote code for all those formats, but because they internally use ffmpeg. The tradeoff seems to be reliability. FCP is definitely more reliable overall.

I always used Handbreak. Fast, easy, good quality. I have to (I hate it, too) convert these couple times a month.

And no, macOS internal converter (nor FCP nor Compressor nor QT Player) will read these.

The other similar option is using Shutter Encoder, which (like HandBrake) is using ffmpeg under the covers. The difference is Shutter Encoder is a Mac-only solution and IMO it's a bit easier to use.

However, once you get the hang of it, HandBrake is not hard to use and works well.

Q - "At present I am using HandBrake to convert them to .mp4 using the same frame size, frame rate and approximately the same bit rate.

Is this the best method to use or is there something better?"

A - Yes, that is the best method, stick with it, it's what many of us use, you're on the right path there.

Do you know if the System Service Encode Selected Video Files offers the same conversion quality? (There's also one for Audio depending on the file you select.)

[Right click on a webm (or other codec) video file and select:

(Some of those other services I made with Automator...)

macOS 26 does NOT convert webm files via Finder or anything else natively, period. Tested it throughly yesterday, nope, doesn't do it. I stopped using FFMPEG cause it is a royal pain to set up and use, very awkward, IMHO. But Handbreak does the job super fast, and super easy, with a GUI I can fly through.

What I usually do is throw the WebM files into FF*Works and put them into a .mov container without re-encoding anything. FCP and everything else will see them just fine that way with the same exact video and audio that was in the WebM, bit-for-bit.

BTW, in the image you posted, at the bottom of the screen, you have hardware acceleration set to "none." Try setting all three to VideoToolbox.

I have re-encoded webm files with it — as a matter of fact I tested it on webm files to get the screenshots (and I'm still using Mojave!)

I agree that ProRes might be overkill since webm are probably among the most compressed video files there are to begin with. There are Service options for H.264/AAC, but the max resolution is 1080p. It appears, however, that selecting 1080p will not enlarge a smaller res video [at least not webm files] but may "cap" larger res vids to 1080 (the ProRes option does not have a selectable vertical resolution option)... You also get the same frame rate in the re-encoded file as the webm file was encoded in ( I transcoded one that was 3fps!)

I honestly cannot tell the difference in quality between the webm files and the Service encoded files.

Is ffmpeg native to Unix? Or, does it have to be installed? (That's what I usually try to avoid...LOL).

fox_m wrote:

I have re-encoded webm files with it — as a matter of fact I tested it on webm files to get the screenshots (and I'm still using Mojave!)

I now tested that Services encode in Sequoia 15.7.3 and in my setup it still refuses to open .webm (and VP9 wrapped as .mp4). QuickTime Player behaves the same. On the other hand, Opus audio support was added in Sonoma. So maybe you have some add-on that enables VP9 (I have video support files that FCP 11.2 prompts to install)?

I have installed ffmpeg via MacPorts. It ignores many of the system libraries and software that is already available in macOS. "MacPorts pulls in the whole world" vs "Homebrew makes use of what you already have". Because of that Homebrew has some bad press because it sometimes conflicts with the unix-tradition and might cause problems with macOS pre-installed stuff. There are those pre-built binaries that avoid that. I use also other such Terminal apps and I'm too lazy to install from source and take care of all pesky dependencies and MacPorts has worked fine. Only a few times I have booted to an external test volume to install and try some app via Homebrew when it was not available in MacPorts (it is not recommended to have both installed).

BTW It is possible to execute ffmpeg commands via Shutter Encoder. Select input and output info in Shutter Encoder GUI and leave '-i input.mov' and output off from the commands you'd use in the Terminal. Also exiftool works but the last time I tested it had a very old version bundled and I asked the author to update also it.

AFAIK macOS doesn't yet natively support .webm input so that Services > Encoder Selected Video Files can't re-encode that.

I now tested in Monterey and there that macOS built-in Services encoder output is ProRes 422 and 32-bit PCM for H.265 input (the ffmpeg example above is ProRes 422HQ but there are also other ProRes options available).

I have not done any real quality tests and I guess ProRes might be overkill for most tasks.