Convert WebM to MP3

Where WebM files come from

WebM is the web's own video format, so it turns up wherever a browser does the recording or the saving:

• Browser screen and webcam recorders, the kind that run in a tab with nothing to install.
• Recorded calls, classes and webinars from web apps that save them through your browser.
• Voice and video messages from sites and apps built on the web.
• Clips saved from web pages, when the video is yours or you have the right to keep it.

Many of these hold no picture worth keeping, just a talking head or a shared slide, which makes the sound the part to save. Plenty of programs do not open WebM: Apple's apps, many editors, car stereos, TVs and music players among them. MP3 is the opposite, the sound format almost everything takes. Sound-only WebM files, which end in .weba, convert the same way.

From Opus to MP3

The sound inside a WebM is Opus or, in older files, Vorbis. Both are efficient, Opus especially at low bit rates. An MP3 cannot hold either one as it is, so Octoolo always encodes the sound once as MP3, and the bit rate you choose decides the size:

• Small, 128 kbps: about 1 MB a minute, and right for speech, which is most of what browsers record.
• Balanced, 192 kbps: about 1.4 MB a minute, and safe for music.
• High, 320 kbps: about 2.4 MB a minute, usually more than a browser recording needs.

If your player handles Opus, there is a lossless shortcut. Pick OGG or OPUS in place of MP3 and keep As it is: the Opus sound then goes into the new file as it was, with no second encoding. The Opus to MP3 and OGG to MP3 guides cover those files later on.

Silent or quiet recordings

A screen recording made with the microphone and the computer's sound switched off has no sound track at all. Octoolo spots this as soon as you add the file and marks it “This video has no sound to save”, rather than making an empty MP3. The rest of the batch converts as normal, so one silent file never holds up the others.

Recordings made through a laptop microphone tend to be quiet, with fan or room noise underneath. Once you have the MP3, open it in the Audio Editor to raise the volume up to twice as loud, reduce the background noise or even out the loudness to the level podcasts use. If the talking starts late or runs on, the MP3 cutter trims both ends.

Next time, skip the WebM

If you record your screen to keep the sound or the video, Octoolo's own screen recorder saves MP4 files straight away, with your voice and the PC's own sound mixed into one track. It can capture everything on a monitor, a single window or a region you mark out, with a level meter beside each sound source so you can see it is picking you up before you start. The files land in an Octoolo folder inside Videos, named with the date and time. MP4 opens everywhere, and its sound comes out as MP3 the same way.

For the WebM files you already have, WebM to MP4 keeps the picture too, and WebM to GIF turns a short one into a looping animation for a chat or a bug report.