Convert video to MP3

Which sound format to choose

MP3 is the safe default: when you are not sure what a device or app takes, it is the format it most likely plays. The other nine are there for when a device or program asks for them: AAC, WMA, AIFF, ALAC, AC3, WV, MKA, MP2 and AMR. For sound files you already have, Convert sound files in the Audio Editor writes the same 15 formats.

Sound quality: what you keep

The sound in a video is almost always compressed already, most often as AAC in MP4 and MOV files. There are two ways to treat it:

• Copy it exactly. Choose M4A (or AAC) and leave Quality on As it is. When the video's sound is AAC, Octoolo copies it across untouched: its row reads Copied as it is, nothing re-encoded, it is done in moments, and the sound is identical to the video's.
• Make an MP3. MP3 is a different codec, so the sound is encoded again. With As it is, Octoolo stays close to the video's own bit rate, between 128 and 320 kbps; High uses 320 kbps, MP3's highest rate.

That second encoding never adds anything: an MP3 cannot sound better than the video did, and a higher setting than the source only makes a bigger file. For speech, Balanced at 192 kbps is plenty, which makes it a good fit for lectures and podcasts; keep High for music you care about.

Whole folders of videos

Drop a folder of lectures, interviews or phone clips and every video in it is converted, along with videos up to three folders deeper, 500 at a time. Taking out sound is light work, so several files run at once.

• Each MP3 gets its video's name, beside the video or in one folder you choose, and Octoolo never writes over a file.
• A video with no sound is marked “This video has no sound to save.” and left alone.
• A video with several sound tracks, such as a film with two languages, gives its first track to MP3, WAV, M4A and most other formats. MKA keeps every track.
• Surround sound is mixed down to stereo for MP3; WAV, FLAC and M4A can keep all its channels.

When the batch ends, the summary sets the size of all the videos against that of the new sound files, usually a small fraction of it.

Only part of the sound

The converter takes a video's whole sound. To keep just one song from a concert clip or one answer from an interview, use the Video Editor instead:

• Add the video and trim it to the part you want, or split and delete the rest.
• Press Export, choose Sound only, then MP3, M4A, WAV, FLAC or Opus.

The editor's MP3 is 192 kbps, 48 kHz stereo. Sound only works for a whole project too, so several clips joined on the timeline become one MP3. For finer sound work, such as cutting out several parts, evening out loudness or reducing background noise, open the result in the Audio Editor, or add the video there directly: its sound comes in by itself. And to go the other way, keeping the picture and dropping the sound, see remove audio from a video.