On Thursday, July 19, 2018 at 2:47:13 AM UTC-7, Timothy B. Terriberry wrote: > raycarino--- via dev-media wrote: > >>> I'm on firefox 59. My microphone records audio at a sample rate of > >>> 44.1khz. However, MediaRecorder outputs OGG Opus audio at 48khz. > >> > >> This is what you wanted, right? > > Thank you for the quick reply! > > > > Sorry, for the typo. Expected: 48kHz output. Actual is 44.1kHz. It seems > > that the resampling logic either failed or wasn't reached. > > No worries. I figured there was a typo somewhere, just trying to figure > out exactly where. > > The Ogg Opus file format does not actually support encoding 44.1 kHz > audio directly, so unless you can hear some sort of weird pitch shifting > going on, that means it hit the resampling logic correctly. > > What it does do is store the original sampling rate in the header as > metadata. That lets other tools resample back to the original sampling > rate if that is appropriate. E.g., if the input was originally 44.1 kHz, > it's normal to resample back to 44.1 kHz when decoding to a file to > avoid surprises for users who don't know that Opus internally only > supports sample rates that evenly divide 48 kHz. But if you were just > playing the file back, you'd normally skip that resampling as most > soundcards run at 48 kHz natively. > > I hope that helps! It does. Thank you so much Timothy and Andreas!
Re: Andreas' question about how I'm checking the output files. I was only checking the input sample rate section of the OGG header. I expected it be the encoded sample rate, but that assumption was wrong and clarified by Timothy. _______________________________________________ dev-media mailing list [email protected] https://lists.mozilla.org/listinfo/dev-media
