Sample rate : changing 44.1 to 48000

[bomber1978]

Hi,
I'm editing into a video new audio from a different source, so I need to change the 16bit/44.1 audio to 48000, is the correct way to do it in Audacity to simply just load into Audacity the 44.1 file and in the bottom left corner change project rate to 48000 then export?
Thanks.

[kozikowski]

Or let the video editor do it. Most video editors "know" about 44100 and just automatically convert.

You don't get any benefit from the conversion. Your Nyquist quality doesn't go up. It's already been limited by the passage through 44100.

Are you just assuming your editor needs the conversion? Did they explicitly say so?

Koz

[bomber1978]

Hi,

The editor will do it, but I'm not very familiar with editing video, so I wasn't sure if the editor would do it the 'correct' way, or if an audio programme would do it better...
As I have to shorten the audio file by cutting off the start and end, plus speed correct the audio and change volume, as well as fixing some DC offset I thought I might as well just export as 48000 while I was doing the rest!

Plus I also needed to know about changing from 44.1 to 96000, purely for audio, as I have a rare soundboard transfer from cassette to 16bit/96000 which I want to add some 44.1 stuff to, so I'm sure now I can just load in the 44.1 file and export as 96000 using project rate at the bottom left of Audacity?

Thanks

[Gale Andrews]

Audacity project rate always determines the export sample rate.


Gale

[bomber1978]

I'm pretty certain I'm correct in saying unlike changing from 48000 to 44.1 which would use dither, going up from 44.1 to 48000 doesn't use dither does it?

[Gale Andrews]

I'm pretty certain I'm correct in saying unlike changing from 48000 to 44.1 which would use dither, going up from 44.1 to 48000 doesn't use dither does it?

Dither is for use when downconverting bit depth, not sample rate. http://wiki.audacityteam.org/wiki/Dither.

Audacity correctly applies dither when exporting from a 32-bit project to 16-bit audio but wrongly applies dither when exporting from a 16-bit project to 16-bit audio. That is a known bug.

If you are worried about dither and prefer quantisation noise, turn Dither off before exporting (in the Quality Preferences, under the High-quality conversion section).


Gale

[bomber1978]

Hi,
Too much editing today! Not sure why I asked about dither when talking about sample rate!, yeah I know dither is used when downconverting bit depth, in fact you might remember I pointed out here some time ago a bug I found, shaped dither was adding an extreme amount of hiss to WAV files (stereo but not mono) and not FLAC, an administrator here, I think Steve, then reported it to the developers who said they planned to fix it in future releases...., I think that was 2.0.3 from memory, but can't remember off the top of my head!

[steve]

I think that was 2.0.3 from memory, but can't remember off the top of my head!

I thought it was longer ago than that. Anyway it's been fixed for a good while now.

[bomber1978]

Just looked at some old posts, seems I came across that bug in 2013, version 2.0.3, as the developers said they wouldn't have it fixed in time for 2.0.4, they said the bug went back 7 years!
Which just made me wonder, isn't Shaped dither the default for all versions going back years?, meaning anything exported as WAV with the default dither will have the excessive hiss going back 7 years?, or maybe Shaped hasn't always been the default?

[steve]

meaning anything exported as WAV with the default dither will have the excessive hiss going back 7 years?, or maybe Shaped hasn't always been the default?

Shaped dither has been the default for a long time, though I always used to change it to "triangle" for my own use. Since the fix, I now use "shaped".