Dither for YouTube / Vimeo

[Jusep]

Hello All,

I'm wondering about everyone's dither process when working with sound for video. Specifically when it comes to web based material (where ultimately all of my media is showcased).

Most often I will work in PT and my session will be at 24 / 48k. I will have an L2 at the very last step on my master bus. I select 24bit dither but I was always unsure if that was correct. I usually then take my final audio and import that along with my final video file into Premiere. I sometimes do fade in/outs in Premiere and began to question if I should be dithering in Premiere as opposed to PT. I'm just somewhat confused because Premiere is ultimately where I do my audio compression (from 24 /48 WAV) to AAC 320kbps / 48K.

I'm doing the tedious task of making all my videos more even in terms of loudness from video to video (and close to 16 LUFS). I don't want to have to to this all over again so I just want to know if I'm dithering at the proper point.

Any insight would be great.

[albee1952]

If your session is at 24 bit, and Premier accepts a 24 bit file to work on, then I would use no dither in Pro Tools. The only time you NEED dither is when you are reducing the bit rate, like going going from a 24 bit file to a 16 bit file, to burn onto an audio CD.

[Chief Technician]

Originally Posted by Jusep

Most often I will work in PT and my session will be at 24 / 48k. I will have an L2 at the very last step on my master bus. I select 24bit dither but I was always unsure if that was correct.

If you are bouncing out a 24bit file, using any dither on the master fader is incorrect.

Originally Posted by Jusep

I usually then take my final audio and import that along with my final video file into Premiere. I sometimes do fade in/outs in Premiere and began to question if I should be dithering in Premiere as opposed to PT. I'm just somewhat confused because Premiere is ultimately where I do my audio compression (from 24 /48 WAV) to AAC 320kbps / 48K.

This depends upon whether or not Premiere automatically uses dither for fade operations. In Pro Tools, this is an option in the fade dialog window. I have no idea if or where this option exists in Premiere.[/QUOTE]

[Jusep]

If you are bouncing out a 24bit file, using any dither on the master fader is incorrect.

Thanks for the info, I was bouncing out a 24 bit track.

When I import the 24/48 file into Premiere and export the audio (embedded with the video) I compress down the audio from 24/48 wav to AAC/320kbps/48kHz. These are Vimeo's audio suggestions. So I assume the only place to dither would be within Adobe Premiere correct, since this is where my audio compression is taking place?

[tom_lowe]

Originally Posted by Jusep

Thanks for the info, I was bouncing out a 24 bit track.

When I import the 24/48 file into Premiere and export the audio (embedded with the video) I compress down the audio from 24/48 wav to AAC/320kbps/48kHz. These are Vimeo's audio suggestions. So I assume the only place to dither would be within Adobe Premiere correct, since this is where my audio compression is taking place?

The AAC encoder accepts 24-bit audio, so no dithering is required.

[conleec]

Originally Posted by tom_lowe

The AAC encoder accepts 24-bit audio, so no dithering is required.

I think this is correct. In fact, dithering may negatively impact the AAC encoding by artificially adding noise to the signal? Although it's also possible the low-level noise introduced by dithering is part of what AAC throws out anyway?