Convert 44.1 Khz Audio To 48khz Premiere

[ This article was first published in the June, 2010, issue of
Larry’s Monthly Final Cut Studio Newsletter. Click here to subscribe. ]


Convert 44.1 Khz Audio To 48khz Premiere

I got burned by this when I was prepping my most recent webinar for posting. My audio slowly slipped out of sync.

I hate when that happens.

Sound files with this extension are recorded into 8 or 16 bit per sample. A standard option for CD Audio is an audio stream of 16 bit per sample and sampling frequency of 44.1 KHz. One second of sound corresponds to 88 Kb of internal memory. WAV files can store metadata in the INFO chunk, and they also include integrated IFF lists. Sr-convert is most often used to convert between 44.1 kHz and 48 kHz. For example, if you record your own music at 48 kHz, you can downconvert it to 44.1 kHz for burning to CD. Or, if you rip CDs, you can upconvert them to 48 kHz before you ogg-encode them, which results in slightly better sound quality.

What I discovered is that the Soundtrack Pro sample rate preference setting overrides the sample rate of the Final Cut Pro project, resulting in a slow sync drift that will drive you nuts.

Because there are a variety of places where you can choose the wrong sample rate, I wanted to walk you through my process of posting a webinar to show you where the problem occurred and how to prevent it.

I record all my tutorials and webinars using Telestream’s Screenflow. When I am ready to export the file for editing, I always select “Lossless” to give me the highest quality for editing and compression.

Then, for audio, I export the file as a Linear PCM file. (See the article on choosing the right version of “Endian-ism.”)

Here’s the first opportunity you have to screw things up. Notice that the sample rate is set to 48.000 kHz. The problem is that my audio gear, like most audio gear, records at 44.1 kHz. (Both are excellent choices from a quality point of view.)

While Final Cut can easily handle both 44.1 and 48 kHz sample rates, it prefers 48 kHZ. At least, that’s been my experience when working with the Animation codec and synced audio.

So I make sure to set the audio rate to 48 kHz and export.

When getting ready to edit this in Final Cut, I create a new sequence, then drop my clip into it.

If I get a message asking if I want to change the sequence settings to match the clip, I say Yes.

Then, I remove the clip from the sequence and check Sequence > Settings. Removing the clip allows me to adjust all the settings, which can’t be done once a clip is in the Timeline. The main thing I am checking is to be sure my audio sample rate is set to 48 kHz. If not, I change it.

Once I verify my sequence settings are correct, I edit my project as normal. Because both audio and video settings of the clip match the timeline, there’s no rendering until I add effects.

Finally, I do all my audio clean-up and mixing in Soundtrack Pro. Here’s the third place the sample rate can get accidentally reset.

Before sending my file to Soundtrack Pro I SHOULD have (but didn’t) check to be sure the sample rate preference was set correctly.

To check it, go to Soundtrack Pro > Preferences > Project tab and make sure the project sample rate is set to 48000 (48 kHz).

Then, File > Quit Soundtrack Pro.

In Final Cut, select your sequence in the Browser and File > Send it to Soundtrack Pro.

When Soundtrack opens with your sequence in it, be sure the project sample rate is set to 48 kHz. You check it by looking in the top of the Soundtrack Pro tool bar. If this, too, is set to 48 kHz, all your audio sample rates match across all your programs.

At this point, you’ve maintained a consistent sample rate across all your software and elements and sync will remain constant and locked.

Yes, I’ve added this to my editing checklist.

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From time to time, you may wish to change the sample rate of your audio.

Depending on what program you have, there are different steps to complete.

Software To Change the Sample Rate of Audio Files

This article walks you through how to change the sample rate of your audio in your choice of four different professional-grade audio software:

  • Quicktime Pro
  • Final Cut Pro
  • Adobe Premiere Pro
  • Sony Vegas Pro

Quicktime 7 Pro

Setting up Custom Template in Quicktime

Convert 44.1 Khz Audio To 48khz Premiere Studio

  1. Under File > Render As…change the Save as Type: to Quicktime 7.
  2. Click the Custom button. This opens the Custom Template window.
  3. Click on the Audio tab.
  4. In the Audio tab, click on the drop-down menu next to Sampling Rate (Hz) and select 48,000.

Using the Encoder Button in Quicktime

  1. Visit the Inspector window in the Compressor.
  2. Click on the Encoder button.
  3. In the Encoder window, you will see a Settings button to the right of Audio. Click on Settings.
  4. This opens the Sound Settings window. In the Sound Settings window, there is box to the right of Rate. In this box, enter 48.000 kHz.

Final Cut Pro

Convert 44.1 Khz Audio To 48khz Premiere Download

MPEG2

In Final Cut Pro, there is no overt way to change the audio sampling rate for the MPEG2 file container. However, if your audio sample rate is not at least 44.1 kHz and you are working within the MPEG2 container, then do the following.

  1. Visit the Inspector window in the Compressor.
  2. Click on the Encoder button.
  3. In the Encoder window, you will see an Extras tab. Click on the Extras tab.
  4. In the Extras tab, check the box next to Multiplexed MPEG-1/Layer 2 Audio. Underneath, there are two radio buttons corresponding to Transport Stream and Program Stream, respectively. Choose the audio stream that corresponds the video stream that you chose.

Adobe Premiere Pro

Partition tool free for mac. MPEG2

Khz
  1. Visit the Export Settings window (File > Export > Adobe Media Encoder).
  2. In the Export Settings window, click on the Audio tab.
  3. In the Audio tab, there is a set of options called Basic Audio Settings. Click on the drop-down menu to the right of Frequency and change your audio sampling rate to 44.1 kHz. Google only accepts audio ads that have an audio sampling rate of 44.1 kHz.

H.264

  1. You can change the audio sampling rate of your spot in the Export Settings window (File > Export > Adobe Media Encoder).
  2. In the Export Settings window, click on the Audio tab.
  3. In the Audio tab, there is a set of options called Basic Audio Settings.
  4. Click on the drop-down menu to the right of Frequency and change your audio sampling rate to 44.1 kHz. Google only accepts ads that have an audio sampling rate of 44.1 kHz.

Sony Vegas Pro

MPEG2

Convert 44.1 khz audio to 48khz premiere camera
  1. Under File > Render As, change the Save as Type: to MainConcept MPEG-2.
  2. Next, click the Custom button. This opens the Custom Template window.
  3. Click on the Audio tab.
  4. In the Audio tab, you will see a drop-down menu to the left of Sampling Rate (Hz). Click this drop-down menu and select 44,100.