Nasty Premiere Pro / Soundbooth AC3 bug

[Asterra]

Not looking for help on this one. Just documenting it for posterity's sake.

I'm dealing with a lot of video which has its own AC3 channel. Because I was needing those six channels individually (as six mono channels), and because Premiere Pro (CS4) does not give the user the option to export any audio above stereo, I was forced to use the "Edit in Adobe Soundbooth" option, which automatically generates a six-channel .wav file from the clip and hides it in a temporary folder. I was making use of these generated .wav files.

I noticed early on that the LFE channel exhibited popping at regular intervals - about once every 1.5 seconds. I foolishly assumed it was the camcorder which introduced this anomaly, and figured it was no big deal since the subwoofer would ignore the pops anyway. (I filtered them out regardless.)

Now that I am in the final phase of my home video project, I have been examining the audio up close, minute by minute. And I have discovered that the .wav files generated by the "Edit in Adobe Soundbooth" option exhibit pops fairly reliably, particularly during moments of high amplitude and lower frequencies. Coupled with this, I can occasionally detect spots where the audio has been repeated by approximately 2700 samples. These two phenomena are likely related.

To pinpoint the culprit once and for all, I used ffmbc to extract the audio from the MTS files directly. This process gave a clean result with no sign of the anomalies present in the PPro/Soundbooth method. While this method will require twice as much time and effort to take advantage of, it is at least not something completely unusable.

Just another Premiere Pro bug to add to the pile.

[poisondeathray]

I'm dealing with a lot of video which has its own AC3 channel. Because I was needing those six channels individually (as six mono channels), and because Premiere Pro (CS4) does not give the user the option to export any audio above stereo, I was forced to use the "Edit in Adobe Soundbooth" option, which automatically generates a six-channel .wav file from the clip and hides it in a temporary folder. I was making use of these generated .wav files.

You can export 5.1 from PP through AME, but you have to setup your sequence settings properly (master track has to be set to 5.1)

But I don't know of a way to export mono wavs from premiere directly, what are you using mono wavs for ?

I haven't experienced the audio popping

[Asterra]

You can export 5.1 from PP through AME, but you have to setup your sequence settings properly (master track has to be set to 5.1)

Good info. Not entirely intuitive so I don't feel too bad. ;p

But I don't know of a way to export mono wavs from premiere directly, what are you using mono wavs for ?

Building a 7.1 mix.

I haven't experienced the audio popping

Shrug. It's CS4 I'm dealing with, so perhaps other versions are different. I just tried a new export via Media Encoder (thanks to your observation above) and it still exhibits the popping, whereas ffmbc's output does not. I admit I was getting my hopes up.

[Asterra]

I've figured out that PPro can export 5.1 without adding pops if the source is uncompressed 5.1 wav. This opens possibilities and may reduce the workload this bug has added. Anyway, it suggests that the problem is limited to how PPro handles AC3.