5.1 Audio problem
 

Hello all,

I had my first project which required 5.1 sound. It seemed simple enough - the audio was given to me in 5.1, I imported it into the timeline and it went into its own 5.1 track and was fine. But I could hear these kind of pops every second or so. I didn't know what they were or whether they were only occurring on that PC with those speakers. I've wasted two of my free DD 5.1 encodes and only have one left! Which means I really don't want to screw up my last try. This is only a one off job and I cannot justify buying the encoder to get it done.

The final product only needs to be mastered for storage on a HDD, never burned back to disc or anything, though the quality should be comperable to Blu-Ray.

Can anyone advise me on a preset to choose that will enable a 1920x1080p24 with 5.1 sound at approx. 30Mbps? The setting that I chose was H264 Blu Ray which produced fine picture quality but poor sound - that is to say that the sound is fine aside from the pops.

I can confirm that the pops are even heard in the timeline! However not in the original audio file... I am confused now...

A couple of questions for you...

1) What is the file format of the audio track?
2) Do the bitrate of the file and timeline match? (is one 44.1 and the other 48?)

If your file is already 5.1 you don't need to encode it again. I've never tried to work with encoded files in PP so maybe someone else has advice on that.

Alan

Hey John.

You should be able to do LPCM 5.1 instead of DD. I know Blu Ray's standards can use DD, DTS or LPCM. Also, have you tried having the master audio be mono, which should leave each channel as a separate mono wav (or you need to set Premiere to import it as mono).

Is the original audio encoded in DD or 6 separate wav tracks? If DD, there are several programs that can separate DD into 6 wav files.

The format of the track is DD; 48,000Hz, as is the project. Except Source Audio Format is compressed 6 channels, whereas Project Audio Format says 32 bit floating point 6 channels. I'm pretty sure that's Italian for "whattheheckdoesthatmean". The pop even occurs when playing the clip in the source monitor befor even putting it into the timeline. So maybe it's a Premiere thing... I feel like no matter what project or export settings I select, the popping will be there because of Premiere... The popping definitely isn't there in the original. I play it in WMPlayer, PowerDVD and it's not there. Only Premiere makes it so. And then the exported file has it also...

When I select LPCM as the output format for audio, when it gets to Media Encoder and I click ENCODE, there is an instant error, and the log says that the audio codec is not compatible with this multiplexing mode or something like that.

So if I separate the single 5.1 DD track into 6 separate wav files, would I then import them all as mono tracks into Premiere? And if so, how do I tell each one to be a separate channel? I've only ever worked with L and R channels previously.

I've done a Google to find a program to split it but can't find any. Does Soundbooth do it? The clicking is there in Soundbooth too, and in all of the exported mono files that it created... This is getting the better of me.

In Soundbooth, I can use REMOVE CLICKS AND POPS to get rid of it kind of. But... I cannot do it to the 5.2 file, I have to split it into its mono tracks because the 5.1 file is larger than 4GB, which is apparently unacceptable to Soundbooth...

Even then, I have to move the sliding scale up to 100% remove in order for the pops to be quieter, and they're still not gone - just a little more subtle. Still not good enough...

When I had XP installed, I used several programs to strip DD(AC3) and DTS to play around with compressing my blu rays to store on my computer. I don't remember exactly what I had to do or what needs to be done but these apps should do what you need.

BeLight
or
BeHappy

and

eac3to (this is a plugin or filter for windows to decode DD, which in turn allows the above apps to decode)

I do remember the tutorials always showing how to separate DD/DTS into separate Wav files, but I didn't ever use that function.

The best sites for this are doom9.org and videohelp.com. Both should have links to download the apps as well as tutorials.

I don't have an easily accessible DD file to play around with in Premiere, so I don't know exactly what to do.

When you import the DD audio, does it come into a single DD track or 6 separate mono tracks? (you can set Premiere to import 5.1 as mono by going into Preferences or right-clicking the file in the Project window - you might need to create a new sequence if Source Channel Mapping is changed in Preferences)

This is all I have for now.

It might be aconformed audio problem. Try looking through the media cache files for the matching ".cfa" filename (there should be 6 or them) and deleting them. Once you re-enter PPro, it will reconform the file audio, and the pops may be gone. I have had similar things happen in the past, with pops in the conformed audio that disappear once I have cleared the cached conform files.

If you have a Matrox card, then make sure your audio hardware is set to Matrox and not Premiere Pro. This could very well be your problem.