Strange little problem with Premiere CS4

[Instant Martian]

Hi guys,
I have had a little strange problem during the last days.
I am working on a project with Premiere CS4, for some reason that I don't know it happens sometimes that I drag a wav file from the project panel to drop it on a certain audio track on the timeline but Premiere doesn't let me place the audio where I want, instead it creates another audio track and put the audio in this new track.
Other than that, it won't let me shift the audio from that track to any another.
Anybody knows why?

[poisondeathray]

Is it a 5.1 track in a 2.0 audio track or vice versa ?

They have to match

[Instant Martian]

Hi pdr and thanks for replying.
First thing first, it was not a wav file but an AC3.
Anyway I think you pinpointed the problem.
I am working on a bunch of file and so far all of them were .ac3 2ch.
Now this one is 1ch, hence the problem.
What is the solution now? To turn the 1ch file into a stereo one?

[poisondeathray]

You mean mono ?

You can dupe the mono track (ie. copy the mono channel into 2nd channel to make it "fake" L+R stereo) . e.g. use audacity or any audio editor

[Instant Martian]

Yep!

So I have to make a "fake" stereo file, right?
What about the bitrate? Since I "double" the number of channels have I to "double" the bitrate too?
The original mono file is 192kb/s.

[aedipuss]

i'd make it the same bitrate as the other audio files you are using.

[poisondeathray]

You don't have to , but everything will be decoded to wav in premiere and audio editor anyway

I would keep everything as wav until your final encode

[Instant Martian]

Sorry but I didn't understand.
I have a mono ac3 file, 192kb/s.
I load it in Audacity and make a "fake" stereo, then I import it into Premiere for editing and export as an uncompressed wav.
Load it in Audacity again and export it as a 2ch ac3.
Do I have to set the bitrate to 192kb/s, even if it has 2ch now?

[poisondeathray]

It's up to you . You are essentially cutting the bitrate in 1/2 if you use 192kb/s for stereo.

On high quality sources, you will probably notice a significant deterioration. On some other sources you might not. Do some small tests and see what is good enough for you

You could also make a silent channel .eg. L is normal , R is blank audio . But most people would make the "fake stereo"

[Instant Martian]

Ok, I'll do some tests.
Anyway thank you pdr for your precious help and thanks to you too, Aedipuss.

[non-linear]

Another reason the audio can end up on another track is if the sample type is different than what's already on the timeline. For example, your other audio is at 48KHz, while the track you're adding is 44.1KHz, then Premiere will add it to a different track.

[Instant Martian]

Thanks non-linear for the tip, it could be useful in the future.
As for this case, the problem was I did't realize it was a mono track.
I decided to go for a 192kb/s bitrate even for the "stereo" track.