How do u convert 12 bit to 16 bit audio?

[phillip9]

One of the problems when using iMovie and iDVD is that audio and video may be out of sync if the audio is in 12 bit format. 16 bit audio is preferred. As far as I can tell, my new Panasonic PV GS9 DV camcorder outputs audio in 12 bit. Does Mac software exist that specifically converts 12 bit audo to 16 bit? I am also under the impression that Quicktime Pro allows conversion of 32 kHz audio to 48 kHz audio and that that may be the same as converting 12 bit to 16 bit. Any enlightenment in this regard would be greatly appreciated. Thanks.

[tWoSour]

I'd advise you to just record 16 bit in your camera. Just go in the menu, and find the audio tab. Change it to 16 bit, and that should solve your problem.

[phillip9]

Thanks tWoSour for responding.
However, using the recording and playing Menus of the Panasonic PV GS9, I am allowed to set 16 bit for recording but only 12 bit for playing. This does seem strange, but I have tried to figure out how to change the camera playback to 16 with no luck. When I import the video into iMovie and then output to Quicktime, it tells me that the present audio setting is 32 kHz (which I am assuming means 12 bit). I can change that to 48 kHz before outputting the file as a DV stream but I am uncertain whether this means that it is also being converted to 16 bit. Hence, my post.

[WiseWeasel]

The problem is that iMovie 'Full Quality DV' export option is not really full quality. It resamples the audio to 32 kHz. You need to choose the 'Expert Settings' option, and either choose 'DV Stream' or 'Movie, self-contained' to preserve the audio quality. It's really stupid that Apple named that export option "Full Quality".

[havema-1]

> iMovie 'Full Quality DV' export option is not really full quality. It resamples the audio to 32 kHz

This was fixed in iMovie 4. But another bug was introduced because now "Full Quality DV" export converts DV-PAL footage to DVCPRO-PAL which isn't compatible with at least my PAL Sony TRV320E which took the original footage.

So use expert export settings and DV-PAL with 48 kHz audio. I haven't tested whether the Full Quality DV preset is OK for NTSC (DV and DVCPRO are very much the same for NTSC with 4:1:1 color sampling. DVCPRO-PAL uses 4:1:1 but DV-PAL uses 4:2:0).

Another thing to be aware of is that iMovie 3 and 4 convert the audio of .mov files to 32 kHz when importing. As a workaround I have exported .mov files as .dv before importing them to iMovie.

I have a bug report template of all these things and I regularily send it to iMovie feedback page...

[WiseWeasel]

Problem is they don't listen. I think they purposefully build these limitations into iMovie to encourage people to shell out for FCE or FCP.

[anneo55]

I am under the impressoin that my new Panasonic PV GS9 camcorder is not compatible with my new IBook. But am i reading differently in your messages? Are they compatible? If so, what does it take? Different software? How wonderful if they are! May thanks for the information.

[phillip9]

anneo55. I bought that model Panasonic camcorder a couple of weeks ago (see post at top) and have used it successfully with iMovie 4 and iDVD 4. iMovie recognized the camera and controlled it during play, import, rewind, etc. The first DVD that I burned using iDVD4 had the audio and video out of sync (not unusual). But I was able to get around this problem by extracting the audio from the combined track and placing it in its own audio track (see many posts on this forum and the Apple iMovie Discussions for details). Then I exported ("shared") the edited iMovie to a DV stream in which the 32kHz sound track was converted to 48 kHz (this is oneof the options when sharing). I then launched iDVD4 and dragged the DV file into the iDVD window, chose my themes, buttons, etc. and burned. In this DVD, the audio and video were in sync. Hope this helps.

[anneo55]

thanks so much, phillip9. my ibook (not powerbook) is not recognizing the camera. did you load panasonic PC software? are you using the dv-usb cable that came with the camera? agaon, many thanks.

[phillip9]

There was no camera software to install. iMovie recognizes and controls the camera once the camera is turned on, connected to the Mac, and iMovie is launched. The connection between the camera and the Mac involves a firewire cable (6 pin at the Mac end and 4 pin at the camera end)--not USB. USB is only used when downloading individual pictures to the Mac. Firewire is used to download video.

[anneo55]

Phillp9......That's it! Just bought the cable and made connection! Thanks so much for helping me learn. New for me. Many thanks.