audio format

Sorry if this is a newbie question. I'm working in DVCAM, and am making some quicktime exports from my sequences for re-import into FCP and to possibly to use on other edit systems. I'm doing this to archive some edits and fx sequences for future use. Using quicktime conversion, I've got no problem choosing the right parameters for the video, but not so sure about the audio. The default format seems to be "integer (big endian)" on the movie settings window, and when I click on settings it shows linear PCM as the format. I'm so confused! I just want to preserve the original audio quality, but don't know what's the audio format on my DVCAM files.

48 KHz, 16 bit, Stereo. It's uncompressed. That's an AIFF in Mac Land and WAV in PC land. It's relatively easy to convert between them. I think the conversion just has to change a byte or two here and there (It's Windows. Don't ask).

Pulse Code Modulation (PCM) is one process of how to get to WAV or AIFF from analog audio. That's shortcut for "uncompressed."

44.1 KHz, 16 bit Stereo uncompressed is the format on music CDs. It was designed a million years ago and isn't as good a music format as changing the sample rate to 48KHz which is what most digital video does. I think HDV doesn't do it like that, but I believe all the others do.

Does that help? That's not as clear as I like to be. but it will have to do.

Koz

Even better, don't use Quicktime Conversion - use the 'Quicktime' export option. This will export an exact copy of your timeline, so everything will be native. Make sure your timeline is set to full quality.

Koz,
I understand that DV audio is 48 khz, 16bit. I'm just confused at being asked to choose a format. S I guess linear PCM is fine?

Jude,
The "quicktime movie" export option creates a "final cut pro movie file". I've assumed that this can only be played by FCP, which is not what I want.

No - not true. The Final Cut Pro movie sounds misleading, but it is just a quicktime movie at the same resolution as your timeline. If you need to transfer the files to other systems, add .mov to the end of the file names before transfer. This is a pre FCP 4 quirk, so I'm guessing you are on FCP 3 or earlier?

By using quicktime conversion you are actually adding compression to your files, so they are not as good as they can be.

and take way longer to make.

no need to ad a .mov if you are taking it to another mac in my experience
if you look at this file on a mac that doesn't have FCP, it wil show as a QT file


nick

The human ear can't tell the difference between 16 bit / 44.1 and 24 bit / 48K. Audio engineers might be able to notice a difference when recording super low frequency keyboards at certain levels. Strive to record at 24bit / 48 K but not a big deal. You can always up convert from 16 bit / 44.1 (CD quality) to 24bit / 48K if you want. I used to have a Marantz portable audio recorder and when recording "coins dropping onto tiles" it was completely UNusable in the "PCM" format. I guess it could have been the Sure SM57 mic but I doubt it. I think PCM might be a compressed format.

PCM is just a way how analog audio is stored digital and in normal use it is uncompressed. Most people work with 48kHz/16bit these days so one should stay with that - even if the difference is small.

Just some links for the audio formats:
WAV
PCM
AIFF
Read the "fine print" about AIFF on OS X

Tough both Wave and standard AIFF normally can be used on any platform, I would prefer Wave since it allows to extend the file with metadata, so using a Wave file you can change it into a Broadcast-Wave file and include information about TC, reel, scene, take, note and way more. Broadcast-Wave file chunks are more common and more extensible than the few allowed AIFF chunks.
Currently FCP doesn't support this kind of metadata import (except TC) or export, but it's a good idea to use the Wave format as interchange format as a lot of DAWs can add metadata to it. And there are a lot of metadata readers, so history is much easier to follow.

Andreas

> I used to have a Marantz portable audio recorder and when recording "coins dropping onto
> tiles" it was completely UNusable in the "PCM" format. I guess it could have been the Sure
> [sic] SM57 mic but I doubt it.

Did you have a proper microphone pre-amp? Also, while file formats and settings make a difference, so does hardware. I owned two digital 12-track recorders, the Korg D12 and the Korg D1200mkII, and the D1200mkII produced far, far superior results with the same microphone (an Audio-Technica AT3035), cables, and mike preamp. You still get better results mixing into a dedicated audio recorder rather than straight into the camera even if both devices might be recording at 48kHz 16-bit stereo.


www.derekmok.com

Jude,

I'm using FCP 5 (new user) and the quictime movie export definitely creates a file identified as a "final cut pro movie file" in OSX. Thanks for letting me know it's just a QT file. I just assumed otherwise. I'll use this option from now on

> I'm using FCP 5 (new user) and the quictime movie export definitely creates a file identified
> as a "final cut pro movie file" in OSX.

That distinction doesn't even exist anymore -- "Export Final Cut Pro Movie" hasn't been an option for a while.

The "identification" you're referring to has nothing to do with the file itself. That's your OS. You probably set your system so that .mov files open with FCP by default. Just press APPLE-I on a .mov file and change "Open with" to QuickTime Player. You can do this with many other files, such as MP3s (iTunes and QuickTime will open them). The icon of the file will display the default application, but the file itself doesn't change.


www.derekmok.com

<<<"coins dropping onto tiles" >>>

It's not the SM-57. It takes a small, thermonuclear event to overload the average dynamic mic.

Not so the Mic-Pre, however. That performance would be extremely difficult to record and meter. It falls into the ear/electronics/headroom problem. It would not shock me if the impact sound went right past your ear and the metering. Digital metering is sampled and if the samples happen to miss the impact, instant overload--which in digital land, is deadly.

I can't find it right this second, but Electrovoice or Shure (possibly both) make attenuators you put between the mic and the cable to keep the mic-pre from overloading. Typically, mic-pres do not have attenuation between the mic and the electronics. When you turn a mic-pre down, you're turniing down the output, not the input. Once, because we didn't have anything else to do, we got an EV-635A microphone to produce one volt--all by itself--by screaming into it. That kind of voltage will turn an unprotected mic-pre into charred ruin.

Something you said earlier about keeping the live digital recording right up close to zero can be dangerous and would make this problem worse.

Koz

Derek,

I've already got QT as the default player for .mov files. If I choose export-quicktime movie, I get a file that opens with FCP by default, plus the "FCP movie file" ID. (thanks for telling me how to change that) If I choose export-quicktime conversion, I get a file that opens with QT by default. So it looks like FCP is doing this. A minor point, but interesting. Probably an artifact from that old export option you mentioned.

Ross

What's strange is that you say you're using FCP5. I don't even think "Export - Final Cut Pro Movie" is an option anymore. Even FCP4.5 doesn't have it. When you APPLE-I the .mov file, try also clicking the "Change All" button. That should make OS put a QuickTime icon on all .mov files by default.

I disliked "FCP Movies" as well. Before I had learned to change the default application, one wrong click (well, one wrong double-click) meant FCP would launch and I'd have to get right back out of it.


www.derekmok.com

noooo, I NEVER said I was choosing "export- final cut pro movie". I've never even seen that option, since this is my first version of FCP. What I'm saying is that choosing "export- quicktime movie" creates a "Final cut pro movie" that is set to open with FCP by default no matter what I've previously changed with apple-I. Choosing "export Quicktime conversion", creates a quicktime movie...

just to reiterate:

export QuickTime Movie is a 1:1 data transfer if you stick with the default "Current Settings"

export w QT Conversion involves a re-compression, even if you specify exactly the same settings as your sequence or clip.


nick

Quote

Did you have a proper microphone pre-amp?

No I didn't use a mic pre. Come to think of it I instead recorded the same "dropping coins" directly onto my computer (but through a mixer) and it sounded fine using the same microphone. That Marantz has some resemblance of a mic pre but obviously it ain't worth a damn. A lot of cameras including high end ones like the Panasonic Varicam have dirt cheap preamps that over modulate easily too.

<<<it sounded fine using the same microphone. >>>

Oh, it's totally not the microphone. Dynamics have a very nice graceful overload characteristic.

It's the preamp. People who design good mic pres are very into dark gray, if not black magic. You can't throw four transistors and a 5 volt power supply at it, although a lot of people try.

Coin On Tiles is a grand sound test. Can I use that?

Koz

hello all, can someone confirm for me that if you export the FCP quicktime, PC computers will be able to play them? as well be able to compress it to whatever format from the PC? The reason i'm checking is that a client I need to output a project for wanted an AVI cause that'll be better in quality and workable in their PC environment. Any thoughts on that?