Z1 in DVCAM mode - uncompressed audio?

[Christopher C. Murphy]

Hey, forgive me if this was covered. I did a search to no avail...

Is the Z1 in DVCAM/Mini-DV mode - uncompressed audio? I know the HDV is compressed for sure, but I can't find anything about DVCAM mode having uncompressed audio like a PD170 or other DV cameras.

Thanks!!

[Douglas Spotted Eagle]

It's DV. Yes, it's PCM audio in this mode.

[Ignacio Rodriguez]

I really wonder if the difference is noticeable. At HDV's audio data rate, it should not be.

[Douglas Spotted Eagle]

It absolutely is noticable. Bitrate for HDV/MPEG 1-layer II is compressed, 384kpbs vs PCM@ 1550kpbs.
It's more noticable in editing, so you should be converting to PCM before editing.

[Ignacio Rodriguez]

I see. Can you please describe in which way it is noticable? And how can it get better by going PCM if the source already has noticable compression artifacts?

[Douglas Spotted Eagle]

I should clarify. YOu won't notice any artifacts in the original, what you'll notice is if you attempt to process the already compressed signal without moving it to a more edit-friendly format, that tails, dithers, high frequency EQ's, reverbs, volume adjustments, panning, and similar edits will be noticable. Converting it straight over will prevent this from happening.
If you have a good DAW, you can clearly see the differences. Take a PCM file, convert it to MPG1/layer II audio. Compare the waveforms.

[Ignacio Rodriguez]

I see. Well it is expected to look different. After all, psychoacoustic compression is based on the assumption that we don't actaully hear all the information in a waveform, so the encoding algorith discards the information that we don't hear. Thus, the decoded output should look VERY different but should sound --theoretically-- the same. Of course some people can notice the difference, especially at low bit rates and with wideband content like full-spectrum music.

If, as Douglas says --and as I also believe-- artifacting is not noticable, then MPEG1 layer 2 is a satisfactory aquisition format. I was expecting it to be, especially so for speech. I have not heard Z1 audio yet but I expect to be as good as MiniDisc or 160 Kbps mp3. So I wouldn't see any reason to shoot in DV mode just to get better audio. The Sony preamps might be so poor that they can become the weakest links in the audio chain. If you want very high quality linear audio then double system with a professional DAT machine (they are cheap these days), a portable solid state/hard disk recorder like the Fostex FR-2, a computer with a good audio interface like the Apogee Mini Me or, if have the money, the Fostex PD-6.

Naturally, one should always edit in the highest possible quality. The NLE I use automatically converts audio to a linear form. I believe Adobe Premiere usually does also. Douglas do you use Vegas? I was unaware of any tools that process the audio in compressed form while editing. Very disturbing.

[Douglas Spotted Eagle]

Not all NLE's will process the compressed file in the same way. This is why the file should be converted to an intermediary immediately. Nothing will be using the native format (that I'm aware of), but it all depends on the NLE as to how it will manage the file format in the background. Be sure you know how your app is managing the information.