What is the difference between Stereo, 2 Channels and Dual Stereo?

[LeoKac]

Hello, in Sony Vegas Pro 13 rendering settings, PCM audio format has some options about channels.
.

.

Please tell me what is the difference between these tree options:

Stereo
2 Channels
Dual Stereo

Thanks................

[redwudz]

Stereo would be two separate, different audio channels, usually the right and left audio channels.
Two channels would be different audio channels, maybe two separate languages.
Dual stereo would usually be the same audio on both channels, converted from mono audio.

Just guessing at that as programs may use different terms for those titles. But someone else here can correct me.

[Cornucopia]

It depends upon the context.

All 3 use 2 channels.

The 2nd one could be mono, or stereo, or dolby surround-matrixed (or similar).

"Dual stereo" is a misnomer: it usually says, "dual mono" or "dual channel".
Dual mono is a mono signal that has identical material in both tracks (to maintain the 2 track methodology, even when the content isn't truly 2 channels).

Dual channel CAN be stereo, but it can also be dual mono, and it can also be 2 totally separate channels of independent information (such as the aforementioned 2 languages, though that is not the only application).

If something were ACTUALLY "dual stereo" it would mean it was 4 channels - not a likely configuration.

"Stereo" has a specific meaning: it is 2 channels that have similar & dependent content, such that it provides a panorama of dimensionality between & among the 2 channels. Binaural is similar, but has a special connotation WRT its makeup (requires HRTF mike setup, and headphones/HRTF-set speakers).

In the context of that dialog box, and considering it is LPCM and NOT a bitrate-reduction-efficiency option (e.g. as is listed for mp3*), Stereo & 2 channels will give you basically the same thing. The only difference MIGHT be if a volume control is ganged (meaning: operates equally & simultaneously on both channels). "Stereo" would have some sort of interdependency and "2 channels" would not. For most programming, it makes no difference. The "dual stereo" and "4 channels" options ARE, in this case, both using 4 tracks. XDCAM explicitly accommodates up to 4 tracks, so that's why it's showing up there. Same sort of interdependency or not is applicable here, too.

Scott

*MP3 and other similar lossy-compressed codecs utilize bitrate-reduction efficiency by sometimes doing phase-related tricks. That's why they have items such as "joint-stereo" or "intensity-stereo" or "mid-side stereo", etc. Don't confuse that with what you were asking. They are 2 distinctly different things.

[hello_hello]

I looked in the manual and couldn't find a reference, but it won't stop me having a guess too.....

Mono = mono
Stereo = Stereo
2 Channels = 2 x mono
Dual Stereo = 2 x stereo
4 Channels = 4 x mono

The Sony XDCAM cameras tend to have two digital audio inputs of the AES/EBU variety (BNC connectors) and from here:

http://en.wikipedia.org/wiki/AES3#Channel_status_word_in_AES.2FEBU
byte 1: indicates if the audio stream is stereo, mono or some other combination.
bits 0–3: Indicates the relationship of the two channels; they might be unrelated audio data, a stereo pair, duplicated mono data, music and voice commentary, a stereo sum/difference code.

So that's the basis for my guess, which could be completely wrong....

[Cornucopia]

I think you are fundamentally right about what Vegas was intending to provide as options.

The business about the AES flags really doesn't enter into this, though, because these are encoded LPCM files, not live AES streams (which that link refers to). Plus, I'm not completely convinced that Vegas would be 100% compliant with enforcing the flagging difference between 2(/4) inter-related channels vs. 2(/4) totally independent channels.

Most of the XDCAM camcorders that I know of use XLR inputs - which models use BNC, as that is very non-standard? Maybe you're thinking of SDI?
Also, while the cams are almost all 2-ch, the decks are almost all 4- or 8-channel.

Scott

<edit>I stand corrected: looks like some of those decks do use BNC for AES! My apologies.</edit>