What about AUDIO?

[Justin Kirchhoff]

I don't ask questions much, as I like to do all my research scoping the threads, but recently I have thought of a question that may be legit and not have been asked yet?

I remember watching the interview with Ted and Mike Curtis talking about how much record time the RED Drive gets....around 3 hours.

Well, in a recent post by Jim, he said that there is roughly 2 hours of record time on the RED Drive.

So, what I'm guessing is the discrepancy with footage shot without audio (3 hours of record time) vs. footage shot WITH audio (2 hours of record time).

This is just a hypothetical guess, but I would love to know what and if the audio does take up that much data on the RED Drive, or if it really is all that relevant with the image capture data rate? Any answer would be helpful!

Thanks guy.

[TimothyD]

Interesting question.

I also wonder if the audio is embedded in the redcode file? I assume it is, but you never know I guess.

Tim

[Rob Lohman]

The difference is because we haven't fully nailed down compression levels and such. It's probably going to be somewhere in between 2 - 3 hours (4K @ 24 fps) *without* audio.

Audio is embedded indeed.

[Álex Montoya]

That's interesting: that means that the recorded datastream for REDCODE 4K@24fps will be between 33 and 50 MB/s.

That is good news IMO since the spec of 27MB/s might be a bit low compared to other RAW wavelet codecs such as Cineform's.

[Justin Kirchhoff]

The difference is because we haven't fully nailed down compression levels and such. It's probably going to be somewhere in between 2 - 3 hours (4K @ 24 fps) *without* audio.

Audio is embedded indeed.

Thanks Rob for clearing that up. That's good news, at least for me! You guys make me happy every time I get information...

[Chris Kenny]

24 bits x 48000 samples/sec = 1152000 bits/sec, or 141 KB/sec. Four channels would be 564 KB/sec.

Not going to make much difference.

[Stuart English]

You got it right Chris - relative to the video data rate audio is trivial.

The hours per mag discrepancy is just that the codec's AVERAGE and PEAK data rates are still being tweaked. In addition, some comments fall on the conversative side of that equation, some comments reflect the assumption its 27MB/s as per our IBC estimate.

Unlike tape decks that have a requirement of a fixed data rate, we have a lot of flexibility in using constant or variable bit rates and / or higher bit rates as may be most appropriate to the task at hand.

More later ...