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-   -   Is there a standard for audio levels in video? (https://www.dvinfo.net/forum/all-things-audio/24147-there-standard-audio-levels-video.html)

Rob Moreno April 5th, 2004 10:02 PM

Is there a standard for audio levels in video?
Can anyone tell me what the generally accepted audio level for the final mix recorded to video is? Coming from a music recording background, I've always set the levels so that the highest peak in the audio track is at 0 db, to get the best signal to noise ratio. Since working in the video editing field though, I see a majority of tapes mixed with the peaks at -12 db. I've tried doing this, but the volume always seems way too low when played back on VHS through regular TV speakers. Other FCP editors I've talked to seem to prefer mixing at around -6 db. What you do?

Bryan Beasleigh April 5th, 2004 10:08 PM

I used to try for average at -12 and peaks to 0. Now i have the preamps bypassed the camera is a lot more forgiving. I push for -6 average

Peter Jefferson April 6th, 2004 03:20 AM

depends on your final output, as if your going for ac3 Dolby Digital, you have other aspects such as phase shifting and dynamic range compressions to consider.

generally when recording, -12 is ideal, normalisation can then take place with enough headroom to adjust the freq if needed.

Rob Moreno April 6th, 2004 03:39 AM

My final output is usually to Betacam, DV Cam or VHS (Betacam and DV Cam for projection in large presentation halls, and VHS for viewing on a TV set).

I should clarify that I'm inquiring into the audio levels used when dubbing the final output from the editing system (FCP, etc.) to tape, not the audio signal recorded by the camera when shooting raw footage.

Marty Atias April 6th, 2004 08:35 AM

As with any format of program, you set nominal levels according to the media you are recording to.

If making a digital recording, -12 to -16dBfs for zero tone gives enough headroom for most audio peaks.

Recording to an analog medium requires more balancing noise floor to headroom than digital does. Setting tone to -3 to 0VU should do it depending on the dynamics of the program.

Douglas Spotted Eagle April 6th, 2004 11:00 AM

The ATSC standard is -20 avg (www.atsc.org) Digital zero is equal to -20 analog. While many choose -12, -18 as their reference point, and this is perfectly fine, the 'standard' as defined by ATSC is -20. I'd imagine it's that low to accomodate for mis-calibrated digital hardware in a broadcast situation.

Rob Moreno April 6th, 2004 05:57 PM

Thank you, everyone, for your information so far!

So, is it safe to conclude that I should set my levels from -20 db to -12 -db when dubbing to DV tape and from -3 db to 0 db when dubbing to VHS?

Jim Giberti April 6th, 2004 08:35 PM

I think the issue for you may be one of useage . If the relative volume seems low on VHS dubs, then I'd just mix with my ears. If you're masterung for say, DVD distibution or sending to networks, I'd go with Douglas' genereal advice.

I spend the other half of my studio life as a music producer, and since we all moved from giant analog consoles and 2" multitrack to all digital consoles and DAWs there's been the ongoing discussion (surprise) at the various pro audio groups over word length, bit performance, dithering etc.

Like you, I mix at 0 nominal levels in the recording studio. Whether it's for CD pressing or broadcast, I run out of my digital mixer (I never do my workk at this level on the computer...not enough buttons and knobs) and into a t.c. Finalizer 96k for mastering and final normalizing.

Ultimately, if it's going on air (as music) I push it right before clipping. If I'm sending it out to a separate mastering engineer for say a CD release, I'll bypass the Finalizer stage and leave him the headroom for the final master.

If I'm going to broadcast or DVD for film/video, I treat it the same as if i were mixing for broadcast radio, and master my multitrack mix throught the Finalizer and really normalize the levels pushing 0.

Ultimately, when I lay this back into FCP4, and the out to DV master (or Beta for stations) I'm hitting a pretty tight -12 on the final tape . I always use -12 for my test and reference tone in my Print to Video window.

Jim Giberti April 6th, 2004 08:44 PM

A follow up thought to that. I had a really talented director/producer on staff who mostly did music video, MTV stuff before he joined us. Like a lot of film/video producers...the ones like so many of us that tend to direct, shoot and bring it back to the studio, audio was not a strength.

I remember sitting down with a reel of work and getting blown away (not the good kind) by the levels when I first put it up on the console. All the levels were nailing the meters on the Beta deck, and that's not all that unusual. in my experience.

Headroom is a good thing, especially if you've got a great signal (great mics and preamps) at acquisition through final mix and mastering.

Douglas Spotted Eagle April 7th, 2004 02:10 AM

To add comment to Jim's post, I'll say that I use a WAVES Ultramaximizer on everything, set to -.03 for my peaks. I'm very happy with this, and have never had anything sent back, ever.

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