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Understanding audio requirements for broadcast (A1, A2, A3, A4)

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Richard Steele
Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 3, 2013 at 11:37:37 am

Hi,

I'm still quite new in the business and recently received my first broadcasting contract. Great news. But now I have to deliver the goods... (I'd like to avoid asking them directly and looking like an amateur)
I've just been editing on FCP in a very simple way (my audio tracks are all over the place on my timeline), I have no experience in transferring to DigiBeta. Could anyone help me understand the following requirements :

" - Audio tracks 1 and 2 : Program Stereo. Stereo final mix soundtrack to be recorded on audio channel A1 (Left or left total) and A2 (Right or right total).
- Audio tracks 3 and 4 Music and Effects Stereo. International sound to be recorded on audio channels A3 (Left or left total and A4 (Right or right total)."

Cheers !!!

Richard


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Michael Gissing
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 3, 2013 at 12:02:16 pm

I strongly recommend you get a proper sound post facility to mix and provide broadcast stereo mixes plus international deliverables like pre mix stems. Issues like levels, loudness, dynamics processing and pre mix stems are well beyond the capabilities of FCP which is at best a simple offline editor for sound.

No offence but broadcast specs and deliverables requires a whole skill set as well as the appropriate tools and FCP is far from the right tool and if you don't already understand deliverables terminology I can only we a world of pain ahead trying to get tech acceptable results.


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Alex Elkins
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 3, 2013 at 1:26:02 pm

In principal I do agree with Michael's point, but sometimes (usually) budgets force inexperienced editors to have to jump in at the deep end and try to swim. A few years ago I faced exactly the same situation as you, Richard, and the fastest way to learn was to HAVE to get it right. So here, hopefully, is a useful guide for you.

First, you need to understand the difference between audio tracks in your timeline (which you say are all over the place) and mastered audio tracks (or audio channels). Think of A1 and A2 (Channel 1 and Channel 2) as the stereo mix you're hearing out of your speakers when you play back your timeline - the net result of all of the audio clips in your timeline.
A3 and A4, the M&E Mix (a.k.a. International Mix) will be the same as A1 and A2, only with the voiceover mute, i.e. Music and Effects only. This is so that when the programme is sold to a non-English-speaking country, they can add their own voiceover. Note that you usually include interview and presenter audio in an M&E mix because it would be strange for them to be completely mute, even if they were re-voiced in another language. Tech specs for this scenario vary by broadcaster, but you'd normally want to drop the levels by about 12dB - 15dB to allow for the re-voicing.


Here's how you do it:

1. Tidy up your timeline. I lay mine out like this.
A1: Presenter audio
A2: Interview audio
A3 & A4: Sound effects and any audio recorded in-camera that ISN'T someone speaking
A5, A6, A7, A8: Music
A9 & A10: Voiceover


2. Mix your audio
Technical specifications vary by country (and sometimes by broadcaster). Here in the UK we mix to an average level of -14dB to -12dB, with peaks no higher than -10dB. If this side of it is completely new to you then you might want to seek further advice. As a very general guide, you can't go too far wrong with the following:
- VO, Interview and Presenter audio between -14dB to -12db
- Sound Effects between -20dB to -14dB
- Music at -12dB when there's no VO, then dipped down to around -19dB when you have VO/interview/presenter audio. This can vary depending on the type of music you're using. Do what sounds right for each music track.

All of this is a guide. Nothing is set in stone and you just have to use common sense. For example, if there's the sound of gunfire in your mix then it would be suitable for that to peak at -10dB, because it should be loud.


3. Duplicate all of the audio except for the voiceover
- Lasso all of the audio except A9 & A10.
- Hold 'Alt', then click and drag the selected audio down so that the copy of A1 is now duplicated onto a new tack, A11.
You should now have 18 audio tracks, where A11 - A18 are exact copies


4. Tell FCP to output 4 channels of audio, rather than the 2 you currently have set-up
- Press CMD+0 (or go to Sequence > Settings)
- Click the tab called 'Audio Outputs'
- On the drop-down menu labelled 'Outputs', change it to 4


5. Route your M&E mix to channels 3&4
If you played back your timeline at any point after step 3 you'll have noticed that everything (except VO) is twice as loud as it should be. This is because every track in your timeline is still routed to play through channels 1 & 2.
- Right-click somewhere inside the track panel on A11. The track panel is the bit on your timeline where you click to lock and mute tracks.
- You should see a little menu like in the screenshot below:



- Select 3 & 4. If you right-click in the same area again you should see that there is now a little tick next to 3 & 4.
- Repeat this step for avery track that needs to be routed to channels 3 & 4, i.e. tracks A11 - A18 in your timeline, if you've followed my track layout.


That's it. When you play back you will find that you can no longer hear the M&E mix over the top of the English mix. This is because you only have two speakers. If you had 4 speakers, and they were set up correctly, you'd of course be monitoring all 4 channels.



Good luck with it. It's not really as complicated as it sounds. To get a really good sound mix you should, of course, use a professional sound engineer, but there's no reason why you shouldn't be able to get pretty good results if you're comfortable with the technical side of it.

Alex Elkins
Twitter: @postbluetv
http://www.postblue.tv
Post Blue showreel
Latest work: Greyhounds in Motion at 500fps
My Vimeo Pro page


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Richard Steele
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 3, 2013 at 1:43:37 pm

Now that's the kind of help I was looking for. Thanks Alex !

My last (major) problem is that I don't have a digibeta deck... what kind of file(s) can I hand over for the transfer ?

Richard


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Alex Elkins
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 3, 2013 at 2:13:16 pm

Glad I could help.

We don't have decks here either, we just rent them in as required. To be honest though, it's not that much more expensive to just take a file on a harddrive to a dubbing facility and let them take care of it for you. Tape dubbing is a pretty technical process and not really the sort of thing that can be easily explained on the internet as there are so many variables, so if you're completely unfamiliar with it I'd do that. Or even hire an engineer to come to your office to show you how to set it up if you are prepared to make that sort of investment.
It sounds like you are planning to take a file somewhere anyway. Just about every facility you might take it too will accept a ProRes QuickTime file, which if you output it correctly will maintain the 4 audio channels. Maybe post here again when you're at that stage of the process, but in the meantime the facility you choose to use will be able to offer advice too.

All the best.

Alex Elkins
Twitter: @postbluetv
http://www.postblue.tv
Post Blue showreel
Latest work: Greyhounds in Motion at 500fps
My Vimeo Pro page


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Michael Gissing
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 4, 2013 at 12:05:04 pm

Undipped stems are a normal deliverables, not just stereo M&E. Track based dynamics is required to control loudness. Loudness needs to be metered as there are now requirements to fit loudness profiles. Edit accuracy better than frame is needed.

FCP will not be the right tool to get broadcast acceptable audio mixes. Seriously I cannot stress the importance of getting a sound professional to finish. If you are delivering to international broadcast distributors you will soon find major limitations with FCP. At the very least, learn to use Sound Track Pro.


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Alex Elkins
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 4, 2013 at 4:04:24 pm

[Michael Gissing] "FCP will not be the right tool to get broadcast acceptable audio mixes. Seriously I cannot stress the importance of getting a sound professional to finish."

You're absolutely right, of course, but what you're talking about is the ideal scenario. These days there are many occasions where inexperienced editors are thrown into this sort of situation and expected to make things work. Those who get through it unscathed are the ones that go on to be re-hired, so I can see where Richard is coming from. After all, it's not he who is forcing the budgets down, it's the broadcasters and producers. So I feel for Richard and others in similar situations. Telling him to hire someone else isn't much help if he's not the person in control of how the money is spent, even if we all know full well that it's the best way to operate.

So Richard, just to reassure you, it can be done. I did it, and have never had a sound mix done inside FCP rejected by a broadcaster. And these are major broadcasters in the UK and worldwide. Yes, learn Soundtrack Pro or whatever, but know that if you have to, you can mix audio to professional standards in FCP. It takes longer, is more cumbersome and the results will never be as good as a professional sound designer using dedicated audio software, but it can be done.

Alex Elkins
Twitter: @postbluetv
http://www.postblue.tv
Post Blue showreel
Latest work: Greyhounds in Motion at 500fps
My Vimeo Pro page


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Michael Gissing
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Jan 4, 2013 at 11:31:47 pm

Alex, after sound posting 800+ broadcast docos I totally get the budgets tightening. My rates have been static for 18 years. However it is a false economy for an inexperienced editor to use a tool like FCP to create broadcast deliverables. Broadcasters have very rigid tech specs and the recent changes to loudness metering have made it harder to meet spec.

Whilst your ideas on creating an M&E are a clever workaround, it produces a dipped M&E which will be rejected by most broadcasters. It also doesn't address undipped stems which are almost always required.

Unless you intend to mix for nothing then then time it will take for an editor using FCP to try to match the result a sound post pro can do (virtually impossible) will cost the same if not more, create a lesser result and possibly get the producer into hot water with lots of tech rejection from broadcasters.

I understand you are trying to help but just think it is likely to lead to a false sense that this is an OK approach.


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Richard Steele
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Feb 12, 2013 at 5:33:48 pm

Hi Alex, if you're still around.

Been quite busy with other things. I've followed all your instructions, I'm now at the ProRes stage. How do I create a 4-track ProRes Quicktime file ? (right now, when I got to the ProRes audio export options I can't click on anything more than 2)

Cheers.


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Alex Elkins
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Feb 12, 2013 at 6:18:48 pm

Hi Richard,

I'm not entirely sure what you mean when you say you're at the ProRes stage. I presume you mean you're ready to export...

It sounds like what you're doing is going to File > Export> Using QuickTime conversion...
What this does is it mixes down all of your audio channels into a single stereo mix.

What you need to do instead is go to File > Export> QuickTime Movie...
If you've followed my instructions correctly (specifically points 4 and 5) you will find that the QuickTime file that is exported will contain 4 tracks (or rather, 2 stereo tracks) - you can quickly verify this by re-importing it into FCP and seeing how many tracks it has.

Tip:
If you set in/out points on your timeline before exporting you will be able to test all this on a short segment rather than the entire sequence.


Good luck.

Alex Elkins
@postbluetv
http://www.postblue.tv
View my new colour correction reel


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Richard Steele
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Feb 13, 2013 at 11:36:03 am

Yep, I was using the Quicktime conversion mode. My ProRes file in Quicktime movie mode does come out with 4 tracks, great.

Putting aside the multiple audio track issue, what will the difference be between exporting from an uncompressed timeline setting with ProRes Quicktime conversion and exporting from a ProRes timeline setting using the Quicktime movie export ?

What are the pros and cons between Quicktime movie export and export using Quicktime conversion ?

Richard


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Justin Crowell
Re: Understanding audio requirements for broadcast (A1, A2, A3, A4)
on Feb 15, 2013 at 5:13:17 pm

It's really bizarre that I just found this thread, because this is EXACTLY what I'm doing right now. We are an audio post facility, however, so we did all of our mixes in Pro Tools and are now just doing laybacks in FCP.

My question is: Our mixes are all prepped for broadcast levels (the broadcaster gave us the exact voice vs M+E info). Under "Audio Outputs" in Sequence settings, do I want to make A1/A2 (full mix) and A3/A4(M&E) both stereo pairs or dual mono? Do I want to set my Downmix Db to 0, or off?

This site makes me think I should be doing dual mono, as my levels are all set and should basically be passed through: http://blog.abelcine.com/2009/02/05/final-cut-pro-stereo-downmix-confusion/

To your question about QT conversion: that is used if converting the sequence to something other than the sequence compressor. So, you'd use this if you were prepping for web with H.264, or transcoding to something like XDCAM or something that the layback house is looking for (these days Prores is almost always adequate). Most transcoding will cause a drop in quality, so only do it if you need to.

Video editor, animator, composer, producer
JustinCrowell.com


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