I discussed this with a very nice guy at NatGeo's QC Washington. My question was, if I actually used the headroom to -2 truepeak on the full mix, it would be very hard to ALSO get a decent sounding stereo mixdown. I got this answer:
"The level question is a little more complicated. Because our 5.1 and stereo mixes are used in different ways around the world, we need them to meet certain specs to please all of our regions at the same time. This necessitates a blending of the old analog specs and the current digital standards. While the NGC spec allows for 5.1 stem peaks to -2dbfs, a -23 db LKFS 5.1 mix that peaks at -2 dbfs will be well over the -10 dbfs peak requirement for the stereo mix when downmixed. Having a -10 dbfs peak on the stereo mixes is important for our regions that still broadcast the stereo mix as an analog signal. Keeping the average level the same between the 5.1 mix and the stereo mix allows other regions use the stereo mix as a SAP option without a noticeable change in volume. To achieve the spec here in house, we generally limit our 5.1 stems to -10dbfs so that a stereo downmix will peak close to -10 dbfs. This way, no one limiter is doing too much work."
There you have it... Now try and convince the director that louder isn't always better ;-) Seriously, put a really good limiter on the stereo mix and doublecheck the loud parts when you're done with the 5.1.
Quote:
Originally Posted by wheresmyfroggy
Having read through the latest Nat-Geo spec for 5.1 delivery before starting a major series, I was glad to see that the 5.1 mix was given more headroom, being able to go up to -2 truepeak. So we took advantage and mixed the 5.1 utilising that extra headroom.....Yay!
9 episodes later, without any rejections, we get a note in the record report on one episode that says:
"on Dolby Full Mix tracks 1-3 PEAK levels register high @ -5 dbfs throughout. Ideal PEAK levels are @ -10 dbfs"
Although they have not failed it, have we taken this new freedom too far and its taken them 9 episodes to notice?
Please let me know how you approach Nat-Geo 5.1 mixes...
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