CAS Quarterly

C A S Q U A R T E R L Y I FA L L 2 0 2 1 35 filmmakers, we use those stems as the source for our mastering process." STREAMING AND NETWORK The inclusion of loudness requirements in addition to peak limitations is unique to streaming and broadcast projects. Additionally, these loudness requirements are forever evolving. Consider the following specifications as examples of the detailed variances between companies. (Please note all specifications provided are meant to be examples. While derived from actual projects, this information is subject to change and is not provided to define or describe any specifc requirements (or designate an individual to this task on your team when on a streaming or broadcast project), these requirements should not necessarily change your approach to telling the story. Re-recording mixer Matt Waters CAS (Game of Thrones, The Old Guard, Booksmart) explains, "I approach every storytelling opportunity with a different lens. How much time? What kind of story (show) is it? I think the biggest difference is that I don't mix differently for film vs. broadcast. We have to hit a dialogue norm. So, we might lower the monitors so we print louder, but I mix based on hearing. When done with the mix, we will do a print master pass where we might raise or lower the material to meet the broadcast requirement. network's standards. Always check your project's deliverable spec sheet.): Network A, a streaming empire, may require all their content to be -27 LKFS +/- 2 LU dialogue-gated. Peaks must not exceed -2 dB True Peak. Audio is to be measured over the full program according to ITU-R BS.1770-1. Simultaneously, streaming Network B may require -27 +/- .4 using 1770- 1 with -2 dB peaks for their 5.1 and -24 +/- .4 for their 2.0 using 1770-3, also with peaks not to exceed -2 dB. While yet another broadcast-based Network C may ask for an average -24 +/- 2 1770-3 with the peak limited to -6 dB. All while, streaming and broadcast Network D may need an average loudness level of -24 LKFS (+/- 2 dB), as measured using a meter compliant with ITU-R BS.1770-3 with peaks no higher than -2 dB. Additionally, many streaming and broadcast clients require unique content specifications. Some deliverable documents call for specifically dipped or undipped splits or sub-mixes. "Dips" refer to volume reductions for other elements outside the sub-mix category, such as volume reductions on the music stem in response to voiceover, dialogue, or SFX elements present in the full mix. Some require spatial preferences, such as National Geographic, which has required 5.1 mixes with no center channel music, diegetic dialogue, or SFX, allowing only narration to exist in the center channel. While it is paramount to always read each line of your audio technical "Typically, we try and go ahead and achieve a mix that satisfies, first and foremost, their initial [distribution] requirements of streaming, but will also play in a theatrical environment." –Marti Humphrey CAS

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