The New Digital
Broadcast Standard
The New Digital Broadcast
Standard-How It Affects You And Standard-How We Can Help:
Three main events are redefining practices within the broadcast community:
1. The switch to Digital Television Transmission in the summer of 2009 has created new formats and new requirements for deliverables.
2. The US Government has mandated (in the form of the CALM ACT signed into law in Dec 2010) new requirements for loudness control of commercials.
3. Increasingly, networks and cable broadcasters are moving towards an all HD workflow-known in broadcast circles as “Single Threaded Delivery”.
Sound Lounge is taking a proactive response to these changes to ensure the highest quality and compatibility of our mixes. Here is what we are doing and why:
1. For spots airing on broadcast television, we will supply you with a 5.1 channel (Surround Sound) Mix, and 5.1 Surround Sound will be the primary focus of the mix.
We are doing this because a 5.1 channel mix is the audio delivery format preferred and requested by the networks for HDTV transmission. In addition, it’s very important to under-stand that for all HD commercials delivered with a 5.1 channel mix, only the 5.1 mix is broadcast, even if a separate stereo mix is also supplied (according to all the networks, the separate stereo mix is discarded for broadcast). That means that anyone listening in stereo to this HD broadcast is hearing a stereo mix derived from the 5.1 mix and not a separate stereo mix, even if one was provided. For this reason, as we mix, we’ll monitor the derived stereo mix as well as the 5.1 mix to assure all viewers hear what is intended. For clarity, and to differentiate this derived stereo mix from a traditional stereo mix, we’ll call the derived mix “LTRT MIX”. This is the stereo mix you will be listening to and approving as we mix. (The term LTRT, which stands for Left Total/ Right Total, is used to denote that it is derived from the 5.1)
What is Upmixing?
Upmixing is a practice employed by some broadcasters in an attempt to provide the sur-round sound experience to all of their HD viewers at all times. What they do is take pro-grams that are supplied stereo only, and from that, create a fake 5.1 surround mix to broad-cast. Why should this concern you? Well, since the stereo mix people hear is derived from the 5.1 mix as explained above, those listening in stereo to an HD channel are really hearing a mix created from that fake 5.1 broadcast, and not your original stereo mix (the one
approved by you and your clients).
What will it sound like? Who knows! This is why we recommend that we supply a true 5.1 mix, and not leave it up to the networks.
Continued...
2. We will supply an LTRT MIX, which is a stereo mix derived from the 5.1 mix exactly as it will be when broadcast. This is the stereo mix everyone heard at the mix session and should be used for SD broadcast.
3. We will supply 5.1 channel Surround splits.
4. For your convenience, and as long as you need them, we will continue to supply sepa-rate stereo splits that correlate to the LTRT MIX. We recommend that you use these splits as reference only, because only the stereo mix derived from the 5.1 mix is guaranteed to be heard by viewers. We will label them REF (Reference) for clarity.
Although at this time broadcasters are still accepting traditional stereo mixes, as they continue the move towards an all HD workflow, we anticipate a time when stereo ele-ments will no longer be required or requested for television broadcast.
5. As per recent network specs (which coincide with standards adopted in the newly passed CALM ACT, and to be fully implemented by the FCC by the end of 2012), we will mix broadcast commercials to a loudness level of -24LKFS +/- 2dB, unless otherwise speci-fied. (See following Additional Info page for more explanation)
6. For Radio, alternative, and non-television broadcast mediums, we will continue to pro-vide stereo mixes and splits created the traditional way. We anticipate other formats being developed for these mediums, and will keep you abreast of the technology as it becomes available.
7. While we are dedicated to providing you with the correct deliverables for this transi-tioning time in Digital Television broadcasting (and any other new formats that may
become available such as Mobile broadcast), we acknowledge the need to give you what-ever elements you may need for any situation you may encounter. If you have any addi-tional or special requirements, please let us know. We will be happy to advise and accom-modate.
Additional Info:
What is LKFS?LKFS is a new value of measurement, used to express the perceived loudness of program sound. It is expressed as a number between -1 and -31, the target number now mandated by the government being -24 +/-2dB. If we don’t mix our audio levels to meet this number, the networks are compelled to either reject the mix, or adjust the levels themselves. This applies to 5.1 channel Surround and Stereo mixes.
What is the CALM ACT?
The “Commercial Advertisement Loudness Mitigation (CALM) Act”, which was signed into law in Dec. 2010, makes it illegal for commercials to be overly loud compared to the rest of the programming on a given channel. This law mandates that the FCC write rules to enforce loudness levels, and references documents that explain how to measure those levels
(Which also defines the target level of -24LKFS +/- 2dB). By the end of 2012, these rules will be in full effect and all broadcasters will need to abide by these rules to avoid fines and other penalties.
