The last step in commercial music production is mastering. Typically this involves making a recording sound as good as it possibly can through the application of equalization and multiband compression. In the case of LPs and CDs (remember those?), this also includes setting up the flow from one tune to the next and balancing out levels so the entire product has a consistent sound. Video post has a similar phase, which has historically been in the hands of the finishing or online editor.
That sounds so sweet
The most direct comparison between the last video finishing steps and commercial music mastering is how filters are applied in order to properly compress the audio track and to bring video levels within legal broadcast specs. When I edit projects in Apple Final Cut Pro 7 and do my own mixes, I frequently use Soundtrack Pro as the place to polish the audio. My STP mixing strategy employs tracks that route into one or more subgroup buses and then a master output bus. Four to eight tracks of content in FCP might become twenty tracks in STP. Voice-over, sync-sound, SFX and music elements get spread over more tracks and routed to appropriate subgroups. These subgroups then flow into the master bus. This gives me the flexibility to apply specific filters to a track and have fine control over the audio.
I’ll usually apply a compressor across the master bus to tame any peaks and beef up the mix. My settings involve a low compression ratio and a hard limit at -10dB. The objective is to keep the mix levels reasonable so as to preserve dynamic range. I don’t want to slam the meters and drive the signal hard into compression. Even when I do the complete mix in Final Cut, I will still use Soundtrack Pro simply to compress the composite mix, because I prefer its filters. When you set the reference tone to -20dB, then these levels will match the nominal levels for most digital VTRs. If you are laying off to an analog format, such as Betacam-SP, set your reference tone to -12dB and match the input on the deck to 0VU.
Getting ready for broadcast
The video equivalent is the broadcast safe limiting filter. Most NLEs have one, including Avid Media Composer and both old and new versions of Final Cut. This should normally be the last filter in the chain of effects. It’s often best to apply it to a self-contained file in FCP 7, a higher track in Media Composer or a compound clip in FCP X. Broadcast specs will vary with the network or station receiving your files or tapes, so check first. It’s worth noting that many popular effects, like glow dissolves, violate these parameters. You want the maximum luminance levels (white peaks) to be limited to 100 IRE and chrominance to not exceed 110, 115 or 120, depending on the specs of the broadcaster to whom you are delivering. In short, the chroma should stay within the outer ring of a vectorscope. I usually turn off any RGB limiting to avoid artifacts.
It’s often a good idea to reduce the overall video levels by about five percent prior to the application of a broadcast safe filter, simply so you don’t clip too harshly. That’s the same principle as I’ve applied to the audio mix. For example, I will often first apply a color correction filter to slightly lower the luminance level and reduce chroma. In addition, I’ll frequently use a desaturate highlights or lows filter. As you raise midrange or highlight levels and crush shadows during color correction, the chroma is also driven higher and/or lower accordingly. Red, blues and yellows are most susceptible, so it’s a good idea to tone down chroma saturation above 90 IRE and below 20 IRE. Most of these filters let you feather the transition range and the percentage of desaturation, so play with the settings to get the most subtle result. This keeps the overall image vibrant, but still legal.
Let me interject at this point that what you pay for when using a music mastering specialist are the “ears” (and brain) of the engineer and their premium monitoring environment. This should be equally true of a video finishing environment. Without proper audio and video monitoring, it’s impossible to tell whether the adjustments being made are correct. Accurate speakers, calibrated broadcast video monitors and video scopes are essential tools. Having said that though, software scopes and modern computer displays aren’t completely inaccurate. For example, the software scopes in FCP X and Apple’s ColorSync technology are quite good. Tools like Blackmagic Design Ultrascope, HP Dreamcolor or Apple Cinema Displays do provide accurate monitoring in lower-cost situations. I’ve compared the FCP X Viewer on an iMac to the output displayed on a broadcast monitor fed by an AJA IoXT. I find that both match surprisingly well. Ultimately it gets down to trusting an editor who knows how to get the best out of any given system.
Navigating the formats
Editors work in a multi-standard world. I frequently cut HD spots that run as downconverted SD content for broadcast, as well as at a higher HD resolution for the internet. The best production and post “lingua franca” format today is 1080p/23.976. This format fits a sweet spot for the internet, Blu-ray, DVD and modern LCD and plasma displays. It’s also readily available in just about every camera at any price range. Even if your product is only intended to be displayed as standard definition today, it’s a good idea to future-proof it by working in HD.
If you shoot, edit and master at 1080p/23.976, then you can easily convert to NTSC, 720p/59.94 or 1080i/29.97 for broadcast. The last step for many of my projects is to create deliverables from my master file. Usually this involves creating three separate broadcast files in SD and two HD formats using either ProRes or uncompressed codecs. I will also generate an internet version (without bars, tone, countdown or slate) that’s a high-quality H.264 file in the 720p/23.976 format. Either .mov or .mp4 is fine.
Adobe After Effects is my tool of choice for these broadcast conversions, because it does high-quality scaling and adds proper cadences. I follow these steps.
A) Export a self-contained 1080p/23.976 ProResHQ file from FCP 7 or X.
B) Place that into a 720×486, 29.97fps After Effects D1 composition and scale the source clip to size. Generally this will be letterboxed inside of the 4×3 frame.
C) Render an uncompressed QuickTime file, which is lower-field ordered with added 2:3 pulldown.
D) Re-import that into FCP 7 or X using a matching sequence setting, add the mixed track and format it with bars, tone, countdown and slate.
E) Export a final self-contained broadcast master file.
F) Repeat the process for each additional broadcast format.
Getting back there
Archiving is “The $64,000 Question” for today’s digital media shops. File-based mastering and archiving introduces dilemmas that didn’t exist with videotape. I recommend always exporting a final mixed master file along with a split-track, textless submaster. QuickTime files support multi-channel audio configurations, so building such a file with separate stereo stems for dialogue, sound effects and music is very easy in just about any NLE. Self-contained QuickTime movies with discrete audio channels can be exported from both FCP 7 and FCP X (using Roles).
Even if your NLE can’t export multi-channel master files, export the individual submixed elements as .wav or .aif audio files for future use. In addition to the audio track configuration, remove any titles and logos. By having these two files (master and submaster), it’s very simple to make most of the future revisions you might encounter without ever having to restore the original editorial project. Naturally, one question is which codec to use for access in the future. The preferred codec families these days are Avid DNxHD, Apple ProRes, uncompressed, OP1a MXF (XDCAM) or IMX. FCP editors will tend towards ProRes and Avid editors towards DNxHD, but uncompressed is very viable with the low cost of storage. For feature films, another option to consider would be image sequences, like a string of uncompressed TIFF or DPX files.
Whichever format you standardize on, make multiple copies. LTO data tape is considered the best storage medium, but for small files, like edited TV commercial masters, DVD-ROM, Blu-ray and XDCAM media are likely the most robust. This is especially true in the case of water damage.
The typical strategy for most small users who don’t want to invest in LTO drives is a three-pronged solution.
A) Store all camera footage, elements and masters on a RAID array for near-term editing access.
B) Back-up the same items onto at least two copies of raw SATA or SSD hard drives for longer storage.
C) Burn DVD-ROM or BD-ROM copies of edited master files, submasters, project files and elements (music, VO, graphics, etc.).
A properly polished production with audio and video levels that conform to standards is an essential aspect of delivering a professional product. Developing effective mastering and archiving procedures will protect the investment your clients have made in a production. Even better, a reliable archive routine will bring you repeat business, because it’s easy to return to the project in the future.
Originally written for DV magazine/Creative Planet/NewBay Media, LLC
©2012 Oliver Peters
Ever since the launch of 
The 4K discussion starts at sensor size. Camera manufacturers have adopted larger sensors to emulate the look of film for characteristics such as resolution, optics and dynamic range. Although different sensors may be of a similar physical dimension, they don’t all use the same number of pixels. A RED EPIC and a Canon 7D use similarly sized sensors, but the resulting pixels are quite different. Three measurements come into play: the actual dimensions, the maximum area of light-receiving pixels (photosites) and the actual output size of recorded frames. One manufacturer might use fewer, but larger photosites, while another might use more pixels of a smaller size that are more densely packed. There is a very loose correlation between actual pixel size, resolution and sensitivity. Larger pixels yield more stops and smaller pixels give you more resolution, but that’s not an absolute. RED has shown with EPIC that it is possible to have both.
The biggest visual attraction to large-sensor cameras appears to be the optical characteristics they offer – namely a shallower depth of field (DoF). Depth of field is a function of aperture and focal length. Larger sensors don’t inherently create shallow depth of field and out-of-focus backgrounds. Because larger sensors require a different selection of lenses for equivalent focal lengths compared with standard 2/3-inch video cameras, a shallower depth of field is easier to achieve and thus makes these cameras the preferred creative tool. Even if you work with a camera today that doesn’t provide a 4K output, you are still gaining the benefits of this engineering. If your target format is HD, you will get similar results – as it relates to these optical characteristics – regardless of whether you use a RED, an ARRI ALEXA or an HDSLR.
Quite a few large-sensor cameras have entered the market in the past few years. Typically these use a so-called Super 35MM-sized sensor. This means it’s of a dimension comparable to a frame of 3-perf 35MM motion picture film. Some examples are the 
This year was the first time that the industry at large has started to take 4K seriously, with new 4K cameras and post solutions. Sony introduced the F65, which incorporates a 20-megapixel 8K sensor. Like other CMOS sensors, the F65 uses a Bayer light filtering pattern, but unlike the other cameras, Sony has deployed more green photosites – one for each pixel in the 4K image. Today, this 8K sensor can yield 4K, 2K and HD images. The F65 will be Sony’s successor to the F35 and become a sought-after tool for TV series and feature film work, challenging RED and ARRI.
The Canon EOS C300 and EOS C300 PL use an 8.3MP CMOS Super 35MM-sized sensor (3840 x 2160 pixels). For now, these only record at 1920 x 1080 (or 1280 x 720 overcranked) using the Canon XF codec. So, while the sensor is a 4K sensor, the resulting images are standard HD. The difference between this and the way Canon’s HDSLRs record is a more advanced downsampling technology, which delivers the full pixel information from the sensor to the recorded frame without line-skipping and excessive aliasing.
RED launched SCARLET-X to a fan base that has been chomping at the bit for years waiting for some version of this product. It’s far from the original concept of SCARLET as a high-end “soccer mom” camera (fixed lens, 2/3” sensor, 3K resolution with a $3,000 price tag). In fact, SCARLET-X is, for all intents and purposes, an “EPIC Lite”. It has a higher price than the original SCARLET concept, but also vastly superior specs and capabilities. Unlike the Canon release, it delivers 4K recorded motion images (plus 5K stills) and features some of the developing EPIC features, like HDRx (high dynamic range imagery).
Software is easy, but what about hardware? Both AJA and Blackmagic Design have announced 4K solutions using the 
Video captured through Avid’s i/o hardware is mapped to this 16-235 range. Video imported from the computer, like stills and animation can have either a full range of 0-255 (so called “full swing”) or a digital video range of 16-235 (so called “studio swing”) values. Prior to AMA (Avid Media Access), Avid editors would determine these import values in the Media Composer settings, by selecting to import files with RGB values or 601/709 values. You can “cheat” the system by importing digital camera files with an expanded range (spreading the levels to “full swing” of 0-255). Doing so may appear to offer greater color grading latitude, but it introduces two issues. First, all clips have to be color corrected to adjust the levels for proper output values (legal for broadcast). Second, some filters, like the BCC effects, clip rendered files at 16 and 235, thus defeating the original purpose.
It has now become a lot more complex in the file-based world. The files you import are no longer just stills and animation, but also camera and master files from a variety of sources, including other NLEs, like FCP – or HDLSRs, like the Canon 5D. Thanks to AMA in Media Composer 5, this is now automatically taken care of. AMA will properly import files at the right levels based on the format. A digital graphic, like a 0-255 color bar test pattern, is imported at the full range without rescaling the color values from 0-255 to 16-235. A digital video movie from a Canon 5D will be imported with values fitting into the 16-235 range.
The YUV processing issues are also affected by the 8-bit, versus “high-precision” rendering options. When you elect to process all video as 8-bit, excursions above 100% and below 0% caused by color correction will be clipped. 
One way to fully protect “full swing” 0-255 levels is to work in RGB processing. A 0-255 color bar pattern will be correctly displayed, but unfortunately all video is spread to the full range, as well. This would mean that all clips would have to be color corrected to adjust for proper video levels. The only way that I’ve found for FCP to display both a 0-255 and a 16-235 clip on the same timeline and maintain correct levels is to apply a color correction filter to adjust the levels on one of these clips.
