In the second part of DSLR Media Management with Mike McCarthy, Mike delves into the file format of the post-production workflow. Then, he discusses frame rates, editorial options, and finishing. Visit HD4PC for even more in-depth technical information on the post-production workflow process.
If you haven’t done so already, be sure to read Part 1 of DSLR Media Management with Mike McCarthy. In Part 1, Mike provides crucial details about Canon DSLR workflow, how to backup your footage for best results, and best practices for sorting and logging your footage.
DSLR Post-Production Workflows with Mike McCarthy
Here at Bandito Brothers, we have handled the post aspect of Shane’s DSLR-based projects since the first Terminiator Webisodes. The tools available have developed during the past year from a relative hack job to a reasonably well-supported workflow.
The first thing we need to understand about a work flow, is what we are starting with. In the case of Canon DSLR footage, we have full raster HD footage in YUV 4:2:0 with a full range (0-255) of 8bit color values at a variety of frame rates. This is saved into Quicktime files, encoded with H.264 compression at about 40Mb/s, with 44.1khz audio. While high bit rate H.264 files preserve a tremendous amount of detail into a relatively small file size, that level of compression makes it difficult to playback the native files in any editing program.
In almost all cases it will be easier and more efficient to convert the footage into an intermediate editing format before editorial. This choice of formats will probably be dictated by your NLE options. DNxHD will be the format of choice for Avid, with ProRes for FCP, and a couple other options like Motion-JPEG, MPEG2-IF, or Cineform for Premiere Pro.
From a post-perspective, the most obvious unique workflow challenge presented by the original Canon 5DMk2 was “30P!?” Since a transcode to an intermediate format was already required by most workflows, we slowed the footage and the audio by .1% to 29.97 for our first few projects. So, 29.97-based workflows can be relatively simple. They are even easier now with the true 29.97 support in the 7D and 1D – and recently the 5D, as well.
Intercutting with film on the other hand usually requires editing and finishing in 24p. By which I always mean 23.976p – a much more complicated challenge with 5D footage. As Shane previously mentioned, the simplest solution requires that you edit in Avid, and online with Twixtor in AE and Premiere Pro CS4. We use Re:Vision Effects’ Twixtor plug-in to convert our 30p clips to 24p, with true motion compensated frame blending. It works quite well for more footage, but it is extremely render intensive. Plus, it takes a long time to process footage.
The details of the relinking process for Twixtored footage with Avid edits are fairly complicated, but can be found on my site, (Link to Avid page on my site) for anyone who is interested in going down that path. For footage shot at 24p on a DSLR, the on-lining process should be relatively straightforward by comparison, and have no unique challenges over 29.97p DSLR workflows.
While Premiere and FCP are both useful tools that will work well on smaller DSLR-based projects, Avid is the most stable and responsive editing program, for large projects that encompass hundreds of hours of footage spread across thousands of individual clips. Most Avid edits of DSLR footage will use DNxHD as their editing codec. Since Canon MOVs have a full 0-255 color range, you have to select the RGB (0-255) color space when importing the files into Avid, in order to maintain the full range of the color space.
If you are going to use you Avid output as your master, without a separate online conform, using a 10bit editing codec like DNxHD175x will prevent you from losing bit depth during the Rec709 conversion on the initial import transcode. We use 8bit DNxHD36 offline files in our Avid edits, since this is offline, because we aren’t editing at the 5D’s native frame rate, and we use simple EDLs to online in CS4 via file name relinking after the frame rate conversion. There are other more expensive options for on lining Avid edits, but I am not as familiar with any of them, since Adobe’s Creative Suite satisfies most of our current needs.
The Advantages of Pro Res
Now as a PC guy, I will still be the first to admit that Macs do have their uses. (Specifically, generating Pro Res files and accessing HPFS volumes.) For Final Cut Pro workflows, life is a little simpler in that Pro Res is capable of 10bit color by default, as long as the host application supports it.
Batching your DSLR files to Pro Res in Compressor should allow you to maintain the full resolution and color space. Compressor also has the capability to solve the 30p to 24p issue through use of Apple’s Optical Flow technology. Compared to Twixtor, our tests have found this process to be slower and the results aren’t quite as good, but if you can’t afford a dedicated conversion plug-in, this is probably the next best thing.
Now, let’s consider Premiere based edits. While DSLR files can be played directly on the timeline, using an intermediate format will provide a more responsive and stable editing experience. Adobe Media Encoder will give you the proper processing bit depth to convert your files into a variety of possible third-party formats, for editing or on-lining in CS4.
At Bandito Brothers, we batch process our Canon 5D footage in After Effects. This allows us to use Twixtor to convert our 30p clips to 24p. If the footage is already in the right frame rate, AME is totally sufficient and processes the conversions much faster. We usually online with Cineform AVI files, to utilize the headroom that 10bit color offers. Especially since SpeedgradeXR can access native files, which is usually our next step after the conform.
After exporting an online conform, preferably in 10bit color, there’s one more step that should be added to DSLR workflows. There are a number of cleanup processes that can be undertaken to deal with common imaging issues with DSLRs. This is similar to a dust-busting pass on film workflows.
Typically caused by dust on the sensor, dead pixels are more frequent on DSLRs. This is due to their large sensors and interchangeable lenses. This can also happen to any camera, by the way. These artifacts are usually static and can be fixed by overlaying nearby pixels that were unaffected. Usually directly above or below. You may also see rolling shutter issues caused by the top of the frame. It captures a slightly different moment in time than the bottom.
Certain types of rolling shutter artifacts, especially ones related to camera motion, can be fixed with plug-ins. Other rolling shutter artifacts like horizontal bands caused by flashes of light are much harder to fix. Well, unless you manually replace the image data with information from another nearby frame. And if you ran a frame conversion process like Twixtor on your footage, this is when you should replace any frames that interpreted poorly with frames from the original source files. These processes are all very labor intensive and require quite a bit of fine tuning to perfect your image. As with any step in the process, consider your available resources and carefully prioritize the issues you want to fix.
The Bottom Line
Once you are finished fixing any defects in the footage, the resulting files should be similar to any other workflow. Then, proceed to visual effects, color correction, tape lay back, web encoding, or disc authoring. The same as you would a project from any other acquisition source.
Most of the things that are key to an efficient DSLR-based workflow take place at the beginning of the process. Once you are off to a proper start, the subsequent steps should come together the same way as any other tapeless project.
Hopefully the tips above will provide a solid overview of the potential pitfalls along with solutions to stay one step ahead. You can find more detailed information available at HD4PC. At HD4PC, I continue to update as new developments are released.
Looking for mentorship in the film industry? Schedule a 1-on-1 meeting with Shane Hurlbut, ASC today! This is where you can get expert advice from an industry professional on your career or a particular project.
About Filmmakers Academy Cinematographer Mentor Shane Hurlbut, ASC
Director of photography Shane Hurlbut, ASC works at the forefront of cinema. He’s a storyteller, innovator, and discerning collaborator, who brings more than three decades of experience to his art. He is a member of the American Society of Cinematographers, the International Cinematographers Guild/Local 600, and The Academy of Motion Picture Arts and Sciences.
Hurlbut frequently joins forces with great directors: McG’s Netflix Rim of the World and The Babysitter, plus Warner Bros. We Are Marshall and Terminator: Salvation; Scott Waugh’s Need for Speed and Act of Valor; and Gabriele Muccino’s There Is No Place Like Home and Fathers and Daughters. His additional film credits include Semi-Pro; The Greatest Game Ever Played; Into the Blue; Mr 3000; Drumline; 11:14, which earned Hurlbut a DVDX nomination; and The Skulls. Notably, his television credits include the first season of AMC’s Into the Badlands.