High Definition 24P Primer

Update: December 7th, 2009

High Definition 24P Primer

(The 12 Easy Steps)

Scott Thomas
Director of Engineering
the Victory Studios

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First, remember HD 24P is not film. There are some differences, but creating a good 24P project is subject to many of the same rules as creating a good film project. 24P has many of the characteristics of film: high resolution, 24 frames per second, and a beautiful look. It also has some characteristics that are not in film: it does not have grain, it currently doesn’t have the latitude of speed and exposure that film offers, and because it is electronic, it is very easy to work with. A good 24p project does not throw out all of the lessons that have been learned producing on film over many decades, but adds functionality that only a digital medium can provide. Here are some tips that we at the Victory Studios has discovered to help 24P productions run smoothly:

Phase 1 Pre Production

Decide how you are going to deliver the finished product. When shooting HD, you have a wide, 16×9 screen that you can use. If your final product is going to be delivered 4×3, decide if you are going to deliver letterboxed or edge cropped. Use the script as a guide as to whether 24P acquisition is appropriate for your production. Some productions that the Victory Studios has been involved in have shot on 24P exclusively, some have shot on a mix of 24P and film, and some have shot entirely on film and had it all transferred to 24P for finishing. Decide what is going to work for you.

Phase 2 Shooting

The rules of good image acquisition haven’t changed. Light well, frame well, have a good crew. Usually the only change from a film shoot to a 24P shoot is the replacement of a film loader with a video engineer. If using the Sony HDW-F900 camera, several independent sources have rated it at 320 ASA in 24P mode. Light well and have a HD waveform monitor on set to watch exposure levels. If the Final output is going to be Edge Cropped, frame primarily in the 4×3 center area, but protect for the entire width.
Some other hints for DP’s (source: B. Sean Fairburn SOC):

  1. HD exposes like color reversal (Slide film rather than negative)
  2. HD has less latitude than film I call it 4.5 Under and 1.5 Over.
  3. HD has much more bottom end in the blacks than top end in the highlights, better to under expose rather than over expose.
  4. You can get in essence Timed dailies in Camera which I have found gives you More range than had you done nothing to the image. “Best way to get to a good image is to start with one.”
  5. You can do a Digital color correction session after the picture is locked then again after it gets “Filmed out” transferred to Negative before it gets printed. Take every opportunity given.
  6. HD is Tungsten base so ND and Color correction filters are built into the camera and are ND.6 ND1.2 ND2.4, also an 85B+81B.
  7. Electronic Shutter set to ON @ 1/48th is equal to a 180° shutter. Shutter OFF increases blur in motion equal to 24 FPS @ 1/24th.
  8. Like any new Film stock Test it to determine how your lighting style looks with this medium if adjustments should be made.
  9. Insure your 1st AC’s and operators know how to properly set the Back Focus or your images will be soft.
  10. Shoot Record run Timecode even if you do multiple cameras. Cameras do not need to match TC for post to sync it up. It creates more problems than it’s worth to shoot Free running TC.

Also make sure that the audio is recorded properly (see Audio Sync Tips when shooting 24P).

Phase 3 Downconverting

Bring your HD masters to the Victory Studios for downconversion to BetaSP, Digital Betacam, DVCam, etc. We will convert your video and make sure that timecode is translated properly because that is the guide that will be used later in the online session. We recommend getting your downconversions in a letterbox format with both the 24 frame and 30 frame timecodes window burned below the picture. This allows for the offline editor to make sure that the entire frame is acceptable for use in the finished 16×9 master, and gives a visual reference on the offline master that can be used in the online session later if there are any problems with the Edit Decision List (EDL).

Phase 4 Offlining

Spend your creative time working in the non-linear environment. Because you can use a standard definition non-linear system, it allows you to spend more time getting it right. It is cheaper and faster to do your creative work this way than offlining on a High Definition non-linear system. Take the downconverts from the Victory Studios and digitize them into your non-linear editing system. You can offline as either a 24 Frame project or as a standard 30 frame video project. For best results:

If you are digitizing as 24 frame, remember that the ‘A’ frame is always a timecode number that ends in either a 0 or a 5 if the cameras were shooting Record Run Timecode.
Label tapes with 6 character alpha/numeric preferable numeric (Example: A_0001, 000128.)
Make your 1st video layer the main body of the program, spot, or feature.
Video layer 2 and above are for effects such as PIP, (picture in picture), keys, etc.
Make notes in list regarding color treatments, effect dissolves, picture flip, DME moves and any other anomaly in the show.

Phase 5 Effects Prep

Once your shot decisions are finalized, take the sequences that you will be doing effects work for (Compositing, Slow-Mo, etc) and get them made. Once you have them done, make a HD Effects reel, have it downconverted, and insert these new shots into your offline. This allows for everything to be timed right in the online session. This is also a good time to output a sample EDL and send it to your editor at the Victory Studios so that we can process it and tell you of any potential problems that may need to be addressed.

Phase 6 Online Prep

Use the Effects Reel downconvert to replace the original shots in the sequence. Once everything is finalized you should output an Edit Decision List (EDL) for the online:

EDL’s should be provided on a PC formatted 3.5″ HD disk with 8 character max file names.
We would like a CMX 3600 A mode (”‘A’ Sort” or “record in”) EDL with B-Roll indication.
Layers need to be split into separate EDLs.
If you offlined on an Avid, it is useful to bring the whole project in on a zip, incase there is a problem with your EDLs.
For further information using Avid’s EDL Manager, click here.

Output the show from the non-linear system onto tape to bring to the Online session. This gives you a visual guide to refer to in case of problems during the online edit. Also you then have a scratch audio track to put down on the master.

Phase 7 Online

Bring your Camera Reels, EDL, and Offline Cut.  There are two ways that we can do the assembly:

A-Mode – A sequential assemble mode, starts at the beginning of the show and goes to end in order. This allows viewing the show as it is being built, but is slow because it often requires changing tapes often.
D-Mode – Fastest assembly. This mode does all events on a particular camera reel, and then moves on to the next reel. This builds the show in a checkerboard fashion. Because the show is built out of order, it is hard to follow the events in the show as it is being built.

Phase 8 Audio Sweetening

Once the online is completed, make a downconvert and send to the audio house. They can begin the sweetening process while you go on to color correct.

Phase 9 Color Correction

Using both primary and secondary color correction, the Victory Studios’ colorists can color match the program to create the look that you want. These changes are stored for easy recall and changes.

Phase 10 Titles

Now is the time to add your titles. Pick your fonts, design your graphics, and compile the list of credits for your show. Titles and credits can be imported into the Chyron Duet-HD from a text document (for rolling credits, use our Credit Template). This saves time and the spelling will be correct.  Graphics and titles information can also be found here.

Phase 11 Audio Layback

Get the final audio mix from the sound house. The Victory Studios will join the audio with your final HD master. Audio can be delivered on DA-88, DAT, MMR-8, or most other devices that have a timecode track and can lock to video.

Phase 12 Delivery

Once you have your 24P master edited, color corrected, titled, and the audio inserted, you have completed your project. The Victory Studios duplication department can then make 24P duplicates or convert your program for delivery in NTSC, PAL, 1080/60i, 1080/50i, or 1080/25P. The 24P master can also be printed to film. All lists and effects are put on disc and enclosed with the masters for future revisions or rebuilds.

Sound easy enough, doesn’t it? The Victory Studios has completed many projects this way and have the experience to make your 24P experience fun and easy.

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