Using EDLs, Timecode, and Frame Numbers to Conform Projects

Using careful data management, you can track the relationship of the original camera negative to the video or digital transfers that have been made for offline editing using timecode. The following sections provide information on how Color tracks these correspondences.

How Does Color Relink DPX/Cineon Frames to an EDL?

The key to a successful conform in Color is to make sure that the timecode data in the EDL is mirrored in the scanned DPX or Cineon frames you're relinking to. The correspondence between film frames and timecode is created during the first telecine or datacine transfer session.

How Is Film Tracked Using Timecode?

A marker frame is assigned to the very beginning of each roll of film, at a point before the first shot begins (typically before the first flash frame). A hole is punched into the negative, which permanently identifies that frame. This marker frame is assigned the timecode value of XX:00:00:00 (where XX is an incremented hour for each subsequent camera roll being transferred), creating an absolute timecode reference for each frame of film on that roll. Each camera roll of film is usually telecined to a new reel of videotape (each reel of tape usually starts at a new hour), or datacined to a separate directory of DPX files.

This makes it easy to create and maintain a film frame-to-timecode correspondence between the original camera negative and the transferred video or DPX media. This correspondence carries through to the captured or converted QuickTime media that you edit in Final Cut Pro. As an added benefit of this process, you can always go back to the original rolls of camera negative and retransfer the exact frames of film you need, as long as you accurately maintain the reel number and timecode of each clip in your edited sequence.

If you’re having a datacine transfer done, you also need to request that the frame numbers incorporated into the filenames of the transferred image files be based on the absolute timecode that starts at each camera roll’s marker frame. Your final DPX or Cineon image sequences should then have frame numbers in the filename that, using a bit of mathematical conversion, match the timecode value in the header information, providing valuable data redundancy.

How Color Relinks DPX/Cineon Media to EDLs Using Timecode

Later, when Color attempts to relink the EDL that you’ve exported from Final Cut Pro to the transferred DPX or Cineon image sequence media, it relies on several different methods, depending on what information is available in the image sequence files:

  • First, Color looks for a timecode value in the header metadata of each DPX or Cineon frame file. If this is found, it's the most reliable method of relinking.

  • If there's no matching timecode number in the header metadata, then Color looks for a correspondence between the timecode value requested in the EDL and the frame numbers in the filename of each DPX or Cineon frame. This also requires that the files be strictly named. For more information, see Required Image Sequence Filenaming.

  • Color also looks for each shot’s corresponding reel number (as listed in the EDL) in the name of the directory in which the media is stored. Each frame of DPX or Cineon media from a particular roll of camera negative should be stored in a separate directory that’s named after the roll number it was scanned from. If there are no roll numbers in the enclosing directory names, then Color attempts to relink all the shots using the timecode number only.

After you import an EDL with linked DPX or Cineon image sequence media, a Match column appears in the Shots browser. This column displays the percentage of confidence that each shot in the Timeline has been correctly linked to its corresponding DPX, Cineon, or QuickTime source media, based on the methods used to do the linking. For more information, see Explanation of Percentages in the Match Column.

Relinking DPX/Cineon Frames to an EDL Using a Cinema Tools Database

If issues arise when conforming an EDL to DPX or Cineon media in Color, you can create a Cinema Tools database with which to troubleshoot the problem.

If you don’t already have a Cinema Tools database tracking your film media, you can easily create one. To create a Cinema Tools database from one or more directories of DPX or Cineon image sequences, simply drag all of the enclosing directories onto the Cinema Tools application icon, and a database is generated automatically. If necessary, you can use the Cinema Tools interface to check the reel numbers and timecode values of each shot, correcting any problems you find.

Afterward, when you’re conforming an EDL to DPX or Cineon media in Color, you can choose the Cinema Tools database as your source directory in the EDL Import Settings window. (See Importing EDLs for more information.) This way, your updated reel numbers and timecode values will be used to link your Color project to the correct source media.

For more information on creating Cinema Tools databases from DPX or Cineon media, see the Cinema Tools documentation.

Note: Changing information in a Cinema Tools database does nothing to alter the source media files on disk.

Parsing EDLs for Digital Intermediate Conforms

This section explains how Color makes the correspondence between the timecode values in an EDL and the frame numbers used in the timecode header or filename of individual image sequence frames.

Here's a sample line from an EDL:

001 004 V C 04:34:53:04 04:35:03:04 00:59:30:00 00:59:40:00

In every EDL, the information is divided up into eight columns:

  • The first column contains the edit number. This is the first edit in the EDL, so it is labeled 001.

  • The second column contains the reel number, 004. This is what the directory that contains all of the scanned DPX or Cineon image files from camera roll 004 should be named.

  • The next two columns contain video/audio track and edit information that, while used by Color to assemble the program, isn't germane to conforming the media.

The last four columns contain timecode—they're pairs of In and Out points.

  • The first pair of timecode values are the In and Out points of the original source media (usually the telecined tape in ordinary online editing). In a digital intermediate workflow, this is used for naming and identifying the scanned frames that are output from the datacine.

  • The second pair of In and Out points identifies that shot's position in the edited program. These are used to place the media in its proper location on the Timeline.

Required Image Sequence Filenaming

Here's a sample filename of the first image sequence file that corresponds to the EDL event shown in Parsing EDLs for Digital Intermediate Conforms:

fileName_0494794.dpx

The first portion of the filename for each scanned frame (the alpha characters and underscore) is an ignored but necessary part of the filename. The file's frame number should equal the (non-dropframe) timecode conversion of that value appearing in the EDL.

For example, a frame with timecode 05:51:18:28 would have a frame number of 632368. Numeric extensions must always be padded to seven digits; in this case, you would add one preceding 0, like this:

fileName_0632368.dpx

The following filename formats are also acceptable:

fileName 0632368.dpx
fileName0632368.dpx
fileName-0632368.dpx
fileName.0632368.dpx

Important: For Color to be able to link to a media file, filenames need at minimum an alpha-only character name (consisting of at least one upper- or lowercase character), frame number, and a .dpx or .cin file extension.