Is That a File or a Codec?

As we continue to wade in the shallows of what a file based workflow means for television and film, we can slosh past some important but sometimes overlooked quagmires. This usually applies  to the computer based techno-babble that sometimes asserts itself to the point where you find yourself saying what is that geek saying, only to realize the geek is yourself.

Old style Film to Tape Workflow

It used to be easy. There was tape. O.k. so that made me sound old.  We would telecine from film to tape and then everything from then on was some form of tape to tape process. We new what the master was going to be at the end. Yup you guessed it – tape. This probably meant HDcam SR or D5 in the most recent incarnations. But it used to be D2 or Digibeta in the Standard Def days. How simple and quaint it used to be.  And while you might still deliver to a Network on tape (A little terrifying if you think about it), we live in the world of files now. And here we are back to the minefield I mentioned earlier.

We have abandoned film and tape (mostly) but that doesn’t mean we understand what has replaced them. We have moved from the tangible to the intangible. Film and tape to ones and zeros.  I mean when someone like me talks about a file based workflow, what exactly am I saying. What is a file exactly?

 What is a File?

At some level you know what a file is. A .doc file is how I am writing this on my laptop. But when you get into the video file world it is a little more arcane than that, with more layers.

Think of a file as a box that holds important information. Files are sometimes called wrappers or containers. You might recognize a few of them like .mov or .mxf. You move the container and its contents around from place to place with the contents intact.  Taking the wrapper analogy further think of it like it is a piece of candy, the wrapper (file) says Godiva on it, the codec is what is on the inside of that wrapper. It could be chocolate or caramel or some combination (thanks Scott for that insight).

The information itself inside this container is generally broken down into three elements or streams. They are audio, video and metadata.

 What then is a codec?

Codec came from (en)coder/decoder or sometimes it is known as Compressor/Decompressor. It is what enables a program to utilize the video or audio in a file. In other words it is the process that allows you to encode media for storage or transportation or decode it for use in editing or manipulation.

You have no doubt heard of ProRes or DNX36. These are picture codecs. DNX36 is usually in an .mxf wrapper or file for Avid. But it can also be .mov file, often for vfx.

Another familiar codec is ProRes which is used for .mov files and  are what Final Cut Pro uses for editing as well as one of the codecs that the Alexa camera can shoot.

The important distinction is that in the quick paced world of television of feature post production, it is not enough to say I have a Quicktime file (.mov) or Avid file. Those statements isolated don’t convey much information. We need to understand what we are shooting, editing and finishing on. Sometimes, although rarely, they are all the same.  Most often we must transcode between formats. But that is a subject for another day.

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