… for Codecs & Media

Tip #104: Why Is a Smooth Audio Fade Called +3 dB?

Larry Jordan – https://LarryJordan.com

Audio is a Strange Beast

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Unlike video, audio levels are logarithmic. For example, whenever the audio level increases (or decreases) by around 10 dB, the perceived volume is doubled (or cut in half). These log values also have an impact in cross-fading between clips.

A +3 dB transition adds a 3 dB increase in volume to both clips in the middle of a cross-fade. If the software did not, the audio would sound like it is getting fainter in the middle of a transition, then louder at the end.

When fading to or from black, a straight-line (linear) transition is best. When cross-fading between two clips, both of which have audio, a +3 dB transition is best.

EXTRA CREDIT

Some software allows you to change the shape of the curve manually. These rules still apply, but manual adjustments allow much greater control over how the transition sounds.

The general rule is: Whatever sounds the best to you IS the best.


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… for Codecs & Media

Tip #086: How to Create Custom Poster Frames

Larry Jordan – https://LarryJordan.com

Poster frames illustrate the contents of a movie clip in the Finder

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Ian Brown suggested this tip.

There’s a very fast way to create a poster frame for a QuickTime movie. (Poster frames appear in the Finder, and other locations, to illustrate the contents of a clip.)

  • Open the video in QuickTime Player
  • Move the playhead to the frame you want to use as a poster frame
  • Choose Edit > Copy (shortcut: Cmd + C)
  • Close the video
  • Select the file icon in the Finder
  • Choose File > Get Info (shortcut: Cmd + I)
  • Select the small icon in the top left corner
  • Choose Edit > Paste (shortcut: Cmd + V)

Done.

EXTRA CREDIT

Actually, anything you paste into that top left box will become the poster frame. It doesn’t need to be a still from your video – though it can’t be a video itself.


… for Codecs & Media

Tip #100: Optimize Media for YouTube

Larry Jordan – https://LarryJordan.com

Uploading a video isn’t enough.

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I was reading a blog recently by Richard Tiland about posting videos to YouTube. In it, he wrote: “Uploading your video to YouTube isn’t enough. You need to include metadata so that the site understands what your video is all about.”

His points included:

  • Optimize the title with keywords. Keep it short, but searchable.
  • Add a detailed and accurate description. Length is less important here.
  • Include a transcript to help viewers take in your content without turning up the sound.
  • Organize content using playlists. This helps both viewers and YouTube’s search algorithms.
  • Create a cohesive look to improve branding. Make your videos look like they are coming from the same creative source.
  • Finally, don’t forget the Call to Action. This is the explicit behavior you want the audience to take after watching your video.

Metadata always seems intimidating somehow. But, really, all we are doing is enabling viewers to find our media faster and easier. And that is always a good thing.


… for Codecs & Media

Tip #067: Which Files Should Be Copied From a Camera Card?

Larry Jordan – https://LarryJordan.com

“Pick-and-Choose” is the wrong option for best results.

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All of them.

Select the entire contents of the card, even the folders and files that you don’t recognize, and copy the entire contents of the camera card into its own folder on your hard disk.

One folder per camera card. Always.

Why? Because, depending upon the codec, different parts of your media are stored in different folders on the card; especially metadata. Copying everything from the card into its own folder on your local storage means that whichever NLE you use for editing is able to assemble all the pieces and assemble all your media and related metadata without any problems.

BONUS

Copying each card into its own folder allows you to create meaningful folder names for tracking and importing media.


… for Codecs & Media

Tip #099: Benefits of working with 4K in 1080

Larry Jordan – https://LarryJordan.com

4K has benefits aside from increased resolution.

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I was reading Jason Boone‘s blog on the Benefits of Working with 4K Footage in a 1080 Sequence.

First, while it could be argued that we can’t actually SEE 4K in most situations, that hasn’t stopped distributors from requesting it. Still, even if you don’t plan to deliver 4K, there are benefits to shooting it, as Jason outlines:

  • Reframe a shot. 4K provides so many extra pixels to choose from, you can convert a wide shot into a close-up. However, cutting into the frame won’t change depth of field, so the image won’t look the same as if you had zoomed (or dollied) in.
  • Use the same take multiple times. Using the same take for both wide shots and close-ups makes it seem as though you have two cameras. The benefit is that where talent is looking doesn’t change. The disadvantage is that background and depth of field won’t change either.
  • Create camera moves. Using keyframes you can create movement where there was none in the original shot. However, like moves on a still, elements won’t change position as they would if you used a dolly on set.
  • Stabilize your footage. This is powerful. Stabilization always zooms into a shot. By having lots of extra pixels to work with, the image won’t lose detail or sharpness.
  • Adjust the image for graphics. There’s nothing worse than graphics you can’t read. 4K gives us extra pixels for scaling and repositioning.

4K may not be visible to the eye, but it can be a BIG benefit in post.


… for Codecs & Media

Tip #105: Why Do We Need Intermediate Codecs?

Larry Jordan – https://LarryJordan.com

Intermediate codecs simplify editing.

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An “Intermediate Codec” is a video format that we use for editing. It is placed between the format shot by the camera and the format we need for final distribution. We convert between formats using “transcoding.”

There are two different reasons for using an intermediate codec:

  • To make really large files manageable
  • To make highly-compressed files easier to edit

MANAGEABILITY

For example, we often use proxy files when rough cutting 4K or larger frame sizes, or working with HDR media, simply because these source files are incredibly massive. Using a smaller intermediate codec allows us to successfully work with less storage on slower systems.

HIGHLY-COMPRESSED

Files that are optimized for editing store each image individually in the file (called an “I-frame”.). These include formats such as ProRes, DNx, and Cineform. I-frame compression means that as soon as the playhead lands on an image, it can be displayed.

I-frame files are very efficient for editing, but large.

Highly-compressed files, such as AVCHD, H.264 or HEVC, only record one image every 15 frames or so. The rest of the “images” are actually text descriptions of the changes between the source frame (“I”) and all the derivative frames (“B” and “P”). In order for the computer to display a B or P frame, it needs to go back to the I frame, then apply all those text-based change documents to calculate the frame the playhead is currently parked on.

If you are playing a clip, GOP compression is not a big deal. But, skimming clips, playing backward, jumping randomly around in a file, or multicam editing can take a while to calculate and display these images because the computer always needs to jump back to the nearest earlier I-frame and recalculate.

Transcoding to an intermediate codec means that editing, rendering and exporting will be faster by converting GOP-based encoding into I-frames.