… for Codecs & Media

Tip #578: Media Codec Issues on Windows

Larry Jordan – LarryJordan.com

Windows Media Player has its own challenges in finding and playing codecs.

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Windows Media Player includes some of the most popular codecs, like MP3, Windows Media Audio, and Windows Media Video. However, it doesn’t include the codecs required for Blu‑ray Disc files, FLAC files, or FLV files. If something isn’t working in Windows Media Player, you might not have the right codec on your PC. The easiest way to fix this problem is to go online and search for the codec you need.

How can I find out which codecs are installed on my PC?

  1. On the Help menu in Windows Media Player, select About Windows Media Player. If you don’t see the Help menu, select Organize > Layout > Show menu bar.
  2. In the About Windows Media Player dialog box, select Technical Support Information. Your web browser will open a page that includes a lot of detailed info about the related binary files, codecs, filters, plug-ins, and services installed on your PC. This info should help you troubleshoot problems.

How do I tell which codec was used to compress a file and what format a file is in?

There isn’t a way to determine with absolute certainty the codec used to compress a file, but the following are your best options:

  • To determine what codec was used with a specific file, play the file in the Player, if possible. While the file is playing, right-click the file in the library, and then select Properties. On the File tab, look for the Audio and Video codec sections.
  • Use a non-Microsoft codec identification tool. To find one, search for “codec identification tool” on the web. You’ll find several tools as well as useful related info.

You might be able to tell the format of a file by looking at the file name extension (such as .wma, .wmv, .mp3, or .avi). However, there are limits to this approach. Many programs create files with custom file extensions. And it’s possible for anyone to rename a file without changing the file’s format. A file with an .mpg or .dvr-ms extension, for example, is usually just an AVI file that’s been compressed by using some version of an MPEG video codec.


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… for Visual Effects

Tip #556: Blend Modes in Brief

Larry Jordan – LarryJordan.com

Blend modes create textures.

Blend mode options in Photoshop.
Blend modes combine textures between clips. They are found in all modern NLEs, like this list from Photoshop.

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Iain Anderson, at MacProVideo, wrote this up in more detail. But I liked his summary of blend modes, which I have modified from his article.

Blend modes allow us to combine textures, and sometimes colors, between clips or elements that are stacked vertically on top of each other.

Whether you are in Photoshop or Premiere, Final Cut or Motion, blend modes work the same way. These are arithmetical expressions, with nothing to adjust. You either like the effect or you don’t.

NOTE: If you don’t like the effect, tweak either the gray-scale or color value of the top clip and the results will change.

All these settings should be applied to the top clip. It will be the only clip that changes. Here’s what the settings mean.

  • Normal. This leaves the top clip’s image unaltered
  • Subtract, Darken, Multiply, Color Burn, and Linear Burn. These combine clips based upon darker grayscale values. For example, the top clip will darken clips below it. Multiply usually works best for adding darker areas.

NOTE: If nothing changes when you apply this setting, your top clip is too light. Darken it.

  • Add, Lighten, Screen, Color Dodge, and Linear Dodge. These combine textures between clips based upon lighter grayscale values. Screen usually works best for adding bright elements like sparks and flame.

IMPORTANT: Avoid using Add. It creates highlights that exceed legal white values. Screen does not.

  • Overlay, Soft Light, Hard Light, Vivid Light, Linear Light, Pin Light, and Hard Mix. These combine textures based on mid-tone grayscale values, often in a way that increases contrast. Overlay usually works best, though more often these days, I find myself using Soft Light.

NOTE: For better results, reduce opacity and play with the grayscale settings.

  • Difference and Exclusion. These mess with color values to create very hallucinogenic effects. What’s happening is that color values in the top clip are mathematically removed from the clips below in slightly different ways. Also useful for spotting the difference between two clips.
  • Stencil Alpha and Stencil Luma. These insert the background image into the foreground image. Use Stencil Alpha, provided the foreground has an alpha channel. If it doesn’t, use Stencil Luma, but the results may not be as good.
  • Silhouette Alpha and Silhouette Luma. These cut a hole into the background image based upon the foreground image shape. Again, use Silhouette Alpha if the foreground image has an alpha channel.
  • Behind. This displays the clips below the current effect. It is used when you are also using Stencil Alpha to insert one image into another.

The bottom choices will vary by application, and are covered in the Help files.


… for Codecs & Media

Tip #559: What is “Frame Reordering” in Apple Compressor?

Larry Jordan – LarryJordan.com

This defaults to on. Leave it that way.

The Frame Reordering option in Apple Compressor.

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Ever wonder what Frame Reordering does in Apple Compressor? Me, too. So, I did some research. Here’s what I learned.

Frame reordering is the concept of allowing frames to be decompressed in a different order than their display order. For almost all cases, leave this box checked for H.264 encoding. Some more advanced compressors use “frame reordering” to more efficiently represent movie data.

Important: If you select “Allow frame reordering,” your output file may be more efficiently compressed but may not be compatible with decoders on older hardware. For example, if someone asks you to create your content with “B-frames turned off.”

In looking at YouTube’s latest upload specs, they make no mention of this setting. My suggestion is to leave it on unless you are specifically required to turn it off.


… for Codecs & Media

Tip #560: What is “Clean Aperture” in Apple Compressor?

Larry Jordan – LarryJordan.com

This option should be off for most media today.

Uncheck “Add clean aperture information” when working with digital media.

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One of the checkboxes in Apple Compressor is “Add clean aperture information.” What is this and should it be checked or unchecked?

Apple’s Help Files state: Select this checkbox to define clean picture edges in the output file. This property adds information to the output file to define how many pixels to hide, ensuring that no artifacts appear along the edges. When you play the output file in QuickTime Player, the pixel aspect ratio will be slightly altered. This process doesn’t affect the actual number of pixels in the output file—it only controls whether information is added to the file that a player can use to hide the edges of the picture.

For example, this setting would clean up edges from a VHS tape transfer that waver.

YouTube, on the other hand, prefers this option be unchecked to prevent the video from being cropped during playback.

My suggestion: If you are dealing with digital media with clean edges, uncheck this before starting compression.


… for Codecs & Media

Tip #561: Optimize Compression Settings for YouTube

Larry Jordan – LarryJordan.com

In most compression software, the optimal settings are not the default.

Video compression bitrates for YouTube for SDR media.

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Here are settings you can use to optimize audio and video compression for YouTube. (These are based on published settings from YouTube, a link to which is below.)

Container: MP4

Video codec: H.264

  • Progressive (deinterlace interlaced media)
  • High Profile
  • Closed GOP
  • Variable bit rate
  • Chroma subsampling: 4:2:0

Audio codec: AAC-LC (AAC if no LC choice is available)

  • Bit rate: 384 Kbps stereo / 128 Kbps mono

Frame rate: The frame rate you shot. Do NOT convert frame rates.

Bit rate: See screen shot for table.

If given the choice:

  • Turn off mulitpass compression if your hardware is more recent than 2015.
  • Turn on Frame Reordering
  • Turn off Add clean aperture information

NOTE: These settings differ from the YouTube default settings in Apple Compressor.

EXTRA CREDIT

Here’s the link to YouTube’s Support Site with more details.


… for Apple Motion

Tip #538: What Does “Four Corner” Do?

The “Four Corner” setting determines image distortion.

The Four Corner settings (top) determine image distortion (bottom).

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When you select an object in Motion, one of the adjustments you can make is Four Corner. Inspector > Properties > Four Corner allows you to distort whatever you have selected. Here’s how it works.

When you adjust Inspector > Properties > Position, you can modify the position of the frame containing whatever you have selected.

However, when you adjust Inspector > Properties > Four Corner, you can distort the object itself, as illustrated in this screen shot.

Four Corner also provides separate control over the horizontal and vertical position of each corner.

EXTRA CREDIT

Keep in mind that all these distortion settings can be keyframed to animate a shape over time.


… for Visual Effects

Tip #542: What is Rotoscoping?

Larry Jordan – LarryJordan.com

Rotoscoping allows us to transfer an object onto a different background.

Image in the public domain.
Max Fleisher’s original rotoscope (1915).

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Rotoscoping is an animation technique that animators use to trace over motion picture footage, frame by frame, to produce realistic action. Originally, animators projected photographed live-action movie images onto a glass panel and traced over the image. This projection equipment is referred to as a rotoscope, developed by Polish-American animator Max Fleischer. This device was eventually replaced by computers, but the process is still called rotoscoping.

In the visual effects industry, rotoscoping is the technique of manually creating a matte for an element on a live-action plate so it may be composited over another background.

Rotoscoping has often been used as a tool for visual effects in live-action movies. By tracing an object, the moviemaker creates a silhouette (called a matte) that can be used to extract that object from a scene for use on a different background. While blue- and green-screen techniques have made the process of layering subjects in scenes easier, rotoscoping still plays a large role in the production of visual effects imagery. Rotoscoping in the digital domain is often aided by motion-tracking and onion-skinning software. Rotoscoping is often used in the preparation of garbage mattes for other matte-pulling processes.

Rotoscoping has also been used to create a special visual effect (such as a glow, for example) that is guided by the matte or rotoscoped line. A classic use of traditional rotoscoping was in the original three Star Wars movies, where the production used it to create the glowing lightsaber effect with a matte based on sticks held by the actors. To achieve this, effects technicians traced a line over each frame with the prop, then enlarged each line and added the glow.

Learn more at Wikipedia.


… for Visual Effects

Tip #543: What is Planar Tracking?

Larry Jordan – LarryJordan.com

Planar tracking solves problems with lost tracking points.

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A planar tracker uses planes and textures to track as opposed to points or groups of pixels. This allows the tracker to stay on track even if your shot contains motion blur or a very shallow depth of field. Here’s a quick overview.

Planar tracking was developed by Allan Jaenicke and Philip McLauchlan in the University of Surrey. They founded Imagineer Systems in 2000 to provide commercial applications for this technology.

“Planar Tracking” gains its name from how the system analyzes the source video. It seeks out different ‘planes’, isolating surfaces that can be followed through a shot. The user can define a plane for the computer to follow, and if tracked successfully, the movement of the ‘tracked’ object can be used to drive the motion of newly composited elements, or inversely to stabilize footage within a frame.

Mocha, by Imagineer Systems, is an example of this technology. Once tracking information is derrived from a videoclip within Mocha, it can be used in After Effects to animate the motion of any composited layer. Virtual elements can use this tracking information to control what is essentially a camera move that mimics that of the original shot, so that the virtual and live action elements appear to have been shot by the same camera.

EXTRA CREDIT

While mocha was the first planar tracker, similar technology can be found in:

  • Nuke, The Foundry
  • Syntheyes, Andersson Technologies
  • Flame, Autodesk
  • fayIN, fyateq

Learn more from BorisFX, who acquired Imagineer Systems, here.


… for Codecs & Media

Tip #535: How to Convert 32-bit Media

 

Media based on 32-bit codecs needs to be converted before it can be played.

Kyno allows conversion of older media even when running on Catalina.

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Since the release of macOS Catalina (10.15) older media based on 32-bit codecs no longer plays. If you were able to convert all your media before updating, great. If not, read this.

There’s nothing you can do in Catalina that will allow you to play older media based on 32-bit codecs. Catalina doesn’t support 32-bit anything. However, you are not totally out of luck.

If you have older media, you have two options:

  1. Transfer it to an older system, or borrow or rent one, and convert your media.
  2. A 3rd-party utility – Kyno – can find and convert older media, even if Kyno is running on a Catalina system.

Link to Kyno: Kyno.software.


… for Codecs & Media

Tip #539: What is a Sidecar File?

Larry Jordan – LarryJordan.com

Sidecar files track data that the main image file can’t.

Image courtesy of Pexels.com.
Sidecars hold stuff the main file can’t.

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Sidecar files are XML computer files that store data (often metadata) which is not supported by the format of a source file. There may be one or more sidecar files for each source file.

In most cases the relationship between the source file and the sidecar file is based on the file name; sidecar files have the same base name as the source file, but with a different extension. The problem with this system is that most operating systems and file managers have no knowledge of these relationships, and might allow the user to rename or move one of the files thereby breaking the relationship.

Examples include:

  • XMP. Stores image metadata.
  • THM. Stores digital camera thumbnails
  • EXIF. Stores camera data to keep it from becoming lost when editing JPG images.

EXTRA CREDIT

Rather than storing data separately, it can be stored as part of the main file. This is particularly done for container files, which allow certain types of data to be stored in them. Instead of separate files on the file system, multiple files can be combined into an archive file, which keeps them together, but requires that software processes the archive file, rather than individual files. This is a generic solution, as archive files can contain arbitrary files from the file system.

Container formats include QuickTime, MXF and IFF.