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T351 Week 11 - Fall 2014

Agenda

  • Advanced Editing
  • Legal Issues
  • Codecs / Digitizing / Color Sampling
  • Production tips

Readings:

Cybercollege.com units 66 & 67

Announcements / Reality Check

  • Art Video Critiques - Remember to submit one before the start of your lab time next week.
  • Storytelling exercises: Your pre-production materials (treatment and script) were due last week. (Group grade) There will be no lab next week as the time is for your groups to shoot your projects. Completed projects are due next week. Please remember to let me know this week if your group plans on submitting a shared edit (and what your plan for it will be). Otherwise I expect everyone in a group to have their own edit. We'll start watching these at 10:00 AM during your lab time. We're all going to review and critique the Storytelling Videos, just like we did with the Interview Feature Stories.
    • Monday Lab:
      • “Tea Party” A man has secrets in his basement.
        • Jacob
        • Greg
        • Eli
      • “The Unspeakable Event”
        • Tyler VL
        • Nick
        • Ben
    • Wednesday Lab:
      •  “Chalking Happiness” A man finds happiness through a daydream
        • Victoria
        • Jason M
        • Nick M
        • Ernest
      • “Mac- King of Taunters” Joe wants to be happy, but Mac (a clown) taunts him. Joe decides to help Mac cross over
        • Logan
        • Andrew
        • Emilee
        • Adam
        • LiNa
  • Final Projects: Your final project proposal and treatment were due last week. In the next two weeks you need to meet with me for 10 minutes so we can walk through your Final Project treatment. Scripts are due by the end of next week.

Advanced Editing----------------------

Setting up HD sequences in Adobe Premiere

Many have made the mistake of down converting their footage in Premiere, mainly because they used the DV preset (which seems to load by default on our lab computers).

Assuming you've shot in HD, it's usually best to change your sequence setting to match your clip settings. When you drop your first clip into your sequence you might see this:

If so, then click on "Change sequence settings". This will set your sequence to match your source footage.

That being said a few good codes to use for HD broadcast work include:

  • Apple ProRes
  • XDCam EX (HQ)
  • AVCHD (not anamorphic)

Generally speaking you want to use something at least 35 mbps for broadcast work. Going to 50 mbps is great, but only if you have really fast media access (like a RAID) and lots of room.

It's nice to have a Data Rate Calculator. AJA makes a good one that's free and available for just about any OS or opertaing system.

Link to AJA software

 

Timeline Techniques - Make sure you know how to do these:

Audio

Strive to get consistent audio- especially with dialog and narration. Don't just trust just your ears, but use the audio meter to make sure all of your clips reach the same level. For example, you might use -20 as the average level for your dialog & narration. As you add or edit narration, make sure its average level is -20.

Know how to Normalize - Have you ever had an audio track that even when boosted was too soft? (Here's an example.) You can fix this with the normalize function. This adds gain, so keep in mind that this will also boost the noise.

Adobe Premiere - Look under the Clip menu: Clip/Audio Options/Audio Gain.

Use markers to edit video to the beat. Visual markers are really helpful for editing video to the music and also for editing audio. Make sure you know how to set clip markers. (Not sequence markers- though these are useful too.) FCP, Premiere & Avid each do this but a little differently. (EC - WFTEOTW)

  • Adobe Premiere - The m key creates markers, but in the sequence and not on the clip. You can assign a key easily through the "Keyboard Shortcuts" menu (under the "Premiere Pro" top menu category). Look for "Add Clip Marker" and assign any available key to it. Once you've set up the keyboard shortcut you can select the clip, play it in real time, and tap the keyboard shortcut key to make clip markers.
  • Avid Media Composer - Like Premiere, you can assign markers to a particular key. Go to the settings tab in the project window. Then click on the keyboard. This will show you the keyboard and whatever shortcuts are assigned. Use the "Command Palette" to assign marker creation to a key. (Drag & drop the command onto whatever key you wish to assign it to.) Similar to the other software you need to select the track you want to add markers onto, otherwise they will be placed in the sequence.

Check sequence settings - these can differ from the clip settings. If they are different, you'll have to render your video each time a new clip is placed in the sequence.

Know how to add & delete tracks

Linking and Unlinking tracks - You sometimes want to link or unlink tracks. Select the tracks and choose link or unlink from the drop down "Modify" menu..

Splt edits, also known as J or L edits, can be made in many ways in Premiere & FCP. The easiest way is to hold down the Option key, while dragging the start or end of the clip left or right. In Avid this is easily accomplised by lassoing &/or trimming.

Match frame - Have a frame in your timeline that you want to find the original clip for? In Premiere, put the time indicator over the highlighted frame in the timeline and press the f key. Voila your clip will load into the viewer. (This also works in Avid) Also, if you want to locate the clip in its bin, place the time indicator over the highlighted clip and press the F key. Your clip should be shown in the Browser.

Applying effects to an entire sequence or a particular section - There are many reasons why you might want to apply an effect to an entire sequence or a section of one. For instance you might want to add a color treatment and a vignette to give a flashback or memory a dreamy look.

  • Apple FCP - Nest your edited sequence into another, and apply the effect to the new sequence.
  • Avid Media Composer - Add the effect to a filler video track directly above the selection

Legal Issues

In terms of the law, news & entertainment programming are viewed differently and afforded different restrictions or freedoms.

Laws are constantly being challenged through litigation. Legal lines are often fuzzy and constantly being re-drawn.

As producers, videographers, or editors, it's important to understand some of these boundaries and the basics of law as it pertains to TV.

Intellectual Property (IP) & Copyright Law

Work of the mind is known as Intellectual Property, often abbreivated as IP. The essential notion behind IP law is that once someone creates something (a story, song, painting, invention, etc.) their idea is protected by law. IP law can be divided into several categories.

  • Inventions and devices can be patented.
  • Logos can be trademarked.
  • Music, poetry, film, dance and other creative works can be copyrighted.

Patents and trademarks and registered through the US Patent & Trademark Office, an agency of the Department of Commerce. Copyrights are registered through the US Copyright Office, a division of the Library of Congress.

While it's relatively easy to acquire a copyright for a song or other piece of creative work, one does not need a copyright to gain basic protection.

Generally speaking, one should not use existing IP in commercial work. If one does want to use existing music, photos, video, film or other elements in a commercial work, they need a license agreement.

Fair Use - Allows existing intellectual property to be used in teaching, news and other applications with public benefit. This is not clearly defined.

Privacy - everyone is entitled to this. However those in the public spotlight are given less protection.

Intrusion - When you intrude into a person's privacy.

Access - Generally shooting on public property is OK. Private property for news is another matter.

Commercial appropriation - It is NOT OK to use someone else's likeness to further your own cause.

Staging - Can't "stage" or reenact events unrealistically for news or documentary purposes. Be careful with using comparable footage as well.

Shield Laws - Protecting sources. States offer differing protection than the Feds.

Defamation (libel & slander) - Presenting content that lowers the public's estimation of a person. Negligence (not bothering to check facts).

Public Domain - Copyright has expired.

Legal contracts:

There are three types of legal contracts you should be familiar with:

  • Model Releases
  • Location Releases
  • License Agreements

Model/Talent Releases: These agreements outline the conditions of which the talent will appear in a program. In order to be legally binding, they must specify a time period (duration) and some form of compensation.

Location Releases: These agreements outline the conditions of which a certain location is used in a program.

License Agreements provide for the limited use of someone else's copyrighted material (intellectual property). Anything that has been created, written, composed etc is given some level of protected by Federal copyright law. Music is usually the easiest thing to procure a clearance for (most TV & radio stations have blanket licenses with BMI and ASCAP). Prints, photos, paintings & other visual items are much trickier.

Examples:

Be careful with what you have in the background on a commercial production. Avoid showing existing IP (E.g. identifiable artwork NOT in the public domain).

ASCAP, BMI & SESAC too

These three organizations do similar things: they represent the IP rights of musical artists, publishers & composers.

  • Blanket License - Allows the holder (E.g. TV or radio station) to play any of the recordings. Typically broadcasters would want them from both BMI & ASCAP.
  • Mechanical rights define the terms an existing copyrighted work may be used in an audio-only product, such as CDs.
  • Master Use Rights specify the terms of using a master recording
  • Synchronization (Sync) rights are used to define how a work can be used in a soundtrack to a video or film (E.g. music for a montage). The are obtained from the music publisher/copyright holder and are licensed to the producer of the film or program.
  • Performance rights are necessary to broadcast or perform the work publicly. Broadcasters also need to obtain Performance Rights, since they are publicly transmitting the material. They pay BMI & ASCAP in order to broadcast existing music.

Insurance -----------------------------

Liability - This is the basic insurance all videographers should have if they are doing professional work.

E & O Insurance - Errors and Omissions insurance is a sort of "catch-all" type of insurance that protects you against many unforeseeable issues. All producers should have this.

Video Codecs vs. architecture/container ------------

A few popular multimedia systems include:

  • Quicktime (Apple)
  • ASF (Advanced Systems Format) & WMV (Windows Media)
  • MXF (Material Exchange Format)

Don’t confuse codecs with the container or architecture. QuickTime is multimedia architecture or container created by Apple. It supports many different file types and codecs. Similarly, Windows Media is Microsoft’s audio/video architecture. Another popular Internet architecture is Real Systems.

Files that end in ".mov" are supported by QuickTime, but you have to take a closer look to see what it actually is and what codec it uses. It might be an AIF audio file or a DV video clip. All you can determine from seeing the "mov" is that it's a QuickTime file of some sort.

Apple uses the QuickTime architecture. If you see media ending in .asf, it's supported by Windows Media.

In order to play back multimedia files, you need the matching player, which is sometimes refered to as a "component". For instance if you have a new PC with a fresh version of Vista, you'll need to buy the MPEG-2 decoder component in order to play back DVDs.

Each architecture supports a variety of different codecs.

What is a codec?

Codec is an acronym that stands for coder/decoder or compressor/decompressor. A codec is a method for compressing and decompressing digital information. It can use specialized hardware, software or a combination of both.

Videographers have more potential production codecs on hand than ever before. Some codecs are optimized for efficient capturing and distribution (E.g. H.264). Others provide for better color handling and editing.

Most DSLRs capture video in H.264. WHile an efficient acquisition codec, it is NOT optimized for editing. This is why it's good to convert these files to something else before you edit. If you are editing on an Avid, you likely should convert these files on import to DNxHD. If you are editing on an Apple with Premiere or Final Cut you might want to use Apple ProRes.

Here's a short video primer on codecs.

Intraframe vs. Interframe (GOP)-based codecs

Codecs like DV, DNxHD, and Apple ProRes compress and treat every frame individually. These are known as intraframe codecs. These types of codecs generally take up more room than a interframe (GOP) based codec, but they are better for editing.

Codecs such as MPEG-2 (used in HDV and SD DVD-Video) break the image down into macro-blocks and compress over time as well as spatially. These are known as interframe codecs. The data is compressed into a group of pictures (GOP).

Generally speaking, intraframe codecs are much easier for non-linear editors to process. Interframe codecs such as HDV do a nice job of compression, but the GOP-based structure is taxing for non-linear editing systems.

Some popular video codecs:

Apple Pro-Res (variable compression, Intraframe codec)

Avid DNxHD (variable compression, intraframe codec)

DV - Uses 5:1 compression Other variants of DV include DVCAM (Sony) and DVCPRO (Panasonic).

Flash – This is an excellent video codec optimized for distribution.

H.261 & H.263 - Video-conferencing codecs

H.264 - A version of MPEG-4 used for mass distribution and Blu-ray

MPEG - (Moving Picture Experts Group) uses interframe compression and can store audio, video, and data. The MPEG standard was originally divided into four different types, MPEG-1 through MPEG-4.

MPEG-2 is widely used and is found in standard definition DVD-Video and in HDV.

MPEG-4 is a good all-purpose multimedia codec. The H.264 variant is also used in Blu-ray HD DVDs.

XDCam – Developed by Sony

SMPTE VC-1 - Developed by Microsoft for Blu-ray authoring

Sorenson – Well supported by a number of platforms.

To convert video into a digital signal for any of the above mentioned codecs, we need to first digitize it.

Digitizing

Digitizing is the process of converting an analog signal into digital form. We do this to create digital video. Digital video is video that has been digitized and is now represented by binary code- 1s and 0s.

When we digitize video, we have to store the data somewhere- onto magnetic tape, disk, or solid state memory. While it is possible to record forms of raw, uncompressed video data, compression using a specialized encoding method (codec) is usually employed, in order to make the data small enough to write it to storage.

Visit http://www.adamwilt.com/DV-FAQ-tech.html#colorSampling for a more detailed explanation of this.

How It Works

A video signal consists of luminance (black and white) and chrominance (color) information. While the luminance and chrominance are combined to create a TV display, the two signals are treated differently. TV works sort of like a coloring book. The luminance defines the brightness (darks and lights) and the luminance is the color.

You can see the luminance portion of the signal on a TV monitor by turning the color (chrominance) all the way down.

Most of the important information is in the luminance portion of the signal.

Sampling (frequency) & Quantizing (bit-depth/color depth):

When we digitize video, we sample it. We take a digital snapshot and convert it into 0s and 1s. This is true for audio, video or a combination of the two.

  • Sample rate is how many times per second we take a snapshot.
  • Quantifying (bit depth/color depth) is how many variations within the sample we have. (How good the snapshot is.)

Here are a few different ways audio can be digitized:

  • 8 bit at 22KHz (low end, computer alert sounds)
  • 16 bit at 44.1 kHz (DAT, CD, MP3 at high quality)
  • 16-bit at 48 kHz (DV, DAT/mini disc)
  • 24 bit at 48 kHz (High-end DATs & workstations)

The higher (faster) the sampling rate, the better the quality. The larger or deeper the bit depth, the better the quality is.

The digitizing process:

1. Capture the original signal from an analog source (tape or live)

2. Sample the input signal. This simulates the analogue signal in the digital domain

3. Quantize the signal. This gives each sample a numeric value.

4. Compress the signal. The overall amount of data is reduced to a more reasonable size.

5. Record the signal. Once digitized, the signal may be recorded on a tape, RAM, optical disk or computer disk.

Color difference signals are one way to break down the information in a video signal. (Other ways include composite video, Y/C or S-Video, and RGB.) The color difference signals can be expressed as R-Y, B-Y or Cr, Cb or sometimes U, V. This color difference signals are used in the digitizing process. What the heck is a color difference signal?

Color difference signals: TV uses an additive color system based on RGB as the primary colors. Well if the RGB data were stored as three separate signals (plus sync) it would take a lot of room to store all the information. Fortunately some great technical minds figured out a way pack this information into a smaller box (figuratively speaking) devising a way to convert the RGB information into two new video signals that take up less room, with minimal loss in perceived picture quality. The color difference signals and are typically represented by UV or Cr Cb. So when you see YUV it is referring to Y (luminance) and UV (the two color difference signals).

Combining the RGB signals according to the original NTSC broadcast system standards creates a monochrome luminance signal (Y). So you can basically pull out the blue and red signals and subtract them from the total luminance to get the green info.

So instead of three component color signals (R G B) we process video as a luminance signal and 2 color difference signals (Y Cb Cr)

4:4:4 vs. 4:2:2 vs. 4:1:1 (Chroma subsampling)

Today’s digital technology provides us with several ways to digitize video, mainly 4:2:2 and 4:1:1. What do they refer to?

Quite simply, they refer to the ratio of the number of luminance (Y) samples to the samples of each of the two color difference signals.

In the video signal, the most important component is the luminance as it gives us all the detail absolutely necessary in the picture. As a result, we must sample luminance at a very high rate, 13.5 Megahertz (million times per second).

Given that the luminance portion is sampled at 13.5 MHz. Let's apply the before mentioned ratios: 4:2:2 and 4:1:1. In a 4:1:1 component digital sample, the color information is sampled at 1/4 the luminance rate: 3.375MHz. In a 4:2:2 system, the color is sampled at 1/2 the rate of the luminance or 6.75MHz.

What about 4:2:0?

The 4:2:0 is used in MPEG-2 sampling. The two color difference signals are sampled on alternating lines.

What does this mean?

Quite simply, the color depth of a 4:2:2 component digital signal is twice that of a 4:1:1 signal and, from the standpoint of color bandwidth, is twice that of today’s popular component analog formats. This means better color performance, particularly in areas such as special effects, chromakeying, alpha keying (transparencies) and computer generated graphics.

Vocabulary

  • ASCAP
  • Bit rate
  • BMI
  • Codec (coder/decoder)
  • Color difference signal
  • Interframe (GOP)
  • Intraframe
  • IP (Intellectual property)
  • Multimedia container
  • Sample rate
  • SESAC
  • Sync license

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