T351 Week 11 - Spring 2014
- Legal Issues
- Codecs / Digitizing / Color Sampling
- Production tips
- Framed - short story for the day: http://vimeo.com/31013938
Cybercollege.com units 66 & 67
Announcements / Reality Check
- Art Video Critiques - Remember to submit one this week.
- Storytelling exercises: Your pre-production materials
(treatment and script) are due this week. (Group grade) There will be no lab this 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.
- Final Projects: Your final project proposal and treatment are due this week. I've met with the entire Wednesday lab about their projects but not everyone in the Friday lab. Please let me know if you have time Wednesday morning to walk through your treatment.
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
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.
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.
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
- ASCAP (American Society of Composers, Authors and Publishers)
- BMI (Broadcast Music Incorporated)
- SESAC (Society of European Stage Authors and Composers)
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.
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
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.
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.
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
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 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
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
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
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
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
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
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
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
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
- Bit rate
- Codec (coder/decoder)
- Color difference signal
- Interframe (GOP)
- IP (Intellectual property)
- Multimedia container
- Sample rate
- Sync license
Back to Jim Krause's T351 Home Page