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DIGITAL VIDEO
Fireworks demo
Helices courtesy
NASA
A DIGITAL Video means that a video media
format that has been digitized and can
record, edit/manipulating, store and play back video images digitally
in PC
or respective media players.
The Digital DV format offers more precise image detail and color
accuracy than analog video. By digitally recording images and sound .Digital video is the key to content when streaming media
on web/internet.
Starting in the late 70s to the early 80s, several types of video
production equipment- such as time base correctors (TBC) and digital
video effects (DVE) units (two of the latter being the Ampex ADO, and
the NEC DVE)- were introduced that operated by taking a standard
analog video input and digitizing it internally. This made it easier
to either correct or enhance the video signal, as in the case of a TBC,
or to manipulate and add effects to the video, in the case of a DVE
unit. The digitized and processed video from these units would then be
converted back to standard analog video.
Later on in the 1970s, manufacturers of professional video broadcast
equipment, such as Bosch (through their Fernseh division), RCA, and
Ampex developed prototype digital videotape recorders in their
research and development labs. Bosch's machine used a modified 1" Type
B transport, and recorded an early form of CCIR 601 digital video.
None of these machines from these manufacturers were ever marketed
commercially, however.
Digital video was first introduced commercially in 1986 with the Sony
D-1 format, which recorded an uncompressed standard definition
component video signal in digital form instead of the high-band analog
forms that had been commonplace until then. Due to the expense, D-1
was used primarily by large television networks. It would eventually
be replaced by cheaper systems using compressed data, most notably
Sony's Digital Betacam, still heavily used as a field recording format
by professional television producers.
Consumer digital video first appeared in the form of QuickTime, Apple
Computer's architecture for time-based and streaming data formats,
which appeared in crude form around 1990. Initial consumer-level
content creation tools were crude, requiring an analog video source to
be digitized to a computer-readable format. While low-quality at
first, consumer digital video increased rapidly in quality, first with
the introduction of playback standards such as MPEG-1 and MPEG-2
(adopted for use in television transmission and DVD media), and then
the introduction of the DV tape format allowing recording direct to
digital data and simplifying the editing process, allowing non-linear
editing systems to be deployed wholly on desktop computers.
Digital video cameras come in two different image capture formats:
interlaced and progressive scan. Interlaced cameras record the image
in alternating sets of lines: the odd-numbered lines are scanned, and
then the even-numbered lines are scanned, then the odd-numbered lines
are scanned again, and so on. One set of odd or even lines is referred
to as a "field", and a consecutive pairing of two fields of opposite
parity is called a frame.
A progressive scanning digital video camera records each frame as
distinct, with both fields being identical. Thus, interlaced video
captures twice as many fields per second as progressive video does
when both operate at the same number of frames per second. This is one
of the reasons video has a “hyper-real” look, because it draws a
different image 60 times per second, as opposed to film, which records
24 or 25 progressive frames per second.
Progressive scan camcorders such as the Panasonic DVX100 are generally
more desirable because of the similarities they share with film. They
both record frames progressively, which results in a crisper image.
They can both shoot at 24 frames per second, which results in motion
strobing (blurring of the subject when fast movement occurs). Thus,
progressive scanning video cameras tend to be more expensive than
their interlaced counterparts. (Note that even though the digital
video format only allows for 29.97 interlaced frames per second [or 25
for PAL], 24 frames per second progressive video is possible by
displaying identical fields for each frame, and displaying 3 fields of
an identical image for certain frames. For a more detailed
explanation, see the adamwilt.com link.)
Standard film stocks such as 16 mm and 35 mm record at 24 or 25 frames
per second. For video, there are two frame rate standards: NTSC, and
PAL, which shoot at 30/1.001 (about 29.97) frames per second and 25
frames per second, respectively.
Digital video can be copied with no degradation in quality. No matter
how many generations a digital source is copied, it will be as clear
as the original first generation of digital footage.
Digital video can be processed and edited on an Non-linear editing (NLE) station, a device built exclusively to edit video and audio.
These frequently can import from analog as well as digital sources,
but are not intended to do anything other than edit videos. Digital
video can also be edited on a personal computer which has the proper
hardware and software. Using an NLE station, digital video can be
manipulated to follow an order, or sequence, of video clips. Avid's
software and hardware is almost synonymous with the professional NLE
market, but Apple’s Final Cut Pro, Adobe Premiere, Sony Vegas and
similar programs are also popular.
More and more, videos are edited on readily available, increasingly
affordable hardware and software. Even large budget films, such as
Cold Mountain, have been edited entirely on Final Cut Pro, Apple's non
linear editing software.
Regardless of software, digital video is generally edited on a setup
with ample disk space. Digital video applied with standard DV/DVCPRO
compression takes up about 250 megabytes per minute or 13 gigabytes
per hour.
Digital video has a significantly lower cost than 35 mm film and it
could be erased and re-recorded multiple times, viewed on
location without processing.,
Digital video is used outside of movie making. Digital television
(including higher quality HDTV) started to spread in most developed
countries in early 2000s. Digital video is also used in modern mobile
phones and video conferencing systems. Digital video is also used for
Internet distribution of media, including streaming video and
peer-to-peer movie distribution.
Many types of video compression exist for serving digital video over
the internet, and onto DVDs. Although digital technique allows for a
wide variety of edit effects, most common is the hard cut and an
editable video format like DV-video allows repeated cutting without
loss of quality, because any compression across frames is lossless.
While DV video is not compressed beyond its own codec while editing,
the file sizes that result are not practical for delivery onto optical
discs or over the internet, with codecs such as the Windows Media
format, MPEG2, MPEG4, Real Media, the more recent H.264, and the
Sorenson media codec. Probably the most widely used formats for
delivering video over the internet are MPEG4 and Windows Media, while
MPEG2 is used almost exclusively for DVDs, providing an exceptional
image in minimal size but resulting in a high level of CPU consumption
to decompress.
While still images can have any number of pixels the video community
defines one standard for resolution after the other and
notwithstanding the devices use incompatible resolutions and insist on
their resolution and rescale a video several times from the sensor to
the LCD. Anamorph still images are the result of technical limitations
while anamorph videos can be result of standardization aberrations. As
of 2007, the highest resolution demonstrated for digital video
generation is 33 megapixels (7680 x 4320) at 60 frames per second ("UHDV"),
though this has only been demonstrated in special laboratory settings.
The highest speed is attained in industrial and scientific high speed
cameras that are capable of filming 1024x1024 video at up to 1 million
frames per second for brief periods of recording.
=================================================
The High-Definition Multimedia Interface (HDMI) is a licensable
compact audio/video connector interface for transmitting uncompressed
digital streams. It represents the DRM alternative to consumer analog
standards such as RF (coaxial cable), composite video, S-Video, SCART,
component video and VGA, and digital standards such as DVI (DVI-D and
DVI-I).
HDMI connects DRM-enforcing digital audio/video sources such as a
set-top box, an HD DVD disc player, a Blu-ray Disc player, a personal
computer, a video game console, or an AV receiver to a compatible
digital audio device and/or video monitor such as a digital television
(DTV). HDMI began to appear in 2006 on consumer HDTV camcorders and
high-end digital still cameras.[1][2] Shipments of HDMI are expected
to exceed that of Digital Visual Interface (DVI) in 2008, driven
primarily by the Consumer Electronics (CE) Market.[3]
=================================================
General notes
HDMI supports, on a single cable, any TV or PC video format, including
standard, enhanced or high-definition video, plus multi-channel
digital audio. It is independent of the various DTV standards such as
ATSC, and DVB (-T,-S,-C), as these are encapsulations of the MPEG
movie data streams, which are passed off to a decoder and output as
uncompressed video data on HDMI. HDMI encodes the video data into TMDS
for transmission digitally over HDMI.
Devices are manufactured to adhere to various versions of the
specification, where each version is given a number, such as 1.0 or
1.3. Each subsequent version of the specification uses the same
cables, but increases the throughput and/or capabilities of what can
be transmitted over the cable. For example, previously, the maximum
pixel clock rate of the interface was 165 MHz, sufficient for
supporting 1080p at 60 Hz or WUXGA (1920x1200), but HDMI 1.3 increased
that to 340 MHz, providing support for WQXGA (2560x1600) and beyond
across a single digital link. See also: HDMI Versions.
HDMI also includes support for 8-channel uncompressed digital audio at
192 kHz sample rate with 24 bits/sample as well as any compressed
stream such as Dolby Digital, or DTS. HDMI supports up to 8 channels
of one-bit audio, such as that used on Super Audio CDs at rates up to
4x that used by Super Audio CD. With version 1.3, HDMI now also
supports lossless compressed streams such as Dolby TrueHD and DTS-HD
Master Audio.
HDMI is backward-compatible with the single-link Digital Visual
Interface carrying digital video (DVI-D or DVI-I, but not DVI-A) used
on modern computer monitors and graphics cards. This means that a DVI-D
source can drive an HDMI monitor, or vice versa, by means of a
suitable adapter or cable, but the audio and remote control features
of HDMI will not be available. Additionally, without support for
High-bandwidth Digital Content Protection (HDCP) on the display, the
signal source may prevent the end user from viewing or recording
certain restricted content.
PCs with hardware HDMI output may require software support from
Operating Systems such as Windows Vista. Linux currently supports
video output through backward-compatibility with DVI.
In the US, HDCP-support is a standard feature on digital TVs with
built-in digital (ATSC) tuners. Among the PC-display industry, where
computer displays rarely contain built-in tuners, HDCP support is
absent from many models. For example, the first LCD monitors with HDMI
connectors did not support HDCP, and few compact-LCD monitors (17" or
smaller) support HDCP.
The HDMI Founders include consumer electronics manufacturers Hitachi,
Matsushita Electric Industrial (Panasonic/National/Quasar), Philips,
Sony, Thomson (RCA), Toshiba, and Silicon Image. Digital Content
Protection, LLC (a subsidiary of Intel) is providing HDCP for HDMI. In
addition, HDMI has the support of major motion picture producers Fox,
Universal, Warner Bros., and Disney, and system operators DirecTV and
EchoStar (Dish Network) as well as CableLabs and Samsung.
Specifications
HDMI defines the protocol and electrical specifications for the
signaling, as well as the pin-out, electrical and mechanical
requirements of the cable and connectors.
[edit] Connectors
The HDMI Specification has expanded to include three connectors, each
intended for different markets.
The standard Type A HDMI connector has 19 pins, with bandwidth to
support all SDTV, EDTV and HDTV modes and more. The plug outside
dimensions are 13.9 mm wide by 4.45 mm high. Type A is electrically
compatible with single-link DVI-D.
A higher resolution version called Type B is defined in HDMI 1.0. Type
B has 29 pins (21.2 mm wide), allowing it to carry an expanded video
channel for use with very high-resolution future displays, such as
WQSXGA (3200x2048). Type B is electrically compatible with dual-link
DVI-D, but is not in general use.
The Type C mini-connector is intended for portable devices. It is
smaller than Type A (10.42 mm by 2.42 mm) but has the same 19-pin
configuration.
HDMI 1.3 defined two categories of cables: Category 1 (standard or
HDTV) and Category 2 (high-speed or greater than HDTV) to reduce the
confusion about which cables support which video formats. Using 28 AWG,
a cable of about 5 metres (~16 ft) can be manufactured easily and
inexpensively to Category 1 specifications. Higher-quality
construction (24 AWG, tighter construction tolerances, etc.) can reach
lengths of 12 to 15 metres (~39 to 49 ft). In addition, active cables
(fiber optic or dual Cat-5 cables instead of standard copper) can be
used to extend HDMI to 100 metres or more. Some companies also offer
amplifiers, equalizers and repeaters that can string several standard
(non-active) HDMI cables together.
High-definition optical media players
Both introduced in 2006, Blu-ray Disc and HD DVD offer new
high-fidelity audio features that require HDMI for best results. Dolby
Digital Plus (DD+), Dolby TrueHD and DTS-HD Master Audio use bitrates
exceeding TOSLINK's capacity. HDMI 1.3 can transport DD+, TrueHD, and
DTS-HD bitstreams in compressed form. This capability would allow a
preprocessor or audio/video receiver with the necessary decoder to
decode the data itself, but has limited usefulness for Blu-ray and HD
DVD.
Blu-ray and HD DVD permit "interactive audio", where the disc-content
tells the player to mix multiple audio sources together, before final
output. Consequently, most players will handle audio-decoding
internally, and simply output LPCM audio all the time. Multichannel
LPCM can be transported over an HDMI 1.1 (or higher) connection. As
long as the audio/video receiver (or preprocessor) supports
multi-channel LPCM audio over HDMI, and supports HDCP, the audio
reproduction is equal in resolution to HDMI 1.3. However, many of the
cheapest AV receivers do not support audio over HDMI and are often
labeled as "HDMI passthrough" devices.
===========================================
Clarifying those confusing DVD formats
When buying a new DVD player/burner for my computer which one to
chose? There are burners for
DVD-R, DVD+R, DVD-RW, DVD+RW, and even dual-layer ones, and many
players that support a combination of the formats There are also HD-DVD and Blu-Ray
of late released.
It’s best to tackle several categories of DVD media separately, then
understand that they get combined to form a whole bunch of different
media.
The first distinction is + media vs. - media. These two classes of DVD
media, developed separately by different groups of engineers, are
conceptually the same from an end user's perspective, but internally
they are made differently, and they work differently. What you need to
know is that they are different, and that you cannot automatically
assume interchangeability. While virtually all recorders made today
can record both types, at one time, a recorder was either + or - and
would work only with that type of media, and many of these
single-format recorders are still around. So you need to know if your
recorder (or any other recorders that you plan to use) are dual format
or single format. You can actually tell what the recorder will handle
from the logos on the front of the recorder. The groups that created
the two formats created unique logos, and one of the licensing
requirements is that the respective logo must be present if the
recorder handles that format (I’d love to show you the logos, but I
don’t know how to include graphics in this response).
On the player side, about 80% of players (and just about 100% of newer
players) will play both types, but, again, you may run into players
that play only one format or the other. The bad part that there is no
way to tell other than by trying a sample of recorded media, and in a
few cases players may also be finicky about the brand of media. So,
really, to be absolutely sure, you have to actually try the media that
you plan to use. However, most modern computer drives to play both,
where you usually see issues is with older “set top box” DVD players.
As a comment here, my own experience, and I know that most experienced
DVD users would agree, is that the “-“ media is slightly more
compatible than the “+” media, which is interesting because during the
design phase, and “on paper”, it was supposed to be just the other way
around. But the “real world” didn’t read the design specs.
Now that we have the +/- issue resolved, the +/- will be followed by
“R” or “RW”. “R” media is “one-time” media; recording is permanent and
cannot be erased (you can, however, “add to” a partially recorded “R”
DVD, if it was recorded in multi-session by recording software that
supports this). On the other hand “RW” media can be erased and reused,
becoming “completely blank” media over and over again.
One comment here, however, I’d recommend that you avoid “RW” media for
permanent projects. It is not as stable as “R” media, and many, many
people have found that a recorded “RW” disc “faded” over time and that
the data (their recording) was lost. RW media is also both slower and
more expensive (a LOT more expensive) the “R” media, so I think that
the best advice is probably just to avoid it.
So that takes care of 4 media types: DVD-R, DVD+R, DVD-RW, DVD+RW.
Now we can add “dual layer”, which you will see as a “DL” suffix. This
media has almost twice the capacity of single layer media (9 gigabytes
vs. 4.7 gigabytes). Currently, DL media is only commonly found as “+R”
media, although “-R” dual layer media has been approved and may be
found on the market in the future. The long term reliability and
compatibility of DL recording is unproven, although my own experiences
with it so far have been good.
HD DVD and Blu-Ray (BR or BD) are specifications for future drives
with very high capacity (25 to 100 gigabytes), however neither one of
them is currently in production and on the market as drives that you
can add to a PC (however that will change in a matter of months). At
this time, HD DVD and BR are totally incompatible and neither format
will work on any drives designed for the other format. However, I
would not be surprised to see “dual format” drives for these two
formats at some point, but it’s years away, since even the single
format drives are not yet on the market.
As for your purchase decision, you want a dual-layer, dual format
drive. This will do just about anything, it supports all of the
formats. However, virtually all drives currently being manufactured
fit this description, so it doesn’t do much to help you narrow the
choices. The top brands of drives, in my opinion, are Pioneer, NEC,
Sony, Benq (Acer) and LG (other users will have their own preferences
and ranking).
One thing you didn’t ask about is “Lightscribe”, which is a technology
for writing a “label” to the non-data side of the media. To do this
you need a drive that supports this and special “lightscribe” media
that has a laser photosensitive surface on the label side. Whether or
not this is of value to you is a personal choice, but keep in mind the
time required to use this feature, not only to write the label side,
but to design and compose it as well. Lightscribe drives are now
available from several vendors
================================================================
DVD ram is the number 1 choice for DVD Video recorders (VR format)...
It is more expensive because it can be used 100,000 times vs. 1000 of
the RW media.
The surface is far better and more resistent to scratches tha R or RW
media
There are also some new apps. that can read the VR format from the
DVD-Ram (Toast 7, Pixela, etc), so you can copy the videos to the
computer and edit them.
It is more reliable. I've had experienced problems recording video on
DVD+-R/RW, which render a trashed DVD, but NEVER had experienced a
problem with DVD-Ram media.
I record about 40 hours per week Video on DVD-Ram
====================================================================
Just 3 quick points to cover, more definitively, what has been
mentioned, and support that DVD-RAM is the best disc format for data
storage:
DVD-RAM is ''archival grade'' media ... the information burned onto
the disc will remain on the disc for probably 100 years. For
invaluable, irreplaceable data (home movies, family photos, tax data,
personal wills, etc) this is THE best choice of all available media.
DVD-RAM is randomly accessible and uses error correction. If you get
an error on a DVD+/-R/RW disc, whatever information has been recorded
after that point is inaccessible. You'd be able to watch the first 10
minutes, for example, of your home movies, and everything after that
(after the error) would be inaccessible.
DVD-RAM IS an older, PROVEN, technology, which is a reason TO use and
trust it, and, the read/write speed has been updated to 5X. This is
slower than 16X discs, but, at 5X, it would only take 15-20 minutes or
so to back-up the most important data onto a disc.
LG currently (1-20-06) makes a drive that supports most formats,
including DVD-RAM, for less than a $50.00 for
an OEM (just the drive without any paperwork, software,or accessories)
drive. So even if you don't immediately plan to use DVD-RAM, why not
purchase a drive that supports it?
note: JVC and Panasonic standalone "set-top" DVD players, and
Panasonic mini-DVD camcorders, support DVD-RAM.
=============================================================================
DVD RAM is deserving of better, more accurate answers.
-It is the only format of the 3 that uses Random Access Memory (read,
write) technology, a la a regular hard drive, giving it superior
recording ability. Random Access memory allows you to watch the
beginning of a recording while the DVD recorder is still recording the
end of the program.
-DVD-RAM media formatted for PC can be reformatted for use with a
DVD-RAM recorder.
-Unlike DVD RW and R formats, DVD-RAM does not have to be "finalized"
and can be erased and re-recorded a 100 MORE times than the DVD RW
discs that lose future recordable space the more they are re-recorded.
In comparison, DVD-RAM discs can be re-recorded up to 100,000 times
without any decreased record times.
-Unlike the other formats, with DVD-RAM, you can't accidentally record
over something.
The better computer drives typically support DVD RAM, creating a
bridge between video cameras, computers and DVD players and
player/recorders on your TV. A nice list of computer drives and the
formats they support(plus drive ratings) can be found at:
www.videohelp.com/dvdwriters
The varied DVD RAM features are why I bought a computer drive that
supports DVD RAM in addition to DVD +/-RW and +/-R) and a DVD
Player/Recorder for my TV (Toshiba RD-XS52 DVD Player/Recorder) that,
besides writing to DVD-R, also supports the enhanced rewriteability
found in the more robust DVD RAM format.
If consumers educate themselves, they will know to buy computer drives
and stand-alone players/recorders that also support ALL theses
formats. They each have a use and a reason to own.
==================
06 How long do burned CD-Rs and CD-RWs last?
Factory-pressed CDs are totally different from recordable CDs. In a
pressed CD, the data is literally "molded into" (actually pressed
into) the media and will not disappear unless the CD is physically
damaged. Recordable CDs use a dye that changes color or reflectivity
when heated. There are different dye types commonly used in recordable
CDs--phthalocyanine, azo, and cyanine, in particular--and they do not
all have the same life expectancy and stability.
All of the studies that I have seen except one suggest that properly
burned one-time media (-R media, but not -RW media; see below) has an
expected life of decades to possibly even centuries. There was a study
by NIST (a U.S. government agency, used to be the National Bureau of
Standards) on the relative stability of different media here:
http://www.itl.nist.gov/div895/gipwog/StabilityStudy.pdf
You can see some comparisons in the NIST study of the different dye
types. But this study did not attempt to extrapolate the data to a
life expectancy, although it did provide data about the relative
stability of the different dyes and reflection layers behind them.
However, opinions still differ as to how long such media will last.
The OSTA (Optical Storage Technology Association), in a report here:
http://www.osta.org/technology/cdqa13.htm
suggests that optical recordable media will last 50 to 200 years. This
observation is backed by quite a number of studies that I have seen
done both by the media makers and others. However, some storage
experts suggest numbers more in line with your question, for example
the expert in this report suggests a life of only 2 to 5 years:
http://blog.eogn.com/eastmans_online_genealogy/2006/01/life_expectancy.html
(I have a suspicion that this is the article that you read).
-The quality of the burner. A borderline defective burner can “under
expose” the media to the laser beam, producing a seemingly good
recording (at the time of burning) that will “fade” over time (failing
weeks, months, years or decades sooner than it should have had the
laser beam intensity been correct)
-Recording speed. Fast burns (52X) are probably less stable than
somewhat slower burns (say 16x to 32x), but you can burn media too
slowly also. There is a very good analogy here to photographic film
and exposure levels. The dyes on a given media have a certain range of
acceptable “exposures” and outside of that range, you can either under
or over expose the media to the laser beam. However, mechanical jitter
and certain other variables (largely a function of the quality of the
drive) generally will be unconditionally worse at faster speeds.
-Your own handling and storage practices. On a CD, the data “exists”
in a dye layer on the label side of the media. This can be scratched
from the back (from the label side), which will literally and directly
destroy the data. The front side is clear plastic but can also be
scratched. While front side damage may make the data less readable or
completely unreadable, the data is still intact and undamaged on the
label side, and the scratches on the front can normally be removed by
polishing the plastic. On recordable DVDs, the data is on a layer
“inside” the media, but the media is a laminate of several layers and
can delaminate, destroying the data. Flexing – even VERY minor flexing
– is particularly bad at causing such damage. And, also, recordable
DVDs tend to fail from the outside in, so you can increase your
success rate and decrease the incidence of failures by not recording
such media beyond 80% to 90% of capacity, leaving the outside edge,
where the failure rate is greatest and failure occurs first, blank
anyway.
-Labeling: The glues in adhesive labels, or the solvents in pen-type
markers, both applied to the label side (the side containing the data)
can SLOWLY penetrate the reflective backing and dye layers and destroy
the data. Therefore, for archival media, the safest policy is to not
label the CD or DVD itself at all. If you do label it, with either a
label or a pen, you are, at best, taking a chance with your data
(hint: it is safe to write on the clear inner hub (where there is no
data at all) with a suitable pen that won’t rub off).
And, finally, I would be remiss if I did not mention one other factor
which is really huge: Eraseable “RW” media is FAR less stable than
one-time (“R”) media and should absolutely not be used for any
permanent recordings of any kind whatsoever. There is no question that
RW media can and does “fade”. Although I’ve never seen failure of “R”
media that I could attribute with absolute certainty to dye
instability, I routinely see “RW” recordings that are unreadable after
periods of months to a year or two when there is really no other
explanation for the failure. I see this both on CD-RW and DVD+/-RW
media, and I advise people in the strongest possible terms not to use
“RW” media for anything that they want to consider permanent. Since RW
media is also both more expensive (a lot more expensive) and slower,
from my perspective the decision to never even buy RW media at all is
an easy one from my perspective.
==================================
MIDI, a sound recipe
WAV, tasting the meal
MP3, fast food
===========================
The format was licensed from Apple's QuickTime by the MPEG group as
the official file format for MPEG-4 content. It should become more
popular as commercial entities start shipping more MPEG-4 content.
How to install MP4 Splitter :
If you are unable to install the filter, please read this small guide:
How to install/uninstall DLL and AX codec files from Guides section.
Important Note :
- Gabest MP4 Splitter can't be used with the Haali Media Splitter
installed So it's not advisable to have both files installed on your
system in the same time.
============================
MPEG-4 Users Frequently Asked Questions
This FAQ is developed to help answer questions about MPEG-4. It starts
where the official MPEG-4 FAQs finish. The list is maintained by Peter
Haighton. If you have additions or changes, please send them to PeterH@VideoSpheres.com
Last Updated: February 11, 2002
1. What is MPEG-4?
2. Is MPEG-4 complete and usable?
3. If the Standard is complete, then what is ISMA?
4. What are Profiles and Levels?
5. Why are there so many profiles and levels?
6. What are the different parts of the MPEG-4 Standard?
7. What is happening to the licensing of MPEG-4?
8. Where can I purchase the standard?
9. Why do I have to buy the standard? Shouldn't it be free?
10. I went to the ISO site to purchase the specification. What are the
CORs and AMDs?
11. If I have an encoder that does not use all the parts of the
standard, is it compliant?
12. Should I wait for MPEG-7 and skip MPEG-4 for my streaming needs?
13. I tried viewing an MPEG-4 video on another companies viewer and it
crashed? If MPEG-4 is a standard why did it not work?
14. Can video frames be compressed instead of objects?
15. What is the maximum image size that I can use in Simple Profile?
16. Can I do interlaced video with the simple visual profile?
17. Which visual profiles support arbitrarily shaped objects?
18. Where can I find a list of supported tools for a profile?
19. I have heard of a Level 0 for Simple Profile, what is it?
20. Does MPEG-4 Video support H.263?
21. I have heard that MPEG-4 visual is wavelet based. Is that true?
22. I have heard rumours that MPEG is adopting H.26L to replace
MPEG-4, is that true?
23. I see that OBMC is in the visual specification. Which profiles use
it?
24. What does "Max unique quant tables" in the visual profiles and
levels annex mean?
25. I have heard that the MPEG-4 file format is the same as quicktime,
is that true?
26. Is it possible to parse an MP4 file to retrieve metadata without
decoding the content?
27. Can I extract description information from an MP4 file using a
QuickTime parser?
28. Where can I get a copy of the streaming video profile?
29. Where can I get example source code for MPEG-4?
30. Can I play an MPEG-4 bitstream with MPEG-4 audio and MPEG-4 video
on the IM1 reference software?
31. What is low Complexity AAC?
1. What is MPEG-4?
MPEG-4 is the latest compression standard developed by MPEG, the same
group that brought us MPEG-1 and MPEG-2. MPEG-4 builds on the proven
success of three fields:
* Digital Television
* Interactive graphics applications (synthetic content);
* Interactive multimedia (World Wide Web, distribution of and access
to content)
It brings these areas together to develop a standard that enables the
production of content that has far greater reusability and flexibility
than is possible today with individual technologies.
MPEG-4 brings higher levels of interaction with content, controlled by
the content developers. It also brings multimedia to new types of
networks, including those employing relatively low bitrates, and
mobile ones.
2. Is MPEG-4 complete and usable?
Yes. The first version of MPEG-4 was released in 1999 and can be
implemented today. Since the initial release, amendments to the
specification have been developed that add new functionality to the
standard. These additions do not break the original specification, but
instead enhance it. This means that a Simple profile encoder built in
1999 will still conform to the standard today.
3. If the Standard is complete, then what is ISMA?
ISMA is the Internet Streaming Media Alliance (see http://www.isma.tv).
MPEG-4 is a toolbox with many interoperability points (Profiles and
Levels), and in order to have different products from different
vendors to interoperate, there must be an agreement on what parts of
the standard are used for an application. Also, MPEG-4 does not
specify how to transport the bits over various networks. ISMA has
developed a specification based on MPEG-4 that standardizes internet
streaming by agreeing on MPEG-4 profiles and levels and how is the
content transmitted.
4. What are Profiles and Levels?
Profiles and levels are interoperability/Conformance points. In order
to make sure that MPEG-4 products work with other MPEG-4 products from
other vendors, conformance points are developed. These points specify
items such as
* Tools that can be used
* Bitrates
* Image Sizes
* Number of objects
With out these Profiles and Levels, there would be no way to know that
one product could work with another. For more information on MPEG-4
visual profiles and levels, see
http://www.m4if.org/resources/profiles.
5. Why are there so many profiles and levels?
MPEG-4 is a very rich toolbox that targets a number of different
applications. Some of these applications are Studio editing,
Interactive broadcast, Internet Streaming, and wireless devices.Each
application has its own set of requirements. For example, Studio
applications need very large image sizes and high decoding capacity
that could never be supported on a small wireless device. To support
the different applications, conformance points are developed that
permit different vendors to develop products that meet the
requirements of their industry. If a product conforms to a certain
profile and level, then it will interoperate with other products that
conform to the same profile and level.
6. What are the different parts of the MPEG-4 Standard?
Currently MPEG-4 is broken down into 8 Separate parts, some of which
are still under development and are not available for purchase from
ISO.
* ISO/IEC 14496-1 (Systems)
Contains tools such as BiFS, Object Descriptors, FlexMux, MP4 File
Format, etc.
* ISO/IEC 14496-2 (Visual)
Includes natural and synthetic coding as well as Facial and Body
Animation.
* ISO/IEC 14496-3 (Audio)
Including Speech coding, General Audio Coding, Structured Audio, Text
to Speech interface, Parameteric Audio.
* ISO/IEC 14496-4 (Conformance)
Specifies tests to be performed to verify whether bitstreams and
decoders meet the requirements of parts 1, 2, 3, and 6.
* ISO/IEC 14496-5 (Reference Software)
Unoptimized software implementation of the MPEG-4 specification.
* ISO/IEC 14496-6 (Delivery Multimedia Integration Framework
Provides a means for transparent access and delivery of content
irrespective of delivery technologies.
* ISO/IEC 14496-7 (Optimised software for MPEG-4 tools) -- Under
development
* ISO/IEC 14496-8 (4 on IP framework) -- Under developement
A framework for transmitting MPEG-4 over IP neworks
7. What is happening to the licensing of MPEG-4?
Patent Holders are currently working on developing the licensing
necessary for MPEG-4. The current date for licensing the Simple and
Core visual profiles is expected to be early 2002. See
www.m4if.org/patents/index.php for the latest information.
8. Where can I purchase the standard?
The MPEG-4 Standard (ISO/IEC 14496) can be purchased online at the ISO
website.
9. Why do I have to buy the standard? Shouldn't be free?
Developing a standard takes a lot of time and money. In order for ISO
to recover some of the costs associated with the development of the
MPEG-4 standard, it sells the specification. Considering the amount of
work that has gone into developing this standard, it is certainly well
worth the money.
10. I went to the ISO site to purchase the specification. What are the
CORs and AMDs?
COR stands for Corrigenda. A Corrigenda is issued whenever corrections
are needed to fix the specification due to (usually small) editing
errors. AMD stands for Amendment, and is issued whenever new
functionality is added to the standard, such as the streaming video
profiles. Amendments in MPEG-4 do not invalidate earlier, already
deployed products. They enhance the standard
11. If I have an encoder that does not use all the tools in a
profile/level, is it compliant?
Yes, as long as the bitstreams from the encoder do not exceed the
bounds defined by the profile/level combination, such as bitrate,
buffer sizes, etc. It is possible in the simple profile to make an
encoder that only encodes Intra frames (Key frames) that is fully
compliant. Leaving out tools such as Inter frames, AC Prediction, and
data partitioning is not in violation of the standard, but the video
will be of low quality. This is important to note: the standard does
not specify the encoding process.
12. Should I wait for MPEG-7 and skip MPEG-4 for my streaming needs?
MPEG-7 does not compress multimedia data for later playback. Instead,
it is a standard for describing multimedia content. For more
information on MPEG-7, see Overview of the MPEG-7 Standard and MPEG-7
Alliance.
13. I tried viewing an MPEG-4 video created by one company on another
company's viewer and it crashed? If MPEG-4 is a standard why did it
not work?
This can be due to a host of reasons. An MPEG-4 decoder should never
crash. A decoder must be resilient to all error conditions. In this
case, the problem could be in the encoder, in the decoder, or the
bitstream could simply be corrupted.
M4IF is carrying out interoperability tests to make sure the products
of different vendors do indeed work together seamlessly.
14. Can video frames be compressed instead of objects?
Simple Answer: Yes.
Involved Answer: Everything inside MPEG-4 is an object. It does not
matter whether the object is arbitrary-shaped or a rectangular video
frame, or even 5.1 channel audio. The simplest visual profiles support
only rectangular objects (frames).
15. What is the maximum image size that I can use in Simple Profile?
With the exception on Level 0, the visual specification does not
specify what maximum size an image can be. It does however specify the
number of macroblocks (16 x 16 areas) that can be used. For example,
Level 1 allows up to 99 macroblocks that can be configured as 1584 x
16 or 176 x 144 (QCIF) or 16 x 1584 - or any other rectangular size
(divisible in each direction by 16) in between.
Level 0 and Level 1 support up to 99 Macroblocks each.
Level 2 and Level 3 support up to 396 Macroblocks each.
Level 0 has an additional restriction. The horizontal size can not be
greater that 176 and the vertical size can be no greater than 144.
16. Can I do interlaced video with the simple visual profile?
No. Interlaced Video is not supported in the Simple Profile. It is
supported in Advanced Simple from Level 4 and up.
17. Which visual profiles support arbitrarily shaped objects?
The following visual profiles support arbitrary shaped objects
* Core
* Main
* N-bit
* Advanced Coding Efficiency
* Core Scalable
The following visual profiles do not support arbitrary shaped objects
* Simple
* Simple Scalable
* Advanced Real Time Simple
* Advanced Scalable Texture
* Advanced Simple
* Fine Granularity Scalable
18. Where can I find a list of supported tools for a profile?
The visual specification (ISO/IEC 14496-2) contains a list of all
tools that can be used for a particular profile. An abridged version,
listing the most popular profiles is also available at the M4IF
website.
19. I have heard of a Level 0 for Simple Profile, what is it?
Level 0 of the simple profile was designed to target to the wireless
industry where screen sizes are small, and processing power is low.
Level 0 has the same functionality as the other Simple profile levels
but with the following additional restrictions.
1. The maximum frame rate shall be 15 frames per second;
2. The maximum f_code shall be 1;
3. The intra_dc_vlc_threshold shall be 0;
4. The maximum horizontal luminance pixel resolution shall be 176 pels/line;
5. The maximum vertical luminance pixel resolution shall be 144 pels/VOP;
6. If AC prediction is used, the following restriction applies : QP
value shall not be changed within a VOP (or within a video packet if
video packets are used in a VOP). If AC prediction is not used, there
are no restrictions to changing QP value.
Level 0 is available in the Streaming Video Profile Amendment.
20. Does MPEG-4 Video support H.263?
Yes. H.263 Baseline (No Annexes) is incorporated as part of MPEG-4. It
is known as 'short header' inside the specification.
21. I have heard that MPEG-4 visual is wavelet based. Is that true?
Yes and No. The visual specification still uses the Discrete Cosine
Transform (DCT) for its video compression, however, the still texture
part uses the Discrete Wavelet transform.
22. I have heard rumours that MPEG is adopting H.26L to replace
MPEG-4, is that true?
No. MPEG has started talking with the video compression group inside
ITU for joint compression development. Output from this joint venture
would result in a new part to the MPEG-4 standard, to be finalized in
early 2003. It will become part of the MPEG-4 framework.
23. I see that OBMC is in the visual specification. Which profiles use
it?
Although OBMC (Overlapped Block Motion Compensation) was integrated
into the MPEG-4 visual specification, currently no MPEG-4 Profile
supports this tool. It may become part of a new profile if new
requirements are developed.
24. What does "Max unique quant tables" in the visual profiles and
levels annex mean?
This column of the profiles and levels table specifies the maximum
number of unique quantization tables that each profile/level
combination can use for all of the objects in a visual scene. How the
tables are configured (ie how many of each type) is left to the
encoder.
For example, Main Profile/Level 2 allows up to 4 unique quantization
tables for 16 objects. Without gray-shapes, it is possible to have 3
intra tables and 1 inter table, or 2 intra and 2 inter tables etc.
With gray-shapes, it is more likely that the table configuration would
result in 2 texture tables (1 intra and 1 inter), and 2 gray-shape
tables (1 intra and 1 inter).
25. I have heard that the MPEG-4 file format is the same as quicktime,
is that true?
No. Although Apple's QuickTime file format was adopted as the basis
for the MPEG-4 file format, it has gone though many changes in order
to support all the functionality of MPEG-4. Apple has however, played
a key role in the development of MP4, the MPEG-4 file format.
26. Is it possible to parse an MP4 file to retrieve metadata without
decoding the content?
Yes, the meta-data and structure parsing is uniform; there are no
profiles of the structure of the file format.
27. Can I extract description information from an MP4 file using a
QuickTime parser?
Yes, the sample description (which in MPEG-4 contains an ESD) is in
the same place as a QuickTime file.
28. Where can I get a copy of the streaming video profile?
It can be purchased in the form of the Final Draft Amendment (FDAM)
from ISO. ISO/IEC 14496-2:2001 FDAM 2 to be exact. The FDAM is going
through a final balloting round, but the outcome of that ballot will
not affect the text of the standard. To order a copy send an email to
sales@iso.ch requesting the FDAM.
29. Where can I get example source code for MPEG-4?
Reference software was developed as a normative part of the MPEG-4
standard and is used to help understand and implement the
specification. It is sepearated into 3 parts, audio, visual and
systems and each piece of software implements a different part of the
standard.
Example source code (reference source code) for MPEG-4 can be found on
the ISO website or click here. There are some restrictions regarding
its use, so read carefully.
30. Can I play an MPEG-4 bitstream with MPEG-4 audio and MPEG-4 video
on the IM1 reference software?
No. Each part of the reference software is self contained and does not
interoperate with any other part. Both the Visual and Audio software
are able to read and write elementary bitstreams compliant to their
parts, while the systems software (also known as IM1) uses the MPEG-4
file format to read and display contnent specific to its part. For
testing purposes, IM1 uses the ITU-T standards H.263 for video and
G.723 for audio.
31. What is low Complexity AAC?
Low Complexity AAC (Advanced Audio Coding) is similar to standard AAC
except that prediction is not used and there is a lower order Temporal
Noise Shaping (TNS) filter
====================================
MPEG Licensing Information
MPEGIF does not license patents. Neither does MPEGIF bear any
responsibility for licensing patents.
MPEGIF initiates discussions leading to the potential establishment of
patent pools outside of MPEGIF, that should grant a license to an
unlimited number of applicants throughout the world under reasonable
terms and conditions that are demonstrably free of any unfair
competition. MPEGIF only initiates these discussions; the formation of
joint licensing schemes and licensing of MPEG technology will be run
by patent owners, independently from MPEGIF. Licensing and membership
of MPEGIF are, by nature, independent. MPEGIF does not require
anything of its members in terms of licensing their patents, and
MPEGIF's discussions should result in initiatives outside MPEGIF that
are equally open to members and non-members.
MPEG Patents - A Brief Explanation Of Who Is Responsible (And Who Is
Not!)
There are quite a few misunderstandings about the role of the
different organizations involved in getting MPEG deployed, notably
when patent licenses are concerned. Below is a short clarification of
the role of some of the main players.
There is ISO/IEC MPEG. This is the group that makes MPEG standards.
MPEG does not (cannot, under ISO rules) deal with patents and
licensing. It asks of companies that propose technologies that get
adopted into the standard to sign a statement that they will license
their patents on Reasonable and Non-Discriminatory Terms (also called
RAND terms).
There is the MPEG Industry Forum, MPEGIF. MPEGIF has in its statutes
that it shall not license patents or determine licensing fees. It can
discuss issues pertaining to licensing though, some of which hopefully
lead to patent pools that should grant a license to an unlimited
number of applicants throughout the world under reasonable terms and
conditions that are demonstrably free of any unfair competition.
MPEGIF has acted as a catalyst, in the very literal sense, of getting
patent pools going, strictly outside of MPEGIF. MPEGIF encourages more
patent pools to be created, if possible even competing ones.
(Competition is good, also in licensing). By the way, nobody is forced
to do business with the pool; one can also go straight to all the
individual licensors (e.g., 20+ in MPEG-4 Visual). It's a bit
cumbersome though, and one might well end up paying more in the end.
MPEGIF does not receive anything of the collected royalties, nor does
it want to. MPEGIF has among its members licensors, licensees and
entities that are neither of those. Collectively, the members have an
interest in fair and reasonable licensing, because the standard will
fail without it.
Licensing and membership of MPEGIF are, by nature and statute,
independent. MPEGIF does not require anything of its members in terms
of licensing their patents, and MPEGIF's discussions that address
licensing are always aimed at achieving initiatives outside MPEGIF
that are equally open to members and non-members. MPEGIF's initiatives
seek to promote competition and benefit the user. In keeping with
antitrust laws, MPEGIF allows opinions to be expressed, but does not
seek consensus or agreement on acceptable royalties.
There are the 'patent pools' (joint licensing schemes) and their
administrators. MPEG LA is one example, licensing portfolios of
patents essential to MPEG-2 Video, MPEG-2 Systems, MPEG-4 Visual and
MPEG-4 Systems. Via Licensing Corporation, an independent subsidiary
of Dolby Laboratories, licenses patents essential to MPEG-2 AAC, and
MPEG-4 Audio including AAC and High Efficiency AAC. Thomson licenses
patents essential to MP3 (MPEG-1 Layer III Audio). Patent holders
determine the fees; Licensing Agents collect royalties on behalf of
the patent owners and distribute the proceeds. There are probably
other licensing agents and/or companies, not mentioned here, licensing
patents essential to an MPEG standard. This description does not seek
to give an exhaustive list of licensors of patents essential to MPEG
standards.
It must be noted that these joint licensing schemes are not carried
out on behalf of ISO, MPEG or MPEGIF, nor are they, or do they need to
be, officially 'blessed' by any organization (including ISO, MPEG,
MPEGIF). In other words, there is no 'authority' involved in
licensing, it is a matter of private companies working together to
offer convenience to the market. In some instances, the licensing
administrator seeks some reassurance from governments to make sure
that no anti-trust liability exists. For example, in the case of
MPEG-2, MPEG LA obtained a 'comfort letter' from the US Department of
Justice, and a similar letter was issued by the European authorities.
---------------------------------
MPEG-4 is the global multimedia standard, delivering
professional-quality audio and video streams over a wide range of
bandwidths, from cell phone to broadband and beyond.
MPEG-4 was defined by the Moving Picture Experts Group (MPEG), the
working group within the International Organization for
Standardization (ISO) that specified the widely adopted, Emmy
Award-winning standards known as MPEG-1 and MPEG-2. Hundreds of
researchers around the world contributed to MPEG-4, which was
finalized in 1998 and became an international standard in 2000 and
included in QuickTime in 2002.
Based on a Time-tested Technology
While audio and video are at the core of the MPEG-4 specification,
MPEG-4 can also support 3D objects, sprites, text and other media
types.
MPEG Components Sound familiar? It should. You’ve been able to mix
media with Apple’s QuickTime technology for over a decade, storing
each new type in a separate track. With this kind of extensibility,
it’s no surprise that the ISO chose the QuickTime file format as the
foundation for the new MPEG-4 standard.
Just as QuickTime does, MPEG-4 also scales to transport media at any
data rate — from media suitable for delivery over dial-up modems to
high-bandwidth networks. Because of the DNA-level relationship between
MPEG-4 and QuickTime, MPEG-4 inherits QuickTime’s stability,
extensibility and scalability.
Tomorrow’s Media Today
MPEG-4 is designed to deliver DVD-quality video (MPEG-2) at lower data
rates and smaller file sizes. And the same folks who created the
popular .mp3 file format — a.k.a. MPEG-1 layer III — developed the new
Advanced Audio Coding (AAC) codec, providing much more efficient
compression than MP3 with a quality rivaling that of uncompressed CD
audio.
MPEG-4 is ready to stream incredible-quality audio and video today in
QuickTime. With the free QuickTime Player or browser plug-in, you can
play back any compliant MPEG-4 file. Upgrade to QuickTime Pro, and you
can author your own MPEG-4 content. QuickTime Streaming Server and
Darwin Streaming Server are also available to stream .mp4 files. And
with QuickTime Broadcaster, you can produce live events in MPEG-4,
making the QuickTime workflow (Broadcaster to Server to Player) the
industry’s best and most cost-effective end-to-end, standards-based
architecture.
But that’s not all. Because hundreds of multimedia authoring
applications are built upon the QuickTime architecture, QuickTime
instantly adds MPEG-4 capabilities to all these tools. This allows you
to immediately create MPEG-4 content in programs such as Final Cut Pro
and Adobe Premiere.
Plays Well With Others
Like MPEG-1 and MPEG-2 previously did for CD-ROMs and DVDs, MPEG-4
promises to create interoperability for video delivered over the
Internet and other distribution channels. MPEG-4 will play back on
many different devices — from satellite television to wireless
devices.
To ensure that different products that use MPEG-4 each implement the
standard in the same way, Apple, together with Cisco, IBM, Kasenna,
Philips and Sun Microsystems, formed the Internet Streaming Media
Alliance (ISMA). Other participants include AOL Time Warner, Dolby
Laboratories, Hitachi, HP, Fujitsu and 20 other companies. The ISMA
defines profiles that companies implement to ensure interoperability.
That means you can rest assured that the MPEG-4 media stream you
create using one company’s product will run on another vendor’s
player.
Gaining Momentum
In addition to being adopted by many of the premiere Internet content
providers, the MPEG-4 standard is receiving tremendous support in
other industries. For example, H.264 video, also known as MPEG-4 part
10, has been adopted by the ISO MPEG allowing QuickTime 7 to create
ISO-complaint H.264 video in a .MP4 file. The standards for
high-quality multimedia on wireless devices, 3GPP (3rd Generation
Partnership Project) and 3GPP2 (3rd Generation Partnership Project 2),
are based on the solid foundation of MPEG-4, as well.
Satellite Broadcasters like DirecTV and the DVB have adopted MPEG-4
for the delivery of digital television because of its quality at lower
data rates. This means that they can offer more channels to their
subscribers with the same bandwidth.
Everyone’s a Winner
MPEG-4 provides an open playing field. As an open industry standard,
anyone can create an MPEG-4 player or encoder that will work with
other manufacturers’ devices.
Media companies save time and resources by encoding material once for
playback everywhere. No longer will content providers need to encode,
host and store media in multiple formats. Instead, a single format can
reach a broad audience equipped with playback devices from not one,
but a multitude of companies across a wide array of platforms.
Finally, content creators have a format that will reach a global
audience and will stand the test of time. While other formats and
versions come and go, MPEG-4 will safeguard multimedia content for a
secure future.
And of course, resources saved in encoding, hosting and storing media
can be better used to create a wider library of digital media, which
benefits the entire Internet community.
Exceptional Video
QuickTime File Format
Apple has developed two of its own ISO-compliant video codecs, MPEG-4
part 2 (a.k.a. MPEG-4 simple profile) and MPEG-4 part 10 (a.k.a.
H.264) providing the highest quality results across a wide spectrum of
data rates — from narrowband to broadband and beyond. These
revolutionary codecs offer compression times and video quality that
rival those of the best proprietary codecs available, yet it provides
true interoperability with other MPEG-4 players and devices.
MPEG-4 Part 2 Video
The QuickTime MPEG-4 codec leverages many advances in technology to
provide superior performance. For example, the codec provides rate
control—the encoder can be set to a target data rate that ensures
playback at the appropriate data rate for a particular delivery
mechanism. The versatile encoder can use the single-pass variable bit
rate (VBR) rate controller either to maximize accuracy for the
highest-quality output or to maximize speed for the fastest possible
encode. In addition, the QuickTime MPEG-4 codec features rigorous
color management, a high-performance quantizer and a motion estimator
optimized for both precision and speed. The decoder also provides an
optimized post-processing stage to remove coding artifacts. Both the
encoder and decoder are heavily optimized for both the Intel Core Duo
processors, as well as the 64-bit G5 and the G4 Velocity Engine.
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