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What Is a MPEG-3?

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  • Written By: A. McCollam
  • Edited By: J.T. Gale
  • Last Modified Date: 28 July 2014
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Regulated by the Moving Picture Experts Group (MPEG), MPEG-3 refers to coding standards for high definition television (HDTV) signals. The group is part of the International Organization for Standardization. Since 1988, the group has been responsible for creating both video and audio coding standards.

It is important to note that this specific standard no longer exists, and that the standards set forth within it are now a part of MPEG-2. When the group originally took on the responsibility for setting the regulations for HDTV in 1992, they were simultaneously working on the other standard. It was discovered, however, that MPEG-2 encoding could accommodate HDTV signals as well, so the new standard was therefore discontinued.

MPEG-2 supplies coding standards for all HDTV signals that are sent at 1080p, which is a shorthand term for the video mode known as full high definition. In addition, it includes coding standards for all broadcast signals. This includes digital satellite and cable TV, as well as protocol for digital video disks (DVDs).

This standard is only one of five formats that the Moving Picture Experts Group oversees. The organization is also responsible for MPEG-1, which handles the audio coding standards for the popular MP3 music format, and MPEG-4, which offers coding standards for 3D content. Two other coding standards that deal with multimedia content fall under their umbrella, as well.

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The Moving Picture Experts Group puts forth these standards to offer a reliable and consistent method for coding audio and video. At its most basic, coding refers to the way that electrical and computer engineers turn data into what is seen on television screens or heard on MP3 players. This transformation of data into real sound and visible images is quite complex and technical. At its core, the process is essentially threefold: compressed data is transferred into more recognizable samples, the samples of picture and sound are cut into smaller segments, and then these segments are transformed into a frequency that can be coded and transmitted.

MPEG-2 goes a step beyond this basic process. Thanks to sophisticated technology, the standards allow the raw picture data to be predicted based on reconstructed images that have been seen in other things before. Then, only data that is different from the old images must be coded to create the video that viewers see.

People should not confuse MPEG-3 with MP3, which actually stands for MPEG-1 (and MPEG-2) Audio Layer III. The MP3 encoding format is audio only, and is a common standard for digital audio compression for consumer use.

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Discuss this Article

anon925569
Post 8

AVI is a container for other types of CODECs. Some are uncompressed and some are compressed at various levels. There are even CODECs that can reside within an AVI container file that are MPEGs!

So, it's incorrect to say that AVIs have better video quality than MPEGs because it all depends on what type of CODEC that particular AVI encoder is using, and its settings.

One problem with MP3 is that it is not an "open" format, meaning that if you want your program to be able to use MP3 you're SUPPOSED to obtain a license from the original developers of MP3, Fraunhofer-Gesellshaft, a German company.

There are several alternatives to MP3, but I'd say OGG is the best. It is fairly well supported and not patented. It achieves the same or better compression and quality as MP3 but doesn't require any licensing.

For "perfect" audio, there are audio codecs that can create and read LOSSLESS (a perfect 1:1 copy of the original audio) audio, but with pretty good compression. (MP3 and OGG are both LOSSY, meaning they are not 1:1 perfect copies of the original audio if you compare the waveforms). FLAC, or Free Lossless Audio Compressor, does a decent job of compression (much better than an uncompressed .WAV file which can be HUGE) and is currently the best option for "perfect" audio at smaller file sizes.

And yes, there are also LOSSLESS (perfect) video CODECS, such as HUFFY, Motion PNG and Motion JPEG 2000 (in lossless mode). Of these, I favor Motion PNG, but it is not well supported by third parties. --

Toddles

TreeMan
Post 7

@hamje32 - I agree that MP3 quality music you find online and on programs is just as good as what you can get on a CD.

No matter how you explain it to some people, though, they'll always find a reason to say lower quality files are no good. I know a person who thinks he has super hearing. He pays big money to get really nice speakers and headphones and everything else. He is always carrying on about only buying music that is above a certain bitrate, because he doesn't like listening to files that are too compressed.

In reality, though, I think it's all in his head. I've listened to the exact same song as an uncompressed file all the way down to very compressed, and I could barely tell any difference. The highly compressed file did sound worse, but places like iTunes always sell music that is high enough quality that you can't tell a difference between it and the uncompressed files. The human body just isn't capable of picking up a difference at that point.

cardsfan27
Post 6

The article says that MPEG-2 and MPEG-3 can both handle HDTV video. It also says that these formats were around in the early 90s. If that is the case, why weren't there high definition TVs around at that time.

It seems like HDTVs are a relatively new phenomenon (within the 2000s, at least). Is it the case that HDTVs were just too expensive or hard to mass produce for the home until that time, or is there more to the story? Perhaps what the article is calling high definition signals is something completely different than what allows us to have high-definition now.

Izzy78
Post 5

@hamje32 - MP3 files are really just the sound portion of an MPEG file? Who would have thought? It makes sense given the names. What exactly does MP3 stand for, though? Is it anything specific, or is that just the abbreviation that separates the audio from video (since the videos are always .mpg or .mpeg)?

I bet that explains why you can obtain just the audio from videos. I bet the fact that they are both together also explains how some videos will not have sound or will have sound and no picture.

kentuckycat
Post 4

@Charred - Great info! I knew as I was reading this that I had downloaded movies in MPEG format, but I never had any idea that there were different types of MPEGS.

I have also noticed what you pointed out that AVI files are always larger but have better quality. I didn't know how they were different than MPEGs, though.

Even though the AVI files are larger, I still think it's the way to go if you are making a video. I used to make YouTube videos, and I always chose to go with AVI over MPEG just for quality purposes.

miriam98
Post 3

One thing I’d like to point out is that you should never assume that you have the correct codec for MPEG installed on your system.

The reason I say this is that some time ago I was working with an old install of Adobe After Effects. I wanted to export the video in MPEG format, but I noticed that option was grayed out. Upon further investigation I discovered that the MPEG codec was not installed on my system.

Fortunately there are websites you can go to download the correct codec. I downloaded all of the MPEG codec standards and I was able to export fine.

hamje32
Post 2

@Charred - Yes, MPEG video achieves high compression ratios. It should be noted that MP3 also gets good compression too, sometimes as high as ten to one or more in some cases. MP3 is also known as MPEG layer 3 (it was the audio portion of this standard).

Basically the way it works is that the compression algorithm throws away parts of the audio signal that are beyond human hearing levels – the really silent parts of the music. Then it uses what’s left over.

Even though it throws information away, you barely notice it because it is stuff you wouldn’t have heard anyway. I think you’ll agree that the quality of MP3 music is on part with CD quality in a lot of cases. The reduced file sizes also make it possible to store tons of songs on an MP3 player.

Charred
Post 1

MPEG achieves a high compression ratio for videos. In the old days I used to export all of my videos out as AVI (Audio Video Interleave) files. This format is uncompressed so there is no loss in image quality.

However, with the better video quality comes increased file size. AVI files are huge and problematic when you are trying to upload them to video sharing sites.

When I convert to MPEG however there is a huge reduction in file size. And the images stay fairly true from one frame to the next. Since the compression algorithm focuses only on pictures that are different from frame to frame, you can get very high compression ratios – almost 100 to 1 in some cases.

However this would happen only if the video has more consistency in its footage rather than a lot of different images from one frame to the next.

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