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-   -   mpeg1,2,3,4.........whats the difference? (https://www.dvinfo.net/forum/open-dv-discussion/35654-mpeg1-2-3-4-whats-difference.html)

Ian OBrien November 29th, 2004 01:25 PM

mpeg1,2,3,4.........whats the difference?
 
I know that mpeg is an abbreviation for Motion Picture Experts Group, but thats about as far as it goes, Can anybody tell me
what is what with the different ones Pleeeease!!


Many thanks

Mark Sloan November 29th, 2004 02:35 PM

MPEG1 includes the common MP3 (which is really mpeg1, layer 3, the audio layer) that you listen to today. It was the first compression by the group and became very popular, especially in Asia where Video CDs became really popular but is only 320x240 if followed strictly. It was good for the time, but has been surpassed by more recent compression algorithms.

MPEG2 is what DVDs are based on. A much more flexible codec than MPEG1 you can control the compression quality and therefore the size of your MPEG2 files so you can do a trade off of file size vs. quality.

There is no MPEG3, mp3 I addressed above.

MPEG4 is an open standard that is partly based on Quicktime that is much more flexible than even MPEG2. It has a much better encoder and can deliver content to anything from a phone with a tiny screen to HD quality video. It is being widely adopted and a lot of video players like the archos players, support this format. MicroSoft is pushing hard for its own, but MPEG4 is the more universal I'd say.

That is kind of a high level... I'm sure I missed some details... but really MPEG1 is really old and bloated, but highly supported. MPEG2 is mostly used for DVDs. And MPEG4 is being adopted widely for internet and on demand video streams and will add support for H264 (?) to do HD level video.

Ian OBrien November 29th, 2004 03:32 PM

Hi Mark
Your reply is very much appreciated and well explained, so many
thanks.
I am relatively new to DV and have found a good deal of useful
information from this great website and would like also to know
something else, I have been buying CD-R's from the local super-
market as they have been on offer, The outer box states that
the discs are suitable for music, data, photo and video ( remember
i'm a novice ) so since then I have burnt all video onto these discs
and been happy with the result, until I tried burning onto DVD+R!!
Wow, what a difference!!
so am I right or wrong in saying CD-R's have a similar quality to
the VHS format and the manufacturer of these discs I bought
were being a bit misleading?

Many Thanks

Rob Lohman November 29th, 2004 04:07 PM

Just so you know, popular codecs like DiVX and XviD are variations
on MPEG4 and are compatible with general MPEG4 codecs.

Ian: in theory you could store the same kind of data on a CD and
a DVD (like audio, video, data etc.). It is just a different media.
However, there are certain things that are "standards":

CD's:
- audio CD
- (Super) Video CD
- CD-ROM (data CD)

(there are also hybrid forms, combinations of the ones above)


DVD's:
- DVD Audio
- DVD Video (is what we mainly associate when we say "DVD")
- DVD Rom (data DVD)


The video on a CD is usually in (compliant) VideoCD format and
thus in MPEG1 at half-resolution of your full signal. DVD-Video
however usually contains MPEG2 (it can also contain MPEG1, but
no-one really uses that [lower quality]) but is a bit harder to
put together than a VideoCD was/is on a CD, but the process
is basically the same.

So yes, a DVD should look better since it has much more space
(4.5 GB for a single layer disc instead of 650 - 700/800 MB on a CD)
and thus allow for less compressed / higher resolution file, that
in combination with a better encoding algorithm (MPEG2) produces
far superior images (if encoded properly!).

Mark Sloan November 29th, 2004 05:03 PM

It does depend on the settings of the DiVX and XviD files, but yeah, because it is an open standard, anyone really can make a compatible MPEG4 file...

As Rob stated, CDs are generally burned using MPEG1, which look about the quality of VHS, sometimes lower, sometimes higher. The label on the box simply states what you can put on a CD.

If you are using something like Toast to burn your videos, then it automatically chooses the "Video CD" standard using MPEG1 at 320x240 to burn your video. When you put in a DVD+-R, it will create a "DVD" using MPEG2 at full standard resolution. These are the two formats supported by a large number of DVD players.

All of the other formats, including MPEG4, QuickTime, WMV and AVI are not supported as standalone files on DVD players. Generally, only computers can deal with those right now. But when you choose to burn them using something like Toast, the program is smart enough to convert your files into MPEG1 or MPEG2 as needed.

In the future you will probably see DVD players and HD/Blue Ray DVD players that can take a computer CD-ROM/DVD-ROM and read whatever is on it, though most likely only JPG photos, MP3s and MPEG1,2,4 files. Currently, some DVD players can take a CD-ROM with MP3s on it and read the file structure decently enough to play them... but support for this is hit or miss.

Patrick Jenkins November 30th, 2004 10:09 AM

Unrelated, but for anyone in the market...

LiteOn (LVD-2001) and Philips (DVP-642) both make DVD players that read mpeg4/divx/xvid discs. The playback quality of the Philips isn't as good as the LiteOn, but the LiteOn is a bit sluggish responding and loses synch on *improperly* encoded files (as a reference, the Philips doesn't - every now and then it looks at the overall duration of the video vs. the current playback position and skips/repreats a few video frames to keep time with the audio). (I have both players)


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