The future of the MPEG-2 format?

Reading Bug · #1 08-13-2010, 10:44 AM

from Question about video archiving codec choice...

Quote:

Originally Posted by admin

MPEG-2 and H.264 are going to be part of the video world for a long, long time. Both have been around quite a while. MPEG-2 is going on 20 years old right now, while H.264 is going on a decade old. Neither one is going anywhere for the next decade, either.

This might seem like a superfluous question, but are there any developments in the video world that might lead one to predict a move away from MPEG-2 as a standard format? I use it for archiving and hope I will always be able to view/handle the videos as they are (especially since very little can be done to video without re-encoding).

In terms of progress, is there any reason to believe video (at least SD video) would ever need to move to another format? Thanks!

lordsmurf · #2 08-13-2010, 04:49 PM

As per the quoted text, MPEG-2 was displaced about 10 years ago already. In practice, the replacement only started about 5 years ago, however. Dish Network, for example, began using H.264 for HD around 2005. Cable operators and other satellite providers did the same, although it took a little longer for some of them. Over the air broadcasts are now mostly via H.264, although I don't know the ratio of MPEG-2 to H.264.

Most Blu-ray is H.264, although I'd dismiss that as being a major player in the disc market. People still prefer DVDs, and there's no forecast for that to change for quite a while.

Most consumer cameras, and even many pro cameras, now shoot in H.264 digital formats.

Streaming video, such as Youtube and Hulu, are shifting to H.264. Even the underground video scenes have shifted to use H.264 in MKV containers, instead of XVID and other now-dead formats.

All video formats have sort of coalesced into using H.264, because of how robust it is, both in quality and in size. It's easy to transport, and it looks great even with low bitrates at high resolutions.

None of this, however, will make MPEG-2 disappear. MPEG-2 is still very entrenched in editing workflows, higher-end production work, and even a lot of lower-end methods used by amateurs. The unshakable popularity of DVD has earned it a long-term place in the video work. I would imagine we'd still be able to play MPEG-2 50 years from now!

If nothing else, the ease and low computing requirements of MPEG-2 make it very popular. H.264, on the other hand, requires massive amounts of computing strength. Even today's best multicore 64-bit computers are strained by H.264, much how MPEG-2 strained computers in 1995-2000. I would imagine it's going to be another decade before H.264 is as easy to work with as MPEG-2 is. Maybe 5-6 years, at minimum.

You're safe to archive as MPEG-2.

Steve(MS) · #3 08-13-2010, 10:01 PM

I find it interesting that mpeg 2 will still be around despite pressure from h.264.
I have a couple of questions and there is no rush for you to answer.
What is the magical bitrate or whatever that separates standard definition from high definition?
From what I have read blu-ray uses mpeg 2 also so that got me to wondering.
From my limited understanding up till now, that difference is the 500 lines verses 720/1080 resolution but assume there is more to it than that.
Next question, what is the minimum TV screen size where someone can really tell standard def from high def, disregarding
noise and other imperfections like found in analog sources?

admin · #4 08-14-2010, 07:21 AM

Resolution...

It's resolution, not bitrate, that separates.

Carefully review these measurements, and compare to one another:

Low resolution SD = 352x240 and below (anything below 352x480, actually, with 352x240 / 320x240 being common)
Medium resolution SD = 352x480 / 480x480 ~ 512x384
"Full" resolution SD = 720x480 ~ 704x480 / 640x480
Standard HD = 720p a.k.a. 1280x720 / 1080i a.k.a. 1920x540 (active) ~ or effectively half of 1920x1080
"Full" HD = 1080p a.k.a. 1920x1080
In an analog>digital equiv, "500 lines" analog = 720x480 digital
VHS "240 lines" = ~352x480 / 335x480
8mm "220-240 lines" = ~352x480, but practically lower due to heavy grain of the format
S-VHS / Hi8 "400 lines" = ~480x480 / 500x480
There is no analog for HD, it's all digitally measured.

Most people online entirely screw up lines of resolution, converting analog to digital equivalents. This includes many hackjob services out there -- people who don't understand video very well. Most fail to properly comprehend the HD resolutions, too.

Bitrates...

Bitrates simply control the quality of the image. Bitrates needed vary from format to format, resolution to resolution. Not enough bitrate leads to blocks in MPEG, or soft fuzzy image (with some noise) in H.264. Too much just bloats the file real big, making it take more disc space (or more overhead and bandwidth in the broadcast spectrum).

For MPEG-2 Blu-ray, you're looking at 25Mbps versus the 8Mbps often found on DVDs. Broadcast specs go up to about 50Mbps. MPEG-2 can theoretically be encoded well in 100Mbps, on certain profiles. The MPEG-2 encoding specs also differ in other ways. For example, DVD-Video is using MPEG-2 MP@ML encoding, while HD uses one of the higher profiles. MPEG-2 is more than just bitrate and resolution.

For a good 720p web stream, you can get away with 3-4Mbps, and it looks fine. Youtube, for example, uses less. Hulu is a bit better about bitrates. On a disc, or in broadcast spectrum, it's generally about double that. It will vary from provider to provider, studio to studio.

To see the difference in SD vs HD...

The biggest advantage of HD material is not just in the resolution, but in the quality of color. HD uses a different color profile, and also does not degrade in transit like analog sources did.

The most obvious issue is that HD is all 16:9 widescreen (or put into a 16:9 matte, should it be wider). Older 4:3 content is pillar boxed, with black bars on the sides. Some morons stretch 4:3 content to 16:9 to "fill the screen". I can't stand that; I'd rather not watch it at all, than watch it all stretched out.

I would suggest, based on the above two factors alone, that SD and HD can be seen even at 19" screen. In terms purely of resolution, you'd be looking at something in the 30-40" range before seeing major clarity differences.

Much of this depends on the quality of the set, too. A small Sony set will look exceptionally better than some cheap Vizio or other off-brand.

To see the differences in HD (720p / 1080i vs 1080p)...

With a 55" screen, and 20/20+ vision, I have to flip sources quite a few times to see 720p, 1080i, and 1080p. And even then, I can get it wrong. It's not obvious. Some people insist it's obvious at 30-40 inches. However, it's generally just their imagination. They think it's better, therefore it is. Realistically, about 60" is the minimum size to be able to clearly notice the HD resolution differences. Anything below that, and you're really just guessing.

There is an image law, long known to photographers (because we use it to our advantage!), that an image appears sharper as it gets smaller. The pixel density on a 30-50" screen is so small that 1080p looks more like 720p/1080i anyway. Only when you're able to fully see the individual pixels clearly, will you be able to tell the difference. And to do that, you really need a huge screen. While 60" is big, it's a minimum. It's generally on those big 96-104" projectors that 1080p really helps maintain a clear image.

Again, quality of the set matters. Sony quality will be obvious sooner than something like LG or Samsung. The lower quality sets tend to have more noise in the image (or lack of image clean-up, should the input be the source of the noise). Many people falsely perceive noise as "detail", which is where many arguments on video sharpness originate.

Sossity · #5 08-15-2010, 08:32 PM

would the image looking sharper smaller apply to the images on my Panasonic camera screen versus viewing the images on my PC screen? I also notice that images look brighter on the camera screen, what looked ok in low light actually looks a bit darker on my PC screen after downloading.

admin · #6 08-15-2010, 08:40 PM

Yes.

The brighter camera screen is due to it being a small LCD that is likely overpowered (as is common on most LCDs). And then size creates the illusion of sharpness -- it's harder to see errors, flaws, softness, etc, at those small sizes.

The computer is an opposite effect. Computer monitors, LCD or not, are often underpowered and dim (although some are also overpowered -- few are "just right"), and tend to amplify errors because of the pixel-perfect display.

You're also looking for errors, I bet. It's a bad habit, and I do it all the time. Oops. Just today I was watching a DVD of The Flintstones, and got sidetracked looking at the encoding noise and lack of deflicker. Bad Warner Brothers, bad!