MPEG1 Vs. MPEG2

[j1d10t]

This is probably a stupid question, and I'll probably get a lot of people responding with links to other pages, but I'm wondering what the difference is between MPEG1 and MPEG2. Aside from the fact that DVD's use MPEG2. Is the data in an MPEG2 file compressed differently than MPEG1? The reason I ask is because I noticed that some of Kwags KVCD templates are MPEG1 with a resolution of 704x480, and they look exactly the same as an MPEG2 with the same resolution. Can anyone explain the differences of MPEG1 and 2 to me, in English? I've tried to read some of the technical stuff, and it makes my head hurt. Thanks

[jsnkc1]

The basic answer

MPEG video - Video compressed according to the MPEG encoding system. MPEG-1 is typically used for low data rate video such as on a Video CD. MPEG-2 is used for higher-quality video, especially interlaced video, such as on DVD or HDTV.

The more detailed answer

MPEG
A Codec adopted by ISO's Motion Pictures Expert Group for compression and playback of full-motion video and audio streams-- often referred to as 'MPEG video.' MPEG-1 is now an open standard (ISO/IEC 11172, 1991)--which establishes the structure for a standard MPEG file, and specifies a transfer rate of 1.5Mb/sec, with a resolution of 352x240 at 30 fps. MPEG-2 accepts transfer rates up to 15Mb/sec, with a high resolution of 720x480 at 30 fps, and it also requires a 2MB buffer. Today, most of the demands of multimedia and full-motion video are met by various MPEG add-on boards. Incidentally, CD-I uses MPEG-1, and Video CD was promoted as the first MPEG-1 optical disc for multiple platforms. MPEG add-on boards use special chip sets for compression and decompression--but there are various software-only MPEG decoding programs. High-end hardware solutions claim compression ratios up to 50 to 1. But, since MPEG is lossy, such high compression rates often signify lower quality playback at 30 fps. MPEG-2 (ISO 13818-1, 1994) offers higher quality and speeds than MPEG-1. In certain circles, it is considered a temporary solution in the wait for a software solution (which will require CPUs to provide code streams above 10 Mbits/sec). DVD, however, uses MPEG-2 primarily, and all DVD-players will include hardware to handle MPEG-2 contents.

[vitualis]

The limits to framesize and bitrate limits to both MPEG-1 and MPEG-2 are much higher than what jsnkc1 suggests.

Assuming the same material and same bitrate, MPEG-1 will look quite similar to MPEG-2. However, this is relatively more difficult to test as different MPEG encoders are optimised from different material and perform optimally at different bitrates. For example, most MPEG-2 encoders are optimised for higher bitrates (logically, as MPEG-2 is often used for higher bitrate applications such as SVCD and DVD). MPEG-1 encoders are often optimised for lower bitrates (logically as MPEG-1 is often/traditionally used for VCDs/CD-i etc.)

MPEG-2 yields a number of advantages over MPEG-1, foremost the ability to handle interlaced material. MPEG-1 is progressive only.

If you do a search on MPEG-1 and MPEG-2 you will find plenty of technical documents on the web further highlighting the difference between the two.

I no longer follow kwag's XVCD exploits and I don't know why he chose MPEG-1. There may (speculative) be a number of reasons including: (i) XVCDs are often more compatible than otherwise similar spec XSVCDs and (ii) TMPGEnc has a very good MPEG-1 encoder.

Regards.

[vdvorsta]

@vitualis
This is the anwer that I search for a long time. I've testting a lot of mpeg1&2 comps and yes mpeg1 is the best in lower bitrates.

So I will make non standard VCD with HRes and low bitrate to compare it with SVCD (too look what quality and movie length i can drop on one VCD vs SVCD) But I have a problem to play it on my stand-alone DVD player. The VCD norm is that I can't play higher resolutions than 352x288 on my samsung s224. So here is my question:

Is there some (header) trick to play VCD with higher resolution than the standard ?

[vitualis]

No.

You will have to understand how the header trick came around to understand why.

Many people were noticing that their (US) DVD players did not support SVCDs but were able to play XVCDs (i.e., non-standard VCDs). Moreover, they noticed that they could play higher resolution SVCD style MPEG-2 files as long as the disc is AUTHOURED as if it were a VCD (hence, the need to remultiplex the MPEG-2 file with the appropriate MPEG-1/VCD header).

VCDs and XVCDs based on MPEG-1 will already have the MPEG-1/VCD header... you can't change it to itself...

Regards.

[vdvorsta]

Can I authorize an mpeg1 in SVCD ?

[vitualis]

Yes you can try but I doubt it would work (though you'll never know unless you give it a go)...

Regards.

[vdvorsta]

Thanks Vitualis for the quick response. I will give it a try.

[Conquest10]

Can I authorize an mpeg1 in SVCD ?

why would you want to do that?

[j1d10t]

So "basically" the difference between MPEG1 and MPEG2 is the standard? MPEG1 has a lower "standard" resolution, and bitrate, and MPEG2 can support a variety of resolutions and bitrates as "standard"? Is that it, "basically"? It pretty much comes down to what the "standards" are? Correct me if I'm misinterpreting this

[Conquest10]

i think standards are directed towards vcd and svcd standards.

[j1d10t]

Yeah, that's what I meant. The "basic" difference between MPEG1 and MPEG2 is the VCD "standard" and the SVCD/DVD "standard". Is that pretty much correct? In laymen's terms

[vitualis]

Yeah, that's what I meant. The "basic" difference between MPEG1 and MPEG2 is the VCD "standard" and the SVCD/DVD "standard". Is that pretty much correct? In laymen's terms

No it is not correct.

That is not the basic difference between MPEG-1 and MPEG-2 at all. I avoided all the technical stuff because it isn't that important anyway. MPEG-2 is a superset of MPEG-1. It is based on MPEG-1 but supports a number of additional features (do a websearch and you will find more details).

Both MPEG-1 and MPEG-2 can use low bitrates and low framesizes and very high bitrates and high framesizes.

However, because the common applications of MPEG-1 was in lower framesize (basically, non-broadcast video), most MPEG-1 encoders are optimised for lower framesizes and bitrates. MPEG-2 was designed with broadcast video in mind (which is why it support interlaced video) and as such the common applications for MPEG-2 are usually higher bitrate and framesize. As such, most MPEG-2 encoders are optimised for this usage.

MPEG-1 and MPEG-2 have many differences and similarities but is not based on VCD and SVCD standard.

Indeed, it is the other way around. One of the fundamental differences between VCD and SVCD is that VCD uses MPEG-1 compression while SVCD uses MPEG-2 compression.

Regards.

[vdvorsta]

Can I authorize an mpeg1 in SVCD ?

why would you want to do that?

Just for this reason:

When you want to make an svcd you need also high bitrate for the good of quality. The higher you bitrate - the smaller your movie on one CD.

When you decrease resolution and bitrate on svcd, the quality comes like looking trouh an old coke bottle. (make an svcd 352 x 240/288 @ 1150 kbits/sec and compare it with vcd)

Vica versa:
Make an vcd with hihger resolution but still using the lower bitrate (1150 kbits/sec) and compare the movie length on one CD with svcd.

It's just to find out the quality fitting much as possible to one CD.

[Conquest10]

why not make an xvcd?

[vdvorsta]

Like I write it before: my samsumg s224 (stand alone) doesn't support it.

[Conquest10]

well, according to the compatitbility chart, it does.

[Cecilio]

well, according to the compatitbility chart, it does.

I know this isnt relevent, but i was wondering if you make an XVCD at a bitrate of 2,200 and a reselution of 352*240 would it look clear on a big screen tv, the same way like it does in a 27 inch television.

[Conquest10]

it will look real smooth if your source is dvd. it will not look too clear because of the resolution.

[energy80s]

Another difference between MPEG1 and MPEG2 is that MPEG2 needs a lot more processing power to decode it. A fast 486 will quite happily play an MPEG 1 VCD file, but to get smooth playback of an MPEG2 SVCD you will need at least a Pentium 2 300, and for DVD quality MPEG2 you are over the 400MHz processor speed.