Comments on: 15 reasons why MPEG4 sucks

By: DeServ – Info » MPlayer/MEncoder – Manual traduzido online – Completo

Fri, 18 Dec 2009 23:16:02 +0000

[...] or Xvid. (Advanced codec developers may be interested in reading Michael Niedermayer's opinion on "why MPEG4-ASP sucks".) Likewise, you should get better quality using MPEG-4 ASP than you would with MPEG-2 codecs. [...]

By: Coderjoe

Coderjoe — Fri, 28 Jul 2006 20:08:32 +0000

I, too, am disgusted that interlacing isn’t going to die. Interlacing was FINE back when TV was invented, as it allowed for a higher resolution image while using less bandwidth. (Analog NTSC signals fit well within a 6MHz chunk of spectrum). But now, with the (extremely slow) migration to digital TV, there isn’t really a need to carry interlacing across. I noticed that my 720p HD locals are using 60fps (59.94fps, actually), which can handle movie telecine just as well (better, actually) as 29.97 interlaced video.

The biggest reason for needing to prevent “Start code simulation” is for when you are jumping in midstream, like when you tune in an HD channel. Before you can start decoding, you need to find a proper TS packet start code. If there are fake instances of it in the stream, it just makes it take longer to start decoding streams while you search.

By: Greg

Greg — Tue, 25 Jul 2006 13:10:39 +0000

I hate the fact that the aspect ratio is so widely ignored with mpeg4 but so widely used in mpeg 2. When converting between formats data ether has to be lost or just made up.

By: Shy

Shy — Wed, 21 Dec 2005 02:03:40 +0000

About interlaced content, heck, I’m so disappointed it hasn’t disappeared from the world yet with the moronic 1080i standard. You would have thought that by now people learned a few lessons.

In regard to Jim’s last comment, I thought I’d mention that my machine (Athlon 64 3200+) plays 640×480x60fps mpeg-4 asp (without quarter pixel which of course makes performance much worse) very well with the libavcodec decoder, with performance in very intensive parts avaraging around 30% cpu time usage, but in avarage, almost always less than 20%.

By: Jim Leonard

Jim Leonard — Tue, 29 Nov 2005 19:38:16 +0000

“hmm, i do like the lack of field coding, actually i wouldnt mind if there where no interlacing support at all”

Well, what am I supposed to do with all my interlaced content then? :-) I tried creating a 60fps MPEG4 using both quicktime and nero and both accepted it and then happily quantized time by x2 and I ended up with a 30fps file. Besides, I’m not sure my machine would even play back a 720×480x60fps MPEG-4 file…

By: Michael

Michael — Tue, 29 Nov 2005 11:03:21 +0000

Hi Skal

> some additional missed points in MPEG4, IMHO:
> = you can’t change the VOL header along the sequence. In particular, no adaptive qpel switching, or quant type switching.

yes, or qpel&quant_type should be rather in the VOP header, also keep in mind that switching things in the VOL header is tricky if the VOL header is stored only in a specific single place like in .mp4

[...]
> = no pure field coding (unlike MPEG2). Oh, and supporting field MB is a mess too.

hmm, i do like the lack of field coding, actually i wouldnt mind if there where no interlacing support at all :-)

[...]
> = 4-warp points sprite: not used. Unreadable spec.

i think though i might be wrong (too lazy to look at the spec now) that the 4-wrap point sprite is used in some part of mpeg4 just not for GMC, and yeah the “GMC equations” are scarily obfuscated

[...]

another missed point is the motion vector coding, the per picture fixed number of LSB bits is hmm not so optimal, not to mention annoying for rate distortion during ME

By: skal

skal — Tue, 29 Nov 2005 10:04:47 +0000

Hi Michael :)
some additional missed points in MPEG4, IMHO:
= you can’t change the VOL header along the sequence. In particular, no adaptive qpel switching, or quant type switching.
= Reduced resolution (could have been a good idea, but it’s a miserable failure.)
= no pure field coding (unlike MPEG2). Oh, and supporting field MB is a mess too.
= no adaptive VLC tables
= some oddness in the (Run,Level) codes
= RVLC bwahaha
= 4-warp points sprite: not used. Unreadable spec.
= Mesh coding and facial animation ?! gee…

Now, fortunately, there are some also good points in mpeg4.