XviD can give Studio Quality!

[Bishep]

About 2 years I thought, that MPEG4 cannot give professional or studio quality. I mean quality of video which is visually indistinguishable from the original. For these purposes I used MPEG2, that magnificent quality allowed, however demanded very high bitrate :scared: (8-20 Mbit/s - for the resolution 1024x576).

Yesterday I have made the discovery for myself, that at use 'MPEG-Custom' opportunities of codec MPEG4 not simply increase, they become huge. It gives great quality & rather small size. Certainly I’m talking about XviD! :D

I used XviD 14.05.2003 and the following parameters of compression:

Encoding Mode: 1 Pass - quantizer
Quantizer: 2
Quantization type: MPEG-Custom

// It is the most important parameter: here it is possible to use the matrix 'andreas_78er' or to put down values in all fields 'Custom Quantization Matrix' equal a range from 8 up to 16.

VHQ mode: 4 - Wide Search
Maximum I-frame interval: 300
Minimum I-frame interval: 1
Enable lumi masking: NO
Quarterpel: NO

// Use Quarterpel can lower quality of the image (make it differ from the original) and will demand much more processor power of a computer. It can make impossible use, for example, HDTV resolution (1280x720). Quarterpel perfectly copes with other role – it makes the sharpness detailed image at rather low bitrate. To get such picture without use Quarterpel, it is desirable to increase bitrate at least in 1.5x time. Quartelpel to me slightly reminds philosophy of MP3Pro: MP3Pro generates high frequencies, Quarterpel generates high sharpness of a picture - from here its pluss and minuses.

Use chroma motion: YES
Global Motion Compensation: NO
Maximum B-frames: 2
B-frame quantizer ratio (%): 150
B-frame quantizer offset: 100
B-frame threshold: 0
Chroma optimizer: NO

Many thanks to XviD team for their work, for an opportunity to adjust 'Quantization Matrix' - due to this codec XviD is obliged to be successful, I sincerely wish it to you.

Also, I have some questions:

1. What values can be used in 'Custom Quantization Matrix?' I always considered, that it is a range from 8 up to 255, correct me if I am not right.

2. Whether is 'Quantization type: MPEG-Custom' completely compatible with standard MPEG4. If yes, to what Profile it concerns: Simple or Advanced Simple? :confused:

3. There is a problem at use 'ffdshow' - as a result of video has many artifacts. For an example I have grabed framem from known Dolby video encoded. In my opinion 'ffdshow' and 'MPEG-Custom' for today are incompatible: http://covergallery.com/bishep/dolby.png Certainly such problems are not present at use native 'XviD Decoder'. :p

[Bishep]

PS. I’ve made small testing and have changed my opinion concerning 'Quarterpel'. Use of this option as a rule does not result in quality decrease on high bitrate, usually it improves picture, however very little. Therefore quality 'Quarterpel' when use high bitrates – very subjective factor. Much more objectively increase in the processor power necessary for decoding of such videostream.

[lighty]

Have you tried Quarterpel on scenes containing moving fog or smoke? In my experience QPel goes berserk and produce "pumping" effect while everything goes to normal when turning it off. Good example is "Others" where most of the film is taking place in fog and smoke.

[temporance]

Studio quality is normally taken to mean a high bitrate (>34Mbit/s) and the use of 4:2:2 colorspace. xvid always encodes in 4:2:0, so you lose half the chrominance vertical resolution and, by convention, xvid is not capbable of studio quality.

Having said that, if xvid fulfils your needs, then use away :)

[Bishep]

May be not 'Studio', but 'Professional'. I's very personal... Hope, that 'Professional' doesn't mean anything. ;)

[LigH]

To follow your thoughts beyond its purpose: A member of the german doom9 / Gleitz forum already asked for any MPEG4 codec supporting the "Studio Profile". As far as I searched, specifications are hard to find, most sources say "it is planned" (obviously they seem a bit outdated). You may set the DivX 5 codec per command line parameter (http://www.divx-digest.com/articles/DivX5CLIParameters_dut.html) to one of the studio profiles, but I personally doubt that they really are supported.

I guess, the best approach one can take to store video in its best possible quality in MPEG4, is to chose XviD with unrestricted encoding, lowest useful QF and a special matrix. Or is there somethine else I do not yet know?

[sysKin]

Originally posted by LigH
To follow your thoughts beyond its purpose: A member of the german doom9 / Gleitz forum already asked for any MPEG4 codec supporting the "Studio Profile". As far as I searched, specifications are hard to find, most sources say "it is planned" (obviously they seem a bit outdated). You may set the DivX 5 codec per command line parameter (http://www.divx-digest.com/articles/DivX5CLIParameters_dut.html) to one of the studio profiles, but I personally doubt that they really are supported.But mpeg-4 does not have studio profiles. Only mpeg-2 has them.
I guess, the best approach one can take to store video in its best possible quality in MPEG4, is to chose XviD with unrestricted encoding, lowest useful QF and a special matrix. Or is there somethine else I do not yet know? [/B]Mpeg-2 studio profiles support different colourspaces (YUY2) and have slightly different quantization (allows 12-bit DC precision, normal profiles can't go higher than 8 bit).

[LigH]

Originally posted by sysKin
But mpeg-4 does not have studio profiles. Only mpeg-2 has them.

http://www.m4if.org/resources/profiles/index.php

Thanks to Hybrid for pointing that out.

[Soulhunter]

Btw, long time ago Ive already requested the 4:2:2 colorspace for XviD but without any response till now... :(


Bye

[RadicalEd]

Kind of sad that we're ready to move on to AVC without ever passing ASP :| A big portion of hype (that I saw, anyway) about mpeg 4 was Core's arbitrary shape coding. Mpeg 4's been forced to shed its skin without even growing up :*|
cry with me.

[sysKin]

Originally posted by LigH
http://www.m4if.org/resources/profiles/index.php

Thanks to Hybrid for pointing that out.
(...) MPEG-4 Visual levels for the Studio profiles defined in the 1st Extension to the 2nd Edition of the MPEG-4 Visual standard [MPEG01a]. 1st extension to 2nd edition of the standard? Interesting, but I'm not buying the extension nor the standard so that I can code stuff. Sorry :P

Radek

[LigH]

Please don't misunderstand me: I just told you that

a) one user is searching for an MPEG-4 codec supporting studio profiles
b) studio profiles exist for MPEG-4

but I didn't want to urge anyone to implement them. If the XviD team decides to put this task on the schedule for version 2.0, that's fine for me. If they say it would be way too much effort - I can stand that, too.

From my point of view, it is an "Other People's Problem" (see Douglas Adams' "Hitchhiker's Guide to the Galaxy"), at least as long as there is probably no hardware available to support such a data flow in realtime.

[sysKin]

Actually, I would very much like to implemet them - it appears to be interesting, maybe even useful :)

[ac-chan123]

The only Information about Studio Profile wich came from JTC 1 SC 29 W 11 is ISO/IEC JTC1/SC29/WG11 N4668 from March 2002 at site 16

In subsequent Versions, the following Profiles were added:
16. The Advanced Simple Profile looks much like Simple in that it has only rectangular
objects, but it has a few extra tools that make it more efficient: B-frames, ¼ pel motion
compensation, extra quantization tables and global motion compensation.
17. The Fine Granularity Scalability Profile allows truncation of the enhancement layer
bitstream at any bit position so that delivery quality can easily adapt to transmission and
decoding circumstances. It can be used with Simple or Advanced Simple as a base layer.
18. The Simple Studio Profile is a profile with very high quality for usage in Studio editing
applications. It only has I frames, but it does support arbitrary shape and in fact multiple
alpha channels. Bitrates go up to almost 2 Gigabit per second.
19. The Core Studio Profile adds P frames to Simple Studio, making it more efficient but also
requiring more complex implementations.

AC-Chan(Robert Vincenz)

[LigH]

The member in our forum said, he has rendered 3D material which he would like to store both in highest possible quality (but not necessarily really losslessly), and well-compressed at the same time. He expected that a codec supporting MPEG-4 Studio Profile would allow that. But it appears that not one yet exists.