Talk:MPEG-2

message: When do the patents expire?  Great job on the list of patent holders, but does anyone have the list of actual For Part 1 and 2 you can look into the ITU-T Patent Database, since they both parts are common texts. They are known in the ITU-T side as H.222.0 and H.262, respectively. Here is the URL for the database:
http://itu.int/ITU-T/dbase/patent
:2020s.  US 7,020,204 doesn't expire until at least 2021.  There is now a list of US patents in the article, so feel free to check more closely.  Jrincayc (talk) 15:32, 1 June 2008 (UTC)
replies: text:  Back in the early 90's, the rule for patent life was basically the later of 20 years from date of filing or 17 from the date of issue.  Some patents, however are continuations or divisions of other patents.  A continuation is where the assignee files another set of claims using the original disclosure at some point during the patent examination, where as a divsional is where an application is split into two sets of claims related to different parts of the invention which each get seperate examinations.  The example above of US7,020,204 is actually a division of US6,563,875 which itself is a continuation of another application which is based on a foreign patent application filed back in 1988 and therefore expires well before 2022.  The expiration of continuations is generally close to the expiration of the original 'parent' applicaton.  The table below does not account for these factors.  Generally, most of the patents should be expired by around the 20th anniversary of the public release in 1996 (~2016).  Many will be well before that.   Dspark76 (talk) 23:48, 3 June 2010 (UTC)
replies: text:  Update, I just looked on the MPEG LA List and US 7,020,204 already expired on January 29, 2010. Dspark76 (talk) 00:01, 4 June 2010 (UTC)
replies: text: I have updated the program to try and take account of continuations and divisions.  However, all the information is not in machine parseable form.  (On example of missing data is that Patent term adjustment data is not available in the text versions, only in the pdfs.)  Never the less, this should be better. Jrincayc (talk) 03:44, 11 April 2011 (UTC)
replies: text: Now the program grabs the term extension from Google's OCRed data.  These should be closer.  However, there are still some times that the data needed is only in the English that is in the case text, so these still can be somewhat inaccurate.  US7,020,204 is now calculated by the program to be January 1, 2010, which is a lot closer to its actual expiration date of January 29, 2010 than before, when it was 2022.  Jrincayc (talk) 12:34, 21 April 2011 (UTC)
thread_title:  Patents 

message: In compressing Your materials into MPEG2 format (for DVD), for the best results You should go with VARIABLE 2 PASS compression, where the lowest bitrate shouldn't be under 1.5 Mb/s, and the hightest 8 Mb/s...
: There's nothing wrong with going under 1.5Mb/s. Some scenes CANNOT be coded with a bitrate higher than this. Many others will look just fine below this bitrate. Snacky 17:57, 27 May 2006 (UTC)
replies: text: The problem is that players aren't required by the spec to play stuff like this, and many of them won't. If your player plays it, more power to you. The spec (officially) allows a maximum video bitrate of about 9.8mbit/s. Feel free to go above 8mbit/s, as any compliant player will support this with no problem. Read the DVD article. Snacky 17:57, 27 May 2006 (UTC)

text: "maximum bitrate" is only a meaningful in the context of a buffer size, which is 1835 kbits in the case of DVD. In theory, this means local bitrate may actually exceed the allowed max (9800kbit/s) as long as it does so for a period of less than about 0.187 seconds, and as long as it doesn't fill up the 1835 kbit buffer. Snacky 17:57, 27 May 2006 (UTC)
thread_title:  How many seconds of bitrate buffer is allowed in the restriction of MPEG-2 DVD? 

message: Since almost all modern motion compensated codecs use the same techniques, there should be a separate article about it. And it could start based off of the "Video coding (simplified)" section. That exact section could be copied word-for-word to the much leaner MPEG-1 article, and it'd be equally accurate. Snacky 19:34, 28 May 2006 (UTC)
replies: text: Definately, a simple and generic video coding article would be better than having the content here. AlyM 15:30, 29 May 2006 (UTC)
thread_title:  Split off "Video coding" 

message: http://en.wikipedia.org/wiki/File:Mpeg.svg
The diagram may be misleading as it does not show the lower level containerization of the MPEG PES (Program Elementary Stream) as being a level below TS (DVB Transport Stream). Also, DVB-S2 is an 8 point constellation of QPSK that allows for additional bitrate in the satellite transponder by optimizing the error correction scheme and the Nyguist roll-off factor, but the DVB-S2 System does not modulate MPEG-4 directly as shown. The same MPEG containerization scheme and the same 188/204 DVB Transport Stream Schemes are used. Also, MPEG-4 does appear in DVB-C, DVB-S, and DVB-T (particularly in Italy and Spain) but the higher bandwidth requirements of MPEG-4 HD force fewer PES per carrier. This is a problem that is improved bt DVB-S2, and will be improved by DVB-T2 (coming soon), and DVB-C2 (under definition). Never-the-less, DVB-S, C, and T do carry high definition (not implied by the diagram). 123.192.95.51 (talk) 11:27, 21 December 2009 (UTC)
thread_title:  Intro Block Diagram 

message: NTSC MPEG-2 also allows for a 640x480 resolution at 29.97 fps.
El Mariachi94 06:30, 1 December 2006 (UTC)
thread_title:  Aspect ratio 

message: The video compression article mentions "D-frame".
What is a D-frame ?
When I click on "D-frame" to learn more, I am redirected here to MPEG-2.
But this MPEG-2 article never mentions "D-frame".
(Is there some other article that would be a more appropriate destination for that redirect?)
--68.0.120.35 03:09, 8 February 2007 (UTC)
replies: text: There is no "D-frame" in MPEG-2 video (see ISO/IEC 13818-2 Table 6-12), therefore this redirection sounds wrong. Motonari 16:57, 29 September 2007 (UTC)
thread_title:  [[D-frame]] 

message: In Macroblocks, it reads:
  To correct for this, the encoder computes the strings of coefficient values as described above for both macroblocks and,
  then, subtracts one from the other.
Encoders first subtract a reconstructed block (= pixel value) from a predicted block, and then computes DCT coefficient on the difference. So, I'm afraid the current article has an error here. Motonari 17:35, 29 September 2007 (UTC)
thread_title:  MC is performed before DCT and Quantization 

message: In the latest published standard (ISO/IEC 13818-2 2000), there is no 422P@LL nor 422P@H14. As far as I know, there is no plan to add them. Could anyone provide a reference if there is good reason to say "Potential future"? If there is no such references, I suggest to remove them.
Additionally, 422P@HL is not "potential future" but they are well defined and actually used. I will remove "potential" of that.
NTT VASA Series  —Preceding unsigned comment added by Motonari (talk • contribs) 06:29, 30 September 2007 (UTC)
thread_title:  422P@LL? 422P@H14? 

message: They say that files of MPEG-2 or latest type keep a record-history of changes being done to them by programs. Is this true? And is it also true that MPEG-1 does not do that?  —Preceding unsigned comment added by 150.140.226.32 (talk) 23:18, 18 March 2008 (UTC)
thread_title:  Do the MPEG-2 files keep history if any program changes them? 

message: This has never made sense to me:  Why does the Mpeg-2 standard, in DVD format, allow 4:3, but no resolutions that calculate to 4:3?  Have you ever noticed that the aspect ratios allowed can never be achieved using the allowed resolutions?  Why is that?  There must be a reason.  —Preceding unsigned comment added by 71.169.156.93 (talk) 16:10, 6 September 2008 (UTC)
replies: text: Because the pixels in the 720x480 4:3 format are not "square".  Their height is 10% larger than their width (which makes a 704x480 area within the 720x480 exactly 4:3 and leaves the rest for "overscan").  The 720x480 sampling was designed (a long time ago) so that its sampling rate had a nice relationship with the existing analog signals.  It didn't really matter (at that time) that the width and height of each sample on the screen are not the same, because television displays were not built based on that assumption. The newer 16:9 HDTV formats (1280x720 and 1920x1080) were designed differently — using the more digital-centric "square pixel" concept rather than building them for compatibility with old analog television signals. —Cat5nap (talk) 16:31, 6 September 2008 (UTC)
thread_title:  In Mpeg-2 DVD, why 4:3 and 720x480? 

message: Hi, It'd be nice to have the different filename extensions of MPEG-2, as there is on the article of MPEG-1. Does someone know them all ? —Preceding unsigned comment added by 86.199.63.221 (talk • contribs) 21:31, 6 December 2008
:I want to second that! ! !   Someone asked me to try to recover MPEG-2 files which came from a camcorder, I searched the internet but I couldn't find out which extensions I should be looking for. —Preceding unsigned comment added by 78.149.158.52 (talk • contribs) 01:40, 15 February 2009
::Filename extensions are usually .m2v .mpeg .mpg m2a and .vob; though when recovering data; I'd just look at any big file regardless of extensions; because people tend to use different (nonstandard) extensions all the time Nidomedia (talk) 14:42, 1 April 2009 (UTC)
replies: text:  Yes, but the big question is about MPEG-2 clips that contain both video and audio. -82.80.57.79 (talk) 06:55, 16 October 2009 (UTC)
thread_title:  Different extensions 

message: How did the hd camera bitrate came to be? any calculation I do results in a different number. Nidomedia (talk) 14:42, 1 April 2009 (UTC)
thread_title:  HD camera size 

message: The frame rate discussion in the video coding section implies that the fields in interlaced video are obtained by taking alternate lines from a (progressive) frame.  This is not the case - the fields represent different points in time, and it would be better to say that odd lines are taken from one frame of a 50 (or 59.94) fps video signal and even lines from the next.  (A more complicated algorithm incorporating vertical low-pass filtering is actually used in modern video cameras).  The only exception to this rule is if a low frame-rate progressive signal (eg 1080p25)is being conveyed using a technology designed for interlaced video at a higher field rate (eg HD-SDI at 1080i50) - a process known as "pre-segmented frame" representation.
Elvum (talk) 09:57, 11 December 2008 (UTC)
thread_title:  Frame Rate 

message: I just thought I'd throw it in that "standard definition" DVB-T in the UK (called Freeview, for which there are currently no high definition channels) is done in 1024x576 interlaced. This is a 16:9 ratio for 576i (PAL). I don't know whether it isn't listed because it's not listed in an MPEG spec somewhere but it's definitely used. 86.16.148.129 (talk) 13:54, 17 April 2009 (UTC)
thread_title:  DVB Picture Sizes 

message: Back in early 2008, someone deleted the 422P entry from the table of profiles.  Why?  422P@main level is a perfectly valid MPEG-2 profile.  Is there any good reason not to restore it in the table? 74.95.46.250 (talk) 18:02, 9 June 2009 (UTC)
replies: text: I've done a bit of research and apparently the 422P profile was added in 1997, as an amendment to the 1995 first edition MPEG-2 Part 2 spec, and later (probably) included in the 2000 second edition. Unfortunately, the 2000 edition is not freely available, but the 1995 one is, so some editors might mistakenly believe 422P doesn't exist. I don't have access to the 2000 edition, so I can't make the necessary changes, hopefully someone else does. C xong (talk) 04:25, 4 August 2010 (UTC)

text: I've just gotten my hands on the 2000 edition and I've added two new profiles: 4:2:2 and multi-view. HTH C xong (talk) 01:37, 6 August 2010 (UTC)
thread_title:  Why did the 422P@Main Level entry go away? 

message: The article seems to use a convention different to virtually everywhere else I've seen, halving the number used for interlaced frames. Generally NTSC is considered "60i" (or 59.xxi), and PAL "50i", but for some reason this article uses 30i and 25i respectively.
Before changing it, I'd like to double check: is there some discussion somewhere where Wikipedia settled on this unusual convention? Otherwise I'll change it to the same convention I see in TV specification lists, MPEG encoder descriptions, etc... 66.149.58.8 (talk) 23:00, 21 June 2009 (UTC)
thread_title:  60i not 30i 

message: Does the subtitling technology over MPEG-2 count as an essential component? Maybe it should be added to the patent list. Its owned by Philips.
See SUBTITLING TRANSMISSION SYSTEM. Patent numbers:
* WO9619077
* US6661467
* PT745307
* MX9603393
* JP2008079325
Patent Information can be found here:
* http://v3.espacenet.com/publicationDetails/biblio?DB=EPODOC&adjacent=true&locale=en_V3&FT=D&date=20000115&CC=AT&NR=188327T&KC=T
Abstract is Here:
A method of simultaneously transmitting a video signal and encoded data representing graphic images is disclosed. The invention is particularly applicable for transmitting multilingual subtitles with a video program. The graphic images are rectangular regions within the active video area. They are transmitted in the form of bitmaps. The invention not only allows any character font or size to be displayed, but also the definition of e.g. a program provider's logo. The encoded data includes a time stamp to specify the time at which a subtitle is to be displayed. Preferred embodiments of the invention include the transmission of colour-look-up-table (CLUT) data and a compatibility code indicating a required minimum number of entries of said colour-look-up-table. For receivers with a CLUT having more entries than necessary, a map table is transmitted for mapping the pixel data width to the input width of the relevant CLUT. The method is applicable to Direct Video Broadcast systems wherein the video signal is MPEG2 encoded and the graphic images are accommodated in a private data stream of an MPEG2 Transport Stream. 
Speedplane (talk) 17:56, 14 July 2009 (UTC)
thread_title:  Subtitle Patent? 

message: It seems that many/most digital still cameras and video camcorders (among them professional models selling for $8000) use only a license for "personal use and non-commercial" purposes (likely mobile phones with cameras as well).
According to  this is for instance problematic when showing a clip on a site together with advertisements (as on youtube, vimeo or on a private web site which also uses advertisements).--95.117.227.52 (talk) 14:23, 2 May 2010 (UTC)
replies: text: Seems like a useful addition to the article.  Go for it.  Jrincayc (talk) 02:58, 3 May 2010 (UTC)
replies: text: I'm not that much into the topic and there seems to be more than one position about this . Not being familiar with the US legal system (or for that matter the legal system of the country I live in) and not being a native speaker I'm not going to add this to the article. Thanks for the encouragement though:) --95.117.202.214 (talk) 19:19, 5 May 2010 (UTC)
thread_title:  Impact of MPEG LA patent portfolio remains unclear in article 

message: I have several pieces of software which normally play DVDs on my computer without problems.  Recently I bought a DVD that does not play.  Windows Media Player says that I have to purchase a plug-in to make the DVD play because it is MPEG-2.  Does anyone have more information about this?  —Preceding unsigned comment added by 72.89.74.153 (talk) 20:47, 8 September 2010 (UTC)
thread_title:  playing DVDs recorded in MPEG-2 on a PC 

message: Interesting ;-P
KSM-2501ZX, IP address:= 189.120.138.176 (talk) 19:26, 12 September 2010 (UTC)
thread_title:  Not a word about Blu-Ray, nor HD-DVD ? 

message: I was just reading here that "Silicon Philosophies - formerly Front Porch Video - engineered the world's first MPEG-2 encoder for Toshiba and Warner in 1996". I came to the article, not specifically to check on the accuracy of that, but to get a general idea of the development timeline. No joy. I note the section already has an expansion tag. Some fleshing out would be welcome. Wwwhatsup (talk) 11:57, 24 January 2013 (UTC)
thread_title:  Chronology 

message: The Patent pool section lists prices of $2-$2.50 and lists the year 2010.
According to the official website the prices changed on 1 January 2016.
Quotes:
From January 1, 2016 forward, the royalty rate for MPEG-2 Decoding Products will be $0.50 per unit with right of voluntary termination on 30-days written notice, but Licensees may elect a royalty of $0.35 with right of voluntary termination on or after January 1, 2018 on 30-days written notice.
From January 1, 2016 forward, the royalty rate for MPEG-2 Encoding Products will be $0.50 per unit with right of voluntary termination on 30-days written notice, but Licensees may elect a royalty of $0.35 with right of voluntary termination on or after January 1, 2018 on 30-days written notice.
From January 1, 2016 forward, the royalty rate for Consumer Products will be $0.50 per codec with right of voluntary termination on 30-days written notice, but Licensees may elect a royalty of $0.35 with right of voluntary termination on or after January 1, 2018 on 30-days written notice.
http://www.mpegla.com/main/programs/M2/Pages/Agreement.aspx
Sjfeenstra (talk) 12:38, 3 June 2016 (UTC)
thread_title:  Patent pool licenses. 

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thread_title:  External links modified 

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