Talk:MPEG-1

New Article - 2008/04/19
Introducing what may be the single largest diff in Wikipedia history... I was tempted to mark it "minor" just for the pure irony.

I wrote this article myself, entirely from scratch. It was easier than trying to fix all the existing (inaccurate, disorganized and poorly written) ones, and has given rather good end results. I have done my best to make this article approachable, and explain even highly technical issues in a simple fashion, while not hand-waving away the actual, functional details, and thereby making it useless. If you find anything difficult to understand, please be very SPECIFIC about exactly what, and I'll try to address it.

Although it is long, I strongly discourage splitting it: The whole is greater than the sum of its parts. Independent articles always end up more generalized, do not make the relationship to the whole nearly as clear, and lower readability simply by virtue of forcing readers to switch to sub-articles, and come back, over and over again. MPEG-1 is also low traffic enough that more eyes in one place should significantly improve article quality.

And please edit carefully. Hopefully this article can maintain a decent level of quality and accuracy, unlike just about every other multimedia article here on WP. I can't watch it forever, so ultimately, it will deteriorate to whatever level of quality all of you are willing to accept. Good luck. Try not to tear it to shreds. Rcooley (talk) 21:48, 19 April 2008 (UTC)

Can MPEG-1 be used without Licensing Fees?
The article had claimed that MPEG-1 could be used without any patents licensing fees. However, Dave Singer's post claimed that it might still be patented. Since MPEG-2 is still patented, there is a list of patents that it uses, and it is a superset of MPEG-1, if we can show that none of the patents that it still has are relevant for MPEG-1, then we have demonstrated that MPEG-1 is not patented. There are three ways to do this:
 * 1) Show that no patents for MPEG-2 filed after the date of the MPEG-1 standard (or maybe 1 year after the date) are relevant. I.e. no patents for MPEG-2 filed after 1992 (or maybe 1993) are  unexpired.
 * 2) Show that no patents for MPEG-2 filed after about 1990 are still unexpired, and that any changes between the draft MPEG-1 standard and the final MPEG-1 standard added no new patents.
 * 3) Show that all patents that are in MPEG-2 that are unexpired are not relevant to MPEG-1.

I have been working on adding the filing date and granting date for all the patents in the MPEGLA's MPEG-2 portfolio to the MPEG-2 article. It is looking like number 1 is not going to be true (since it would have to have been granted by 1991, which means it would have to have been filed by about 1989). However, there is still hope for 2 or 3. Jrincayc (talk) 15:04, 4 May 2008 (UTC)


 * The article never claimed MPEG-1 was free of patents... It could be read that the patent holders are simply not pursuing license fees. More to the point, the numerous citations directly support that fact.  The first link you added to the article does not address the question, either way.  The second link claims MPEG-1 is identical to H.261, which is clearly not true, so that's not a reliable source no matter what it says.  But I have no desire to argue.  Do as you like.  Rcooley (talk) 04:25, 15 May 2008 (UTC)


 * You're right about what the article said, so I renamed this thread, and edited part of my comment. I think that there are patents that the owners seem to be pursuing licensing fees for MPEG 1 Layer 1/2 audio (see the Audio MPEG handled patents in MPEG-2 and ).  Do we know how the Draft standard was distributed?  As in did it require a non-disclosure agreement (in which case it doesn't count as a publication) or was it more openly distributed? As to the question of licensing fees, unless all the patent holders have granted usage rights, then it still can't be used without licensing fees, at least not legally. Jrincayc (talk) 12:39, 15 May 2008 (UTC)


 * It doesn't appear to be true that Audio MPEG (Sisvel) is asserting any MPEG-1 Layer I/II patents. From their home page:  "Products not currently licensed by Audio MPEG and Sisvel include CD, Video-CD and DVD players not able to encode or decode MP3 files, DAB (Digital Audio Broadcast) products, and "Grand Alliance" standard high definition televisions."   On a technical note, considering that MUSICAM was a fully developed codec, circa 88, there are very few areas where valid, non-expired patents can even potentially be asserted on MP2 audio.  Rcooley (talk) 05:07, 7 October 2008 (UTC)


 * I agree with you on the Audio MPEG since they do mention Video-CD. Do you have any references on the age of MUSICAM? Jrincayc (talk) 12:18, 7 October 2008 (UTC)


 * I can't even guess which specific papers (out of the hundreds that I've read--particularly while writing the article) specifically discussed the development timeline of MUSICAM. After trying just a couple from the article, I can at least point you to one which cites MUSICAM and ASPEC being submitted and working in 1989. Rcooley (talk) 15:51, 7 October 2008 (UTC)


 * Okay, here is a source: Digital Video and Audio Broadcasting Technology: A Practical Engineering Guide (Signals and Communication Technology) ISBN 3540763570 pg 144: "In the year 1988, the MASCAM method was developed at the Institut für Rundfunktechnik (IRT) in Munich in preparation for the digital audio broadcasting (DAB) system.  From MASCAM, the MUSICAM (masking pattern universal subband integrated coding and multiplexing) method was developed in 1989 in cooperation with CCETT, Philips and Matsushita."  So, MUSICAM is 1989 (from both sources).  I wonder if there was a publicly available specification of MUSICAM or MASCAM?  Then it would be good prior art.  Jrincayc (talk) 03:38, 8 October 2008 (UTC)


 * Try: "Low bit-rate coding of high-quality audio signals. An introduction to the MASCAM system" by G. Thiele, G. Stoll and M. Link, published in EBU Technical Review, no. 230, pp. 71-94 pp. 158-181, August 1988. Rcooley (talk) 23:10, 9 October 2008 (UTC)


 * Thank you. I just got it yesterday by interlibrary loan.  Note: It is pages 158-181 (changed in your comment).  Based on my skim reading of the paper MASCAM seems to have every major feature of MPEG-1 Audio Layer II.  This includes scale factors, subband coding, allocating different numbers of bits to different subbands for each sample.  Based on filing and expiration dates for the US patents for MP3 all the ones that were filed before August 1989 (which is when this would have counted as prior art) have expired.   So now we have H.261 from 1990 for most of the video parts and MASCAM from 1988 for most of the audio parts for MPEG-1 video with layer II audio, so there seems to be a very good chance that it is patent free.  After I read the paper more carefully, I'll put some of the relevent information from this discussion in the MPEG-1 Layer II audio article.  Jrincayc (talk) 13:30, 4 November 2008 (UTC)


 * I wish patent law was that straight-forward... Remember that ASPEC existed at the same time as MUSICAM (1989), yet MP3 has numerous outstanding patents that won't expire for several years yet.  Patents were filed for every implementation detail and trivial change.
 * Honestly, MPEG-1 Audio Layer II is a waste of time. It's poorly written, inconsistent, entirely uncited (until I added a couple), horribly inaccurate, and I don't see that it contains any useful info that isn't here.  MP3 at least includes adoption, players, and cultural aspects of MP3, though the technical and historical/development info would best be removed entirely.  I wrote this article specifically to avoid (even more work) "fixing" those two terrible articles, and I was just never willing to put up with the drama and hassle of "merging" (deleting) them afterwards.  Rcooley (talk) 17:22, 8 November 2008 (UTC)
 * Yes, you're right about patent law not being that straight forward. After all in Alcatel-Lucent v. Microsoft Microsoft got sued for some MP3 patents that were filed well after the 11172 committee draft was published.  A more accurate statement might be that the remaining patents are weak.
 * For MP2, I don't understand the purpose of the two parts for decoding labeled "Build a 512 value vector U" and "Window by 512 coefficients" in Figure A.2 in ISO 11172-3. Where did they come up with the Di coefficients of the synthesis window and what do they do?
 * For removing stuff from articles, usually, I just cut it from the article, copy in to the discussion page and say something like moved to talk page in the article edit, and put my reasons why in the discussion page. Then it is easier for a proper discussion to happen if the info might be useful for the article, and if it is junk, it is more obvious since the cut text is right there in the talk page. Jrincayc (talk) 15:48, 9 November 2008 (UTC)


 * Rcooley suggested looking at for MPEG-1 patents.  Jrincayc (talk) 03:25, 7 October 2008 (UTC)

MPEG-2 patents that might apply to MPEG-1
List of MPEG-2 patents that were filed by August of 1994, since that is one year after the MPEG-1 standard was published. These may be applicable to MPEG-1. Jrincayc (talk) 04:05, 17 May 2008 (UTC) Note that wikipedia does not give legal advice, so consult a patent lawyer if you really need answers. Patents that probably do not apply to MPEG-1 are Struck out and patents that probably do apply to MPEG-1 are bold. Always give a reason if marking a patent. Data here is only as valid as the reason given. Refiled patents are included if they were initially filed by August 1994. Patents are also can be marked as to whether they are Video or Audio and whether they are for Encoding, Decoding or both. Please jump in and add reason why patents do or don't apply to MPEG-1.

Video

 * US Re 35,093 -- Systems and methods for coding even fields of interlaced video sequences -- Filed: December 9, 1994 Granted: November 21, 1995   Reissue of 05193004 Filed: Dec., 1990 Granted: Mar., 1993


 * US Re 37,568 -- Inverse Quantizer  -- Filed:  March 31, 1999 Granted: March 5, 2002  Reissue of 05617094 Filed: Nov., 1993 Granted: Apr., 1997


 * US Re 36,015 -- Apparatus and method for processing groups of fields in a video data compression system -- Filed: October 2, 1995 Granted: December 29, 1998  Reissue of 05293229 Filed: Mar., 1992 Granted: Mar., 1994
 * US Re 36,507 -- Apparatus and method for processing groups of fields in a video data compression system to encode a single frame as an I-field and a P-field -- Filed: October 21, 1997 Granted: January 18, 2000  Reissue of 05293229 Filed: Mar., 1992 Granted: Mar., 1994
 * US Re 39,276 -- Method for determining motion compensation -- Filed: April 27, 2000 Granted: September 12, 2006 Reissue of 05745182 Filed: Jul., 1994 Granted: Apr., 1998
 * US Re 39,278 -- Method for determining motion compensation -- Filed: April 13, 2001 Granted: September 12, 2006 Reissue of 05745182 Filed: Jul., 1994 Granted: Apr., 1998
 * US Re 39,280 -- Method for determining motion compensation -- Filed: May 30, 2001 Granted: September 12, 2006 Reissue of 05745182 Filed: Jul., 1994 Granted: Apr., 1998


 * US 4,970,590 -- System and device for package multiplexing in transmission of many data flows generated by a sole algorithm -- Filed: December 21, 1989 Granted: November 13, 1990  Video Encoding
 * US 5,453,790 --  Video decoder having asynchronous operation with respect to a video display -- Filed: March 26, 1993 Granted: September 26, 1995  Video Decoding
 * Maybe it would apply to MPEG-1. It describes a specific way of buffering the images that are received from a packet switching network before displaying.  It would probably not apply to an implementation that only read data from a disk drive.


 * US 5,291,284 -- Predictive coding and decoding with error drift reduction -- Filed: July 23, 1991 Granted: March 1, 1994


 * US 4,982,270 -- Video data transmitting system -- Filed: February 3, 1989 Granted: January 1, 1991


 * US 5,068,724 -- Adaptive motion compensation for digital television -- Filed: June 15, 1990 Granted: November 26, 1991
 * US 5,091,782 -- Apparatus and method for adaptively compressing successive blocks of digital video -- Filed: April 9, 1990 Granted: February 25, 1992
 * US 5,093,720 -- Motion compensation for interlaced digital television signals -- Filed: August 20, 1990 Granted: March 3, 1992
 * MPEG-1 does not have interlaced video, so not applicable.


 * US 5,235,618 -- Video signal coding apparatus, coding method used in the video signal coding apparatus and video signal coding transmission system having the video signal coding apparatus -- Filed: November 6, 1990 Granted: August 10, 1993


 * US 5,486,864 -- Differential time code method and apparatus as for a compressed video signal  -- Filed: May 13, 1993 Granted: January 23, 1996
 * US 5,491,516 -- Field elimination apparatus for a video compression/decompression system -- Filed: January 14, 1993 Granted: February 13, 1996
 * US 5,796,743 -- Data word indicator in a system for assembling transport data packets -- Filed:  November 30, 1993 Granted: August 18, 1998


 * US 5,223,949 -- Coding means for a signal processing system -- Filed: April 17, 1992 Granted: June 29, 1993


 * US 4,954,892 -- Buffer controlled picture signal encoding and decoding system -- Filed: October 4, 1989 Granted: September 4, 1990
 * US 5,072,295 -- Adaptive quantization coder/decoder with limiter circuitry -- Filed: August 20, 1990 Granted: December 10, 1991
 * US 5,268,846 -- Method and apparatus for nonsequential multimedia data interchange in a data processing system -- Filed: April 10, 1991 Granted: December 7, 1993


 * US 5,021,879 -- System for transmitting video pictures  -- Filed: September 24, 1990 Granted: June 4, 1991
 * US 5,027,206 -- High-definition television systems  -- Filed: September 13, 1989 Granted: June 25, 1991
 * US 5,128,758 -- Method and apparatus for digitally processing a high definition television augmentation signal  -- Filed: June 2, 1989 Granted: July 7, 1992
 * US 5,179,442 -- Method and apparatus for digitally processing a high definition television augmentation signal  -- Filed: November 26, 1990 Granted: January 12, 1993
 * US 5,333,135 -- Identification of a data stream transmitted as a sequence of packets  -- Filed: February 1, 1993 Granted: July 26, 1994


 * US 5,461,421 -- Encoding and decoding method and apparatus thereof -- Filed: November 29, 1993 Granted: October 24, 1995
 * US 5,467,086 -- Apparatus and method of coding/decoding video data  -- Filed: June 18, 1993 Granted: November 14, 1995


 * US 4,864,393 -- Motion vector estimation in television images  -- Filed: May 31, 1988 Granted: September 5, 1989
 * US 5,191,436 -- Method for recording coded motion picture data -- Filed: April 30, 1991 Granted: March 2, 1993
 * US 5,291,486 -- Data multiplexing apparatus and multiplexed data demultiplexing apparatus  -- Filed: August 7, 1992 Granted: March 1, 1994
 * US 5,298,991 -- Variable length coding apparatus and method for motion vector -- Filed: July 24, 1992 Granted: March 29, 1994
 * US 5,343,248 -- Moving image compressing and recording medium and moving image data encoder and decoder  -- Filed: July 16, 1992 Granted: August 30, 1994
 * US 5,428,396 -- Variable length coding/decoding method for motion vectors  -- Filed: December 27, 1993 Granted: June 27, 1995
 * US 5,461,420 -- Apparatus for coding and decoding a digital video signal derived from a motion picture film source  -- Filed: September 17, 1993 Granted: October 24, 1995
 * US 5,543,847 -- Picture coding and decoding method for random accessing -- Filed: December 13, 1993 Granted: August 6, 1996
 * US 5,559,557 -- Motion video coding with adaptive precision for DC component coefficient quantization and variable length coding  -- Filed: September 28, 1993 Granted: September 24, 1996
 * US 5,663,763 -- Picture signal encoding method and apparatus and picture signal decoding method and apparatus  -- Filed: October 18, 1993 Granted: September 2, 1997
 * US 5,982,437 -- Coding method and system, and decoding method and system -- Filed: October 15, 1993 Granted: November 9, 1999


 * US 5,289,276 -- Method and apparatus for conveying compressed video data over a noisy communication channel -- Filed: June 19, 1992 Granted: February 22, 1994
 * US 5,365,272 -- Method for formatting compressed video data into transport cells  -- Filed: July 2, 1993 Granted: November 15, 1994
 * US 5,381,181 -- Clock recovery apparatus as for a compressed video signal  -- Filed:  	 May 13, 1993 Granted: January 10, 1995
 * US 5,422,676 -- System for coding an image representative signal -- Filed:  	 October 22, 1993 Granted: June 6, 1995
 * US 5,442,400 -- Error concealment apparatus for MPEG-like video data -- Filed: April 29, 1993 Granted: August 15, 1995e


 * US 5,317,397 -- Predictive coding using spatial-temporal filtering and plural motion vectors  -- Filed: May 29, 1992 Granted: May 31, 1994
 * US 5,424,779 -- Video coding apparatus  -- Filed: November 24, 1993 Granted: June 13, 1995


 * US Re 34,965 -- Inter-frame predictive encoding system with encoded and transmitted prediction error  -- Filed: January 14, 1993 Granted: June 13, 1995
 * US Re 35,158 -- Apparatus for adaptive inter-frame predictive encoding of video signal  -- Filed: December 28, 1992 Granted: February 20, 1996
 * US 5,103,307 -- Interframe predictive coding/decoding system for varying interval between independent frames -- Filed: January 18, 1991 Granted: April 7, 1992
 * US 5,175,618 -- Compression method for interlace moving image signals -- Filed: October 30, 1991 Granted: December 29, 1992


 * US 5,214,742 -- Method for transmitting a signal  -- Filed: October 1, 1990 Granted: May 25, 1993
 * US 5,227,990 -- Process for transmitting and receiving a signal  -- Filed:  January 17, 1992 Granted: July 13, 1993
 * US 5,384,811 -- Method for the transmission of a signal -- Filed: August 24, 1992 Granted: January 24, 1995
 * US 5,455,833 -- Process for the detecting of errors in the transmission of frequency-coded digital signals  -- Filed: April 26, 1993 Granted: October 3, 1995
 * US 5,321,729 -- Method for transmitting a signal  -- Filed: April 26, 1993 Granted: June 14, 1994


 * US Re 35,910 -- Moving image signal encoding apparatus and decoding apparatus -- Filed: May 12, 1994 Granted: September 29, 1998
 * US 5,606,539 -- Method and apparatus for encoding and decoding an audio and/or video signal, and a record carrier for use with such apparatus  -- Filed: August 31, 1994 Granted: February 25, 1997
 * US 5,740,310 -- Method of maintaining display continuity from a CD with slow-motion or freeze capability -- Filed: June 28, 1994 Granted: April 14, 1998
 * US 5,457,701 -- Method for indicating packet errors in a packet-based multi-hop communications system -- Filed: January 6, 1994 Granted: October 10, 1995
 * US 5,418,782 -- Methods and apparatus for providing virtual service selection in a multi-service communications system -- Filed: January 6, 1994 Granted: May 23, 1995
 * US 5,420,866 -- Methods for providing conditional access information to decoders in a packet-based multiplexed communications system -- Filed: March 29, 1994 Granted: May 30, 1995
 * US Re 37,222 -- Video signal transmitting system  -- Filed: July 19, 1994 Granted: June 12, 2001
 * US 5,481,553 -- Methods and apparatus for preventing rounding errors when transform coefficients representing a motion picture signal are inversely transformed  -- Filed: February 28, 1994 Granted: January 2, 1996
 * US 5,539,466 -- Efficient coding apparatus for picture signal and decoding apparatus therefor -- Filed: September 26, 1994 Granted: July 23, 1996
 * US 5,459,789 -- Packet TV program component detector -- Filed: April 22, 1994 Granted: October 17, 1995
 * US 5,483,287 -- Method for forming transport cells for conveying compressed video data  -- Filed: August 3, 1994 Granted: January 9, 1996
 * US 5,467,136 -- Video decoder for determining a motion vector from a scaled vector and a difference vector -- Filed: February 17, 1994 Granted: November 14, 1995

Audio

 * US 5,341,457 -- Perceptual coding of audio signals  -- Filed: August 20, 1993 Granted: August 23, 1994
 * US RE39,080 -- Rate loop processor for perceptual encoder/decoder -- Filed: August 13, 2002 Granted: April 25, 2006


 * US 4,972,484 -- Method of transmitting or storing masked sub-band coded audio signals -- Filed: July 21, 1988 Granted: November 20, 1990
 * Sub-band coded audio used for MPEG-1 Layers 1,2,3


 * US 5,214,678 -- Digital transmission system using subband coding of a digital signal -- Filed: May 31, 1990 Granted: May 25, 1993
 * US 5,323,396 -- Digital transmission system, transmitter and receiver for use in the transmission system -- Filed: December 21, 1992 Granted: June 21, 1994
 * US 5,606,618 -- Subband coded digital transmission system using some composite signals  -- Filed: December 27, 1993 Granted: February 25, 1997


 * US 5,610,985 -- Digital 3-channel transmission of left and right stereo signals and a center signal -- Filed: January 21, 1994 Granted: March 11, 1997
 * MPEG-1 only has left and right stereo channels.


 * US 5,559,834 -- Method of reducing crosstalk in processing of acoustic or optical signals  -- Filed: April 15, 1994 Granted: September 24, 1996
 * US 5,742,735 -- Digital adaptive transformation coding method  -- Filed: August 25, 1994 Granted: April 21, 1998

Does "chroma" mean "red and blue"?
This is a minor issue, but the parenthesis within the statement "each pair of (red and blue) chroma blocks" is confusing. Although green is the closest of the RGB colours to luminance, I think that to suggest that chroma represents red and blue is misleading. Unless, that is, I have misunderstood. —Preceding unsigned comment added by 138.37.33.46 (talk) 10:02, 31 July 2008 (UTC)


 * Here is a bit of explanation of the idea that the chroma blocks correspond to red and blue: Ignoring some minor details of scaling and constant offsets, the transformation from R'G'B' to Y'CbCr (where Y' is a luminance value and Cb and Cr are chrominance values) can be considered as a two step process.  Step 1 is to compute the luminance value using the equation Y' = A1 * R' + A2 * G' + A3 * B', where A1 through A3 are constants.  Step 2 is to compute Cb = B' - Y' and Cr = R' - Y'.  From those last two equations you can see that Cb represents "blueness" and Cr represents "redness".  A gray image (with some brightness but no color hue or saturation) will have Cb = 0 and Cr = 0.  A blueish image will have Cb > 0.  A reddish image will have Cr > 0. It may also be worth noticing that Cb and Cr can be negative. —Mulligatawny (talk) 17:28, 5 September 2008 (UTC)

Philips Patents on Video CDs
These are all the US patents listed on http://www.ip.philips.com/services/?module=IpsLicenseProgram&command=View&id=52&part=4 as a table. Jrincayc (talk) 14:47, 10 October 2008 (UTC)
 * And I filled in the assignees. --Damian Yerrick (talk | stalk) 20:59, 17 September 2011 (UTC)

Trying to find reference on MPEG-1 audio synthesis windows
I am trying to understand the MPEG-1 synthesis windows and I found a mention of this reference: S. Searing, "Suggested Formulas for Audio Analysis and Synthesis Windows", ISO/IEC JTC1/SC29/WG11 MPEG 91/328, November 1991. However, I have not been able to find a way to get a hold of this. A couple google searches as well as worldcat that I tried have only turned up the book that I found the reference in, and nothing on the original paper. I also tried searching at both iso and iec, and could not find it though maybe I am searching for it incorrectly there. Any ideas? Thanks. Jrincayc (talk) 13:19, 26 January 2009 (UTC)

Achieving much higher compression
Achieving much higher compression is simply not possible without discarding some perceptible information.

That seems ulikely to be true, as AAC archives much higher compression.

The reason for this disparity with both earlier and later tests is not clear, but strangely, a sample of applause is notably absent from this test.

The rason seems to be obvious - the first test tested matrix encoded two channel MP2 vs full six channel audio other formats. That gave large advantage to MP2. It's so obvious actually I would say that the test was intentionally biased in favor of MP2.

--90.179.235.249 (talk) 12:29, 11 June 2010 (UTC)


 * The entire audio section of this article is heavily biased in favour of MP2. It's full of POV, commentary, glowing praise for MP2 and disparaging remarks about MP3 and other codecs. The technical details are interesting, but it's clear that the author has a real axe to grind, and it doesn't seem credible that a twenty-year-old codec is somehow better than anything else subsequently invented.
 * 109.170.137.220 (talk) 16:06, 30 May 2011 (UTC)


 * You two are mistaking "bias" for a painstaking attempt to very clearly explain away some common misconceptions, which you are now helping to perpetuate in your ignorance. MP2 is poor at low-bitrate encoding (which is where AAC and other modern codecs have focused all their efforts), but it's also one of the few temporal-domain codecs, making it among the very best at high-bitrate encoding.  What's more, it's so close to the theoretical limits of Perceptual Entropy that it ISN'T POSSIBLE, even in theory, for any codecs to do significantly better...  least of all any frequency-domain codecs like MP3, AAC, etc.  I explained the issues as clearly as I could in the article, I suggest you re-read it, and the relevant references that are included, until you understand why it's a scientifically provable fact.  The facts don't care if it "doesn't seem credible" to you. Rcooley (talk) 07:11, 13 September 2012 (UTC)

External links modified
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 * Added archive https://web.archive.org/20060916012236/http://www.ee.columbia.edu/~marios/courses/e6820y02/project/papers/Perceptual%20coding%20of%20digital%20audio%20.pdf to http://www.ee.columbia.edu/~marios/courses/e6820y02/project/papers/Perceptual%20coding%20of%20digital%20audio%20.pdf

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One random but potentially very difficult question
Something that I haven't been able to find any further information on, after coming across some DVD / VCD encoding header tables on an external page (whilst looking for info about where the MPG2 field order flag is hidden ... still hunting that as well!) - what's the deal with all the strange and somewhat arbitrary-seeming pixel aspect ratios that can be set in an MPG1 video file? The only ones valid for VCD and DVD are those corresponding to 4:3 and 16:9 modes for each of PAL and NTSC. However, there also exists not only a computer-targeted-footage friendly 1:1 ratio, but nine other options, that run to wider than PAL 16:9 (otherwise the widest), narrower than NTSC 4:3 (otherwise the narrowest), and fill in several intermediate points besides. None of them seem at all familiar, I have so far failed to come up with resolutions and/or frame aspect ratios where they make sense (especially not in the sub-400x300 range that they're presumably intended for, though I'm open to any alternative setting up to 4096 x whatever), and there is ab. so. lute. ly nothing about it on the rest of the web that I can find. My one recourse might be to buy a copy of the ISO standard, but it's not beyond the realm of imagination that even that may be barren (though the listed numbers must have come from SOMEWHERE!). They're not just the wild imaginings of some random video professional trying to troll his rivals via the internet by bulking out the list - that particular stat is contained in a 4-bit field (16 entries), and the "useful" options are distributed through it and the unusual ones in a non-uniform manner, and unless you set the correct 4-bit code for those values, your video isn't gonna work right.

All but four options (plus a carried-over "forbidden" and "reserved") exist in MPG2 - 1:1 pixels, plus 4:3, 16:9 and 2.21:1 frame - packed up against the head of the table with all the others having been quietly dropped (and only 1:1 in the same position as before), and decoders expected to infer PAL/NTSC from the input resolution and framerate in order to both set the key features of the output signal and, if necessary, reformat the images contained within according to that and the aspect tag. (Somehow video-capable machines were not considered capable of that remarkably simple piece of truth-table navigation two years earlier!)

So presumably they were considered potentially useful for video conferencing and general-purpose progressive digital video encoding, but of no interest as far as high quality conversion of interlaced televisual content to the digital domain for optical disc and VOD delivery to consumers... strange-o.

...seriously, anyone got ANY pointers here? It's a completely pointless question and useless knowledge, but the insatiable geek within me won't rest until it gets its question answered... 193.63.174.254 (talk) 19:47, 16 March 2017 (UTC)

External links modified
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 * Corrected formatting/usage for http://mpeg.chiariglione.org/meetings.htm
 * Added archive https://web.archive.org/web/20090723213246/http://bmrc.berkeley.edu/research/mpeg/software/Old/mpegfa31.txt to http://bmrc.berkeley.edu/research/mpeg/software/Old/mpegfa31.txt
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 * Corrected formatting/usage for http://mpeg.chiariglione.org/meetings/paris94/paris_press.htm
 * Added archive https://web.archive.org/web/20131231054907/http://kikaku.itscj.ipsj.or.jp/sc29/29w42911.htm to http://kikaku.itscj.ipsj.or.jp/sc29/29w42911.htm
 * Corrected formatting/usage for http://213.130.34.82/resources/technical/mpegcompared/index.htm
 * Added tag to http://bmrc.berkeley.edu/research/mpeg/software/Old/Mpeg93.ps.gz
 * Added tag to http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=5214678
 * Added archive https://web.archive.org/web/20090503020732/http://bmrc.berkeley.edu/frame/research/mpeg/mpeg_overview.html to http://bmrc.berkeley.edu/frame/research/mpeg/mpeg_overview.html
 * Corrected formatting/usage for http://www.telos-systems.com/techtalk/mpeg/default.htm
 * Corrected formatting/usage for http://mpeg.chiariglione.org/technologies/mpeg-1/mp01-aud/index.htm
 * Corrected formatting/usage for http://www.cs.columbia.edu/~coms6181/slides/6R/mpegaud.pdf
 * Corrected formatting/usage for http://dafx04.na.infn.it/WebProc/Proc/P_157.pdf
 * Corrected formatting/usage for http://www.mpeg.org/MPEG/audio/aac.html
 * Corrected formatting/usage for http://mpeg.chiariglione.org/meetings/singapore94/singapore_press.htm

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External links modified
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I have just modified one external link on MPEG-1. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://web.archive.org/web/20150208104604/http://www.mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm to http://www.mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm

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Cheers.— InternetArchiveBot  (Report bug) 14:00, 26 July 2017 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified 2 external links on MPEG-1. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://web.archive.org/web/20081006133233/http://bmrc.berkeley.edu/research/publications/1992/101/101.html to http://bmrc.berkeley.edu/research/publications/1992/101/101.html
 * Added archive https://web.archive.org/web/20080612140755/http://bmrc.berkeley.edu/frame/research/mpeg to http://bmrc.berkeley.edu/frame/research/mpeg/

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Cheers.— InternetArchiveBot  (Report bug) 19:09, 10 January 2018 (UTC)