MPEG-2
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MPEG-2 is a standard for "the generic coding of moving pictures and associated audio information".[1] It describes a combination of lossy video compression and lossy audio data compression methods which permit storage and transmission of movies using currently available storage media and transmission bandwidth.
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[edit] Main characteristics
MPEG-2 is widely used as the format of digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. It also specifies the format of movies and other programs that are distributed on DVD and similar discs. As such, TV stations, TV receivers, DVD players, and other equipment are often designed to this standard. MPEG-2 was the second of several standards developed by the Moving Pictures Expert Group (MPEG) and is an international standard (ISO/IEC 13818). Parts 1 and 2 of MPEG-2 were developed in a joint collaborative team with ITU-T, and they have a respective catalog number in the ITU-T Recommendation Series.
While MPEG-2 is the core of most digital television and DVD formats, it does not completely specify them. Regional institutions can adapt it to their needs by restricting and augmenting aspects of the standard. See Profiles and Levels.
MPEG-2 includes a Systems section, part 1, that defines two distinct, but related, container formats. One is the Transport Stream, designed to carry digital video and audio over possibly lossy media, such as broadcasting, examples of which include ATSC, DVB and SBTVD. MPEG-2 Systems also defines Program Stream, a container format designed for reasonably reliable media such as optical discs, DVDs and SVCDs. MPEG-2/System is formally known as ISO/IEC 13818-1 and as ITU-T Rec. H.222.0.[2]
The Video section, part 2 of MPEG-2, is similar to the previous MPEG-1 standard, but also provides support for interlaced video, the format used by analog broadcast TV systems. MPEG-2 video is not optimized for low bit-rates, especially less than 1 Mbit/s at standard definition resolutions. However, it outperforms MPEG-1 at 3 Mbit/s and above. All standards-compliant MPEG-2 Video decoders are fully capable of playing back MPEG-1 Video streams. MPEG-2/Video is formally known as ISO/IEC 13818-2 and as ITU-T Rec. H.262.[3]
With some enhancements, MPEG-2 Video and Systems are also used in some HDTV transmission systems.
The MPEG-2 Audio section, defined in part 3 of the standard, enhances MPEG-1's audio by allowing the coding of audio programs with more than two channels. This method is backwards-compatible, allowing MPEG-1 audio decoders to decode the two main stereo components of the presentation.
Part 7 of the MPEG-2 standard specifies a rather different, non-backwards-compatible audio format. Part 7 is referred to as MPEG-2 AAC. AAC is more efficient than the previous MPEG audio standards, and is in some ways less complicated than the its predecessor, MPEG-1 Audio, Layer 3, in that it does not have the hybrid filter bank. Advanced Audio is also defined in Part 3 of the MPEG-4 standard.
[edit] History
MPEG-2 evolved out of the shortcomings of MPEG-1.
MPEG-1's known weaknesses:
- a less efficient audio compression system
- lack of flexibility (fewer variations of acceptable packet types)
- does not support interlaced footage
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[edit] Video coding (simplified)
An HDTV camera generates a raw video stream of up to 233,280,000 bytes per second. This stream must be compressed if digital TV is to fit in the bandwidth of available TV channels and if movies are to fit on DVDs. Fortunately, video compression is practical because the data in pictures is often redundant in space and time. For example, the sky can be blue across the top of a picture and that blue sky can persist for frame after frame. Also, because of the way the eye works, it is possible to delete some data from video pictures with almost no noticeable degradation in image quality.
TV cameras used in broadcasting usually generate 25 pictures a second (in Europe) or 29.97 pictures a second (in North America). Digital television requires that these pictures be digitized so that they can be processed by computer hardware. Each picture element (a pixel) is then represented by one luma number and two chrominance numbers. These describe the brightness and the color of the pixel (see YCbCr). Thus, each digitized picture is initially represented by three rectangular arrays of numbers.
A common (and old) trick to reduce the amount of data is to separate the picture into two fields: the "top field," which is the odd numbered rows, and the "bottom field," which is the even numbered rows. The two fields are displayed alternately. This format is called interlaced video; two successive fields are called a frame. The typical frame rate is then 25 or 29.97 frames per second. If the video is not interlaced, then it is called progressive video and each picture is a frame. MPEG-2 supports both options.
Another common practice to reduce the data rate is to "thin out" or subsample the two chrominance planes. In effect, the remaining chrominance values represent the nearby values that are deleted. Thinning works because the eye better resolves brightness details than chrominance details. The 4:2:2 chrominance format indicates that half the chrominance values have been deleted. The 4:2:0 chrominance format indicates that three quarters of the chrominance values have been deleted. If no chrominance values have been deleted, the chrominance format is 4:4:4. MPEG-2 allows all three options.
MPEG-2 specifies that the raw frames be compressed into three kinds of frames: intra-coded frames (I-frame), predictive-coded frames (P-frames), and bidirectionally-predictive-coded frames (B-frames).
An I-frame is a compressed version of a single uncompressed (raw) frame. It takes advantage of spatial redundancy and of the inability of the eye to detect certain changes in the image. Unlike P-frames and B-frames, I-frames do not depend on data in the preceding or the following frames. Briefly, the raw frame is divided into 8 pixel by 8 pixel blocks. The data in each block is transformed by a discrete cosine transform. The result is an 8 by 8 matrix of coefficients. The transform converts spatial variations into frequency variations, but it does not change the information in the block; the original block can be recreated exactly by applying the inverse cosine transform. The advantage of doing this is that the image can now be simplified by quantizing the coefficients. Many of the coefficients, usually the higher frequency components, will then be zero. The penalty of this step is the loss of some subtle distinctions in brightness and color. If one applies the inverse transform to the matrix after it is quantized, one gets an image that looks very similar to the original image but that is not quite as nuanced. Next, the quantized coefficient matrix is itself compressed. Typically, one corner of the quantized matrix is filled with zeros. By starting in the opposite corner of the matrix, then zigzagging through the matrix to combine the coefficients into a string, then substituting run-length codes for consecutive zeros in that string, and then applying Huffman coding to that result, one reduces the matrix to a smaller array of numbers. It is this array that is broadcast or that is put on DVDs. In the receiver or the player, the whole process is reversed, enabling the receiver to reconstruct, to a close approximation, the original frame.
Typically, every 15th frame or so is made into an I-frame. P-frames and B-frames might follow an I-frame like this, IBBPBBPBBPBB(I), to form a Group Of Pictures (GOP); however, the standard is flexible about this.
[edit] Macroblocks
P-frames provide more compression than I-frames because they take advantage of the data in the previous I-frame or P-frame. I-frames and P-frames are called reference frames. To generate a P-frame, the previous reference frame is reconstructed, just as it would be in a TV receiver or DVD player. The frame being compressed is divided into 16 pixel by 16 pixel macroblocks. Then, for each of those macroblocks, the reconstructed reference frame is searched to find that 16 by 16 macroblock that best matches the macroblock being compressed. The offset is encoded as a "motion vector." Frequently, the offset is zero. But, if something in the picture is moving, the offset might be something like 23 pixels to the right and 4 pixels up. The match between the two macroblocks will often not be perfect. 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. This "residual" is appended to the motion vector and the result sent to the receiver or stored on the DVD for each macroblock being compressed. Sometimes no suitable match is found. Then, the macroblock is treated like an I-frame macroblock.
The processing of B-frames is similar to that of P-frames except that B-frames use the picture in the following reference frame as well as the picture in the preceding reference frame. As a result, B-frames usually provide more compression than P-frames. B-frames are never reference frames.
While the above generally describes MPEG-2 video compression, there are many details that are not discussed including details involving fields, chrominance formats, responses to scene changes, special codes that label the parts of the bitstream, and other pieces of information.
[edit] Audio encoding
MPEG-2 also introduces new audio encoding methods. These are
- low bitrate encoding with halved sampling rate (MPEG-1 Layer 1/2/3 LSF)
- multichannel encoding with up to 5.1 channels
- MPEG-2 AAC
[edit] Video profiles and levels
MPEG-2 video supports a wide range of applications from mobile to high quality HD editing. For many applications, it's unrealistic and too expensive to support the entire standard. To allow such applications to support only subsets of it, the standard defines profile and level.
The profile defines the subset of features such as compression algorithm, chroma format, etc. The level defines the subset of quantitative capabilities such as maximum bit rate, maximum frame size, etc.
A MPEG application then specifies the capabilities in terms of profile and level. For example, a DVD player may say it supports up to main profile and main level (often written as MP@ML). It means the player can play back any MPEG stream encoded as MP@ML or less.
The tables below summarizes the limitations of each profile and level. There are many other constraints not listed here.
| Abbr. | Name | Picture Coding Types | Chroma Format | Aspect Ratios | Scalable modes |
|---|---|---|---|---|---|
| SP | Simple profile | I, P | 4:2:0 | square pixels, 4:3, or 16:9 | none |
| MP | Main profile | I, P, B | 4:2:0 | square pixels, 4:3, or 16:9 | none |
| SNR | SNR Scalable profile | I, P, B | 4:2:0 | square pixels, 4:3, or 16:9 | SNR (signal-to-noise ratio) scalable |
| Spatial | Spatially Scalable profile | I, P, B | 4:2:0 | square pixels, 4:3, or 16:9 | SNR- or spatial-scalable |
| HP | High profile | I, P, B | 4:2:2 or 4:2:0 | square pixels, 4:3, or 16:9 | SNR- or spatial-scalable |
Exempting scalability (a rarely used feature where one MPEG-2 stream augments another), the following are some of the constraints on levels:
| Abbr. | Name | Frame rates (Hz) | Max horizontal resolution | Max vertical resolution | Max luminance samples per second (approximately height x width x framerate) | Max bit rate in Main profile (Mbit/s) |
|---|---|---|---|---|---|---|
| LL | Low Level | 23.976, 24, 25, 29.97, 30 | 352 | 288 | 3,041,280 | 4 |
| ML | Main Level | 23.976, 24, 25, 29.97, 30 | 720 | 576 | 10,368,000, except in High profile, where constraint is 14,475,600 for 4:2:0 and 11,059,200 for 4:2:2 | 15 |
| H-14 | High 1440 | 23.976, 24, 25, 29.97, 30, 50, 59.94, 60 | 1440 | 1152 | 47,001,600, except that in High profile with 4:2:0, constraint is 62,668,800 | 60 |
| HL | High Level | 23.976, 24, 25, 29.97, 30, 50, 59.94, 60 | 1920 | 1152 | 62,668,800, except that in High profile with 4:2:0, constraint is 83,558,400 | 80 |
[edit] Applications
[edit] DVD
The DVD standard uses MPEG-2 video, but imposes some restrictions:
- Allowed Resolutions
- 720 × 480, 704 × 480, 352 × 480, 352 × 240 pixel (NTSC)
- 720 × 576, 704 × 576, 352 × 576, 352 × 288 pixel (PAL)
- Allowed Aspect ratios (Display AR)
- 4:3
- 16:9 (1.85:1 and 2.35:1, among others, are often listed as valid DVD aspect ratios, but are actually just a 16:9 image with the top and bottom of the frame masked in black)
- Allowed Frame rates
- 29.97 frame/s (NTSC)
- 25 frame/s (PAL)
- Note: By using a pattern of REPEAT_FIRST_FIELD flags on the headers of encoded pictures, pictures can be displayed for either two or three fields and almost any picture display rate (minimum ⅔ of the frame rate) can be achieved. This is most often used to display 23.976 (approximately film rate) video on NTSC.
- Audio+video bitrate
- Video peak 9.8 Mbit/s
- Total peak 10.08 Mbit/s
- Minimum 300 kbit/s
- YUV 4:2:0
- Additional subtitles possible
- Closed captioning (NTSC only)
- Audio
- Linear Pulse Code Modulation (LPCM): 48 kHz or 96 kHz; 16- or 24-bit; up to six channels (not all combinations possible due to bitrate constraints)
- MPEG Layer 2 (MP2): 48 kHz, up to 5.1 channels (required in PAL players only)
- Dolby Digital (DD, also known as AC-3): 48 kHz, 32–448 kbit/s, up to 5.1 channels
- Digital Theater Systems (DTS): 754 kbit/s or 1510 kbit/s (not required for DVD player compliance)
- NTSC DVDs must contain at least one LPCM or Dolby Digital audio track.
- PAL DVDs must contain at least one MPEG Layer 2, LPCM, or Dolby Digital audio track.
- Players are not required to play back audio with more than two channels, but must be able to downmix multichannel audio to two channels.
- GOP structure (Group Of Pictures)
- Sequence header must be present at the beginning of every GOP
- Maximum frames per GOP: 18 (NTSC) / 15 (PAL), i.e. 0.6 seconds both
- Closed GOP required for multi-angle DVDs
[edit] DVB
Application-specific restrictions on MPEG-2 video in the DVB standard:
Allowed resolutions for SDTV:
- 720, 640, 544, 480 or 352 × 480 pixel, 24/1.001, 24, 30/1.001 or 30 frame/s
- 352 × 240 pixel, 24/1.001, 24, 30/1.001 or 30 frame/s
- 720, 704, 544, 480 or 352 × 576 pixel, 25 frame/s
- 352 × 288 pixel, 25 frame/s
For HDTV:
- 720 x 576 x 50 frame/s progressive (576p50)
- 1280 x 720 x 25 or 50 frame/s progressive (720p50)
- 1440 or 1920 x 1080 x 25 frame/s progressive (1080p25 – film mode)
- 1440 or 1920 x 1080 x 25 frame/s interlace (1080i25)
- 1920 x 1080 x 50 frame/s progressive (1080p50) possible future H.264/AVC format
[edit] ATSC and ISDB-T
The ATSC A/53 standard, used in the United States, uses MPEG-2 video at the Main Profile @ High Level, with additional restrictions:
- The maximum bitrate of the MPEG-2 video stream is exactly 19.4 Mbit/s for broadcast television, and exactly 38.8 Mbit/s for the "high-data-rate" mode (e.g., cable television). (The practical limit is somewhat lower, since the MPEG-2 video stream must fit inside a transport stream, with overhead, sent out at 19.3927... Mbit/s for broadcast.)
- The amount of MPEG-2 stream buffer required at the decoder (the vbv_buffer_size_value) must be less than or equal to 999,424 bytes.
- In most cases, the transmitter can't start sending a coded image until within a half-second of when it's to be decoded (vbv_delay less than or equal to 45000 90-kHz clock increments).
- The stream must include colorimetry information (gamma curve, the precise RGB colors used, and the relationship between RGB and the coded YCbCr).
- The video must be 4:2:0 (chrominance resolution must be 1/2 of luma horizontal resolution and 1/2 of luma vertical resolution).
Allowed video resolutions, aspect ratios, and frame/field rates:
- 1920 × 1080 pixel (16:9, with square pixels), at 30p, 29.97p, 24p, 23.98p, 30i, or 29.97i
- 1280 × 720 pixel (16:9, with square pixels), at 60p, 59.94p, 30p, 29.97p, 24p, or 23.98p
- 704 × 480 pixel (either 4:3 or 16:9 – either way, with non-square pixels), at 60p, 59.94p, 30p, 29.97p, 24p, 23.98p, 30i, or 29.97i
- 640 × 480 pixel (4:3, with square pixels), at 60p, 59.94p, 30p, 29.97p, 24p, 23.98p, 30i, or 29.97i
Note that although the ATSC A/53 standard limits transmission to these 18 formats (and their 1000/1001-rate slowed-down versions), the U.S. Federal Communications Commission declined to mandate that television stations obey this part of the ATSC's standard. In theory, television stations in the U.S. are free to choose any resolution, aspect ratio, and frame/field rate, within the limits of Main Profile @ High Level. Many stations do go outside the bounds of the ATSC specification by using other resolutions – for example, 720 × 480.
Also note that the ATSC specification and MPEG-2 allow the use of progressive frames, even within an interlaced video sequence. For example, NBC stations transmit a 1080i30 video sequence – meaning the formal output of the MPEG-2 decoding process is sixty 540-line fields per second. But for prime-time television shows, those 60 fields can be coded with 24 progressive frames. Some NBC stations do this, meaning they actually transmit an 1080p24 video stream (a sequence of 24 progressive frames per second) with metadata instructing the decoder to interlace them (and repeat them in 3:2 pulldown) before display.
Thus, it would be incorrect to say that the ATSC standard doesn't contain 1080p video, or that broadcast HDTV doesn't use 1080p video. The ATSC specification allows 1080p30 and 1080p24 sequences – just not 1080p60 sequences. They aren't used in practice, because broadcasters want to be able to switch between 60 Hz (news, soap operas) and 24 Hz (prime-time) content without ending the MPEG-2 sequence. However, the ATSC specification also allows broadcasters to transmit progressive frames within an interlaced sequence, and some broadcasters actually do this in practice. Their transmissions could fairly be described as 1080p24, since they contain 24 progressively-coded frames per second. (This is the same mechanism used by HD-DVD to code 1080p24 content – progressive frames within an interlaced sequence.)
Note: The 1080-line formats are encoded with 1920 × 1088 pixel luma matrices and 960 × 540 chroma matrices, but the last 8 lines are discarded by the MPEG-2 decoding and display process.
MPEG-2 audio was a contender for the ATSC standard during the DTV "Grand Alliance" shootout, but lost out to Dolby AC-3. The Grand Alliance issued a statement finding the MP2 system to be "essentially equivalent" to Dolby, but only after the Dolby selection had been made. Later, a story emerged that MIT had entered into an agreement with Dolby whereupon the university would be awarded a large sum if the MP2 system was rejected. Dolby also offered an incentive for Zenith to switch their vote (which they did), however it is unknown whether they accepted the offer. [4]
Note: All the text about MPEG-2 in ATSC is also valid for ISDB-T, except that in the main TS is aggregated a second program for mobile devices compressed in MPEG-4 H.264 AVC for video and AAC-LC for audio, mainly known as 1Seg.
[edit] ISO/IEC 13818
- Part 1
- Systems – describes synchronization and multiplexing of video and audio. Also known as ITU-T Rec. H.222.0.[2] See MPEG transport stream.
- Part 2
- Video – compression codec for interlaced and non-interlaced video signals. Also known as ITU-T Rec. H.262.
- Part 3
- Audio – compression codec for perceptual coding of audio signals. A multichannel-enabled extension of MPEG-1 audio.
- Part 4
- Describes procedures for testing compliance.
- Part 5
- Describes systems for Software simulation.
- Part 6
- Describes extensions for DSM-CC (Digital Storage Media Command and Control).
- Part 7
- Advanced Audio Coding (AAC).
- Part 9
- Extension for real time interfaces.
- Part 10
- Conformance extensions for DSM-CC.
- Part 11
- Intellectual property management (IPMP)
(Part 8: 10-bit video extension. Primary application was studio video. Part 8 has been withdrawn due to lack of interest by industry.)
[edit] Patent holders
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Approximately 640 patents worldwide make up the "essential" patents surrounding MPEG-2.[5][6] These are held by over 20 corporations and one university. Where software patentability is upheld, the use of MPEG-2 requires the payment of licensing fees to the patent holders via the MPEG Licensing Association. The patent pool is managed and administered by MPEG Licensing Authority, a private organization. Other patents are licensed by Audio MPEG, Inc.[7] The development of the standard itself took less time than the patent negotiations.[8][9]
[edit] MPEG-LA Patents
- Alcatel-Lucent
- US 4,833,543 -- Image processing system and phaselocked loop used therein (Expired) -- Filed: December 24, 1986 Granted: May 23, 1989 [2]
- 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 [3]
- US 5,453,790 -- Video decoder having asynchronous operation with respect to a video display -- Filed: March 26, 1993 Granted: September 26, 1995 [4]
- British Telecommunications plc
- US 5,291,284 -- Predictive coding and decoding with error drift reduction -- Filed: July 23, 1991 Granted: March 1, 1994 [5]
- Canon Inc.
- US 4,982,270 -- Video data transmitting system -- Filed: February 3, 1989 Granted: January 1, 1991 [6]
- CIF LICENSING, LLC
- US 5,068,724 -- Adaptive motion compensation for digital television -- Filed: June 15, 1990 Granted: November 26, 1991 [7]
- US 5,091,782 -- Apparatus and method for adaptively compressing successive blocks of digital video -- Filed: April 9, 1990 Granted: February 25, 1992 [8]
- US 5,093,720 -- Motion compensation for interlaced digital television signals -- Filed: August 20, 1990 Granted: March 3, 1992 [9]
- Columbia University
- US Re 35,093 -- Systems and methods for coding even fields of interlaced video sequences -- Filed: December 9, 1994 Granted: November 21, 1995 [10] Reissue of 05193004 Filed: Dec., 1990 Granted: Mar., 1993
- France Telecom (CNET)
- US 4,796,087 Expired [11]
- Fujitsu
- 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 [12]
- General Electric Capital Corporation
- General Instrument Corp. (now the broadband division of Motorola)
- GE Technology Development, Inc.
- US 5,426,464 -- Field elimination apparatus for a video compression/decompression system -- Filed: October 18, 1994 Granted: June 20, 1995 [17]
- US 5,486,864 -- Differential time code method and apparatus as for a compressed video signal -- Filed: May 13, 1993 Granted: January 23, 1996 [18]
- US 5,491,516 -- Field elimination apparatus for a video compression/decompression system -- Filed: January 14, 1993 Granted: February 13, 1996 [19]
- US 5,600,376 -- Field elimination apparatus for a video compression/decompression system -- Filed: March 20, 1995 Granted: February 4, 1997 [20]
- US 5,796,743 -- Data word indicator in a system for assembling transport data packets -- Filed: November 30, 1993 Granted: August 18, 1998 [21]
- Hitachi, Ltd.
- KDDI Corporation (KDDI)
- LG Electronics Inc.
- US Re 37,057 -- Apparatus and method for converting an HDTV signal to a non-HDTV signal -- Filed: May 18, 1998 Granted: February 20, 2001 [22] Reissue of 05519446 Filed: Nov., 1994 Granted: May., 1996
- US Re 37,568 -- Inverse Quantizer -- Filed: March 31, 1999 Granted: March 5, 2002 [23] Reissue of 05617094 Filed: Nov., 1993 Granted: Apr., 1997
- Matsushita / Panasonic
- US Re 35,910 -- Moving image signal encoding apparatus and decoding apparatus -- Filed: May 12, 1994 Granted: September 29, 1998 [24] Reissue of 05113255 Filed: May., 1990 Granted: May., 1992
- 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 [25] 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 [26] 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 [27] 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 [28] 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 [29] Reissue of 05745182 Filed: Jul., 1994 Granted: Apr., 1998
- US 5,223,949 -- Coding means for a signal processing system -- Filed: April 17, 1992 Granted: June 29, 1993 [30]
- US 5,412,430 -- Image coding method and image coding apparatus -- Filed: May 4, 1994 Granted: May 2, 1995 [31]
- US 5,784,107 -- Method and apparatus for picture coding and method and apparatus for picture decoding -- Filed: January 23, 1996 Granted: July 21, 1998 [32]
- Mitsubishi
- US 4,954,892 -- Buffer controlled picture signal encoding and decoding system -- Filed: October 4, 1989 Granted: September 4, 1990 [33]
- US 5,072,295 -- Adaptive quantization coder/decoder with limiter circuitry -- Filed: August 20, 1990 Granted: December 10, 1991 [34]
- 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 [35]
- US 5,949,489 -- Image signal coding system -- Filed: July 31, 1998 Granted: September 7, 1999 [36]
- US 5,963,258 -- Image signal coding system -- Filed: July 31, 1998 Granted: October 5, 1999 [37]
- US 5,970,175 -- Image signal coding system -- Filed: October 26, 1998 Granted: October 19, 1999 [38]
- US 5,990,960 -- Image signal coding system -- Filed: December 9, 1998 Granted: November 23, 1999 [39]
- US 6,002,439 -- Image signal coding system -- Filed: May 27, 1999 Granted: December 14, 1999 [40]
- US 6,097,759 -- Image signal coding system -- Filed: November 22, 1999 Granted: August 1, 2000 [41]
- US 6,188,794 -- Image signal coding system -- Filed: May 20, 1999 Granted: February 13, 2001 [42]
- US 6,307,973 -- Image signal coding system -- Filed: December 4, 2000 Granted: October 23, 2001 [43]
- Nippon Telegraph and Telephone Corporation (NTT)
- NXP
- Philips
- US 4,849,812 Expired [44]
- US 4,901,075 Expired [45]
- US 5,021,879 -- System for transmitting video pictures -- Filed: September 24, 1990 Granted: June 4, 1991 [46]
- US 5,027,206 -- High-definition television systems -- Filed: September 13, 1989 Granted: June 25, 1991 [47]
- US 5,128,758 -- Method and apparatus for digitally processing a high definition television augmentation signal -- Filed: June 2, 1989 Granted: July 7, 1992 [48]
- US 5,179,442 -- Method and apparatus for digitally processing a high definition television augmentation signal -- Filed: November 26, 1990 Granted: January 12, 1993 [49]
- US 5,333,135 -- Identification of a data stream transmitted as a sequence of packets -- Filed: February 1, 1993 Granted: July 26, 1994 [50]
- 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 [51]
- US 5,608,697 -- Record carrier containing an audio and/or video signal which has been encoded and includes a decoder delay time parameter indicating a time delay for one or more portions of the signal -- Filed: March 18, 1996 Granted: March 4, 1997 [52]
- 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 [53]
- US 5,844,867 -- Methods and apparatus for encoding and decoding an audio and/or video signal, and a record carrier used therewith or produced therefrom -- Filed: September 9, 1996 Granted: December 1, 1998 [54]
- Robert Bosch GmbH
- Samsung
- US 5,461,421 -- Encoding and decoding method and apparatus thereof -- Filed: November 29, 1993 Granted: October 24, 1995 [55]
- US 5,467,086 -- Apparatus and method of coding/decoding video data -- Filed: June 18, 1993 Granted: November 14, 1995 [56]
- US 5,654,706 -- System for variable length decoding digital transmission data which has been compressed by selecting a scanning pattern -- Filed: December 18, 1996 Granted: August 5, 1997 [57]
- US 6,680,975 -- Signal encoding and decoding system and method -- Filed: November 2, 2000 Granted: January 20, 2004 [58]
- US 7,292,657 -- Signal compressing signal -- Filed: July 3, 2003 Granted: November 6, 2007 [59]
- Sanyo Electric Co., Ltd.
- Scientific Atlanta
- 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 [60]
- 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 [61]
- 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 [62]
- Sharp
- Sony
- US 4,864,393 -- Motion vector estimation in television images -- Filed: May 31, 1988 Granted: September 5, 1989 [63] Expired
- US Re 37,222 -- Video signal transmitting system -- Filed: July 19, 1994 Granted: June 12, 2001 [64] Reissue of 05132792 Filed: Oct., 1990 Granted: Jul., 1992
- US 5,191,436 -- Method for recording coded motion picture data -- Filed: April 30, 1991 Granted: March 2, 1993 [65]
- US 5,291,486 -- Data multiplexing apparatus and multiplexed data demultiplexing apparatus -- Filed: August 7, 1992 Granted: March 1, 1994 [66]
- US 5,298,991 -- Variable length coding apparatus and method for motion vector -- Filed: July 24, 1992 Granted: March 29, 1994 [67]
- 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 [68]
- US 5,428,396 -- Variable length coding/decoding method for motion vectors -- Filed: December 27, 1993 Granted: June 27, 1995 [69]
- 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 [70]
- 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 [71]
- US 5,510,840 -- Methods and devices for encoding and decoding frame signals and recording medium therefor -- Filed: May 15, 1995 Granted: April 23, 1996 [72]
- US 5,539,466 -- Efficient coding apparatus for picture signal and decoding apparatus therefor -- Filed: September 26, 1994 Granted: July 23, 1996 [73]
- US 5,543,847 -- Picture coding and decoding method for random accessing -- Filed: December 13, 1993 Granted: August 6, 1996 [74]
- 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 [75]
- 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 [76]
- US 5,666,461 -- High efficiency encoding and decoding of picture signals and recording medium containing same -- Filed: May 30, 1995 Granted: September 9, 1997 [77]
- US 5,701,164 -- Macroblock coding including difference between motion vectors -- Filed: December 19, 1996 Granted: December 23, 1997 [78]
- US 5,946,042 -- Macroblock coding including difference between motion vectors -- Filed: July 2, 1997 Granted: August 31, 1999 [79]
- US 5,982,437 -- Coding method and system, and decoding method and system -- Filed: October 15, 1993 Granted: November 9, 1999 [80]
- US 6,040,863 -- Method of coding and decoding motion vector and apparatus therefor, and method of coding and decoding picture signal and apparatus therefor -- Filed: December 18, 1998 Granted: March 21, 2000 [81]
- US 6,160,849 -- Selectable field and frame based predictive video coding -- Filed: May 30, 1995 Granted: December 12, 2000 [82]
- Thomson Licensing S.A.
- US 4,800,432 Expired [83]
- US 4,969,055 Expired [84]
- 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 [85]
- US 5,365,272 -- Method for formatting compressed video data into transport cells -- Filed: July 2, 1993 Granted: November 15, 1994 [86]
- US 5,381,181 -- Clock recovery apparatus as for a compressed video signal -- Filed: May 13, 1993 Granted: January 10, 1995 [87]
- US 5,422,676 -- System for coding an image representative signal -- Filed: October 22, 1993 Granted: June 6, 1995 [88]
- US 5,442,400 -- Error concealment apparatus for MPEG-like video data -- Filed: April 29, 1993 Granted: August 15, 1995 [89]
- US 5,459,789 -- Packet TV program component detector -- Filed: April 22, 1994 Granted: October 17, 1995 [90]
- US 5,483,287 -- Method for forming transport cells for conveying compressed video data -- Filed: August 3, 1994 Granted: January 9, 1996 [91]
- US 5,565,923 -- Apparatus for formatting a digital signal to include multiple time stamps for system synchronization -- Filed: August 22, 1995 Granted: October 15, 1996 [92]
- US 5,784,110 -- Data processor for assembling transport data packets -- Filed: May 23, 1996 Granted: July 21, 1998 [93]
- US 7,020,204 -- Adaptive method of encoding and decoding a series of pictures by transformation, and devices for implementing this method -- Filed: February 8, 2002 Granted: March 28, 2006 [94]
- Toshiba
- US 5,317,397 -- Predictive coding using spatial-temporal filtering and plural motion vectors -- Filed: May 29, 1992 Granted: May 31, 1994 [95]
- US 5,424,779 -- Video coding apparatus -- Filed: November 24, 1993 Granted: June 13, 1995 [96]
- 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 [97]
- US 5,742,344 -- Motion compensated video decoding method and system for decoding a coded video signal using spatial and temporal filtering -- Filed: April 3, 1996 Granted: April 21, 1998 [98]
- US 5,986,713 -- Video coding apparatus using inter-field prediction -- Filed: June 11, 1998 Granted: November 16, 1999 [99]
- Victor Company of Japan, Limited (JVC).
- US Re 34,965 -- Inter-frame predictive encoding system with encoded and transmitted prediction error -- Filed: January 14, 1993 Granted: June 13, 1995 [100] Reissue of 04985768 Filed: Jan., 1990 Granted: Jan., 1991
- US Re 35,158 -- Apparatus for adaptive inter-frame predictive encoding of video signal -- Filed: December 28, 1992 Granted: February 20, 1996 [101] Reissue of 04982285 Filed: Apr., 1990 Granted: Jan., 1991
- US Re 36,822 -- Moving image signal coding apparatus and coded signal decoding apparatus -- Filed: October 2, 1998 Granted: August 15, 2000 [102] Reissue of 05748784 Filed: Jan., 1996 Granted: May., 1998
- US 5,103,307 -- Interframe predictive coding/decoding system for varying interval between independent frames -- Filed: January 18, 1991 Granted: April 7, 1992 [103]
- US 5,175,618 -- Compression method for interlace moving image signals -- Filed: October 30, 1991 Granted: December 29, 1992 [104]
[edit] Non-MPEG-LA Patents
- Alcatel-Lucent [105]
- Audio MPEG, Inc [108]
- US 4,972,484 -- Method of transmitting or storing masked sub-band coded audio signals -- Filed: July 21, 1988 Granted: November 20, 1990 [109]
- US 5,214,678 -- Digital transmission system using subband coding of a digital signal -- Filed: May 31, 1990 Granted: May 25, 1993 [110]
- US 5,323,396 -- Digital transmission system, transmitter and receiver for use in the transmission system -- Filed: December 21, 1992 Granted: June 21, 1994 [111]
- US 5,539,829 -- Subband coded digital transmission system using some composite signals -- Filed: June 7, 1995 Granted: July 23, 1996 [112]
- US 5,606,618 -- Subband coded digital transmission system using some composite signals -- Filed: December 27, 1993 Granted: February 25, 1997 [113]
- US 5,530,655 -- Digital sub-band transmission system with transmission of an additional signal -- Filed: June 6, 1995 Granted: June 25, 1996 [114]
- US 5,777,992 -- Decoder for decoding and encoded digital signal and a receiver comprising the decoder -- Filed: June 7, 1995 Granted: July 7, 1998 [115]
- US 6,289,308 -- Encoded wideband digital transmission signal and record carrier recorded with such a signal -- Filed: March 8, 2000 Granted: September 11, 2001 [116]
- US 5,481,643 -- Transmitter, receiver and record carrier for transmitting/receiving at least a first and a second signal component -- Filed: April 24, 1995 Granted: January 2, 1996 [117]
- US 5,544,247 -- Transmission and reception of a first and a second main signal component -- Filed: October 25, 1994 Granted: August 6, 1996 [118]
- 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 [119]
- US 5,740,317 -- Process for finding the overall monitoring threshold during a bit-rate-reducing source coding -- Filed: August 30, 1995 Granted: April 14, 1998 [120]
- US 5,878,080 -- N-channel transmission, compatible with 2-channel transmission and 1-channel transmission -- Filed: February 7, 1997 Granted: March 2, 1999 [121]
- US 5,960,037 -- Encoding of a plurality of information signals -- Filed: April 9, 1997 Granted: September 28, 1999 [122]
- US 5,991,715 -- Perceptual audio signal subband coding using value classes for successive scale factor differences -- Filed: August 31, 1995 Granted: November 23, 1999 [123]
- US 6,023,490 -- Encoding apparatus for encoding a plurality of information signals -- Filed: April 9, 1997 Granted: February 8, 2000 [124]
- Thomson [125]
- US 4,821,260 Expired [126]
- US 4,942,607 Expired [127]
- US 5,214,742 -- Method for transmitting a signal -- Filed: October 1, 1990 Granted: May 25, 1993 [128]
- US 5,227,990 -- Process for transmitting and receiving a signal -- Filed: January 17, 1992 Granted: July 13, 1993 [129]
- US 5,384,811 -- Method for the transmission of a signal -- Filed: August 24, 1992 Granted: January 24, 1995 [130]
- US 5,736,943 -- Method for determining the type of coding to be selected for coding at least two signals -- Filed: May 31, 1996 Granted: April 7, 1998 [131]
- 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 [132]
- US 5,559,834 -- Method of reducing crosstalk in processing of acoustic or optical signals -- Filed: April 15, 1994 Granted: September 24, 1996 [133]
- US 5,321,729 -- Method for transmitting a signal -- Filed: April 26, 1993 Granted: June 14, 1994 [134]
- US 5,706,309 -- Process for transmitting and/or storing digital signals of multiple channels -- Filed: May 2, 1995 Granted: January 6, 1998 [135]
- US 5,701,346 -- Method of coding a plurality of audio signals -- Filed: September 12, 1996 Granted: December 23, 1997 [136]
- US 5,742,735 -- Digital adaptive transformation coding method -- Filed: August 25, 1994 Granted: April 21, 1998 [137]
- US 5,812,672 -- Method for reducing data in the transmission and/or storage of digital signals of several dependent channels -- Filed: December 15, 1994 Granted: September 22, 1998 [138]
- US 5,579,430 -- Digital encoding process -- Filed: January 26, 1995 Granted: November 26, 1996 [139]
- US 6,185,539 -- Process of low sampling rate digital encoding of audio signals -- Filed: May 26, 1998 Granted: February 6, 2001 [140]
- US 6,009,399 -- Method and apparatus for encoding digital signals employing bit allocation using combinations of different threshold models to achieve desired bit rates -- Filed: April 16, 1997 Granted: December 28, 1999 [141]
- US 5,924,060 -- Digital coding process for transmission or storage of acoustical signals by transforming of scanning values into spectral coefficients -- Filed: March 20, 1997 Granted: July 13, 1999 [142]
- US 5,703,999 -- Process for reducing data in the transmission and/or storage of digital signals from several interdependent channels -- Filed: November 18, 1996 Granted: December 30, 1997 [143]
According to the MPEG-LA Licensing Agreement MPEG-LA, any use of MPEG-2 technology is subject to royalties.
- Encoders are subject to a royalty of $2.50 per unit.
- Decoders are subject to a royalty of $2.50 per unit.[10]
- Royalty-based sales of encoders and decoders are subject to different rules and $2.50 per unit.[10]
- Also, any packaged medium (DVDs/Data Streams) is subject to licence fees according to length of recording/broadcast.
In the case of free software such as VLC media player (which uses the ffmpeg library) and in which the software is not sold, the end-user bears the royalty.
[edit] See also
[edit] References
- ^ ISO/IEC 13818 MPEG-2 at the ISO Store.
- ^ a b ITU-T Rec. H.222.0
- ^ ITU-T Rec. H.262
- ^ MIT Getting Millions For Digital TV Deal, Keith J. Winsteln, The Tech (Massachusetts Institute of Technology), November 8, 2002
- ^ Mpeg La
- ^ audioMPEG.com - - - US Patents
- ^ audioMPEG.com - - - patent management and licensing company specializing in the licensing of audio technology
- ^ Richard M Stallman, Patents - Barriers to development Theora Video and Vorbis Audio
- ^ [1]
- ^ a b MPEG-2 PATENT PORTFOLIO LICENSE
[edit] External links
- A Beginners Guide for MPEG-2 Standard
- MPEG-2 Overview
- MPEG-2 video compression
- MIT 6.344 – Slides from lectures on video compression at MIT.
- A Discrete Cosine Transform tutorial
- IPTV MPEG and Quality of Experience Testing
- OpenIPMP: Open Source DRM Project for MPEG-2
- ISO/IEC 13818 – MPEG-2 at the ISO Store.
- MPEG Books - A list of MPEG reference books.
- TSAFT - Transport Stream Analysis & Fixing Tool
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