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34-412: Several popular codecs including DivX , Xvid , and Nero Digital implement this standard. MPEG-4 Part 10 defines a different format from MPEG-4 Part 2. MPEG-4 Part 10 is commonly referred to as H.264 or AVC, and was jointly developed by ITU-T and MPEG. MPEG-4 Part 2 is H.263 compatible in the sense that a basic H.263 bitstream is correctly decoded by an MPEG-4 Video decoder. (MPEG-4 Video decoder

68-438: A .wav or .aiff file) has long been a standard across multiple platforms, but its transmission over networks is slow and expensive compared with more modern compressed formats, such as Opus and MP3. Many multimedia data streams contain both audio and video , and often some metadata that permits synchronization of audio and video. Each of these three streams may be handled by different programs, processes, or hardware; but for

102-550: A full list of patent holders. To address various applications ranging from low-quality, low-resolution surveillance cameras to high definition TV broadcasting and DVDs, many video standards group features into profiles and levels. MPEG-4 Part 2 contains approximately 21 profiles. The most commonly deployed profiles are the Advanced Simple Profile (ASP or AS Profile) and the Simple Profile (SP), which

136-530: A large unfavorable impact on speed and adds considerable complexity to the implementation. The Simple Studio Profile has six levels, ranging from SDTV to 4K resolution . SStP allows for up to 12-bit bit depth and up to 4:4:4 chroma subsampling , using intra-frame coding only. SStP is used by HDCAM SR . MPEG-4 Part 2 patents expired worldwide, with the exception of only Brazil. The last US patent expired on November 14, 2023. The following organizations held patents for MPEG-4 Visual technology, as listed in

170-531: A lower bit rate. There are thousands of audio and video codecs, ranging in cost from free to hundreds of dollars or more. This variety of codecs can create compatibility and obsolescence issues. The impact is lessened for older formats, for which free or nearly-free codecs have existed for a long time. The older formats are often ill-suited to modern applications, however, such as playback on small portable devices. For example, raw uncompressed PCM audio (44.1 kHz, 16-bit stereo, as represented on an audio CD or in

204-400: A particular profile (such as DivX or Nero Digital which are implementations of Advanced Simple Profile and Xvid that implements both profiles) are all technically identical on the decoder side. A point of comparison would be that an MP3 file can be played in any MP3 player, whether it was created through iTunes, Windows Media Player, LAME , or the common Fraunhofer encoder. The Simple Profile

238-413: A profound disappointment across the industry - it didn't offer that much of a compression advantage over MPEG-2, and the protracted license agreement discussions scared off a lot of adoption. I was involved in many digital media projects that wouldn't even touch MPEG-4 in the late 1990s to early 2000s because there was going to be a 'content fee' that hadn't been fully defined yet." Codec A codec

272-440: A significantly harmful effect on the speed of software decoders and it is not always beneficial for quality. The global motion compensation feature is not actually supported in most implementations although the standard officially requires decoders to support it. Most encoders do not support it either, and some experts say that it does not ordinarily provide any benefit in compression. When used, ASP's global motion compensation has

306-560: A tendency to reduce the need for lossy codecs for some media. Many popular codecs are lossy. They reduce quality in order to maximize compression. Often, this type of compression is virtually indistinguishable from the original uncompressed sound or images, depending on the codec and the settings used. The most widely used lossy data compression technique in digital media is based on the discrete cosine transform (DCT), used in compression standards such as JPEG images, H.26x and MPEG video, and MP3 and AAC audio. Smaller data sets ease

340-464: Is a device or computer program that encodes or decodes a data stream or signal . Codec is a portmanteau of coder/decoder . In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or data stream, and hence is a type of codec. Endec is a portmanteau of encoder/decoder . A coder or encoder encodes a data stream or a signal for transmission or storage, possibly in encrypted form, and

374-883: Is a subset of the ASP. Other profiles include the Advanced Coding Efficiency Profile (ACEP or ACE Profile), the Advanced Real Time Simple Profile (ARTSP or ARTS Profile), the Core Profile (CP), the Main Profile (MP), and the Simple Studio Profile (SStP or SSt Profile). Most of the video compression schemes standardize the bitstream (and thus the decoder) leaving the encoder design to the individual implementations. Therefore, implementations for

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408-513: Is a television system that uses a resolution that is not considered to be either high or enhanced definition . Standard refers to offering a similar resolution to the analog broadcast systems used when it was introduced. SDTV originated from the need for a standard to digitize analog TV (defined in BT.601 ) and is now used for digital TV broadcasts and home appliances such as game consoles and DVD disc players. Digital SDTV broadcast eliminates

442-409: Is being compressed and uses it as a disguise. This disguise appears as a codec download through a pop-up alert or ad. When a user goes to click or download that codec, the malware is then installed on the computer. Once a fake codec is installed it is often used to access private data, corrupt an entire computer system or to keep spreading the malware. One of the previous most used ways to spread malware

476-461: Is especially true if the data is to undergo further processing (for example, editing ) in which case the repeated application of processing (encoding and decoding) on lossy codecs will degrade the quality of the resulting data such that it is no longer identifiable (visually, audibly, or both). Using more than one codec or encoding scheme successively can also degrade quality significantly. The decreasing cost of storage capacity and network bandwidth has

510-400: Is mostly aimed for use in situations where low bit rate and low resolution are mandated by other conditions of the applications, like network bandwidth, device size etc. Examples are mobile phones , some low end video conferencing systems, electronic surveillance systems etc. The Advanced Simple Profile was not included in the original standard. Its notable technical features relative to

544-538: Is natively capable of decoding a basic form of H.263.) In MPEG-4 Visual, there are two types of video object layers: the video object layer that provides full MPEG-4 functionality, and a reduced functionality video object layer, the video object layer with short headers (which provides bitstream compatibility with base-line H.263). MPEG-4 Part 2 is partially based on ITU-T H.263. The first MPEG-4 Video Verification Model (simulation and test model) used ITU-T H.263 coding tools together with shape coding. The MPEG-4 Visual format

578-441: Is not an ISO standard . There are also other well-known container formats, such as Ogg , ASF , QuickTime , RealMedia , Matroska , and DivX Media Format . MPEG transport stream , MPEG program stream , MP4 , and ISO base media file format are examples of container formats that are ISO standardized. Fake codecs are used when an online user takes a type of codec and installs viruses and other malware into whatever data

612-751: The ghosting and noisy images associated with analog systems. However, if the reception has interference or is poor, where the error correction cannot compensate one will encounter various other artifacts such as image freezing, stuttering, or dropouts from missing intra-frames or blockiness from missing macroblocks . The audio encoding is the last to suffer a loss due to the lower bandwidth requirements. Standards that support digital SDTV broadcast include DVB , ATSC , and ISDB . The last two were originally developed for HDTV , but are also used for their ability to deliver multiple SD video and audio streams via multiplexing . The two SDTV signal types are 576i (with 576 interlaced lines of resolution, derived from

646-472: The patent pool administered by MPEG LA . MPEG-4 Part 2 has drawn some industry criticism. FFmpeg 's maintainer Michael Niedermayer has criticised MPEG-4 for lacking an in-loop deblocking filter , GMC being too computationally intensive, and OBMC being defined but not allowed in any profiles among other things. Microsoft 's Ben Waggoner states "Microsoft (well before my time) went down the codec standard route before with MPEG-4 part 2, which turns out to be

680-566: The European-developed PAL and SECAM systems), and 480i (with 480 interlaced lines of resolution, based on the American NTSC system). SDTV refresh rates are 25, 29.97 and 30 frames per second , again based on the analog systems mentioned. In North America, digital SDTV is broadcast in the same 4:3 fullscreen aspect ratio as NTSC signals, with widescreen content often being center cut . In other parts of

714-774: The Simple Profile, which is roughly similar to H.263 , include: The MPEG quantization and interlace support are designed in basically similar ways to the way it is found in MPEG-2 Part 2. The B picture support is designed in a basically similar way to the way it is found in MPEG-2 Part 2 and H.263v2 . The quarter-pixel motion compensation feature of ASP was innovative, and was later also included (in somewhat different forms) in later designs such as MPEG-4 Part 10 , HEVC , VC-1 and VVC . Some implementations of MPEG-4 Part 2 omit support for this feature, because it has

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748-517: The actual image and 16 pixels are reserved for horizontal blanking, though a number of broadcasters fill the whole 720 frames. The display ratio for broadcast widescreen is commonly 16:9 (pixel aspect ratio of 40:33 for anamorphic ); the display ratio for a traditional or letterboxed broadcast is 4:3 (pixel aspect ratio of 10:11). An SDTV image outside the constraints of the SMPTE standards requires no non-proportional scaling with 640 pixels (defined by

782-440: The data to reduce transmission bandwidth or storage space. Compression codecs are classified primarily into lossy codecs and lossless codecs. Lossless codecs are often used for archiving data in compressed form while retaining all information present in the original stream. If preserving the original quality of the stream is more important than eliminating the correspondingly larger data sizes, lossless codecs are preferred. This

816-560: The decoder function reverses the encoding for playback or editing. Codecs are used in videoconferencing , streaming media , and video editing applications. In the mid-20th century, a codec was a device that coded analog signals into digital form using pulse-code modulation (PCM). Later, the name was also applied to software for converting between digital signal formats, including companding functions. An audio codec converts analog audio signals into digital signals for transmission or encodes them for storage. A receiving device converts

850-552: The digital signals back to analog form using an audio decoder for playback. An example of this is the codecs used in the sound cards of personal computers. A video codec accomplishes the same task for video signals. When implementing the Infrared Data Association (IrDA) protocol, an endec may be used between the UART and the optoelectronic systems. In addition to encoding a signal, a codec may also compress

884-408: The image. Nominal analog blanking should not be confused with overscan , as overscan areas are part of the actual 4:3 or 16:9 image. For SMPTE 259M-C compliance, an SDTV broadcast image is scaled to 720 pixels wide for every 480 NTSC (or 576 PAL) lines of the image with the amount of non-proportional line scaling dependent on either the display or pixel aspect ratio . Only 704 center pixels contain

918-474: The media to be encoded. For example, a digital video (using a DV codec) of a sports event needs to encode motion well but not necessarily exact colors, while a video of an art exhibit needs to encode color and surface texture well. Audio codecs for cell phones need to have very low latency between source encoding and playback. In contrast, audio codecs for recording or broadcasting can use high-latency audio compression techniques to achieve higher fidelity at

952-408: The multimedia data streams to be useful in stored or transmitted form, they must be encapsulated together in a container format . Lower bitrate codecs allow more users, but they also have more distortion. Beyond the initial increase in distortion, lower bit rate codecs also achieve their lower bit rates by using more complex algorithms that make certain assumptions, such as those about the media and

986-538: The packet loss rate. Other codecs may not make those same assumptions. When a user with a low bitrate codec talks to a user with another codec, additional distortion is introduced by each transcoding . Audio Video Interleave (AVI) is sometimes erroneously described as a codec, but AVI is actually a container format, while a codec is a software or hardware tool that encodes or decodes audio or video into or from some audio or video format. Audio and video encoded with many codecs might be put into an AVI container, although AVI

1020-452: The strain on relatively expensive storage sub-systems such as non-volatile memory and hard disk , as well as write-once-read-many formats such as CD-ROM , DVD , and Blu-ray Disc . Lower data rates also reduce cost and improve performance when the data is transmitted, e.g., over the internet. Two principal techniques are used in codecs, pulse-code modulation and delta modulation . Codecs are often designed to emphasize certain aspects of

1054-528: The video into a pillarbox . The pixel aspect ratio is the same for 720- and 704-pixel resolutions because the visible image (be it 4:3 or 16:9) is contained in the center 704 horizontal pixels of the digital frame. In the case of a digital video line having 720 horizontal pixels (including horizontal blanking), only the center 704 pixels contain the actual 4:3 or 16:9 image, and the 8-pixel-wide stripes on either side are called nominal analog blanking or horizontal blanking and should be discarded when displaying

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1088-468: The world that used the PAL or SECAM color systems, digital standard-definition television is now usually shown with a 16:9 aspect ratio , with the transition occurring between the mid-1990s and late-2000s depending on the region. Older programs with a 4:3 aspect ratio are broadcast with a flag that switches the display to 4:3. Some broadcasters prefer to reduce the horizontal resolution by anamorphically scaling

1122-695: Was developed by the Moving Picture Experts Group (MPEG) committee. The specification was authored by Iranian - Swiss engineer Touradj Ebrahimi (later the president of JPEG ) and Dutch engineer Caspar Horne. The standard was developed using patents from over a dozen organizations, listed by MPEG LA in a patent pool . The majority of patents used for the MPEG-4 Visual format were from three Japanese companies: Mitsubishi Electric (255 patents), Hitachi (206 patents), and Panasonic (200 patents). See Patent holders below for

1156-410: Was fake AV pages and with the rise of codec technology, both have been used in combination to take advantage of online users. This combination allows fake codecs to be automatically downloaded to a device through a website linked in a pop-up ad, virus/codec alerts or articles as well. Standard-definition television Standard-definition television ( SDTV ; also standard definition or SD )

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