1080p Blu Ray Bitrate

[Janne Evers]

Indigital communication systems, the physical layer gross bitrate,[6] raw bitrate,[7] data signaling rate,[8] gross data transfer rate[9] or uncoded transmission rate[7] (sometimes written as a variable Rb[6][7] or fb[10]) is the total number of physically transferred bits per second over a communication link, including useful data as well as protocol overhead.

The gross bit rate is related to the symbol rate or modulation rate, which is expressed in bauds or symbols per second. However, the gross bit rate and the baud value are equal only when there are only two levels per symbol, representing 0 and 1, meaning that each symbol of a data transmission system carries exactly one bit of data; for example, this is not the case for modern modulation systems used in modems and LAN equipment.[11]

More specifically, a line code (or baseband transmission scheme) representing the data using pulse-amplitude modulation with 2 N \displaystyle 2^N different voltage levels, can transfer N \displaystyle N bits per pulse. A digital modulation method (or passband transmission scheme) using 2 N \displaystyle 2^N different symbols, for example 2 N \displaystyle 2^N amplitudes, phases or frequencies, can transfer N \displaystyle N bits per symbol. This results in:

An exception from the above is some self-synchronizing line codes, for example Manchester coding and return-to-zero (RTZ) coding, where each bit is represented by two pulses (signal states), resulting in:

In practice this upper bound can only be approached for line coding schemes and for so-called vestigial sideband digital modulation. Most other digital carrier-modulated schemes, for example ASK, PSK, QAM and OFDM, can be characterized as double sideband modulation, resulting in the following relation:

The physical layer net bitrate,[12] information rate,[6] useful bit rate,[13] payload rate,[14] net data transfer rate,[9] coded transmission rate,[7] effective data rate[7] or wire speed (informal language) of a digital communication channel is the capacity excluding the physical layer protocol overhead, for example time division multiplex (TDM) framing bits, redundant forward error correction (FEC) codes, equalizer training symbols and other channel coding. Error-correcting codes are common especially in wireless communication systems, broadband modem standards and modern copper-based high-speed LANs. The physical layer net bitrate is the datarate measured at a reference point in the interface between the data link layer and physical layer, and may consequently include data link and higher layer overhead.

In modems and wireless systems, link adaptation (automatic adaptation of the data rate and the modulation and/or error coding scheme to the signal quality) is often applied. In that context, the term peak bitrate denotes the net bitrate of the fastest and least robust transmission mode, used for example when the distance is very short between sender and transmitter.[15] Some operating systems and network equipment may detect the "connection speed"[16] (informal language) of a network access technology or communication device, implying the current net bit rate. The term line rate in some textbooks is defined as gross bit rate,[14] in others as net bit rate.

For example, the net bitrate (and thus the "connection speed") of an IEEE 802.11a wireless network is the net bit rate of between 6 and 54 Mbit/s, while the gross bit rate is between 12 and 72 Mbit/s inclusive of error-correcting codes.

The net bit rate of the Ethernet 100BASE-TX physical layer standard is 100 Mbit/s, while the gross bitrate is 125 Mbit/s, due to the 4B5B (four bit over five bit) encoding. In this case, the gross bit rate is equal to the symbol rate or pulse rate of 125 megabaud, due to the NRZI line code.

In communications technologies without forward error correction and other physical layer protocol overhead, there is no distinction between gross bit rate and physical layer net bit rate. For example, the net as well as gross bit rate of Ethernet 10BASE-T is 10 Mbit/s. Due to the Manchester line code, each bit is represented by two pulses, resulting in a pulse rate of 20 megabaud.

The channel capacity, also known as the Shannon capacity, is a theoretical upper bound for the maximum net bitrate, exclusive of forward error correction coding, that is possible without bit errors for a certain physical analog node-to-node communication link.

The channel capacity is proportional to the analog bandwidth in hertz. This proportionality is called Hartley's law. Consequently, the net bit rate is sometimes called digital bandwidth capacity in bit/s.

The term throughput, essentially the same thing as digital bandwidth consumption, denotes the achieved average useful bit rate in a computer network over a logical or physical communication link or through a network node, typically measured at a reference point above the data link layer. This implies that the throughput often excludes data link layer protocol overhead. The throughput is affected by the traffic load from the data source in question, as well as from other sources sharing the same network resources. See also measuring network throughput.

Goodput or data transfer rate refers to the achieved average net bit rate that is delivered to the application layer, exclusive of all protocol overhead, data packets retransmissions, etc. For example, in the case of file transfer, the goodput corresponds to the achieved file transfer rate. The file transfer rate in bit/s can be calculated as the file size (in bytes) divided by the file transfer time (in seconds) and multiplied by eight.

As an example, the goodput or data transfer rate of a V.92 voiceband modem is affected by the modem physical layer and data link layer protocols. It is sometimes higher than the physical layer data rate due to V.44 data compression, and sometimes lower due to bit-errors and automatic repeat request retransmissions.

If lossy data compression is used on audio or visual data, differences from the original signal will be introduced; if the compression is substantial, or lossy data is decompressed and recompressed, this may become noticeable in the form of compression artifacts. Whether these affect the perceived quality, and if so how much, depends on the compression scheme, encoder power, the characteristics of the input data, the listener's perceptions, the listener's familiarity with artifacts, and the listening or viewing environment.

The term average bitrate is used in case of variable bitrate multimedia source coding schemes. In this context, the peak bit rate is the maximum number of bits required for any short-term block of compressed data.[17]

The bitrates in this section are approximately the minimum that the average listener in a typical listening or viewing environment, when using the best available compression, would perceive as not significantly worse than the reference standard.

Compact Disc Digital Audio (CD-DA) uses 44,100 samples per second, each with a bit depth of 16, a format sometimes abbreviated like "16bit / 44.1kHz". CD-DA is also stereo, using a left and right channel, so the amount of audio data per second is double that of mono, where only a single channel is used.

For technical reasons (hardware/software protocols, overheads, encoding schemes, etc.) the actual bit rates used by some of the compared-to devices may be significantly higher than what is listed above. For example, telephone circuits using μlaw or A-law companding (pulse code modulation) yield 64 kbit/s.

Streaming video content has become increasingly popular in recent years. A significant reason for this is that technology has become more accessible and affordable. Video content can attract a wider audience than other forms of content, such as blogs or audio podcasts.

Bitrate is important because it affects the quality of your video and audio streams. A higher bitrate means better quality but also requires more bandwidth. So, video bitrate, bandwidth, and resolution are interrelated, and all work together to give you the best streaming quality possible.

Bitrate affects the quality of your video and audio streams by impacting the level of detail and clarity. A higher bitrate will give you a higher quality stream, while a lower bitrate may cause some degradation in quality and result in poor video quality. Both video and audio Bitrate contribute to the overall quality of your stream and engagement.

In terms of streaming video, Bitrate is the number of bits per second transferred from the video source to the viewer. Bitrate is typically measured in megabits per second (Mbps). The higher the bitrate, the higher the quality of the video.

Constant Bitrate means encoding each video and audio segment that consumes a constant number of bits. However, the sound structure may differ, and encoding a silent segment requires far fewer bits than encoding a loud segment.

Unlike constant Bitrate, variable Bitrate adjusts encoding quality at various intervals. Thus, simple slots in encoding terms will use a lower bit rate, while more complex slots will be encoded with a higher bit rate. A variable bit rate allows for higher sound quality without increasing file size.

Ensuring streaming quality over time requires that bitrates be adjusted to match changing conditions. The streaming software automatically increases or decreases Bitrate to maintain a consistent level of quality. This is known as adaptive Bitrate. Castr is the multistreaming software that supports adaptive bitrate streaming to ensure the best possible quality for your live stream.

It also depends on the file format. Some formats are more efficient than others, meaning they can achieve the same quality at a lower bit rate. So, in general, higher bitrates mean better video quality, but other factors also come into play.

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