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 "datalink 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 (data transfer rate)
"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 no data compression is provided by the network equipment or protocols, we have the following relation:
- goodput ≤ throughput ≤ maximum throughput ≤ net bit rate
for a certain communication path.
These are examples of physical layer net bit rates in proposed communication standard interfaces and devices:
|WAN "modems||"Ethernet LAN||"WiFi "WLAN||"Mobile data|
See also "comparison of mobile phone standards
For more examples, see "list of device bit rates, "spectral efficiency comparison table and "OFDM system comparison table.
In digital multimedia, bitrate represents the amount of information, or detail, that is stored per unit of time of a recording. The bitrate depends on several factors:
- The original material may be sampled at different frequencies.
- The samples may use different numbers of bits.
- The data may be encoded by different schemes.
- The information may be digitally "compressed by different algorithms or to different degrees.
Generally, choices are made about the above factors in order to achieve the desired trade-off between minimizing the bitrate and maximizing the quality of the material when it is played.
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 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:
Encoding bit rate 
In digital "multimedia, bit rate often refers to the number of bits used per unit of playback time to represent a continuous medium such as "audio or "video after "source coding (data compression). The encoding bit rate of a multimedia file is the size of a multimedia file in "bytes divided by the playback time of the recording (in seconds), multiplied by eight.
For realtime "streaming multimedia, the encoding bit rate is the "goodput that is required to avoid interrupt:
- encoding bit rate = required goodput
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.
A theoretical lower bound for the encoding bit rate for "lossless data compression is the "source information rate, also known as the entropy rate.
- entropy rate ≤ multimedia bit rate
"CD-DA, the standard audio CD, is said to have a data rate of 44.1 kHz/16, meaning that the audio data was sampled 44,100 times per second and with a bit depth of 16. 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.
The bit rate of PCM audio data can be calculated with the following formula:
For example, the bit rate of a CD-DA recording (44.1 kHz sampling rate, 16 bits per sample and two channels) can be calculated as follows:
The cumulative size of a length of PCM audio data (excluding a file "header or other "metadata) can be calculated using the following formula:
The cumulative size in bytes can be found by dividing the file size in bits by the number of bits in a byte, which is eight:
Therefore, 80 minutes (4,800 seconds) of CD-DA data requires 846,720,000 bytes of storage:
The "MP3 audio format provides "lossy data compression. Audio quality improves with increasing bitrate:
- 32 kbit/s – generally acceptable only for speech
- 96 kbit/s – generally used for speech or low-quality streaming
- 128 or 160 kbit/s – mid-range bitrate quality
- 192 kbit/s – medium quality bitrate
- 256 kbit/s – a commonly used high-quality bitrate
- 320 kbit/s – highest level supported by the "MP3 standard
- 700 bit/s – lowest bitrate open-source speech codec "Codec2, but barely recognizable yet, sounds much better at 1.2 kbit/s
- 800 bit/s – minimum necessary for recognizable speech, using the special-purpose "FS-1015 "speech codecs
- 2.15 kbit/s – minimum bitrate available through the open-source "Speex codec
- 6 kbit/s – minimum bitrate available through the open-source "Opus codec
- 8 kbit/s – "telephone quality using speech codecs
- 32–500 kbit/s – "lossy audio as used in "Ogg Vorbis
- 256 kbit/s – Digital Audio Broadcasting ("DAB) "MP2 bit rate required to achieve a high quality signal
- 400 kbit/s–1,411 kbit/s – "lossless audio as used in formats such as "Free Lossless Audio Codec, "WavPack, or "Monkey's Audio to compress CD audio
- 1,411.2 kbit/s – "Linear PCM sound format of "CD-DA
- 5,644.8 kbit/s – "DSD, which is a trademarked implementation of "PDM sound format used on "Super Audio CD.
- 6.144 Mbit/s – E-AC-3 (Dolby Digital Plus), an enhanced coding system based on the AC-3 codec
- 9.6 Mbit/s – "DVD-Audio, a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio is not intended to be a video delivery format and is not the same as video DVDs containing concert films or music videos. These discs cannot be played on a standard DVD-player without DVD-Audio logo.
- 18 Mbit/s – advanced lossless audio codec based on "Meridian Lossless Packing (MLP)
- 16 kbit/s – "videophone quality (minimum necessary for a consumer-acceptable "talking head" picture using various video compression schemes)
- 128–384 kbit/s – business-oriented "videoconferencing quality using video compression
- 400 kbit/s "YouTube 240p videos (using "H.264)
- 750 kbit/s "YouTube 360p videos (using "H.264)
- 1 Mbit/s YouTube 480p videos (using H.264)
- 1.15 Mbit/s max – "VCD quality (using "MPEG1 compression)
- 2.5 Mbit/s YouTube 720p videos (using H.264)
- 3.5 Mbit/s typ – "Standard-definition television quality (with bit-rate reduction from MPEG-2 compression)
- 3.8 Mbit/s YouTube 720p (at 60fps mode) videos (using H.264)
- 4.5 Mbit/s YouTube 1080p videos (using H.264)
- 6.8 Mbit/s YouTube 1080p (at 60 fps mode) videos (using H.264)
- 9.8 Mbit/s max – "DVD (using "MPEG2 compression)
- 8 to 15 Mbit/s typ – "HDTV quality (with bit-rate reduction from MPEG-4 AVC compression)
- 19 Mbit/s approximate – "HDV 720p (using MPEG2 compression)
- 24 Mbit/s max – "AVCHD (using "MPEG4 AVC compression)
- 25 Mbit/s approximate – "HDV 1080i (using MPEG2 compression)
- 29.4 Mbit/s max – "HD DVD
- 40 Mbit/s max – "1080p "Blu-ray Disc (using MPEG2, MPEG4 AVC or "VC-1 compression)
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.
- "Dolby AC-3
- "Audio bit depth
- "Average bitrate
- "Bandwidth (computing)
- "Baud (symbol rate)
- "Bit-synchronous operation
- "Clock rate
- "Code rate
- "Constant bitrate
- "Data rate units
- "Data signaling rate
- "List of device bit rates
- "Measuring network throughput
- "Orders of magnitude (bit rate)
- "Spectral efficiency
- "Variable bitrate
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This article incorporates "public domain material from the "General Services Administration document "Federal Standard 1037C" (in support of "MIL-STD-188).