Term: Data stream buffering. The video is not loading, the screen says: Buffering

Do you know how to force an internet browser Mozilla Firefox to full buffer video on YouTube? You probably don't know because you keep reading this manual!

Why do users need buffering? First of all, in order to make it as comfortable as possible to watch video material with an Internet connection, simply by first pausing it and waiting for it to fully load.

Secondly, in order to be able to view the video in the selected quality. Without reducing the quality in the settings, and even in offline with an unstable internet connection. By default, the YouTube video service limits the preloading of a video in its player window, breaking it into segments that are loaded as the video is watched.

The quality of the video stream is dynamically adjusted based on network conditions by changing the viewing level. Follow these steps to set Firefox to fully buffer, without the use of various browser add-ons and extensions.

VIDEO BUFFERING

Open an internet browser and in the URL bar write:

and promise to be careful.

Change (simply by double-clicking) the value from "true" to "false".

Reload your browser. Enjoy watching buffered video.

P.S. Even more computer tips can be found in . Recommend instructions to your friends and acquaintances through the buttons social networks, thereby helping the development of this resource. Thank you so much!

When developing programs that work with ADC and DAC data streams, the problem arises to ensure data processing at a sufficient speed.

The data rate is determined by the sampling rate and is not controlled by the program: the physical process cannot wait. If you lose part of the readings, the signal will be corrupted.

In this case, the computer executing the program usually does not work in real time, i.e. if one program step follows "immediately" after another, then this "immediately" should be understood as subsequence operations, not how real time. Some operations (such as writing to disk) can take a relatively long time to complete. Also in multitasking operating system there are many processes interrupting each other, so that the program can "stop" at random times for it (sometimes for quite a long time - for tens, even hundreds of milliseconds).

In addition, when programming, it is sometimes necessary to process data in blocks (portions), and not one by one, otherwise the overhead costs will negate the speed of even a modern computer.

Buffering is used to solve this problem.

A buffer is a fast-access memory array in which incoming data is accumulated (if it is an input stream, ADC) or from which it is sent at a given rate (if it is an output stream, DAC).

When entering data, the process starts with an empty buffer. When outputting, the buffer must be pre-filled, otherwise the buffer may immediately become empty at the beginning of work.

The data processing performance of the computer must be greater than the flow rate (with a margin), but the instantaneous speed can fall, so long as the input buffer does not overflow and the output buffer does not empty. The speed margin is needed to parse the data that has accumulated in the buffer due to a pause (and during output, to fill the buffer again).

Figuratively, you can think of an input buffer as a tank into which water flows from a pipe at a constant rate. We scoop up this water with a bucket, take it to the consumer and return; the larger the tank, the more time we have for unforeseen delays on the road. Ideally, there should be no more than a bucket of water in the tank, then, when leaving, we leave it empty and have the maximum margin of time. If there is a delay and a lot of water has accumulated, we begin to rush to quickly scoop it out.

Everything is the same with the output buffer, only the water leaves the tank at a constant speed (and you can’t interrupt the supply, this is an accident), and we pour it in buckets. Accordingly, a full tank provides maximum protection against delays, and if the level drops, it must be replenished as soon as possible.

In practice, such a scheme can be implemented in the form of a ring buffer or a list of blocks. smaller("buckets") that are queued. As soon as they are ready, they are processed, the released blocks-buckets are placed at the end of the queue.

The simplest option is a scheme with two buffers (two halves of a large buffer): when one half is ready, it is processed, at this time the data is collected in the second half, and during its filling, the processing of the first should be completed, then the halves "change roles". If we continue the analogy with buckets, then there is no tank, but there are two buckets: having collected a full bucket, we immediately substitute an empty one and take the full one to the garden. This is a very simple and efficient scheme, but it ties the processing chunk size (and associated latency) to the buffer size, which is sometimes inconvenient.

For the everyday analogy of a buffer and a bucket used above, we will make an important reservation that a buffer (in data acquisition and control systems) means a sequential structure in which data is not lost (the bucket is not leaky) and the data sequence does not change. In other words, a data sample that has entered the buffer cannot overtake an earlier sample.

We also note that the implementation of the buffer can be not only software, but also hardware, for example, in FPGA, according to the type of a linear queue of a given maximum size"first in - first out" (FIFO - First In, First Out).

If the term "buffering" is considered more broadly, then buffering can be without preserving the natural order of the data, for example, LIFO "last in - first out" (LIFO - Last In, First Out). Another well-known name for the LIFO buffer is the Stack, which is widely used in programming.

When comparing the characteristics of data acquisition systems, it is not just the byte size of the buffer in the system that is important, but the estimated maximum signal buffering time at a given data input rate (for ADC) or data output (DAC). To calculate the buffering time, the required data acquisition rate (samples per second) and the size of the data word occupied by one sample (typically: 2 or 4 bytes) should be taken into account. In addition to the data readout, the word may contain auxiliary index information marking the data flow for various auxiliary tasks when working with data at the upper program level in the PC.

The following articles are related to this topic:

• I/O data synchronous and asynchronous
• Is it possible to process data from an ADC on a PC in real time, sample by sample?

An example of the use of the term

The terminology associated with buffering data streams is widely used in manuals for various data acquisition systems (LTR, E-502, L-502, E14-x40, etc.) when describing them functional diagrams and software interfaces.

ADC/DAC module
16/32 channels, 16 bit, 2 MHz, USB, Ethernet

E-502

ADC: 16 bits; 16/32 channels;
±0.2 V…10 V; 2 MHz
DAC: 16 bit; 2 channels; ±5 V; 1 MHz
Digital inputs/outputs:
18/16 TTL 5V
Interface: PCI Express

what is buffering and got the best answer

Answer from Yosha Besfamilny[guru]
Buffering (from English buffer) - a method of organizing data input and output in computers and other computing devices, which implies the use of a buffer to temporarily store data. When data is entered, some devices or processes write data to the buffer, while others read from it, and vice versa when outputting. The process that wrote to the buffer can continue immediately without waiting for the data to be processed by another process to which it is intended. In turn, the process that has processed a certain portion of data can immediately read the next portion from the buffer. Thus, buffering allows processes that do input, output, and processing to run in parallel without waiting for another process to do its part. Therefore, data buffering is widely used in multitasking operating systems.

Answer from 2 answers[guru]

Hello! Here is a selection of topics with answers to your question: what is buffering

Answer from Sweet[guru]
loading. most often a video or clip, if you watch from the Internet

Answer from 3akypu_nanupocky[guru]
Insertion of silicone implants.
Joke. Buffering (from the English buffer) is a method of organizing data input and output in computers and other computing devices, which involves the use of a buffer for temporary data storage See the source for the full answer

Answer from FAVan[guru]
Copying data to the preliminary clipboard (usually in random access memory) to increase read speed when the device (usually HDD or CD-ROM) is busy with something else.

Answer from NikolaiCh™[guru]
Buffering is the process of building some neighborhood around an object, which in turn can be a new object. Let us give a more detailed definition of a buffer. Let an object (bounded and continuous set) A be located on a plane on which a rectangular coordinate system (X,Y) is specified. A buffer O of radius R is a set of points for which the following condition is satisfied:
x, y belongs to O(R) if p((x,y), (x0, y0))<= R., где p- расстояние. , а x0, y0 может быть любой точкой принадлежащей А
Buffers for objects of various types of localization are shown in Fig. 5.
Buffers are used when it is necessary to build "zones of influence" or "reach zones" defined by some object. Constructed zones can be used to identify areas of the territory that have a combination of certain factors or to find different objects that are "affected" by the original object. Such zones can be: protected zones of engineering communications, zones of increased danger in the production of blasting, transport reach zones, etc.
As an example of the application of buffering, consider the problem of determining the best location for an ore processing plant that receives raw materials from several open pits by road and sends the concentrate to the consumer by rail. Further, let it be known that it is unprofitable to transport raw materials by road at a distance of more than 10 km, and the plant should be located in close proximity to the main railway (up to 1 km). A digital map containing layers of quarries and railways is taken as initial information. The solution to the problem will look like this. First we need to build buffers around the quarries with a radius of 10 km and buffers around the railways with a radius of 1 km. Next, we need to find the intersection of all the constructed buffers (for this, you can use the overlay described above). An enrichment plant can be placed inside this site. If there is no such site, then a partial solution of the problem is possible (servicing only a few open pits), or the solution of the problem is impossible at all.

Each peripheral device has its own specific nature of data exchange, determined by the nature of its external (in relation to the computer) side. According to the nature of the exchange, devices can be divided into three main types.

block devices, such as disk drives. Exchange with them is possible only in blocks of a fixed size - clusters. When communicating with a physical disk, you cannot stop in the middle of a block transfer.

streaming devices, examples of which are printers and scanners A printer is sent a stream of data that it, to the best of its electromechanical abilities, outputs as an image on paper. The stream can be paused at any time, and then continue the transfer without any side effects.

case-sensitive devices, which, as a rule, are not sources or receivers of large amounts of data. Programs usually need to know the current state of these devices and/or generate current control actions. Register-oriented, as a rule, are various interface devices with technological equipment, computerized measuring systems, a joystick (the program polls the current state of buttons and coordinate sensors at certain moments), etc.

In many devices there is a mixture of these basic types, so even the printer has a register-oriented part - in addition to receiving the stream, it transmits signals of the current state (error, end of paper).

A very important task is data buffering. The bandwidth of the internal components of a modern computing system - the processor and RAM - is extremely high in both directions (both for receiving and transmitting), and the bandwidth of the vast majority of external devices is several orders of magnitude lower and varies over a very wide range. Data transferred from RAM to an external device arrives at a very high speed, usually in the form of a packet. It is expedient to save these data in the internal buffer of the interface controller and then send them to an external device in appropriate portions. When transmitting in the opposite direction, it is again advisable to accumulate data from an external device in the buffer of the interface controller so as not to “pull” the RAM “on trifles”. When a significant amount of data has been accumulated, they can all be quickly transferred to RAM in one package. Thus, to ensure the minimum time of possession of the interface (and hence the resources of RAM), the controller of the corresponding interface must work using buffers.

The buffer is a set of internal RAM cells with certain access rules both from the PU controller and from the “center”. The size of the buffer and the discipline of its maintenance are selected based on technical (speed and volume of information, acceptable delays) and economic (price) considerations.

For block devices, a buffer is usually used, the minimum size of which is equal to the block size.

LAN controllers tend to be block devices - they transmit data in whole packets, which must be received and sent at a certain speed (100Mbps, 1000Mbps, 10Gbps - for the first three generations of Ethernet). For them, the volume and organization of the buffer depend on the speed of the transmission medium and the performance of the interface to which they are connected.

For streaming devices, a buffer with a FIFO service discipline (First In - First Out, first in - first out) is often used. The size of such a buffer is usually small (for example, 16.64 bytes). The buffer is placed between the "center" and the device, on the one hand it is filled, on the other - it is emptied. The emptying side can only retrieve data from the buffer when the filling side puts it there. An attempt to retrieve data from an empty buffer is an underflow error, an attempt to put data into a full buffer is an overflow error. The buffer logic monitors the degree of buffer filling and informs the “center” about critical situations. When the “center” (the program executed by the processor) outputs data through the FIFO, the logic monitors the decrease in the buffer filling below the emptying threshold and, if so, signals (usually by interrupting) the need to output the next portion of data. The logic also prevents overflow by rejecting attempts to write extra data and immediately reporting an error (usually via an appropriate software-readable status bit). When data is entered through the FIFO buffer, its logic monitors the availability of free space in the buffer and, if the filling threshold is exceeded, also signals an interrupt. Similarly, it does not allow reading data from an empty buffer and reports this with the appropriate bit. Also, the buffer logic should allow it to be cleared at the initiative of the processor, report on the amount (or at least the presence) of data in the buffer at the request of the processor. The controllability of thresholds allows the program, depending on the external data exchange rate, capabilities and current workload of the computer, to select the optimal exchange mode, which allows you not to "fuss over trifles" and prevent buffer overflows/underruns. Bidirectional devices usually have a pair of FIFO buffers (for full duplex), for simplex devices one is enough.

The buffers of modern external memory devices have a more complex organization that provides data caching; however, they also use the principles of organization described above. Large single-port buffers, as already mentioned, can introduce a noticeable delay. For streaming applications (for example, for playing media files), this delay is usually not very significant and does not affect performance. However, for "loopback" applications, when the buffer is in the request-response chain, its delay can lead to performance degradation. So, for example, data transmission over a network is usually a sequence of data frames, for each of which the transmitting side expects an acknowledgment frame. If each frame "sits" in the buffer, of course, performance will decrease. The “sliding window” method saves from this trouble, in which the transmitting side allows some delay in receiving confirmations.

Under buffer usually understood as some area of ​​memory for storing information in the exchange of data between two devices, two processes, or a process and a device. The exchange of information between two processes belongs to the field of process cooperation, and we have considered its organization in detail in the corresponding chapter. We will consider the use of buffers in the case when one of the participants in the exchange is an external device.

Exist three reasons for using buffers in the basic I/O subsystem:

1) The first reason for buffering- these are different speeds of receiving and transmitting information that the participants in the exchange have. Consider, for example, the case of data streaming from the keyboard to the modem. The speed at which the keyboard delivers information is determined by the speed at which a person is typing, and is usually significantly less than the data transfer rate of a modem. In order not to occupy the modem for the entire time of typing, making it inaccessible to other processes and devices, it is reasonable to accumulate the entered information in a buffer or several buffers of sufficient size and send it through the modem after the buffers are full.

2) The second reason for buffering- these are different amounts of data that can be accepted or received by the exchange participants at a time. Let's take another example. Let the information be supplied by the modem and written to the hard drive. In addition to having different transaction speeds, a modem and a hard drive are different types of devices. The modem is a character device and outputs data byte by byte, while the disk is a block device and for a write operation it is necessary to accumulate the necessary block of data in the buffer. More than one buffer can also be used here. After filling the first buffer, the modem begins to fill the second one at the same time as writing the first one to the hard disk. Since the speed of the hard disk is thousands of times greater than the speed of the modem, by the time the second buffer is full, the write operation of the first one will be completed, and the modem can again fill the first buffer at the same time as writing the second buffer to disk.

3) The third reason for buffering is related to the need to copy information from applications that perform I / O to the buffers of the operating system kernel and vice versa. Let's say that some user process wants to output information from its address space to an external device. To do this, it must execute a system call with the generic name write, passing as parameters the address of the memory area where the data is located, and their size. If an external device is temporarily busy, then it is possible that by the time it is freed, the contents of the required area will be corrupted (for example, when using the asynchronous form of the system call). To avoid such situations, the easiest way is to copy the necessary data to the operating system kernel buffer, which is permanently in RAM, at the beginning of the system call, and output them to the device from this buffer.

under the word cache usually understand a region of fast memory containing a copy of data located somewhere in slower memory, designed to speed up the work of the CS. Buffering and caching should not be confused in the basic I/O subsystem, although often the same memory area is allocated to perform these functions. A buffer often contains a single set of data that exists in the system, while a cache, by definition, contains a copy of the data that exists elsewhere. For example, the buffer used by the underlying subsystem to copy data from a process's user space when it is written to disk can in turn be used as a cache for that data if the block's update and reread operations occur frequently enough.

The buffering and caching functions do not have to be localized in the underlying I/O subsystem. They can be partially implemented in drivers and even in device controllers, hidden from the underlying subsystem.