bitrate do video Archives

What if the bit rate is high?

Free Download Mp4Gain

What if the bit rate is high?

Bitrate

High bit rate = a lot of data can be transferred per second

bitrate
.

Sounds like a good thing.

The network cameras managed by my company send the captured video data to a personal computer for viewing over the network.

If you want to see the video, you want to see a beautiful video that moves sharply with high image quality, right?
However, the amount of data in a beautiful image is surprisingly large …

In such case, if the bit rate is high, a lot of data can be transferred per second, so you can deliver beautiful images to your computer. On the other hand, if the bit rate is low, the amount of data that can be transferred per second is small, resulting in choppy and poor quality moving images.

“Then the bitrate should be high anyway!”

… That is not the case.
In fact, in a surveillance camera system, there are the following disadvantages to increasing the bit rate.

Disadvantages of high bit rate!
Transferring a large amount of data increases the load on the network line and equipment.

There is an upper limit to the bit rate that can be transferred depending on the network environment. This depends on the LAN cable you are using, the performance of the hub, etc., but it will be difficult so I will skip it. Just think that there is an upper limit for the bit rate depending on the environment.

“So what happens if it exceeds the upper limit?”

In the case of video from a network camera, the connection often drops. If you exceed the upper limit, the line will be punctured and you will lose connection with the camera. The image may be interrupted for a moment, but if it is too bad, you will not be able to see the image from the camera at all.
If this happens, it will be very troublesome …

Also, if the bit rate is high, a large amount of data will reach the browsing computer and the recording NVR. When a lot of data arrives, the computer or NVR will not be able to process the data, which may cause abnormal operation (reboot, etc.).

Therefore, the System Kay NVR defines the maximum bit rate that can be supported as a specification. The bit rate that the entire NVR can process such as performance and bandwidth limit per channel are described in the specifications.

Free Download Mp4Gain

Mp4Gain Main Window

Mp4Gain Features

Free Download Mp4Gain

Video distribution Advantages and disadvantages of a high bit rate

The video bit rate is calculated separately for video and audio and added together.

Bit Rate

The sum of the video and audio bit rates is called the oval bit rate (total bit rate).

Expressed in the formula
Oval bit rate = video bit rate + audio bit rate

Will be.

High bit rate benefits
The higher the bit rate, the better the picture and sound quality, and the lower the bit rate, the worse the picture and sound quality.
However, note that if the video bit rate is high, there are cases where the video bit rate is high and the image quality is good, but the audio bit rate is low and the sound quality is poor. On the contrary, there may be cases where the image quality is poor and the sound quality is good.

High bit rate video basically has the advantage of improving image quality and sound quality, but you also need to understand the disadvantages.

Disadvantages of high bit rate
The higher the bitrate, the more net bandwidth is consumed and the more playback load is applied.
For example, increasing the bit rate from 500 Kbps to 1000 Kbps doubles the net bandwidth usage and doubles the playback load or more.

It is easy to increase the bit rate for high image quality, but if you increase the bit rate too much, the CPU will become overloaded and you may not be able to reproduce it well, so be careful.

Especially when the radio wave of the smartphone is bad or the band is limited, it may not play smoothly at a high bit rate.

Even if the bit rate is increased, the image quality and sound quality do not improve above a certain level.
In fact, increasing the bit rate does not mean that the image quality and sound quality will increase without an upper limit.

For example, if the image quality of the original video material shot by the camera is 100, even if it is converted at a high bit rate by video editing software or encoding software, a high-quality video with a quality of 100 or more image of the original video will be created. You can not.

No matter how high the bit rate is, if the quality of the original video material is poor, the quality will not be better.

Let’s think about the optimal bitrate for each video.
When creating a video, you need to think about how to set the optimal codec, resolution, frame rate, and bit rate yourself.

Then
The higher the bit rate, the better the picture and sound quality.
If the bit rate is high, the network and the playback terminal will be overloaded.
Even if the bit rate is increased, the picture quality and sound quality should not be higher than that of the original video material.
It is useful to remember that.

Also, almost all video editing software, encoding software, YouTube, and other free video publishing services commonly used when creating and publishing videos have preset settings with preset codecs, resolutions, frame rates, and bit rates.

However, the image quality of the presets is not always optimal, so use this bit rate knowledge when you need to make fine adjustments.

The difference between progressive download and streaming delivery

Streaming

When a business or organization publishes a video on the web or operates a video service, it is important to select a video distribution method.

streaming

On this occasion, we will explain the characteristics and differences between the two distribution methods, “progressive download” and “streaming distribution”.

What is progressive download?
Progressive download is a delivery technology that downloads data such as video and audio and plays them at the same time.

Sometimes referred to as “pseudo-streaming,” the video data is played back as it is saved as a temporary file on a terminal such as a PC or smartphone.

Thus, once the video data is downloaded, it can be freely viewed offline without having to go through the internet.

What is streaming distribution?
Streaming is a technology that transfers audio and video data, plays it back in sequence, and distributes the data to terminals such as PCs and smartphones without saving it.

Streaming distribution uses a dedicated streaming server for video and audio distribution and transfers only the data required for playback, making it suitable for distribution of long duration video such as movies.

Due to the technology to play while data is transferred, if the communication environment is poor, the data reception cannot be maintained and the video may stop in the middle.

Advantages and disadvantages
Let’s take a look at the pros and cons of “progressive download” and “streaming”.

Progressive discharge
merit
Even if the communication environment is bad, smooth playback is possible after the data download is complete.
Since the video data is saved as a temporary file in the terminal, the saved video data can be played repeatedly as long as the cache remains.
Operation is possible without preparing a dedicated streaming server
* Recently, streaming servers are becoming more common.
Demerit
Since the entire video file is downloaded to the terminal and distributed, it is easily copied and no copyright action can be taken.
* Recent video data security
Large video files put a strain on your bandwidth, so they take time to play.
As the number of concurrent viewers increases, the server will become overloaded and viewing will become difficult.
Transmission delivery
merit
Only the video being played is transferred to the user, so if the communication environment is stable, you can comfortably watch long and large-capacity videos.
Since there is no data left on the device, copyright-related measures such as data redistribution and falsification are higher than progressive downloads.
* Recent video data security
By using a CDN, a stable distribution is possible even if the number of concurrent viewers increases.
Reference: What is a CDN that is often used for video distribution?

Demerit
Stable playback is not possible unless the communication environment is protected.
A dedicated streaming server needs to be set up, which requires upfront and running costs.

Video Distribution Advantages and Disadvantages of High Bitrate Part 2

Bitrate

Let’s think about the optimal bitrate for each video.
When creating a video, you need to think about how to set the optimal codec, resolution, frame rate, and bit rate yourself.

Bitrate

However, the image quality of the presets is not always optimal, so use this bit rate knowledge when you need to make fine adjustments.

Video distribution Advantages and disadvantages of a high bit rate

Bitrate

The video bit rate is calculated separately for video and audio and added together.

Bit Rate

The sum of the video and audio bit rates is called the oval bit rate (total bit rate).

Expressed in a formula
Oval bit rate = video bit rate + audio bit rate

High bit rate video basically has the advantage of improving image quality and sound quality, but you also need to understand the disadvantages.

It is easy to increase the bit rate for high image quality, but if you increase the bit rate too much, the CPU will become overloaded and you may not be able to reproduce it well, so be careful.

Especially when the radio wave of the smartphone is bad or the band is limited, it may not play smoothly at a high bit rate.

No matter how high the bit rate is, if the quality of the original video material is poor, the quality will not be better.

What is a bit rate? Basic bit rate knowledge required for video distribution.

Video Bitrate

Bit rate / bit rate

BitRate

Bit rate is the amount of data per second. Video quality is determined by factors such as “resolution”, “frame rate”, “bit rate” and “codec”. Bit rate is an important factor related to video quality. Therefore, this time, I will explain the basic knowledge of bit rates required for Internet video distribution.

” Table of Contents ”

1. What is a bit rate?
2. Relationship between video bit rate and video image quality
3. Estimated video bit rate
4. Advantages and disadvantages of a high video bit rate
1. What is a bit rate?
The amount of data per second is called the bit rate. Use bps as the unit. This is an abbreviation for Bit Per Second. For example, if it is written as 500 kbps, k is 1,000, which means “the amount of data of 500,000 bits per second.”

There are two types of video bit rates: “video bit rate” and “audio bit rate”. The total value of “video bit rate” and “audio bit rate” is the total bit rate (oval bit rate) of the video file.

Video Bit Rate / Audio Bit Rate

■ Voice bit rate
The audio bit rate is the bit rate associated with the audio in the video file. Generally, the audio bit rate is lower than the video bit rate.
The guideline for the audio bit rate is as follows.

Lossy codecs like MP3, AAC, WMA … 96kbps-128kbps
Sound quality oriented video … 192 to 320 kbps
A codec is a program that encodes (encodes) / decodes (decodes) video and audio data. A lossy codec is a codec that dilutes the data and reduces its weight without affecting it. For more information on codecs, see the following.

[Reference article] What is a codec? Basic knowledge of the codecs required for video distribution.
■ Video bit rate
The video bit rate is the bit rate of the video in the video file. Generally, the video bit rate value is higher than the audio bit rate. The appropriate video bit rate will differ depending on the size of the resolution and the content of the video, such as amount of movement / small amount of movement.

The guideline for video bit rate is explained in “3. Guideline for bit rate”, but the value varies depending on the image quality you want to deliver, such as 500 kps to 70 Mbps. Since the standard for audio is “approximately 96 kbps to 128 kbps”, the video bit rate occupies most of the bit rate of the entire video file.

It can be said that the higher the value of the video bitrate, the better the image quality, but that does not mean that “the higher the value, the better”. When displayed at a small resolution, the roughness is not as noticeable even if the bit rate is reduced. On the contrary, even if you encode at a high bit rate, you will not notice the difference in image quality, and in many cases the file size will only increase.

From now on, we will focus on the bitrate of the video.

What is the encryption mechanism? Part 2

Video Bitrate

However, in the case of moving images, the quality of the image at the time of encoding will vary depending on whether the video material has a lot of movement or the video material has little movement, even if the bit rate is the same. Therefore, it is necessary to thoroughly judge and encode not only the bit rate, but also the frame rate and keyframe settings, which will be explained later, according to the video material. I hope you understand that “there is a relationship between resolution and proper bit rate” as a determining factor for high definition.

videro bit rate

Point 2: Increase the frame rate if movement is important and lower the frame rate if image quality is important.
While the frame rate (number of frames) is set at 29.97 fps for televisions and 24 fps for movies, the frame rate is freely configurable for Internet video encoding. A video is a collection of continuous images (frames) like a flip book. The more frames per second, the smoother the movement.

In video encoding, the bit rate per second is fixed, so if you increase the frame rate, the number of images in the flip book will increase and the movement will be smoother, but the amount of data allocated per frame will decrease, so the image quality will be better to fall.
On the other hand, if you reduce the number of frames, the number of images in the flip book will decrease and the smoothness of the movement will be a little slower, but the image quality will improve because a large amount of data will be allocated to each frame. .

If you want to emphasize the smoothness of motion in a video with a lot of motion, increase the frame rate (video demo 1). On the other hand, if the video has little movement, it is not necessary to increase the number of frames as much (depending on the degree), so it is effective to lower the frame rate and give priority to improving the image quality

Point 3: insert “keyframes” at short intervals for moving images
A keyframe is a frame that exists as a single still image (an image that is not compressed between frames) and is the starting point for difference information. Depending on the encoder settings, the keyframes are inserted when there is a scene change and the difference information is inserted at regular intervals, such as XX frames and once every XX seconds.

■ Keyframes for moving images
In a moving image, things move or change significantly in a short time. Therefore, inserting keyframes at short intervals improves the reproducibility of small movements.
There is also the advantage that the search is smoother for images with many keyframes. The reason is that the search is based on keyframes, so the more keyframes you have, the easier it is to stop at the target scene. If the position where the search stops is not a keyframe but a difference information frame, the information is fetched to a nearby keyframe, but that time is short.
However, if you increase the number of keyframes too much, the keyframe bit rate will be taken over and the overall video quality will deteriorate, so be careful.
For moving images, the keyframe is approximately once every 3 seconds.

■ Keyframes for images with little movement
Since there is little difference information in a video with little motion, you won’t notice much difference in change even if there are few keyframes. However, if you insert keyframes for too long, search may not work properly and playback may take a long time to start. This is the opposite of the case where there are many keyframes, and if the rewind position is far from the keyframes, it will take time to read.
For those with little movement, the guideline for keyframes is approximately once every 6 to 8 seconds.

So far, “What is the encoding mechanism? Five points to consider for encoding HD video [Part 1]”, “Understanding the appropriate bit rate for the resolution you want to distribute”, motion oriented or image quality I explained three points how to change the “frame rate” and “how to insert keyframes” depending on whether it is important. In [Part 2], we will explain “the advantages and disadvantages of bit rate settings

What is the encryption mechanism?

Video Bitrate

5 points to consider for HD video encoding

Video Bit Rate

Encode

The image quality of Internet videos is almost proportional to the bit rate. However, if the bit rate increases unnecessarily, the file size will increase. “Keep bit rate low”, “Reduce file size” and “Reduce load time” are linked, and there is nothing to say if you can encode in high definition while keeping the bit rate low.
Also, at the beginning, I wrote that “image quality is almost proportional to bit rate”, but I think some of you may have experienced that “I increased the bit rate and encoded, but I am not satisfied with the quality of the image. “So, this time, I will explain five points that are often used to do high definition video encoding.

Encoding Mechanism
First, I will briefly explain the encoding mechanism.
An image is a collection of continuous images (frames), and by changing this in a short time like a flip book, it appears that you are visually moving. Japanese television images are 29.97 frames per second (short for 29.97 fps / frame per second) and most movies and animations are standard 24 fps. Since a large number of frames are required for video, the amount of data is also huge. Therefore, data compression is indispensable for distributing videos on the Internet.

When coding

“Prediction in frame” that compresses data within a frame
“Prediction between frames” that compresses data into consecutive frames
The information is reduced to the extent that it does not affect the visual sense and the data is compressed.

■ What is in-frame prediction?
There are various methodologies for data compression, so I will skip the details here, but the basic idea of within-frame prediction is to divide a frame into small blocks called cells and the colors adjacent to each other in the block. they are the same or similar, they are compressed together.
For example, if there is information “blue blue blue blue blue blue blue blue blue blue red red yellow yellow yellow” information in the divided block, the amount of data can be reduced by combining this with “blue 11, red 2, yellow 3”. It’s an image.

An example of data compression in in-frame prediction (image)

■ What is cross-frame prediction?
However, in the case of video with a time axis, the number of frames is large, so there is a limit to the overall weight reduction based solely on the prediction within the frame. On the other hand, in the prediction between frames, based on the idea that “the contents are similar before and after the consecutive frames”, the cells that do not change from the previous frame reduce the amount of data by reusing information, and the cells that change is converted to data as difference information.

Point 1: learn a suitable bit rate guideline for resolution

The above three are excerpts of the same 640x360px image, but the file sizes are different at 1MB, 250KB, and 50KB. The image quality of 250 kB is lower than that of 1 MB and is much coarser at 50 kB. This is because the amount of data allocated per pixel is reduced, resulting in poor image quality.

The same phenomenon can be said of the videos. Bit rate is the amount of data allocated per second and affects the image quality of the video. If you want to view a video on a large screen, such as viewing it full screen on a computer or TV monitor, you need a sufficient bit rate according to the resolution. On the other hand, when displayed at a small resolution, the roughness is not as noticeable even if the bit rate is reduced. On the contrary, even if you encode at a high bit rate, you will not notice the difference in image quality, and in many cases the file size will only increase.

What is the best bit rate for video and sound and what is it?

What is the best bit rate for video and sound and what is it?

Common characteristics of video and audio recordings include the so-called bit rate.

bit rate

Some users do not know how important this figure plays when playing files, along with their size and resolution. What is the bit rate? The bitrate is the number of bits that are used to process and transmit data during a certain period of time. This measurement is used to measure the effective transmission rate on a data stream channel.

In other words, this is the minimum value of the channel capable of passing the flow without delay. The measure of video bit rate is bits per second and its derivatives (kbps, Mbps, etc.). In audio and video transmissions that use degrading compression, this term refers to the degree of compression of the transmission.

Consequently, it indicates the size of the channel within which compression took place. Compression modes In practice, there are three modes of stream compression that cause quality loss: Constant Bit Rate (or CBR). In this encoding option, the initial bit rate is set by the user and then does not change for the entire duration of the audio or video. Its advantage is that it is quite easy to calculate the size of the final file. However, this encoding is not very suitable for audio files that have dynamically changing sound, as it does not provide a good size / quality ratio.

Variable bit rate (or VBR). The bitrate value is selected by the codec, depending on the parameters (the expected quality level). During the encoded fragment, the value of the bit rate may change. When audio is compressed, the required bit rate is set based on the psychoacoustic model. This encoding achieves the best sound quality ratio, but it is difficult to calculate the exact size of an audio or video recording. It can be very different. Average Bit Rate (or ABR).

This is a hybrid of the first two modes. The initial value of the bit rate is set by the user, but then independently changed by the program within certain limits. At the same time, the difference with VBR is that the codec uses the maximum and minimum values within the limits set by the user, and does not exceed them. This encoding allows you to set the processing speed in the most flexible way and allows you to determine the file size with greater precision. Where are the Users and AppData folders and what is stored in them What and how is it measured? When quantifying high data rates, metric or decimal prefixes are used. It looks like this: Speed 1000 bps = 1 kbps (one kilobit or one thousand bits per second). Speed 1,000,000 bps = 1 Mbps (one megabit or one million bits per second). Speed 1,000,000,000 bps = 1 Gbps (one gigabit or one billion bits per second). What bit rate should I choose? When it comes to the common MP3 audio format, it is the audio compression that results in data loss. The higher the bit rate, the better the sound quality. Speaking of the choice of the bit rate for this format, we can say the following: 32 kbps: very low quality sound (valid only for voice recording); 96 – May be applicable for low quality audio transmission or voice recording; 128 and 160: allows you to encode music recordings at an entry level; 192 – music encoding in acceptable quality; 256: high quality music recording; 320 is the highest quality that can be achieved in MP3 format. In video formats, this value is calculated differently. For example, for videos on YouTube, a bit rate of 10-16 Mbps at 720p is sufficient. This will achieve a clear image and a small file size. If better image quality is required, this value can be increased to 18-25 Mbps. The highest image quality will be achieved at 50 Mbps and 1080i resolution. In general, the effect of bit rate on video quality is expressed as follows: Yandex.Direct18 + Start your journey from the station Start on your home planet, explore the universe and find intelligent life in the universe. MORE DETAILS XCRAFT.RU 18+ Read Glukhovsky’s new novel “Post” Exclusively on Booknet, a new post-apocalyptic novel by Dmitry Glukhovsky. MORE DETAILS LITNET.COM 400 kbps: low quality video at 240p; 750 kbps, 1 Mbps: can be used for some YouTube videos at 360p and 480p, respectively; up to 1.15 Mbps – compressed video in VCD format; 2.5 and 3.8 are compressed YouTube videos recorded at 720p; 4.5 and 6.8 are sharper, but still compressed YouTube videos using 1080p; 9.8 – DVD video recordings.

Data compression modes: CBR and VBR

Data compression modes: CBR and VBR

CBR and VBR

Often times an inexperienced (and even sophisticated) DVR owner has a question: “What’s behind the CBR and VBR abbreviations in the recording channel settings?”

CBR and VBR in mp4 H264 video files | Internet with a Brain

In fact, if everything is clear with the video settings (720p, 1080N, 1080p are already established formats in the world of video surveillance), then with the audio settings not everything is so transparent.

The sound from the microphone connected to the recorder is encoded in MP3 format. Today, the MP3 format is the most popular audio file encoding format of all the existing ones. It is generally accepted that the quality of an audio track depends on its bit rate, therefore the most optimal bit rate for an audio track is 192 kbps. This statement, however, is one-sided, because in addition to the bit rate, the sound quality depends on the codec in which the audio was recorded.

There are three main types of MP3 file encoding: CBR, VBR, and ABR. The ABR type is intermediate between the other two and is not used in video surveillance. Therefore, in this article, we will only consider the CBR and VBR encoding types.

CBR (constant bit rate) stands for constant bit rate, which was set by the user during recording or encoding and does not change in the future. That is, regardless of the data type (even if you are recording silence), the number of bits specified by the user is constantly encoded in 1 second. The consequence of this type of encoding is the cumbersome amount of data received, which is a waste of disk space.

VBR (Variable Bit Rate) translates from English as a variable (variable) bit rate. By encoding in VBR, we get a file, the bit rate of which changes depending on the density of the data stream (that is, for example, the bit rate of silence will be less than the bit rate of any sound). This type of encoding continues to improve, reaching new indicators of the amplitude of changes in the bit rate of the data stream. The main disadvantage is that it is impossible to predict the future size of the encoded file. Despite this, this minus sign does not obscure the overall picture in any way – the file size turns out to be smaller than when encoded as CBR. This is due to the fact that the bit rate of silence (s) is lower. Obviously, this format is more acceptable for video surveillance tasks than CBR.