Tag: why is video bitrate important

bits Bit rate

A value that indicates how many bits of information are processed or transmitted / received per unit of time.

Also called transfer fee. The amount of information in one second of audio data and video data is expressed in “bits per second” (bps: bits per second). It is usually used with “k (kilo)” to represent a thousand units or “M (mega)” to represent a million units because the number of digits is large and is expressed as “kbps” or “Mbps” (1kbps is 1000bps, 1 Mbps is 1 million bps). It is often used in the audiovisual (AV) genre, and in the case of audio and image data, the higher the value, the more accurate the information, and the better the sound quality and picture quality. The standard bit rate for MP3, one of the audio compression formats, is 128 kilobits per second (kbps), which compresses the amount of information in an uncompressed WAV file (approximately 1400 kbps) with CD sound quality. to about 1/10. you can see that you are doing it. The bit rate of the video is higher due to the large amount of information, and the high definition terrestrial digital transmission is about 18 megabits per second (Mbps) and the BS high definition digital transmission is about 24 Mbps. a unit that expresses the transfer rate, “bytes per second” (Bps or B / s), which is a reference value that expresses the number of bytes per second. Since 1 byte is 8 bits, Bps can be calculated by dividing bps by 8.

Explanation of the book “Bitrate” that opens when you have a problem with your computer
Bit rate
It is the speed of data communication, which is the amount of data that can be sent and received in a given period of time. The unit is “bps”, which is short for “bits per second”. It is also used to refer to the amount of data used to express one second of video or audio when compressing video or audio. The higher the amount of data (= lower the compression rate), the more faithful it will be to the original, but a high-speed communication line is required.
On the other hand, as the amount of data is reduced (= the compression rate is high), the image quality and sound quality deteriorate, but transmission is possible even in an environment where the communication speed is slow .
⇨  bps, transmission
Source: Asahi Shimbun Publishing Co., Ltd. “Books to open when you have problems with your computer” Information on books to open when you have problems with your computer

Explanation of the “bit rate” dictionary that understands TI terms

Processed per unit of time, or the transfer is a bit number. It is generally expressed as a number per second and uses bps as the unit. It is expressed as a physical quantity, such as the speed of communication on a computer network and the transfer speed in transferring data with a circuit within a computer or peripheral devices. It is also used as a unit to express the amount of information per second when compressing audio and video data, and if this compression method is used, the higher this value, the higher the sound quality and picture quality. ◇ Also called “bit rate”, “bit efficiency” and “bit rate”.

What are aspect ratios, frame rates, bit rates, and codecs? Part 2

Bit rate

In the context of a video, “bit rate” refers to the amount of data bits that the video creates per second, in units of bps (bits per second). The point is “how much information is packed in one second of the video”.

As a general rule of thumb, everyone knows that the higher the quality of data, like videos, the bigger it gets. If you think of a video as a collection of still images, you can see that there is a lot of “information” that extends the data.

Screen resolution (1920 x 1080 pix is ​​heavier than 640 x 480 pix)
Amount of color information (24-bit color is heavier than monochrome)
Frame rate (24 fps of general animation is heavier than 5 fps of security camera)
Voice quality (heavier with sound than without voice, heavier with high sound quality than with low sound quality)
The more these items are packed, the higher the bit rate and quality of the video. However, the higher the quality, the higher the video capacity.

A video with a large file capacity places a strain on both the communication line and the processing CPU. When distributing video, it will be necessary to consider “how much quality is required” and select the optimal bit rate for each video content purpose.

● Reference: general bit rate example (video / audio / total standard frame rate)

High definition digital transmission: 24 Mbps
DVD video: 10 Mbps
Blu-ray video: 54 Mbps
YouTube HD (1080p) Image quality: 1.5-3 Mbps
YouTube HD (480p) Image quality: 0.5-2 Mbps
In addition to the frame rate and bit rate discussed so far, there is a data compression technology “codec” as an important factor related to the data capacity of video. This will be discussed later.

Codec

It is a word that can be understood in various ways, but in the context of video, it is software that compresses and decompresses audio and video data. I explained that the video will increase in capacity depending on the quality. Even if you want high quality, large files are difficult to handle. That’s where data compression, or codecs, comes into play.

For video files, the video is compressed using the “video codec” and the audio is compressed using the “audio codec”. There are several types, but typical examples are as follows.

Video codecs: MPEG-4, MPEG-2, H.264, VP9, ​​VP8, Xvid, etc.
Audio codecs: MP3, AAC, AC-3, FLAC, LPCM, etc.
It is easy to confuse video file format with codec, but video format is different from codec and is called container. It stands for “container” that combines separate video and audio files into a single file. The codecs that are organized by the container are fixed.

File format: .mp4 .avi .mov .mpeg .flv, etc.
The most frequently distributed video on the Internet is probably “H.264 / MPEG-4 AVC”. There is the advantage that the image quality can be kept as is, even at a low bit rate, and if it is also used on YouTube, it seems to be good to call it the current standard codec.

Video distribution even with the “internal newsletter app”

According to a 2018 survey by J-Stream Inc., which provides video distribution services, “ satisfaction with internal public relations is more than 30% overall, but satisfaction is limited to those who frequently view public relations. internal with videos. more than 50%. “By making good use of video content, you may be able to increase the support base of your company’s internal app / web newsletter. Please give it a try. Of course, videos can also be distributed using the” internal newsletter “of Wis Works.

What are aspect ratios, frame rates, bit rates, and codecs?

Explains terms that comprise the basics of video distribution.

What are aspect ratios, frame rates, bit rates, and codecs? Explains terms that comprise the basics of video distribution.

A glossary that presents technical terms that you should know when creating an internal newsletter for web applications. On this occasion, we will explain to beginners the terms necessary to know the video distribution that is being used more and more in the internal newsletter. [[1] App Edition] [[2] Cloud Peripheral Edition] [[3] UI Edition] [[4] Responsive Web Design Edition] [[5] Internet Basic Edition]

The ratio of the width to the height of the screen, such as images and videos. For example, the aspect ratio of digital terrestrial broadcasting in Japan was 16: 9 and that of analog broadcasting was 4: 3. The reason why there are left and right margins in the broadcast of the above program is because the aspect ratio is different. The following four types are typical proportions that you see often.

16: 9 (wide): digital terrestrial broadcasting, DVD, Blu-ray, YouTube
4: 3 (standard): analog terrestrial broadcasting
16:10 (WXGA): PC screen, projector
2.35: 1 (Cinesco) – Movie screen size
For the aspect ratio of the video content of the internal app / web bulletin board, unless there are special circumstances, we recommend the main 16: 9 that you are used to seeing on television. A resolution of 720 x 480 pixels (480p), 1280 x 720 pixels (720p), etc. should be enough.

Transmission
transmission

Transmission

A technology that allows you to immediately play audio and video content on the Internet while downloading it. Everyone will see streaming services like YouTube, Nico Nico Douga, Netflix, and Amazon Prime Video.

Since audio and video have a large amount of data, if you download all the data to your PC or smartphone and then play it back, you have to wait a long time until the reception is complete.

On the other hand, with streaming you don’t have to wait because you can download them little by little and play them in parallel.

● Advantages of transmission

Reduced waiting time
You do not need free space on your PC or smartphone
The distribution load on the server side providing video and music is also light.
It has the effect of deterring copyright infringement, such as the redistribution of video and music data.
● Disadvantages of transmission

Since internet connection is required, it is basically not available offline (even if the paid service provides a media storage feature)
Due to the large data capacity, a certain speed of communication is required. Playback stops and quality deteriorates on slow speed lines
For mobile viewing, you need to be careful about the amount of data communication transferred.
The number of companies that want to use video for internal public relations is increasing. Internal web / app newsletters are also expected to be used as a simple streaming video distribution channel.

frames per second
frames per second

frames per second

A video is a collection of continuous still images. Frame rate is the number of “continuous still images” per second (number of frames). For example, if the movement of “throwing a ball” for 1 second is represented by a still image, 24 frames can be viewed with movement smoother than 3 frames.

In this way, the element that determines “how smooth the video looks” is the frame rate, and the unit is FPS (Frame per second), which is expressed by the number of frames displayed per second.

It’s easy to think that smoothness is better, but the higher the FPS means that the amount of still images per second increases and the amount of video data increases.

For example, when recording event video, fluency is more important than data capacity, but what about security cameras? Instead of smooth movement, it is more significant to reduce the amount of data and continue surveillance recording for as long as possible.

If you want to create video content for your in-house newsletter, the frame rate (around 30 FPS) as shot with a smartphone is sufficient, but if you want to reduce the data capacity, it works fine down to about 20 FPS.

Video frame rate, resolution, bit rate Part 2

Interlaced and progressive

It can be expressed by adding iop to the end of the resolution, such as 1920 x 1080i and 1920 x 1080p.
This is a screen display method called
i: interlaced method
p: progressive method
. For example, if the 8.00 Mbps bit rate screen described below is displayed for only 1 second, the interlaced method displays the screen. The numbers of 1px horizontal lines called scan lines are alternately displayed within 0.5 seconds, the progressive method displays all scan lines as they are for 1 second.
The interlaced method is said to look smooth when the image has a lot of movement and is used primarily on televisions. On the other hand, the progressive method is said to be clearly visible in the case of images with little movement, and it is not mainly used in personal computers, but the interlaced method cannot be compatible with personal computers.
Each has advantages and disadvantages, but it is a level of difference in method and does not fundamentally affect the level of image quality, such as frame rate and bit rate.

3. 3. bit rate
Set the amount of video information that is retained per second. For the bit rate, set the video and audio separately.

Video Bitrate
Regarding the bitrate of the video, the higher the bitrate, the more information the video will have, so the video will be clearer, and the lower the bitrate, the blurrier the video will be.
The higher the bitrate, the better the image, but for example, it is useless to increase the bitrate even if the resolution is low, the playback load will increase, and the file size will increase unnecessarily … In other words, it is important to set a suitable bit rate according to the frame rate and resolution. The guideline is as shown in the following figure.

-Video Bit Rate Settings Guide (Minimum) –

Resolution (image quality) / frame rate Frame rate 29.97 fps or less Frame rate 30 fps or more
1Seg (360px x 180px / 240px) 0.75 Mbps ~ 1.00 Mbps ~
SD (720 px x 480 px) 2.50 Mbps ~ 4.00 Mbps ~
HD (1280px x 720px) 5.00 Mbps ~ 7.50 Mbps ~
Full HD (1920px x 1080px) 8.00 Mbps ~ 12.00 Mbps ~
2K (2560 px x 1440 px) 16.00 Mbps ~ 24.00 Mbps ~
4K (3840px x 2160px) 45.00 Mbps ~ 68.00 Mbps ~
8K (7680px x 4320px) 130.00 Mbps ~ 200.00 Mbps ~

Audio bit rate
The guideline for the audio bit rate is shown in the following figure. The size is very small compared to the video.

-Guide to configure the audio bit rate-

Voice type bit rate
monaural 128 Kbps
stereo 384 Kbps
5.1 Surround Sound (Dolby Digital) 512 Kbps

Bit rate control method
As a method of controlling a bit rate,
CBR (for Constant Bit Rate: Constant Bit Rate)
VBR (Variable Bit Rate: Variable Bit Rate)
ABR: (Average Bitrate Average Bitrate)
has three methods.
Generally, for stability during playback, use CBR where the bit rate does not change in the scene.

4. Profile, level
Profile and Level are names that combine the frame rate, resolution, and bit rate values ​​explained so far for each purpose. So to speak, it can be called the name of the video setup menu.
Every device (iPod, iPad, iPhone, PSP, Switch, Android, etc.) publishes recommended profiles and levels, which will naturally allow you to set the optimal frame rate, resolution and bit rate …
Select the target device with the video editing software, but at this point, select the profile and level internally.
By the way, this profile and level are strictly the H.264 video compression format (video codec) setting standard. See here the video compression format.

-Profile, level list (simplified version) –

Level / Profile Baseline
profile of
Main baseline
profile
main High
profile
high
Level 1.3 Frame rate: 30 fps
Resolution: 352px x 288px
Bit rate: 0.75 Mbps Frame rate: 30 fps
Resolution: 352px x 288px
Bit rate: 0.96 Mbps
Level 2.2 Frame rate: 30 fps
Resolution: 352px x 480px
Bit rate: 10 Mbps Frame rate: 30 fps
Resolution: 352px x 480px
Bit rate: 20.0Mbps
Level 3.2 Frame rate: 60 fps
Resolution: 1280px x 720px
Bit rate: 10 Mbps Frame rate: 60 fps
Resolution: 1280px x 720px
Bit rate: 25.0Mbps
Level 4.2 Frame rate: 60 fps
Resolution: 2048px x 1080px
Bit rate: 50Mbps Frame rate: 60 fps
Resolution: 2048px x 1080px
Bit rate: 62.5 Mbps

Video frame rate, resolution, bit rate

Frames per second

When “Let’s make a video”, the video format is:
-Video format (container) = MP4 (.mp4) -Video format
video compression (video codec) = H.264
-Audio compression format (audio codec) = AAC
It is an option. (The video format is summarized here). Later
, what needs to be configured after that is:
・ Frame rate
・ Resolution
・ Bit rate
. Here I would like to summarize this setup.

Table of Contents
1. 1. frames per second
2. 2. Resolution (angle of view)
3. 3. bit rate
4. Profile, level
1. 1. frames per second
Frame rate is an important setting factor that affects the “smoothness” and file size of videos. The unit is fps (frames / second). You can also tell how many still image frames are embedded per second.

A moving image uses the image persistence phenomenon of the human eye to display still images continuously so that they can be recognized as a moving image. It is said that the ability of the human eye can recognize up to 60 fps. So if you create a video at 60fps, you can tell that the video doesn’t look jerky.
On the other hand, this frame rate has a great effect on file size. Since it is necessary to save 60 still images in 1 second at 60 fps and 1 still image in 1 second at 1 fps, the file size varies greatly depending on the frame rate.
Generally, TVs and DVDs use 30 fps (29.97 fps) and most of them are set to 30 fps (29.97 fps) or less.
Unless you really need to reduce the file size, try specifying this 30fps (29.97fps).
For reference when setting less than 30 fps (29.97 fps), 24 fps for movies and 15 fps for 1Seg TV. It is said that it can be lowered to 15 fps for videos with little movement, such as a person sitting and talking. If you set it to 10fps or less, it will no longer be a video but a slideshow level, and it will definitely look jerky. The lowest line for video is around 15fps.

On the other hand, for videos with a lot of movement, such as sports and actions, you may feel that 30 fps (29.97 fps) at the TV or DVD level is not enough. The file size will be large and it will be difficult to send and receive on the internet line, but if image quality is prioritized, it is worth setting it to 60fps.
Current playback devices that support 120fps are still rare, but next-gen TV streaming standards, 4K and 8K streams are specified up to 120fps.
2. 2. Resolution (angle of view)
It can also be said that it is the size of the area where the video is displayed. In terms of TV streaming,
1Seg → SD → HD → Full HD → 2K → 4K → 8K Custom
As the resolution increases, the rendering area increases, so the video file size naturally increases accordingly.

Resolution (angle of view) TV broadcast Compatible storage devices
SD (720 px x 480 px) Analog broadcast DVD
HD (1280px x 720px) HDTV broadcast
* mainly in Europe ――――
Full HD (1920px x 1080px) High definition transmission
* Japan, strictly speaking,
High Definition BS: 1920px x 1080px Transmission
digital terrestrial: 1440px x 1080px Blu-ray Disc
(BD)
4K UHD (3840px x 2160px) 4K UHD streaming means Ultra HD.
Streaming started on December 1, 2018 with the Next Generation Streaming Standard. Ultra HD Blu-ray Disc
(UHD BD)
8K UHD (7680px x 4320px) 8K Transmission As with
4K, streaming started on December 1, 2018. Unknown current status

When considering Internet video usage, YouTube’s maximum resolution is Full HD (HD1080). With reference to this, if resolution is prioritized, it should be set to Full HD, and if file size is prioritized, it should be set to SD or less.

aspect ratio
It is the aspect ratio of the resolution (angle of view). 16: 9 is the standard for televisions, and 16: 9 monitors have become mainstream for personal computers, but there are still products with aspect ratios such as 16:10 and 4: 3, iPhone 3: 2, and Andoroid 16. : is not unified like 9.
Therefore, if the prepared video file has a 16: 9 aspect ratio and the aspect ratio of the device to be played is different, it will be played by expanding / contracting, making margins, etc. on the side of the playback device.
When uploaded to YouTube, videos other than 16: 9 are automatically rendered with black frames at the top, bottom, left, and right.
For those who create and prepare videos, it is very kind to prepare a video file with each aspect ratio, but if not

Relationship between bit rate, video image quality and sound quality

In short, the higher the bit rate, the better the image quality and the sound quality of the video.

In other words, if the video bit rate is set high, the included color information will increase and even the smallest parts of the screen can be displayed neatly. Therefore, it can be said that the bit rate of the video directly affects the image quality of the video. On the other hand, if you set the audio bit rate high, you can record even the delicate parts of the voice and hear it clearly. In other words, the audio bit rate directly affects the sound quality of the video.

Also, as mentioned in Part 1, it is calculated based on factors that are different from video and audio bit rates, but if you want to improve image quality or sound quality, you need to increase either. .

Differences in picture quality and sound quality due to enhanced items

image quality
Increase frame rate → Smooth screen

Increase the resolution → The color fineness of the screen can be displayed clearly

Sound quality
Increase the sample rate → Soft sound

Increase the bit depth → Increase the expressiveness of the sound, such as finesse and volume

Part 3: Estimated Video Bitrate and How to Change It
As the video bit rate improves, so does the amount of data. Therefore, it is not good to ignore the specifications of the computer and the network environment and set it too high.

Speaking of the standard video bit rate value, 1,000 Kbps to 3,000 Kbps is considered sufficient for on-site playback. Also, although the audio quality is usually less important than the video display, it is common to set the audio bit rate to 128 Kbps and increase the video bit rate a bit.

However, this is one of the so-called guidelines and the value of the appropriate bit rate depends on the purpose of the video. It is also important to adjust the frame rate and resolution. In order to optimally adjust this, I would like to recommend everyone this time the popular video editing software “iMyFone Filme” which is easy to use.

Movie Features:
You can set the frame rate, resolution, bit rate, format, etc. all at once, and you can guarantee video quality with detailed settings.
You can add text and effects, as well as basic editing tasks like cutting, cropping, rotating, splitting, and adjusting the speed to make your video more attractive.
It is possible to export the edited video directly to various platforms, but it is very convenient for people who want to share it on SNS.
Movie Video Editing

Free Download Free Download
The procedure for setting the bit rate is as follows.
Step 1.After downloading and launching Filme, click on the Media Library panel or the three buttons below to install the video file. You can also put videos directly from your computer into your media library.

Import videos from media library

Step 2. Drag and drop the video file whose bit rate you want to change onto the timeline. Then click Output in the upper right corner of the interface.

Video output

Step 3. Click the “gear” icon to set the bit rate and related factors in the settings screen that opens. The maximum video bit rate can be set to “80000Kbps” and the maximum audio bit rate can be set to “320Kbps”, but once selected, press “OK” and “Exit” to finish.

Video Bitrate Settings

Part 4: Recommended bit rate settings on YouTube, etc.
The video sharing platforms we often use, like YouTube and SNS, have their own video bitrate ranges. If you want to post smoothly, you need to preset your video.

Therefore, the recommended bit rates for YouTube, Nico Nico, and Twitter are summarized in the list below. Please refer to it when you make a video.

Recommended video bit rate
YouTube video type (standard frame rate, SDR) smiling Twitter
1080p 8 Mbps 12 Mbps or more –
720p 5 Mbps 6 Mbps or more 2048 Kbps
480p 2.5 Mbps 2 Mbps or more 768 Kbps
360p 1 Mbps – 768 Kbps Recommended audio bit rate
YouTube smiling Twitter
128, 384, 512 Kbps 64, 128, 192 Kbps 32, 64, 128 Kbps

What is a bit rate?

It also explains the relationship with the video standard and quality.
Video Editing Tips

Overview:
Often times, you will want to adjust the bitrate when adjusting your video. Many people find it difficult and annoying in technical terms, but if you don’t know it, you won’t be able to set it up correctly and the video quality will eventually deteriorate, so be careful. This article explains the meaning and function of bitrate in an easy-to-understand way, but if you want to learn more about it, take a look.

Also, it is especially important that the standard bit rate is determined by the resolution and the frame rate, but it is better to change it at the same time as much as possible. This time, I will also introduce the operation procedure with the highly rated “iMyFone Filme” tool that can set all three at once, but let’s download it with the button below and try it out together.

Free Download Free Download
Table of Contents: Display
Part 1: What is bit rate?
Bit rate indicates the amount of data that can be sent and received per second, and the unit is bps (bits per second). For example, if the video bit rate is 1 Kbps, it means that 1000 bits of data can be transferred per second.

And if you break this down more concretely, there are the following three types.

“Video Bitrate
By analogy with the basic definition, video bit rate refers to the amount of video data per second. This value is calculated based on RGB data, frame rate, and resolution displayed by the color information contained in a pixel.

“Voice” bit rate
Similarly, the audio bit rate refers to the amount of audio data per second, but the value is calculated using the sample rate (Hz) and the bit depth (bits). The first indicates how many times the sound is divided and recorded, while the second shows the amount of data per recording.

Bit rate “oval”
Speaking of the calculation formula, it is “oval bit rate = video bit rate + audio bit rate”. Also called total bitrate, this is also what commonly used video bitrates mean.