Detailed explanation of bit rates for video and music files


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What is a bit rate?

Detailed explanation of bit rates for video and music files

Bitrate

What is a bit rate?

Bitrate

Bitrate is an unavoidable experience in video editing and music production.

The word bit rate sounds a bit complicated, but of course, video and audio files. It is also often found in various situations, such as mobile phones and internet lines.

What is the bit rate? It’s surprisingly useful to remember it sensually, so remember it.

I think the person who visited this page is a beginner asking “What is bitrate?” So I hope I can explain it in the easiest and simplest way possible.

Bit rate basics
To briefly explain the bit rate, it refers to the amount of data per second for communication, such as video files, music files, and the Internet.

The so-called reproduction and communication are data streams. This stream uses a unit called bps (bit per second) to indicate how many bits flow in one second (per second).

I think it is easy to understand if you can imagine the road that a car passes by. The car is the data and the data stream is the road.

Taking into account that a road with many cars carries many people and luggage, it can be said that a lot of data (information) flows. This is called high bit rate.

On the contrary, if there are few cars in motion, it can be said that little data (information) flows. This is called a low bit rate.

Image of many cars on the road.
A state in which the amount of data is large and the bit rate of the stream is high

Image that there are not many cars on the road.
A state in which the amount of data is small and the bit rate is low

Should the bit rate be high?
A high bit rate means a lot of information. If there is a lot of information, it sounds great, like high image quality for videos and high sound quality for music, but it has a big disadvantage.

The disadvantage of a high bit rate is that it increases the data capacity of a single file. If the data capacity is too large, it can take time to send someone or move data between hard drives, making it difficult to manage.

Therefore, the codec was developed to reduce data capacity while maintaining high image quality and high sound quality. I’ll talk about codecs another time, but it is necessary to set the bitrate keeping in mind the balance between image quality, sound quality and file capacity so that the data capacity is easy to handle.


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What is the standard bitrate for smartphone videos? Part 3

What is the standard bitrate for smartphone videos? Part 3

Smartphone

Estimated audio bit rate
In the case of audio bit rate, “128 kbps” is basically a guide.

Smartphone bit rate

Generally, for lossy codecs like MP3, AAC, WMA, AC3, Vorbis, a voice bit rate of around 128 kbps is sufficient. On the other hand, if the video is geared towards sound quality, it should be around “192-320kbps”.

Three Points to Consider When Considering the Bitrate of Smartphone Videos

There are a few things to keep in mind when considering the bitrate of your smartphone video.

When creating a video, you should use the appropriate bitrate for factors like size, but when considering bitrate, you need to keep three points in mind.

Here, we will introduce three points to keep in mind when considering the bitrate of smartphone videos, so why not refer to what kind of points to keep in mind?

Bit rate notes 1: The numbers are just a guide.
The proper bitrate for smartphone videos is just a guide.

The bitrate of a video involves multiple factors, not just the size of the image. For example, if you want to save a video with a lot of movement in high quality and a video with little movement that you want to save in medium quality, the appropriate bit rate will be different even if the image size is the same.

So, consider the bitrate you need as a guide only.

Bit rate note 2: consider the resolution according to your purpose
Let’s decide the optimal resolution according to the purpose of the smartphone video.

Even if you call it a smartphone video, it does not mean that a video with almost no motion and a video with high motion should have the same resolution. It is important to select the one that suits your purpose, such as high resolution for videos showing precise movements and low resolution for videos with little movement.

Therefore, when considering the resolution of a video, consider what the video is about.

For seminar videos
Since the seminar video is almost motionless, no high resolution is required.

The seminars and training videos aren’t particularly poignant videos, so lower resolutions won’t be a problem. For example, there is not a big difference between a low image quality of about 300 kbps and a high image quality of about 1500 Kbps, so it is recommended to make a light and low quality video.

For promotional videos
For promotional videos, it is a good idea to have a certain resolution.

It is not attractive that the resolution is low and that the video does not look beautiful in the video for internal promotion. However, it depends on the content of the video itself, so if you are not sure about the resolution, it is recommended to prepare a higher resolution and a slightly lower resolution and compare them.

For sports videos
High resolution is best for sports videos.

The bit rate has the characteristic that it is required since the difference with the previous frame is greater, and it is necessary to set it higher for videos with a lot of movement.

Therefore, if the resolution of the sports video is low, the outline will be broken and the color will fade, resulting in a stressful video.

Bit rate note 3: consider file size
The higher the bit rate, the larger the file size.

Of course, it depends on the content of the video, but as the bitrate increases, so does the file size, so this needs to be taken into account.

What is the standard bitrate for smartphone videos? Part 2

What is the standard bitrate for smartphone videos? Part 2

smartphone bit rate

Video Terms to Remember 1: Resolution
Resolution is the number of vertical and horizontal pixels in a video.

Smartphone BITRATE

The higher the resolution, the better the image will look. For example, if you prepare the same image with the same resolution of “640 x 360” and “2560 x 1440”, the latter will be clearer in detail.

Also, both the resolution and the pixel refer to vertical and horizontal pixels, but in the case of the number of pixels, it is expressed by the total number, so if the resolution is “1980 x 1080”, the number of pixels will be “2,138,400”.

Video term 2: frame rate to remember
Frame rate is the number of still images per second of video.

The frame rate unit is “FPS (Frames Per Second)”. Since a video is made up of a collection of continuous still images, the higher the frame rate, the smoother the video. However, the amount of data will increase accordingly.

Therefore, it is important to set the frame rate to the appropriate size according to the purpose of the video.

Video Term 3: Codec to Remember
A codec is a codec that compresses and decompresses audio and video data.

The larger the size of the video, the greater the amount of data, and the higher the quality, the larger the file size. Therefore, it is necessary to compress the data with a codec.

For example, there are types such as “MPEG-4” and “MPEG-2” for video codecs and “MP3”, “AAC” and “FLAC” for audio codecs.

Estimated bit rate suitable for smartphone videos

For smartphone videos, the standard bit rate is “300 kbps” or “600 kbps”.

Taking as an example the frame size that is often used for inline distribution, if the frame size is 480 x 270 px, 360 x 270 px, the bit rate is “300 kbps” and if the frame size is 640 x 360 px, 480 x 360 px, the bit rate is “600 kbps” will be a guide.

What is the standard bitrate for smartphone videos?

What is the standard bitrate for smartphone videos?

Bitrate

In this article, we’ll give you an overview of bit rates, guidelines for suitable bit rates for smartphone videos, and points to keep in mind when considering bit rates for smartphone videos, so check them out.

smartphone bit rate

What is the important bitrate for smartphone videos?
Bit rate is a term that refers to the amount of data per second.

The amount of data that can be sent and received in one second, and the unit is “bps (bit per second)”. For example, at 1 bps, 1 bit of data can be sent and received per second, and the higher the bit rate, the more data can be transferred.

Therefore, when making smartphone videos, it is necessary to consider the bit rate that viewers can comfortably watch.

Relationship to screen size
The larger the screen size, the greater the amount of data required and, conversely, the smaller the screen size, the less the amount of data.

Therefore, there is a reference bit rate for each screen size. If the screen size is 480 x 360, the bit rate is 500 to 700 Kbps, if it is HD 1280 x 720, it is around 2000 Kbps, and if it is full HD 1920 x 1080, it is around 4000 Kbps It is a guideline for the bit rate.

Three video terms to remember in advance

When creating a video, be aware of the video terminology.

In recent years, there have been many cases of video distribution in companies. However, there are many technical terms in the video, so you need to know the meaning of the terms in order to understand the video properly.

Here are three video terms to remember beforehand, so why not take a look at what they are?

But what role does the bit rate play?

This term is known primarily for describing the quality of lossy compressed audio (eg MP3). Unfortunately, this makes it even more difficult than with channel-separated compression, the bit rate is split between the two channels: stereo MP3 (not to be confused with dual channel) with a 320 kBit / sec bit rate. uses only 160 kBit / sec per channel.

Bit Rate

Or different bit rates per channel: set stereo (mono signal calculated with additional stereo information), on the other hand, it works with volume differences between the two channels and therefore can use the bit rate much more efficiently .

Bitrate

DAC, bit rate

What exactly is the obviously so essential bit rate? For a CD based on the Red Book standard, the bit rate is calculated as follows: 2 channels * 44,100 Hz sample rate * 16 bit depth per sample results in 1,411,200 bits / sec., That is, 1.4112 Mbit / sec. Bit rate. Obviously, this is considerably more than what compressed formats (should) provide. You can see how the compression processes work: last but not least, they more or less cleverly reduce the bit depth per sample at a given sample rate of 44.1 kHz, for example. The amount of data decreases, and that is exactly the goal of every data compression: halving the bit rate means exactly halving the amount of data.

As an example, I have compared some common file formats for digital audio:

Format

Codec (s)

Multichannel

Sampling rate

Bit depth or resulting bit depth from bit rate

Compression
/
subject to acoustic losses

Wav

PCM et al.

yes

any

any

Optionally, depending on the codec, also lossless

AIFF

PCM et al.

Not

any

any

Not

FLAC

FLAC (Free Lossless Audio Codec)

yes

0.001 kHz-655.350 kHz

4, 8, 16, 20, 24, 32

without losses

Apple loses
less
MP4

ALAC (Apple Lossless Audio Codec)

yes

0.001 kHz-384,000 kHz

16, 20, 24, 32

without losses

MP3

MPEG I Layer 3 in various incarnations
as B. LAME

Not

8-48 kHz

8-320 kBit / sec. CBR / VBR or 640 CBR for free MP3 format

with mandatory loss

Most readers will know that lossy compression is often based on psychoacoustic models or natural limitations of human hearing: what humans cannot (should) hear is not stored in the musical signal and is irretrievably lost, apparently not. you need it. The most popular example of this is the old MP3 format already mentioned. For some audiophiles, lossy compression is by definition useless for serious music listening, regardless of whether or not they would notice the loss of compression. For others, the sound is 320 kBit / sec. MP3 encoded for pop music are identical to CDs, they are satisfied.

DAC bit rate

Lossless compression, on the other hand, has become increasingly popular since Internet bandwidths and storage capacities have steadily increased. An example is the FLAC format, which fortunately is also “open source”, which means that it can be used freely and even changed in terms of the program. Meanwhile, most of the time it is directly compatible with proprietary audio hardware, so FLAC files can be played without the help of a computer, and in some cases even created (ripped CDs). As the table above shows, FLAC supports very high sample rates and bit depths, as well as multi-channel sound.

With FLAC, the audio signal is encoded based on computable fixed-point algorithms that conserve computational power, in which blocks are formed step by step and stereo separation is converted to mid-side separation and performed the remodeling of the signal with differential storage. No information is lost, it is stored more efficiently than, for example, on a CD; Depending on the complexity of the audio signal, compression rates of up to 30% can be achieved.

FLAC

It should be clear once again that FLAC or MP3 are file formats and therefore cannot be directly compared to the PCM of the Red Book encoding of a CD or DSD (see next section). Let’s leave it at that on the subject of data compression.

What does “bit rate” mean in a video?

When downloading videos from the Internet or copying videos from disc to your computer, you may have the option of choosing a different bitrate. Even DVDs have specific bit rates. As technology has advanced, video media are able to achieve higher quality, such as high definition DVD, and this is achieved by increasing the video bit rate.

Bitrate

Definition

Bit rate, sometimes referred to as “bit rate”, is the term used to define compression of audio, video, or other multimedia compression in terms of the amount of data, measured in bits, per unit of time in the printed material. Bit rate is the ratio of quality to time. Bit rate is also often measured in kilobits or megabits per second.

Bitrate

Sense

Videos with a higher bit rate will have a larger file size. For example, it will take longer to download or stream from the Internet and upload to a device or computer, and you can burn fewer videos to DVD. However, a higher bit rate usually indicates a higher quality. In this way, your video can be clearer and sharper. When browsing for video or importing it to computer from DVD or camera, choose the highest bit rate for higher quality. However, if space is your main concern, choose the lowest bitrate when downloading or compressing video files.

bit rate factors

Programs will have different bit rates depending on different factors. For example, the output material may have more depth and quality, thus producing a higher bit rate. High definition movies have a higher bit rate than standard definition, for example. Different types of video files have different bit rates and you can also choose different bit rates for the same file. For example, iTunes allows you to compress audio files with a bit rate greater than 128 kilobytes per second to save space on your iPod.

Standard bit rates

Most standard definition DVDs have a maximum bit rate of 9.8 megabits. High definition television has a bit rate range between eight and 15 megabits per second, while the standard for 720p high definition video is approximately 19 megabits per second. At the time of publication, Blu-Ray DVDs have the highest bit rate of all consumer videos with a maximum of 40 megabits per second. This makes the content of Blu-Ray DVDs more than four times that of standard DVDs.

Understanding the bit rate

When you start to make comparisons between video cameras you are faced with a series of aspects to take into account: numbers, characteristics, options … One of the lesser known but no less important issues is the bit rate. Let’s find out what it is, once and for all.

Bit rate

What is the bit rate?

Bit rate is the amount of digital information (bits) that is transferred or recorded in the unit of time.
In the case of video, the bitrate is generally expressed in bits per second, and the amounts being played to date are Mbps (Megabit, that is, millions of bits, per second) or kbps (kilobits, thousands of bits per second).

Bit rate

Because it is important

The bit rate is a parameter to take into account because it affects many aspects of digital production, both technical and more practical (ie economic).
First of all, it affects the quality of the video and the size of the single file: obviously, the more data is transmitted in the unit of time, the higher the quality of the recording. And at the same time, it will increase the size of the recorded file.
However, this should not lead us to think that a very high bit rate is always necessary: ​​in fact, we must bear in mind that as the bit rate increases, the difference becomes more and more marginal.
Basically, bit rate variations made from already high values ​​to reach higher values ​​are less visible than variations made from low values.

Then there is the question of file accessibility on the network: if the bit rate is very high, it will take a long time to download a video and watch it (for example, YouTube recommends not very high bit rates).

Finally, the bit rate also influences our portfolio: if we want to record at very high bit rates, we must first have a higher performance equipment, and then we will have to have more capable and higher performance media. Hence, larger SD, with high write speeds and consequently higher costs.

This is why you need to know what bitrate is, especially if you are serious about creating videos.

Bitrate, framerate and resolution

To get an idea of ​​the concept of framerate you can read this article that talks about 24 fps and the cinema effect. Instead, resolution is simply the number of pixels the camera uses to “describe” the scene – more pixels means more resolution and therefore more detail (up to a certain limit).

Why are we talking about these other two concepts? Because the bit rate is a bottleneck that can make you lose part of the information we want to record.

A little math

Let’s imagine that we have our machine and we set it to 4K and choose a frame rate of 60 frames per second.
Now let’s take the same machine and set it up in HD choosing a frame rate of 30 frames per second.

How will the bit rate change?

Since the bit rate is bit / second, let’s try to calculate the bits to transfer in each case.

-In the first case we will have 4096 × 2160 pixels, all multiplied by the 60 times in one second that the frame is recorded: a total of 530841600 pixels.
In the second case, however, 1920 × 1080 pixels multiplied by 30 frames: a total of 62,208,000 pixels.

That is why the bit rate can be a bottleneck: each pixel is represented by a certain number of bits, and if we record with resolution and framerate parameters that exceed the bit rate possible with a certain machine, this will have to apply compression to the file. And we know that the more compressed a file is, the lower its quality.

What is the bit rate and how does it influence the quality of the videos?

Amid the pandemic we are facing and authorities increasingly asking people to stay home, the use of the Internet, especially broadcast services, is skyrocketing. Amazon Prime Video, Netflix, YouTube, Twitch and others have already announced measures to try to ensure everyone accesses their videos without gagging, but there are differences between the measures on some platforms.

bitrate

YouTube reduces standard video quality to SD worldwide

Netflix, for example, opted for a reduction in the data rate or bit rate without lowering the resolution of the video itself. YouTube is already one of the platforms that now forces you to load at a lower resolution while maintaining the data rate, that is, the final quality, and allows you to increase the image size manually by the user.

bitrate

Oops wait! So does reducing resolution not reduce the quality and quantity of data to transfer? Not quite. Resolution is not the only thing that defines the quality of a video image, or even a JPG image, audio and the like, there are a number of factors. Among them, in addition to the image size, the bit rate that will be transferred from a server to a device, for example.

Data rate versus bandwidth

Reducing the amount of data sent to each user can help guarantee the service for everyone (Photo: Pixabay)
To understand metering on Netflix, you first need to understand the difference between the data rate of a media file and the bandwidth of the connection. Both can be called bitrate and throughput, and whether those terms are correct or not matters little. What matters is that it confuses, so it is necessary to clarify it.

The data rate of a media file refers to the maximum size of a second of the video. A video, as you may already know, is divided into frames, the most common speed is 30 fps (30 frames per second). Each table has its own set of information, and the total of 30 (or 24, 60, 120, and the like) forms the bitrate.

The bandwidth of the connection is the speed of your internet. Brazilian 4G, for example, has an average of 20 Mbps. Some fixed broadband operators offer packages of 100 Mbps, 200 Mbps or even more. This rate is the maximum amount of data that your Internet can receive from a central server.

Data volume

YouTube chose to lower the standard resolution without decreasing the volume of data (Photo: Pixabay)
The bit rate of a media file, therefore, is the amount of data it has each second. Netflix reduced this rate to decrease the amount of information that its servers need to send to each user connected to the platform. This reduces the quality of the image because it is less data, which can slightly reduce sharpness and cause noise, which some call “pixelization”, especially in very dark areas of the frame.

The resolution is not the lowest: it is that this image has less information. When loaded onto a large screen such as a TV, details are missing to display. On smaller screens, you will hardly notice the difference.

Facebook and Instagram will reduce the quality of video in Brazil
Globoplay will reduce video quality to meet demand
In short, Netflix’s decision ensures resolution, keeping sharpness a little closer than the user is used to, but reducing the amount of data transferred, resulting in images with a lower level of detail and sometimes , even more noise, even.

By sending less information to each user, Netflix, as well as Facebook, Globoplay and other services with similar measures, the platform avoids what we call server bottlenecks. This could cause suffocation and connection failures. YouTube’s measure also alleviates traffic because not everyone will manually increase the resolution, which in itself already reduces the amount of information to be transferred.