Video bitrate is a measure of the amount of data that is used to represent a video stream. It is measured in bits per second (bps). Higher bitrates result in higher quality video, but also larger file sizes. Lower bitrates result in lower quality video, but smaller file sizes.
What is the optimal video bitrate for an MP4 file?
The optimal video bitrate for an MP4 file will depend on a number of factors, including the desired quality of the video, the intended use of the file, and the capabilities of the playback device. In general, higher bitrates are required for high-quality video, such as Blu-ray Discs or high-definition television (HDTV). Lower bitrates can be used for lower-quality video, such as standard-definition television (SDTV) or web videos.
How to analyze the video bitrate of an MP4 file?
There are a number of ways to analyze the video bitrate of an MP4 file. One way is to use a video player that displays the bitrate information. Another way is to use a video editing software program that can display the bitrate information.
How to use a video player to analyze the video bitrate of an MP4 file?
Many video players, such as VLC Media Player and QuickTime Player, display the bitrate information for MP4 files. To view the bitrate information, open the video file in the video player and look for the “Bitrate” or “Bit rate” option.
How to use a video editing software program to analyze the video bitrate of an MP4 file?
Many video editing software programs, such as Adobe Premiere Pro and Final Cut Pro, can display the bitrate information for MP4 files. To view the bitrate information, open the video file in the video editing software program and look for the “Bitrate” or “Bit rate” option.
How to use the video bitrate information to make decisions about storing, transferring, or playing an MP4 file?
Once you have analyzed the video bitrate of an MP4 file, you can use this information to make decisions about how to store, transfer, or play the file. For example, if you want to store the file on a portable device, you may want to reduce the bitrate to lower the file size. If you want to transfer the file over a network, you may also want to reduce the bitrate to reduce the file size and the time it takes to transfer the file. If you want to play the file on a device with limited capabilities, you may need to reduce the bitrate to ensure that the device can play the file smoothly.
Additional tips for analyzing MP4 video bitrate
* Use a high-quality video player or video editing software program. A good video player or video editing software program will be able to accurately display the bitrate information.
* Compare the bitrate of different MP4 files. This can help you to determine the optimal bitrate for your needs.
* Experiment with different bitrates. This can help you to find the best balance between quality and file size.
Conclusion
By following these tips, you can analyze the video bitrate of MP4 files and make informed decisions about how to store, transfer, or play these files.
MP4 is a popular video format that is widely used in digital media. It uses a specific compression algorithm to compress video files to make them smaller and easier to share. The bitrate of an MP4 video refers to the amount of data that is used to represent each second of the video. It is typically measured in kilobits per second (kbps) or megabits per second (Mbps). A higher bitrate means that the video will have more data and will be of higher quality, but the file size will also be larger.
Why is MP4 Bitrate Important?
The bitrate of an MP4 video is important because it affects the quality and size of the video file. If the bitrate is too low, the video may appear pixelated or blurry. On the other hand, if the bitrate is too high, the file size will be larger, and it may take longer to upload or download the video. In addition, a higher bitrate requires more bandwidth to stream the video, which may be an issue for viewers with slower internet connections.
How to Choose the Right MP4 Bitrate
When choosing the bitrate for your MP4 video, you should consider the intended use of the video, the resolution of the video, and the file size. For example, a video that is intended to be viewed on a large screen should have a higher bitrate than a video that will be viewed on a smaller screen. Similarly, a video that has a higher resolution will require a higher bitrate to maintain the same quality as a lower resolution video.
As a general rule of thumb, a bitrate of 5-10 Mbps is suitable for 1080p HD video, while a bitrate of 2-5 Mbps is suitable for 720p HD video. For lower resolution videos, such as 480p or 360p, a bitrate of 1-2 Mbps may be sufficient. It’s also important to consider the file size of the video, as larger files will take longer to upload or download and may be more difficult to share.
How to Change MP4 Bitrate
To change the bitrate of an MP4 video, you will need to use video editing software that allows you to adjust the bitrate settings. There are many different video editing software options available, including Adobe Premiere Pro, Final Cut Pro, and Handbrake. These programs allow you to adjust the bitrate settings and other video parameters to optimize the video for your specific needs.
MP4 Bitrate FAQ
What is the maximum bitrate for MP4 videos?
The maximum bitrate for MP4 videos is 10 Mbps. However, this may vary depending on the specific device or platform where the video will be played.
What is the minimum bitrate for MP4 videos?
The minimum bitrate for MP4 videos will depend on the intended use of the video and the resolution of the video. In general, a bitrate of at least 1 Mbps is recommended for standard definition video, while a bitrate of at least 2 Mbps is recommended for high definition video.
What is the recommended bitrate for streaming MP4 videos?
The recommended bitrate for streaming MP4 videos will depend on the resolution of the video and the available bandwidth. As a general rule of thumb, a bitrate of 5-10 Mbps is suitable for 1080p HD video, while a bitrate of 2-5 Mbps is suitable for 720p HD video. For lower resolution videos, such as 480p or 360p, a bitrate of 1-2 Mbps may be sufficient.
However, it’s important to note that these are just general guidelines, and the optimal bitrate will also depend on factors such as the complexity of the video content, the encoding settings used, and the target audience’s viewing preferences.
For example, videos with fast-moving scenes or complex visual effects may require a higher bitrate to maintain a high level of image quality and avoid compression artifacts, while simpler videos with less motion may be able to use a lower bitrate without sacrificing quality.
Additionally, the target audience’s internet connection speed will also affect the recommended bitrate. For viewers with slower internet connections, a lower bitrate may be necessary to ensure that the video plays smoothly without buffering or interruptions.
What are the advantages of using a higher bitrate?
Using a higher bitrate can result in higher quality video with more detail and fewer compression artifacts. This is because a higher bitrate allows for more data to be transmitted and encoded per second, resulting in a more faithful representation of the original video source.
A higher bitrate can also be beneficial for videos with a lot of movement or detail, as it allows the encoding algorithm to capture more information and produce a more detailed image.
However, it’s important to note that using a higher bitrate will also result in larger file sizes and require more bandwidth to stream or download. This can be a disadvantage for viewers with slower internet connections or limited data plans.
What are the disadvantages of using a lower bitrate?
Using a lower bitrate can result in lower quality video with more compression artifacts, such as blurring or pixelation. This is because a lower bitrate means that less data is being transmitted and encoded per second, resulting in a loss of detail and fidelity.
Lower bitrates may also result in a lower overall resolution or frame rate, which can further degrade the quality of the video.
However, using a lower bitrate can also have benefits, such as smaller file sizes and reduced bandwidth requirements. This can be advantageous for viewers with slower internet connections or limited data plans.
Can the bitrate of an MP4 video be adjusted after it’s been encoded?
Yes, it is possible to adjust the bitrate of an MP4 video after it has been encoded. This can be done using video editing software or specialized tools designed for this purpose, such as MP4Gain.
However, it’s important to note that changing the bitrate of a video after it has been encoded can result in a loss of quality or introduce additional compression artifacts. For best results, it’s recommended to encode the video at the desired bitrate from the beginning.
Conclusion
In summary, the bitrate of an MP4 video is an important factor that can affect its quality, file size, and streaming performance. The optimal bitrate will depend on factors such as the resolution of the video, the complexity of the content, and the available bandwidth.
Using a higher bitrate can result in higher quality video with more detail and fewer compression artifacts, while using a lower bitrate can result in smaller file sizes and reduced bandwidth requirements.
If you need to adjust the bitrate of an MP4 video, it is possible to do so using specialized tools such as MP4Gain. However, it’s recommended to encode the video at the desired bitrate from the beginning for best results.
Overall, understanding how bitrate affects MP4 video quality can help you create and deliver video content that meets your needs and those of your audience.
Today, we are going to popularize the concept of bitrate in video playback.
Video bit rate
When formulating RMVB/RM, the main consideration is network communication and the purpose is to use unpleasant network speed to deliver visually acceptable image quality. Therefore, the characteristic of RMVB/RM encoding format is that better video quality can be obtained at lower bit rate. However, in the case of high bitrate, it is not as good as other encoding formats. It is also an RM/RMVB suffixed file, and its internal encoding format is subdivided into R8/R9/R10, etc., but in general, the above-mentioned characteristics are maintained. It’s just that the compression rate is higher, so RMVB is not used in the field of HD encoding. RMVB looks for a high compression rate and acceptable image quality, so it often compresses some details that are not easy to notice. At first glance, the image is good, but if you look closely, you will find that the image is not sharp, the layers are not clear, and it always gives people a feeling of being blurry all the time. The audio encoding part of the RMVB/RM suffix file also has that situation. The sound compression rate is very high, but it can only be heard. Don’t expect beautiful sound.
The popularity of RMVB is due to the fact that the REAL format is suitable for low-speed network transmission and can achieve acceptable image quality with a smaller file size. Second, with the use of RMVB, relatively full-featured transcoding software and solutions have begun to appear, which is convenient for video lovers and expands the video source. However, as network speeds get faster, better encoders like H264 appear, and because RMVB is not suitable for high-definition video production, and if other hardware manufacturers want to support the format RMVB/RM, you have to pay REAL quite expensive The patent fee caused many hardware manufacturers to stop supporting RMVB files. RMVB documentation is not the completely overwhelming advantage it once was.
Many video files spread on the Internet now have suffixes like AVI, MKV, MP4 and 3GP. Among them, MKV is mainly used for HD video files, MP4, 3GP, etc. They are mainly used in mobile phones and portable devices, etc. AVI is more widely used, not only in high-definition video files, but also in portable devices.
The video encoding format used by VCD is MPEG1, and DVD is MPEG2. Both VCD and DVD are mainly used for home video and audio playback, and generally speaking, VCD is encoded with MPEG1 as a fixed bit rate encoding. DVD can support dynamic bit rate MPEG2 encoding.
In order to ensure the clarity of the image when the image changes drastically, the default encoding rate is high, the standard encoding rate of VCD is 1152Kbps, and the DVD is more open. According to the playing time of the movie, it is generally set between 5000Kbps -8000Kbps, so as not to waste DVD discs Under the premise of capacity, please use a higher bit rate as much as possible to get a higher definition. MPEG1 and MPEG2 are not very effective in the case of ultra-low bit rate, and if the bit rate increases too much, the indications generated by the image effect are not obvious. MKV is encoded in H.264 for high definition video and the 1080p image reaches a bit rate of 30 Mbps.
Note:
VBR: “variable bit rate”, VBR encoding means that the encoder’s output bit rate (or decoder’s input bit rate) can be adaptively adjusted based on the complexity of the encoder’s input source signal , to keep The output quality remains the same instead of keeping the output bitrate the same. VBR is suitable for storage (not very suitable for streaming) and can use limited storage space more efficiently: use more codewords to encode high-complexity segments and use fewer codewords to encode low-complexity segments .
CBR: “fixed bit rate”, CBR encoding means that the output bit rate of the encoder (or the input bit rate of the decoder) must be a fixed (constant) value. CBR is very useful when performing multimedia communications on a channel with limited bandwidth, because the higher bit rate is limited at this time, and CBR can use that channel more easily. But CBR is not suitable for storage,
Today, we are going to popularize the concept of bitrate in video playback.
Video Bitrate
Data rate refers to the data flow used by a video file in a unit of time, also called bit rate, sampling rate, and bit stream rate. A popular understanding is that it is the most important part of image quality control in video encoding. Generally, the unit we use is kb/s or Mb/s. Generally speaking, at the same resolution, the higher the code stream of the video file, the lower the compression ratio and the higher the image quality. The higher the bit stream, the higher the sampling rate per unit time, the higher the data stream, the higher the accuracy, the closer the processed file is to the original file, the better the image quality, the clearer the image quality and the higher the decoding capability of the playback device is required.
Of course, the larger the code stream, the larger the file size. The calculation formula is file size = time X code rate/8. For example, a 720P RMVB file with a 1 Mbps stream of 90 minutes is common on the Internet and its volume is = 5400 seconds × 1 Mb/8 = 675 MB.
Generally speaking, a video file includes both image and sound, such as an RMVB video file, which contains both video information and audio information. Audio and video have their own sampling methods and different bit rates, that is, the same video Audio and video file bit rate is not the same. And what we’re talking about is the bitrate of a video file, which generally refers to the sum of the bitrate of the audio and video information in the video file.
Taking the most popular and familiar RMVB video file in China as an example, VB in RMVB refers to VBR, which is short for Variable Bit Rate. The Chinese meaning is variable bit rate, which means that RMVB adopts the dynamic encoding method. , use a higher sampling rate for complex dynamic images (singing and dancing, flying cars, wars, actions, etc.), and use a lower sampling rate for static images, make rational use of resources and achieve the image quality and volume effect
The most fundamental difference between code rate and sample rate is that the code rate is for the source file.
There are many types of encoding formats. With the continuous advancement of technology, various encoding formats have been produced for different purposes. The compression rates of different encoding formats are different and have their own characteristics. Some of them can maintain high image quality in the case of low bitrate, but in the case of high bitrate, the image quality indication is not great and some are suitable for high bit rates. High definition image is maintained, but may not work well at low bit rates. Present some common ones.
To understand how bitrate affects video quality, we first need to understand how video compression works.
Video Bitrate vs Resolution
When you’re compressing video, the compression algorithm does two things:
Convert video from “pixel domain” to “frequency domain” by DCT (Discrete Cosine Transform). If you are not familiar with DCT, you can read our previous article: How to explain DCT to a 5-year-old?
Some of the information in the frequency domain is discarded through a technique called quantization, with the expectation that the human eye will not perceive this loss of information.
Essentially, when you compress a video, you’re throwing away some information while hoping there’s no loss in video quality. When you overcompress the video, you throw away a lot of information, and the human eye perceives the encoding loss. If you don’t compress the video too much, the file size will be huge, while the video quality will be excellent.
This is known as the “rate-distortion exchange (RDT)” in video compression, and the lower the bitrate, the worse the video quality (assuming the resolution is fixed).
What does RTD mean?
Let’s look at the example below. We use FFmpeg to compress the example video (CrowdRun) to 1.5 mbps and 5 mbps, respectively. With the video screenshots below, can you tell me which one is from the higher bitrate video and which one is from the lower bitrate video?
Obviously the bitrate in the image above is lower and the bitrate in the image below is higher. When using a bitrate of 5 mbps @ 1080p, the video quality is excellent. For the same video, when we use a bitrate of 1.5 mbps, the video quality of CrowdRun becomes very poor.
But is it always like this? Does low bitrate always produce poor quality video? We answer this question with a simple experiment.
Let’s test the “low bitrate = low quality” hypothesis using animated videos. For the following video, we used the popular Simpsons trailer and compressed the video to 2.5mbps and 1mbps using H.264/AVC (make sure all encoder settings are consistent).
Many people have this confusion because these two factors can have a profound effect on the encoder’s output.
How do you think it should be chosen?
Choose 1080p or 720p?
Choose 5mbps or 3mbps?
Choose 1080p@5mbps or 1080p@7mbps?
If you don’t know what to choose, great. That’s why I wrote this article: to explain the relationship between bitrate and resolution in simple terms, and to help you choose the right encoder settings.
Let’s start by understanding bitrate.
What is the bitrate of the video?
Video bitrate or bit rate refers to the number of bits transmitted per second of video information. The code rate unit is usually:
kbps or kilobits per second
mbps or megabits per second
When you are compressing video, you usually need to set the video compression software not to exceed a certain bit rate.
For example, if you set the video compression software’s bitrate to 3mbps, the software will compress the video at 3mb per second (on average) and stream it to the decoder or player. This is the code rate.
When you talk about bitrate, you’re really talking about: the relationship between video compression and video quality loss. The more you compress, the lower the quality of the video (and this is not always the case, as we will see later).
When compressing video, the following algorithms can be used for speed control, these are:
CBR (Constant Bitrate) – It is best to keep the bitrate constant if video quality is lost.
VBR (Variable Bitrate) – Maintains consistent video quality, allowing for bitrate fluctuations.
Capped VBR – Keep the video quality as constant as possible, allowing the bitrate to fluctuate within a set range.
This article will not discuss the above frequency control methods in detail. Friends who want to know more, welcome to read: Understanding Frequency Control Modes: What are CBR, VBR, CRF and Capped-CRF?
So when we talk about the bit rate, we should pay attention to the following points:
The quality of high bitrate video is usually higher than that of low bitrate video. I say generally, because the video quality reaches a certain point where it will no longer improve (no matter how much the bitrate increases).
The code rate refers to bits (bit) instead of bytes (byte).
The bit rate alone does not determine the quality of the video, you have to take into account factors like resolution, frame rate, screen size, etc.
Codecs for video compression: H.264/AVC, HEVC, VP9, AV1? If you change the video codec and its settings (or encoding tools), the same bitrate will provide a very different video quality.
What I want to see clearly and occupy a small dot is now converted to rmvb video 512 audio 160K, is there any other way to set it?
Mp4 Bitrate
The mp4 video bitrate is usually set to around 800. The basic algorithm is: bitrate (kbps) = file size (KB) * 8 / time (seconds), for example, D5 disk, the capacity is 4.3G, which takes into account different audio formats, is calculated as 600M, (so the remaining capacity is 4.3*1024-600=3803.2M), so the video file should not have more of 3.7G.
And if the video file capacity is 3.446G and the video duration is 100 minutes (6000 seconds), the calculation result: the bit rate is approximately equal to 4818kbps (3.446*1024*1024*8/6000=4817.857 ).
Bit Efficiency:
1. Bit rate in sound refers to the amount of binary data per unit time after converting analog sound signal into digital sound signal, which is an indicator to indirectly measure audio quality. The principle of bitrate in video is the same as in sound, which refers to the amount of binary data per unit of time after the analog signal is converted to a digital signal.
2. In channel coding, the source data block of symbol size K is mapped to a codeword of symbol size N through coding, and K/N becomes the code rate, where assumes that the symbol table before and after encoding does not change.
What video bitrate is appropriate for video? Part 2
Video Bitrate
Ultra Clear 720P>=1.5M (Standard 1280×720 resolution, minimum 960*540, this and higher resolutions are in MP4 era) [some websites have this minimum requirement to upload]
Video Bitrate
Blu-ray 1080P>=2.5M (1920 × 1080 standard resolution) [optimal 4-8M] [220M when the material is stored] [some websites have this higher requirement for uploading] (it is better to use 720P and 1080P when make videos )
2K=(2048×1080 resolution)
4K=(4096×2160 resolution) [Optimal 8-12M]
The most normative statement is:
reaching 720p resolution is the threshold for high definition signal sources, 720p is called the HD (high definition) standard;
up to 1080p resolution, known as the Full HD (full high definition) Blu-ray standard.
2K refers to 2048 × 1080, and the actual resolution of Quad HD (four times high definition, 2K can be called “four times ultra high definition”) has various specifications, and the ones listed above are just common specifications. ;
4K refers to 3840 × 2160, and the actual resolution of Quad Full HD (four times full HD, 4K is called “four times ultra full HD”) has various specifications, and the ones listed above are just common specifications. .
Blu-ray is the clearest and SD is the worst If your internet speed can’t bring you 1080p, then at least 720p won’t feel blurry to the naked eye.
P refers to the number of horizontal scan lines, and the higher the number, the higher the resolution of the image. The letter P stands for progressive scan.
1. What is the video bitrate?
Video bitrate is the number of bits of video data (color, brightness, and pixels) that are output per second. The unit generally used is kbps.
2. Recommended bitrate for video size and resolution
How much video bitrate is appropriate (above H.264 bitrate, 720P, 1080P output bitrate setting)
3. A set of formulas to set the bitrate is shared with you as follows:
How much video bitrate is appropriate (above H.264 bitrate, 720P, 1080P output bitrate setting)
Regarding the two items of “Use the highest rendering quality” and “Process with the maximum depth” when exporting from PR editing software, the effect of image quality is not obvious on the big screen and the output time can increase exponentially depending on the complexity of the track. I also encountered this problem in the morning. I have been there, it is a waste of time and the effect is average. So I usually don’t choose this.
At present, 720p video recommended minimum bitrate is above, h.264 encoding 2M bitrate is adequate, 1080p is 4M enough
to get a high-quality video, convert it with different bitrates, and then compare the image quality.
Video Bit Rate
The most commonly used are: h.264 encoding, 1080P, 2.5M bit rate or more.
Summary: [h.264 encoding, 2.5M bitrate (up to 4M), maximum 4M bitrate (add 2M to target), most platforms are Blu-ray. 】
1. If the bitrate is higher than the original video, it will not be a bit higher than the original video. When you move, you’ll pick a lower point to compress the file a bit.
2. 1080P 1M bitrate has distortion feeling to watch on computer, and 2M can’t see distortion, you can adjust the bitrate to 4M to get the best.
The following are the bitrate upload requirements for a platform:
How much video bitrate is appropriate (above H.264 bitrate, 720P, 1080P output bitrate setting)
How much video bitrate is appropriate (above H.264 bitrate, 720P, 1080P output bitrate setting)
***Normal 240p, 320p SD, 480p HD, 720p Ultra HD, 1080p Full HD (Blu-ray), 2K, 4k Ultra HD ***
Normal 240P (320×240 standard resolution, it was 3GP, this is basically nobody used)
SD 270P<0.8M (360×270 standard resolution, was 3GP, rarely used) [140M when storing 422 materials]
High definition 480P (360P)>=0.8M (standard resolution of 640 × 480, minimum 480 * 360, was 3GP) [480 re-advertising is called high definition, but the normative statement can only be regarded as standard definition]
What is the difference between 128k and 320k music? Part 2
In simple terms, we can think of a sound wave as a curve.
We know that the curve is made up of points, and the sampling rate is the number of points in the middle of the length per second (the horizontal axis in the figure above). Sampling precision is the number of points in the dynamic range (upper vertical axis). The finer the positioning of these two dimensions, the greater the true sound restoration and the better the sound quality. Of course, the larger the audio file will be. The customer mentioned by the above colleague said that the latest Hi-Res Audio format released by SONY is a 6-channel 192kHz/24-bit recorded audio file. The size of the lossless format, of course, will be more than 200 megabytes.
The sampling frequency is approximately the following depending on the type of use (k is the thousand-bit symbol, 1khz=1000hz):
8khz: used for phones etc, is enough to record human voices.
22.05khz: transmission use frequency.
44.1kb: Audio CD.
48khz: used in DVD and digital TV.
96khz-192khz: used for DVD-Audio, Blu-ray HD, etc.
The common range of sample precision is 8 bits to 32 bits, with 16 bits generally used on CD.
Having said that, my friends are starting to get confused. It’s not the bitrate that determines the sound quality, so why is everyone saying that 320kb sound quality is better than 128kb?
【Audio Compression】
Well, in fact, the bit rate should be said to be another dimension, it is a compression of audio files.
Nowadays, most of the audio formats we use regularly are based on the original “WAV” file of the audio CD (44.1khz sample rate, 16bit sample precision, 2ch). The original recorded sound data is stored in a matrix, which is in PCM format, while WAV format is an encoding format developed by Microsoft. Its function is to reproduce the data in PCM format through encoding.
Since the data in WAV basically completely restores the PCM data, MP3, AAC and other lossless encoding formats are basically recompressed based on the WAV files. Therefore, we can simply think that WAV is the original audio format and other audio formats are compressed formats.
When it comes to compression, storage and transmission are inseparable. The purpose of compression is to improve storage and transmission, so before we talk about compression, we need to understand the basic units of computers.
We all know that the computer is a binary number system, and the files stored by the computer are made up of two numbers, 0 and 1. Therefore, the computer’s transmission is based on each number, and each number is called 1 ” bit”. For example, for an audio piece, its basic data is “0,1,1,1,0,1, 1 ,0”, and when transmitting, these numbers are transmitted one by one. The sampling precision mentioned above is this unit.
The storage unit of the computer is “byte (Byte)”. In the computer, 1 byte consists of 8 bits, that is, 8b(bit)=1B(Byte). In computer parlance, data storage is expressed in decimal and data transmission is expressed in binary, so 1KB=1024B=1024×8b. This is also part of the reason why the hard drive capacity we see does not match the actual capacity.
Go back and talk about audio compression, the bitrate of the audio is actually the compression ratio. So the bitrate really just defines the size of the file, but because under normal conditions the larger the file, the less data you lose, so the sound quality is relatively higher. However, the bit rate itself does not directly affect the quality of the file. For example, if we take a 128kb file as the source file, even if it is converted to a 320kb file, the sound quality will not be better than 128kb. .
