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Video with minimal loss of quality Part 2

There are special algorithms for filtering typical compressed video artifacts. Generally, any compressed video player includes post-processing of the decompressed video with such filters.

How do analog video standards work and on what principles are they based?
This question requires fundamental knowledge in the field of radio physics and engineering, and therefore a complete and detailed explanation is not included in the scope of this FAQ. In a significant simplification, the analog video signal encoding scheme of operation is as follows: the signal is transmitted in the form of timing and information components using partial quantization. The signal itself is analog, but it is divided (quantized) into lines and frames. The PAL standard (and close to it SECAM) assumes the presence of 25 frames per second, each of which contains 576 lines. The NTSC standard assumes 30 frames per second, each with 480 lines. The synchronization component carries information about the beginning / end of lines and frames. The information component carries the luminance component (Y), used in black and white television transmission, and two color components (U / V).

Capture questions
What is video capture?
Video capture is the process of converting analog video to digital format and then storing it on a digital storage medium. The most typical example of video capture is digitizing a TV broadcast or VHS cassette on a specially equipped PC.

What are the minimum system requirements for video capture?
First, you need a video capture device capable of delivering frames of a video stream at a sufficient speed in one of the standard color-coding formats. Such a device is a TV tuner or a video card equipped with a video input. There are also more expensive and “advanced” devices that can immediately compress captured video, but their consideration is beyond the scope of these FAQs.

Second, you will need enough hard disk how fast with a large capacity, capable of recording high bit rate video. So to capture video, which is then supposed to be recorded to a VideoCD (352×288 YUV12), the hard drive must be capable of recording 4MB / s (not MB!). And to capture video with the best quality analog TV broadcast (for example, from a separate DVD player via the S-Video interface, or just from the TV broadcast), you will need a disc with a recording speed over 19MB / sec.

Third, you need a really fast CPU. . Especially if, to reduce the bit rate, the video will be compressed directly during capture. The minimum CPU required is considered Pentium-II 300, however, it is difficult to achieve “comfortable” work with the captured video on any processor with a frequency of less than 550 MHz. If you use MPEG4 algorithms for compression, the best option is Athlon 800-900 (and higher) or Pentium 4, which show excellent performance in tasks of this type.

Fourth, you will need at least 128MB of RAM; otherwise, any instability in the compression rate will have a very detrimental effect on the quality of the captured clip.

In what file format are you capturing the video?
The file format depends on the software used. Today, the three most common formats are AVI, MPEG, and ASF.

AVI (Audio-Video Interleaved – a format with interleaved blocks of audio and video information) is most often used when capturing. It was developed by Microsoft to store and play videos as part of the Video API for Windows. By its structure, this format refers to “chunks”: as in WAV or MIDI, all information is packed into headers, called chunks – chunks. This allows you to record video sequences both uncompressed and with any type of compression in an AVI file. The main disadvantages of AVI are its inability to stream (stream video over networks) and the 2GB file size limitation. And if the inability to stream does not have a noticeable effect on the video capture,

The MPEG format (the name comes from the Motion Picture Experts Group, a group of specialists in compression of video sequences), unlike AVI, involves the use of one of two standard compression algorithms: MPEG1 and MPEG2. MPEG1 is used to compress video with a small frame size (less than 288 vertically) and a bit rate of about 1-2 Mbps, and MPEG2 is used for video with a large frame size (more than 288 vertically) and a bit rate of around 5-10 Mbps.

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Video with minimal loss of quality

Why do I need video on my computer?

In fact, what does storing video information give us on a computer and not on a normal videotape? Basically, digital video storage and processing is attractive for two reasons: First, digital video is not “stuck” from multiple views; secondly, it is essential to obtain a copy of the video material, absolutely identical to the original. These two reasons are enough to save your home video digitally.

What is the principle behind implementing video on a computer?
Just like the rest of the video and the movie. The frames are successively replaced 25 times per second (for Pal / Secam), which our brain perceives as a continuous movement. From this principle, we conclude: long video sequences are huge. So let’s say we save a video with a frame size of 352×288, 24 bits per pixel. It takes approximately 435 MB to save at least one minute of video. This is the main problem with digital video: an incredible gluttony in terms of file size.

How to deal with huge sizes?
There are two main ways of dealing with it: by reducing the basic parameters of video capture and compression. The main parameters of video capture are: frame size, color coding and frame rate.

The term “bit rate” is often introduced. Average bitrate is the size of a video stream in bits, relative to its length in seconds. The unit of bit rate is 1 bit / s – 1 bit per second (1bps – 1 bit (s) per second). Since 1 bit / s is very small for digital video, Kilobits / s (Kbps) and Megabits / s (Mbps) are also entered. For the video in the previous question, the bit rate is 58 Mbps. The compressed video bit rate in VideoCD, which has the same frame size and frame rate, is 1.1 Mbps.

What are the main types of compression?
Compression is divided into two types: lossless (often called “lossless” for short) and lossy (“lossy”). The difference between these types is clearly apparent from their name. Most lossless compression methods do not take into account the visual similarity of adjacent frames in a video stream. In contrast, lossy compression techniques use this similarity in most cases. Because of this, the maximum compression ratio of an average video clip achieved by lossless algorithms does not exceed 3 to 1, while algorithms that operate with loss of quality can compress up to 100 to 1.

Very often, methods that take into account the similarity of adjacent frames in a video sequence are called “recursive.” Only individual frames are fully saved to them, called keyframes (sometimes intra). All other frames contain only differences from the previous ones (sometimes they also contain links to information contained in the following frame).

Techniques that compress each frame separately from the others are called “separate”. In video sequences compressed by such methods, all frames are keyframes.

Lossless compression often uses algorithms similar to those used in archive archives (ZIP, RAR, LZH). Algorithms that use the discrete Fourier transform with the preservation of such a number of coefficients, which is sufficient for the complete restoration of the original information, are compressed more strongly.

In lossy compression methods, algorithms based on the discrete Fourier transform are also used more frequently, but the number of stored coefficients is almost always much smaller than algorithms that work without loss of quality. Lossy compression generally encodes the amount of quality reduction for each frame or the average or instantaneous bit rate of the output file.

What are the problems with video compression?
Lead the so-called. artifacts. Artifacts are visible violations of the video stream quality that occur during the lossy compression process. The most common compression artifact is dividing an image into square blocks. “Recursive” compression algorithms also often have “garbage” near contrasting edges and moving objects, as well as “wavy” and “fuzzy” colors. The number and intensity of artifacts depend on the compression algorithm, the ratio of the output bit rate to the original, and the nature of the compressed image.

How to Compress Video “Lossless” (Reduce Video Size) Part 3

How much space does HD Ready, Full HD, 4K video take up?
On average, it takes 1 minute of video:

When shooting in HD Readry (720p) at 30 frames / second – 60 MB;
When recording in Full HD (1080p) at 30 frames / second – 130 MB;
When recording in Full HD (1080p) at 60 frames / second: 200 MB;
When recording 4K (UHD) at 30 frames / second: 375 MB.
The difference between HD, UHD, 4K and 8K video formats plays a decisive role in determining recording volumes. But there are other parameters that the video file size depends on: audio parameters, bit rate, aspect ratio, color resolution, and more.

Lossless video compression software
Hand brake
It is a free converter that converts video files of almost any format to mp4 (both DVD and Blu-Ray disc). Contains settings for popular tablets, androids, devices like iPhone, AppleTV, etc. Output file types:

video codec (H.265 (x265), H.264 (x264), MPEG-4, MPEG-2 (libav), Theora (libtheora), VP8 (libvpx);
Audio codec (Flac, AAC, CoreAudio AAC / HE-AAC (OS X only), MP3, Vorbis, or AC3)
audio tracks (DTS, AC-3, DTS-HD, MP3, AAC);
container (MKV and MP4 (M4V)).
For example: this program compresses HD video with mov format and sizes from three to four GB (duration 35-40 minutes) in mp4 format to 200-250 MB without losing its quality.

How to set up HandBrake correctly
Having launched HandBrake, you can see a lot of incomprehensible settings and what to do? Sooner or later you will realize, the main thing is to make an effort. So in this program you can edit videos and their sound.

Prepare your video for compression. Click the “Open Source” button and click the “File” item. Now we select our video.

The program contains blanks made by the developers, these are so-called presets. They mean ready-to-use parameters for any device or service. Very useful for those who do not want to dig deeper and understand the settings.

Each preset represents custom audio and video settings for iPhone, Android, Windows Phone, and other devices. Also, if suddenly this is not enough for you and you want to fine tune one or another parameter, after tuning it you can save your preset, which you can then use many more times.

Next, take a look at the most important features of Handbrake to manually configure the video conversion parameters.

In HandBrake, you can adjust the audio parameters. There is an “Audio” tab for this. In fact, audio can take up a lot of space in a video, especially if it is of good quality. In a simple video, so to speak, for the house, you can remove unnecessary tracks and leave only the first one. We configure “MP3” as codec. This will reduce the size of the sound while maintaining quality. We set the bit rate to 160, the sound quality will not be very good. If sound is important, set it to 320.

Choosing the best video container and codec
Ideally, when recording video, you should always set the maximum video settings for the device you are recording with. Only the maximum of a video camera will allow you to get the highest quality video, which can then be compressed with almost no loss of quality. The basis for video reduction is to use the most efficient codec and container for the video.

How to Compress Video “Without Loss of Quality” (Reduce Video Size) Part 2

MPEG-2. There is the MPEG-2 codec (known as x.262) and there is also the MPEG-2 container format. MPEG-2 is used for over-the-air television signals and DVD video. In general, it provides an optimal quality / file size ratio. Supported by almost all players.

Microsoft VC-1. Microsoft VC-1 is used as an alternative to Adobe Flash technology and is used on the Microsoft Silverlight Internet platform. Provides medium compression quality.

MPEG-1. Obsolete video compression codec (replaced by MPEG2). Previously, such a video could be found on CD-ROM. Now it is less and less common, although if you like to watch old videos, you will probably come across it.

WMV. There is a Windows Media video codec and container with the same name. It provides very high quality video compression, with a pretty good picture. Very popular and widespread.

DivX is a video codec, the various versions of which comply with the MPEG-4 part 2, MPEG-4 part 10 (MPEG-4 AVC, H.264) standards.

Xvid (formerly “XviD”) is an MPEG-4 Part 2 video compression library. By the way, the compression methods used in MPEG-4 are proprietary, so it may be illegal to use Xvid in some countries.

About containers

There are now dozens of containers, each with its own pros and cons. The container, in addition to the video compressed with any codec, also contains sound (which is also compressed. Audio, as a rule, takes up a lot of space, so I do not consider audio codecs, their effect on the file size is not significant).

AVI (or Audio Video Interleave) is one of the most popular Microsoft containers. Most of the time, video on a PC is in this format. By the way, many, for some reason, do not recommend compressing modern videos in this format.

MP4. This container format was developed by Motion Pictures Expert Group. Many users call it MPEG-4. Usually video in MP4 files is encoded with the x.264 codec and audio is encoded with the AAC codec. Sometimes you can find other codecs in this container …

VOB and BDAV MPEG-2. It is used to package videos on DVD and Blu-ray discs. Blu-ray discs (.m2ts) can contain videos compressed with the x.264 and VC-1 codecs.

ASF (Advanced Systems Format) – Found in various extensions .asf, .wma, and .wmv. By the way, the .wmv file is most likely compressed with the WMV (Windows Media Video) codec, but the file itself is placed in an ASF container file.

QuickTime. The creation of Apple. The container supports many audio and video codecs. Apple is a supporter of x.264, therefore QuickTime files (formats: .mov, .qt) usually contain video compressed with the x.264 codec.

Flash. By the way, Adobe’s Flash container format is quite popular.

Matroska (.mkv, .mk3d, .mka, .mks) is a very popular and in-demand container today. Free, open source, that’s probably why it went mainstream. Many high-quality videos are distributed in this container.

DiVX. Both codecs and containers are very common. The format also has the same name: “.divx”. By the way, the codec has a “pirate” origin, which allows you to get high-quality videos with strong compression.

For a time, Divx was not recognized by the “big” equipment manufacturers, however, today many already incorporate the DiVX hardware codecs in most equipment (if it were not for the popularity of video files from this format, probably nothing would have happened …).

Which codec and container to choose

If you want maximum video compression, it makes sense to choose the x.264 codec, which provides excellent compression with good quality. However, keep in mind that not all computers (especially newer ones) allow you to view such files. If the video is very high resolution, even modern low-power PCs will not be able to play and display it without lag and crash. By the way, if the video is not compressed by any variation of the x.264 codec (for example, it is in MPEG1, 2 or some other format), it can be compressed without loss of quality into a more “compact” codec. (say, Divx).
If you plan to view the files on DVD players, various devices, etc. – it is recommended to choose the MPEG2 codec and container – it is compatible with almost all equipment;
For various movies, clips, cuts of the finished video, the MP4 container is excellent, as a good compromise between compression ratio and quality.

How to Compress Video “Lossless” (Reduce Video Size)

In general, this is quite a popular question and often beginner video amateurs fall for this “bait”: you can compress any video, only there will almost always be a loss of quality!

Another thing is that in some cases, it shows with the naked eye, in others, even the experienced gaze of a movie buff cannot see the difference!

In this article, I want to talk in more detail about how to compress a video, and how, and in what cases, to do it “without losing quality” (note, the phrase is in quotes).

what you need to know for proper compression
Complex video processing terms are deliberately removed from the article. The article is simplified as much as possible to be understood by the most common users facing the problem of converting and compressing video.

In general, almost all the videos (99.9%) that you find on the net (watch, download, etc.) are already compressed with some kind of codec. Uncompressed video – Takes up a fairly large size on disk (for example, a high-quality movie can take up several terabytes).

So the key here is that different codecs work according to different algorithms and provide different file compression rates. Naturally, this also affects how your file will be displayed later, after compression, and how much disk space the file will take up.

Therefore, in order to compress a video without losing quality, you must proceed from 2 points:

if the video was compressed with a “weak” codec (which provides far from the maximum compression), then you can compress it and reduce the size of the video file without degrading the image quality (by the way, as a rule, in this In your case, you need a more powerful PC to watch. For example, MPEG2 video can be viewed on weaker PC (no jerks or lag) than say MP4, well I’ll say a few more words about that below);
from the device you want to view the video on. For example, if you watch a video on a small screen with a low resolution, then the difference in video quality (be it 1GB or, say, 300MB), you just won’t notice it! To see the difference, you need to open the video on a large TV screen.

That is, I think my message is clear: if you watch a video on a screen with a resolution of 1024×768 (or in that “window” in Windows, and you work on the next one …), and your video quality is 1920×1080 , this video can be compressed. at a lower resolution and better codec.

By the way, here we must not forget one more parameter: the bit rate (the number of bits used to store one second of multimedia content, see Wikipedia).

The higher the video resolution, the higher the bit rate. If the bit rate is very high, it can be reduced to reasonable limits by compressing the file.

For example, the maximum bit rate for creating a Blu-ray disc is 35 mbps. So the difference between 30 and 35 is not easy to notice, but between 5 and 35 is striking …

Note: it is popular now to download videos to your phone / tablet and then watch them somewhere on the road. Therefore, such a video is not only possible, it is even recommended that it be compressed and then downloaded to your mobile device.

Here’s the thing: first, compressed video will take up less space on your flash drive (and mobile devices don’t have that much memory); And secondly, the video will not slow down (as is often the case with a video that is not ready to download on mobile devices).

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In codecs and containers: what to try and what not to compress

There are dozens (if not hundreds) of video formats in which it is distributed. Each format has its own disadvantages and advantages, some of them are already outdated, others, on the contrary, have just appeared.

In this little subsection, I want to focus on the most popular formats that I have to deal with, and also say a few words about the convenience of compressing one format or another.

Note: By the way, you need to distinguish between codec and container. For example, the file format is AVI (this is the container) and it can be compressed using various codecs: Microsoft VC-1 or x.264 (for example).

About codecs

👉 Huge selection of codecs for Windows – featured in my selection ->

x.264 / MPEG-4 AVC is probably the most widely used codec. It is used in most video and photo cameras, where captured frames are stored on hard drives, memory cards, etc. x.264 is probably becoming the most popular codec. Adobe supports it in Flash movies, x.264 can be used with HTML 5 images.

MJPEG (Motion JPEG). An old video compression codec. Today it is outdated, we use it little.

How to Compress a Video File Without Sacrificing Quality Part 3

We set the optimal bit rate

The most important factor in determining the quality of a video is its bitrate, so make sure it is set correctly.

Video bitrate, in simple terms, is the amount of data that is displayed in one second. The more data that is displayed, the less artifacts you will notice and the better the video quality will be.

Most DSLRs record video at a very high bit rate, just to reduce the number of artifacts. Sometimes the bitrate value is too high and it makes sense to lower it.

YouTube, for example, recommends using some bitrate values ​​for some resolutions. So if the bitrate of your video is higher than the recommended value, you can safely reduce it to the recommended value.

In Handbrake, the video quality (bit rate) settings are found on the Video tab in the Quality section. Here you can independently specify the required quality, choosing between two options: set the quality ratio with respect to the original or manually enter the value of the bitrate in the average bitrate.

I also advise you to check the 2-Step Encoding box.

Change the frame rate of the video
Another important parameter when compressing video that you should pay attention to is changing the frame rate. I mean right away that I don’t recommend changing the frame rate in your video files. If someone tells you that you need to lower the frame rate of your videos, don’t listen to them. Every video expert or video editor will tell you to keep your videos at their original frame rates.

The human eye cannot see image jumps above 24 frames per second (FPS). So it might seem logical to lower the frame rate to that range. However, you don’t need to do this, as changing the frame rate affects the smoothness of the video, and especially your amateur footage, which is not without its drawbacks and contains jerky and jerky movements in the frame.

Justified changing the frame rate of the video can only be useful for experiments with slow motion shots.

Frame rate settings in Handbrake are found on the Video tab.

Other tricks to compress video
Now with the help of this guide, you can compress your video files as much as possible without significantly affecting the quality.

How to Compress a Video File Without Sacrificing Quality Part 2

Choosing the best video codec and container

Ideally, when recording video, you should always set the maximum video settings for the device you are recording with. Only the maximum of a camcorder will allow you to get the highest quality video, which can then be compressed without losing virtually any quality. The basis of video reduction is to use the most efficient codec and container for the video.

What is a codec? Basically, a codec is a way to encode or decode video for storage or playback, respectively. The codec converts a video file into a stream of information that is understandable to a video player.

What is the container file format? The file format in which the codec stores streaming audio and video data. Different file formats are needed so that different devices and players can use the same limited list of formats, that is, the same format must be played on different players.

Go to the Video tab and select H.264 as your preferred codec. It is the most efficient and popular codec for high definition video and allows you to compress video by almost half, which is comparable in efficiency to MPEG-4 when compressing video. In addition, today it is compatible with most devices, from a player in Windows 10 to a TV with SmartTV.

A newer codec, which compresses H.265 video files even better, is not yet supported by all devices. If you want to compress a video file as efficiently as possible without losing quality, select H.265 in the settings. But once the compression process is complete, I advise you to check the output video file on the device the video was designed for.

Decrease video resolution
It’s good when your phone can record 4K video, the purchased TV or monitor plays 4K monitor video. But most people have HD Ready or Full HD technology, which isn’t really that bad. After all, the main secret of video quality is not the great resolution, but the bitrate of the video.

Of course, resolution affects video size significantly, but video quality (bit rate) affects just as much. Also, the viewing distance between the viewer and the TV will affect the video quality and the estimated size, for example; TV screen technology.

Here is a list of the most commonly used resolutions on modern playback devices:

2160p (3840 × 2160)
1440p (2560 × 1440)
1080p (1920 × 1080)
720p (1280 × 720)
480r (854 × 480)
360p (640 × 360)
240p (426 × 240)
As a general rule of thumb, to ensure file size reduction, check the original video resolution and select a lower level or two. In Handbrake, the resolution settings are on the Image tab. Here you can independently specify the resolution required for the output video file.

Also, after specifying the resolution, you can click on the kpopku Preview and evaluate the video quality before compression.

If you plan to upload your videos to YouTube, then the resolution can be set to 4K. On Instagram – up to 720p, on Facebook, VK – up to 1080p.

How to compress a video file without sacrificing quality

These days digital SLR cameras, next-gen GoPro devices, and smartphones can record HD Ready and FullHD or even high-quality 4K video.

But every footage shot in FullHD takes up an indecent amount of space on your device, not to mention 4K, which consumes 16GB of memory on iPhone 6 in 35 minutes. When the space on the memory card or the internal memory of the device runs out, each of us experiences that feeling of disappointment with the size of the memory of our device, that we involuntarily think of the minimum of a larger card or even of a new device. which will be able to compress the footage at least minimally. It is good if you have a computer with a large volume of discs to create a video file. But even this volume will end sooner or later.

I propose to consider how to compress a video file without sacrificing quality. And for that, you need to understand that there is a strict balance between video size and quality:

correct settings of the video converter will preserve the quality of the video and reduce its size;
incorrect settings will reduce the quality of the video, but will not reduce its size.
How to reduce the size of the captured video without losing quality.

How much disk space does HD Ready, Full HD, 4K video take up?
The video performance of modern devices has reached very serious heights. And shooting in Full HD at 30 frames / second is a standard and a necessary requirement for any digital camera. All smartphone flagships can shoot in Full HD, practically no less than the resulting image quality from SLR cameras.

And how much space is required for different video formats to shoot. No one will tell you the exact indicators, I will give you some rough data that you can trust when choosing a recording device and video format.

On average, it takes 1 minute of video:

When shooting in HD Readry (720p) at 30 frames / second – 60 MB;
When recording in Full HD (1080p) at 30 frames / second – 130 MB;
When recording in Full HD (1080p) at 60 frames / second: 200 MB;
When recording 4K (UHD) at 30 frames / second: 375 MB.
The difference between HD, UHD, 4K and 8K video formats plays a decisive role in determining recording volumes. But there are other parameters that the video file size depends on: audio parameters, bit rate, aspect ratio, color resolution, and more.

I would not recommend reducing video on smartphones unless absolutely necessary, because no smartphone can save the optimal video quality and compress the video file as much as possible. For the video reduction process, there are optimal computing solutions that cope with this task successfully. Today I will consider one such tool, which very simply and quickly allows you to reduce the size of a video file without compromising on quality.