Technical analysis: Video Encoding and encapsulation formats

Technical analysis: Introduction to video encoding and encapsulation formats
We are talking about HD videos with a resolution greater than 1280x720, which is called SD in the field of display and home appliances ". Some videos have a resolution of 1280x528, which is actually 720 p on the wide screen. Only 1920x1080p videos are generally called full HD fullhd videos. Most of this horizontal evaluation products have a certain level of HD video decoding capability, so we need to carefully talk about the encoding of HD videos. The resolution 1280x690 "Ice Age 3" belongs to the wide screen 720 p
When talking about audio and video files, we often discuss their encoding specifications and encapsulation formats. What are these two things? For example, it can also be a red star or a niulanshan. "Erguotou" is the brewing method of wine, which is equivalent to the code specification. "Red Star" and "niulanshan" are brands and are equivalent to encapsulation formats. Similarly, videos of the x.264 type can be encapsulated as rmvb or MKV. The same file format can be encoded differently. This is mainly because different encapsulation formats have very different requirements on audio tracks and videos. For example, MKV supports multiple audio tracks and a wide range of video encoding specifications, which is very convenient to use, therefore, many p videos on the Internet use MKV encapsulation.

Erguotou is also divided into many brands. The same x264 encoding can also be encapsulated into multiple file formats (the image is a macfans Forum image)
What is the bit rate? In general, it is the volume of the file per unit time. For example, a 5 Mbit/s bit rate is equivalent to a file volume of 110 KB/s per second, storing a video for a-minute movie, the file size is 625 Kbyte/S x 60 s/min x 110 min = 4125 m, which is close to the capacity of a full DVD disk. We often download P movies online, you can achieve a perfect balance between the image quality and the volume for easy download and storage. Different encoding specifications have different image quality performance under different bit rates, but they all have an optimal bit rate, that is, the balance between quality and volume.

The 4989 GB "Ice Age 3" adopts x264 encoded MKV encapsulation, and the video bit rate is K.
Introduction to various encoding specifications

The H.263 specification is derived from MPEG 4 visual, H. 264 is derived from MPEG 4 Part 10. The two are the products corresponding to the two bit rates respectively. The latter has become a major coding standard for Blu-ray HD because of good image quality. H.264, also known as AVC, is the open-source version of H.264, which is most commonly used on the Internet. DivX was also used to make great strides. It was improved by many netizens according to Microsoft MPEG4 V3. Later, some people turned the wisdom of the working people into their own products, turning DivX into commercialization, triggering the "wrath of the Lich King ", as a result, netizens have stirred up a better XviD. In addition, MPEG2 ts is also a frequently used encoding standard for P. It features good image quality, but requires a very high bit rate as the support, at least 15 Mbps, the file size is very large, it is not conducive to online transmission. There are also a lot of videos in the WMV series of Microsoft, but this format is only supported by Microsoft. Although it has been integrated into the Media Player of the Windows system, it is still not widely used. There is also the real rv40. Some rmvb code rates of P on the Internet exceed 7 m, using the rv40 code based on x264. Of course, the most common online version is the hundreds of megabytes of rmvb. The download time is short and it is very easy to obtain the source card.

Introduction to various file encapsulation formats

The encapsulation formats of HD videos include MKV, which supports multiple video encoding formats, including h264, vc1, MPEG2, rv40, and Apple QuickTime, in addition, it supports multiple Audio Encoding packages and supports multiple subtitles. It is very convenient to make multi-language videos. Therefore, the 720p currently downloaded online is mainly h264 encoded MKV, with a size of about GB, it can be burned to a dvdr. Avi is also a frequently used file format. Videos of 700mb and 1.4gb are often encapsulated with Xvid and Avi, downloads can be burned on 1-2 CDRS. rmvb is often used to encapsulate rv40 Based on x264. This encoding bit rate does not significantly improve the image quality, therefore, the online HD videos with a 2 Mbps bit rate of about 2 GB are rmvb .; MP4 adopts the baseline and mainline encoding of MPEG4, which features a higher compression ratio and a smaller size. However, it is suitable for devices with low resolution such as MP4 players; of course, WMV encapsulates Microsoft's own files. As mentioned above, there are not many people using WMV only for Microsoft's brute force attacks; as for dat, vob, and Ts, they are the file formats used by VCD, DVD, and Blu-ray discs, which are essentially the H of MPEG, MPEG2, and MPEG4 part10. 264.

It is also a 1.15 p resolution "banquet", which adopts AVC-based rv40 encoding and is only GB in size.
Optimal Bit Rate for various encodings

The encoding specifications and encapsulation formats are diverse because they correspond to different best bit rates. The low resolution of 640x272 is mainly real video. The best bit rate is 350-600kbps, And the encapsulated file format is RM or rmvb. We often download about M movies online, which are basically realvideo-standard rmvb files; when the resolution is increased to x438, Xvid encoding is generally started, and the bit rate also ranges from to kbps. The encapsulated file is often Avi, and the file size is about MB, we often download x264/AVC-encoded MKV package files with a bitrate of 5-6 MB, and the audio part can reach 5.1 sound effects. The audio and video effects are very good, but the file volume is above GB, the size of a DVD disk usually takes several days to download from the Internet. H is often used for P videos. 264 encoding and vc1 encoding. the bit rate is 30 Mbps and the size reaches 22-40 GB.