"Many cameras currently adopted H.265 coding standards, H.264 encoded cameras gradually decrease, why is H.265 popular? H.264 and H.265 have different?
First, what is H.265
H.265 is a new video coding standard established after ITU-TVCEG followed by ITU-TVCEG. The H.265 standard surrounds the existing video coding standard H.264, reserves the original technologies, and improves some related technologies.
New technology uses advanced technology to improve the relationship between code stream, coding quality, delay and algorithm complexity, reaching optimization settings. Specific research contents include: increasing compression efficiency, improving robustness and error recovery capabilities, reducing real-time delays, reducing channel acquisition time and random access delay, reducing complexity, etc. Since the algorithm optimization, the H265 can be achieved at a speed of less than 1 Mbps, and H265 can realize the transfer of 720P (resolution 1280 * 720) to transmit 720P (resolution 1280 * 720) to transmit the transmission speed of 1 to 2 mbps.
The H.265 is intended to transmit higher quality network videos under limited bandwidth, and only the original half band width can play the same quality video. This also means that our smartphones, tablets and other mobile devices will be able to play directly online 1080P full HD video. The H.265 standard also supports 4K (4096 × 2160) and 8K (8192 × 4320) ultra HD video. It can be said that the H.265 standard allows network video to keep up with "high resolution" footsteps.
Second, what is H.264
H.264, is also the tenth part of the MPEG-4, which is proposed by the ITU-T video coding expert group (VCEG) and the ISO / IEC Dynamic Image Expert Group (MPEG) combined with video group (JVT, Joint Video Team) Highly compressed digital video codec standard. This standard is generally referred to as H.264 / AVC (or AVC / H.264 or H.264 / MPEG-4AVC or MPEG-4 / H.264 AVC) to express its two developers.
The maximum advantage of H.264 is to have a high data compression ratio. Under the conditions of the same image quality, the compression ratio of H.264 is 2 times the MPEG-2, which is 1.5 to 2 times the MPEG-4. For example, if the size of the original file is 88GB, it is 3.5GB after compressing the MPEG-2 compression standard, and the compression ratio is 25: 1, and the compression ratio is compressed by the compression standard to 879MB, from 88GB to 879MB, The compression ratio of H.264 is an amazing 102: 1. The low bit rate has an important role in the high compression ratio of H.264, and the H.264 compression technology will greatly save users' download times compared to compression technology such as MPEG-2 and MPEG-4ASP. Data traffic charges. It is particularly worth mentioning that H.264 also has a high quality image while having a high compression ratio, as in this way, after the H.264 compressed video data, less bandwidth required in the network transmission process, It is also more economical.
Third, H.265 is different from H.264
Before discussing H.265, we may wish to first understand H.264. H.264 is also known as MPEG-4AVC (Advanced Video Coding, Advanced Video Coding), is a video compression standard, and is also a recorded, compressed and release format that is widely used high-precision video. H.264 is famous for its codec standard for a Blu-ray disc, and all Blu-ray players must be able to decode H.264. More importantly, because Apple has finally abandoned Adobe's VP6 encoding, I chose H.264. This standard also walked thousands of households with billions of iPad and iPhone, became the current video coding field. Absolute overlord accounts for more than 80% of the share. H.264 is also widely used in network streaming media data, various high-definition television broadcasts, and satellite TV broadcasts. H.264 has some new features compared to previous coding standards, such as motion compensation, change block size motion compensation, intra predictive coding, etc., H.264 is more than other coding standards by using these new features. High video quality and lower code rates have been widely approved by people.
The H.265 / HEVC encoding architecture is similar to the architecture of H.264 / AVC, which mainly comprises: intra prediction, inter-intermediction, transform, quantization, Go to block filters, entropy codes and other modules. However, in the HEVC coding architecture, the whole is divided into three basic units, namely: Coding Unit, Cu, predictor (PU), and Transform Unit, TUs, respectively.
Fourth, H.265 Why is it better than H.264
More different tools are provided by H.264 / AVC, H.265 / HEVC to reduce the code rate, in the coding unit, the smallest 8x8 to the maximum 64x64. There are not many areas of information (color variations are not obvious, such as the red part of the vehicle body and the gray part of the ground) are large, and the coded is less code, and the details of the details (tires) are divided into macro The block has a small and more, the encoded codeword is more, which is equivalent to the encoding of the image, thereby reducing the overall code rate, and the encoding efficiency is correspondingly improved. At the same time, the intra prediction mode of H.265 supports 33 directions (H.264 only supports only 8), and provides better motion compensation processing and vector prediction methods.
Repeated quality comparison tests have shown that under the same image quality, the video code stream encoded by H.265 is reduced by approximately 39-44% compared to H.265 compared to H.264. This data will also have corresponding changes due to differences in quality control measurement. According to the data derived by subjective visual test, the quality of the H.265 encoded video can be approximately even better with the H.264 encoded video in the case of a rate of 51-74%, which is essentially more than expected. The signal to noise ratio (PSNR) is good. These subjective visual tests have covered many disciplines, including psychology and human eye visual characteristics, and video samples are very broad, although they can't be the final conclusion, but this is also very inspiring results.
The current HEVC standard has three modes: Main, Main10 and Main Still Picture. The main model supports 8Bit color depth (ie, 256 chromasings each having a total of 167 million colors). The MAIN10 mode supports 10 bit color depth, which will be used in UHDTVs (UHDTV). The top two will limit the color sampling format to 4: 2: 0. It is expected that the standard will be expanded in 2014, which will support 4: 2: 2 and 4: 4: 4 sampling format (ie, higher color reduction) and multi-view encoding (eg, 3D stereo video coding).
In fact, H.265 and H.264 standards have some overlap in various functions. For example, the HI10P part in the H.264 standard supports 10 bit color deep video. Another part of H.264 (Hi444PP) can also support 4: 4: 4 chrominance sampling and 14-bit deep. In this case, the difference between H.265 and H.264 reflects that the former can use fewer bandwidth to provide the same function, the price is the device computing power: H.265 encoded video requires more computing power To decode. There is already a chip that supports H.265 decoding - US Broadcom has released a Brahma BCM 7445 chip in the CES exhibition in early January, which is a quad-core processor using 28 nano-processes. It can simultaneously transcode four 1080p video data streams or resolutions of H.265 encoding ultra HD videos in 4096 × 2160.
The birth of the H.265 standard is to transmit higher quality network video under limited bandwidth. For most professionals, the H.265 coding standard is not unfamiliar, which is the video coding standard established after ITU-TVCEG followed by H.264. The H.265 standard is mainly surrounded by the existing video coding standard H.264. In addition to some other technologies, it has increased the relationship between improved code stream, coding quality, delay and algorithm complexity. Related technology. The main contents of H.265 include increasing compression efficiency, improving robustness and error recovery capabilities, reducing real-time delays, reducing channel acquisition time and random access delay, reducing complexity.
Further reading: Integrated wiring common nouns Daquan
5. How to calculate how video storage under H.264 and H.265 technology
1, H.264 technical hard disk capacity calculation
Speaking of calculation, what do we have to calculate? In addition to the number of cameras, there is an important value: code rate! Under normal circumstances, the size of the stream is, the greater, such as We often use the 130W camera, the code stream is 2MB / s, which is 2048kbps. Then I know the code stream, time, channel number, we can directly set the formula.
The formula is as follows: Code rate × 3600 × 24 ÷ 8 ÷ 1024 ÷ 1024 = 1d (one day)
Codeflow table
It should be measured for the code stream, so our capacity should also be converted in seconds, 3600, is 1 hour, 24 is 24 hours a day, 8, is byte, 1024 should be the code stream is The MB is unit, so that the conversion G is to be divided by 1024, replace it to T, then 1024. Fruit is 1 day. Party A needs how long it is stored, and then it is OK by the number of days.
The above is the calculation method of H.264, then let's take a look at the application of H.265 technology.
2, H.256 technology hard disk storage calculation
Example:
H.264 technology, 4 300W storage probably: 60g * 4 * 30 = 7.2T
H.265 Under Technology, 4 300W storage is probably: 30g * 4 * 30 = 3.6T
The following figure is more direct
This is still stored, let's take a look at the bandwidth. In the past, H.264 is required to watch the HD screen of 1 130W pixels remotely, it takes 6m uplink bandwidth, while H.265, 4M network can see a 300W HD picture. 2 200W screens.
Therefore, the cost of reduction is not just a hard disk storage, of course, there is a switch.
b, how to support H.265?
Is it that I use the old camera to receive a video recorder of H.265, can you store it? No, for the webcam and recorder, both parties support H.265 technology.
If there is one support, the other party does not support it? Rest assured, the same as other technical equipment, compatible, that is, other functions are normal in addition to storage reduction.
How to calculate C, H.265 Storage?
Ordinary camera is about 21g a day, is it directly divided by 2? actually not. A more concise method is coming!
200w≈20g
300W ≈30g
400W ≈40g
In fact, H.265 is compressed with a stream.
Be
In summary, the first is that H.265 supports more directions with H.264 on inter prediction and intra prediction, and the algorithm has been improved. At the same time, for each frame, a finer macroblock is divided into more intelligently predicting the coding of different regions to increase coding efficiency. And improve the method of better dynamic compensation and vector prediction. "
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