H.265 HEVC and H.264, Understanding the Difference
H.265 HEVC and H.264The Goal of this article is to help you understand some of the new technology that is having a direct affect on Movie Quality and Streaming on your device. One in particular is the new Compression Format called H.265 or HEVC. What the on earth is that you ask ? Here's some background that will help you understand, without getting to “techie”….. I hope.
What is H.265 aka HEVC.HEVC (High Efficiency Video Coding, sometimes called H.265) is a new video compression format and is the successor of H.264. It was formalized on the 25th of November 2013 and published as ISO/IEC 23008-2:2013. An open source HEVC decoder and encoder (x265) has been developed and is widely adopted. High Efficiency Video Coding (HEVC), also known as H.265, promises twice the compression possible with Blu-ray’s best video compression methods. But how does it work, and is it enough to get us better-looking 4K content?
HVEC vs H.264A technical comparison (with thanks Ana Rodrigues) : Both codecs work by comparing different parts of a video frame in order to find the ones that are redundant within the subsequent frames. These areas are replaced with a short information, describing the original pixels. What differs HEVC/H.265 from H.264 is the ability to expand the size of these areas into bigger or smaller blocks, called coding tree units (CTU) in the HEVC/H.265.
- The pattern CTU sizes can be from 4×4 to 64×64, whilst H.264 only allows a maximum block-size of 16×16 (CTU is particular feature of HEVC).
- An improved CTU segmentation, as well as a better motion compensation and spatial prediction require much more signal processing capability for video compression. But has a significantly less impact on the amount of computation needed for decompression.
- Motion compensated prediction, another great progress in HEVC/H.265, references blocks of pixels to another area in the same frame (intra prediction) or in another frame (inter prediction).
H.264So how does all of this affect you the end user? Lets show you some examples of H.264 v H.265. The following was done on a Clean version of Krypton (no build) Movies were Blade Runner 2017 & Star Trek Into Darkness. The device was a PC with W/10 in order to create these screenshots. Once you have selected the media file and depending on what Fork of Kodi you have installed, you should be able to see some of the basic bits of Information relating to the File. The “Kato” Fork of Kodi Krypton for Windows was used for this article.
- As shown above, you can see the the Audio is 5.1
- DTS (Digital Theater Systems)
- ratio of 2:40:1
- and the Compression of H.264 ( or MPEG-4 part 10)
Letter OTo achieve the screen above, Select the Letter O on the keyboard while the movie is playing as shown in the photo above. There are Four areas of Information that are of interest. For this article we will focus on those indicated by the Red Dot.
- Video decoder-ff.h.264
- Video stream– 1920 x 800 px (resolution) 2.40 ar (Average Video Rate) 23.976 FPS (Frames per second)
- Audio stream– FL, (front left) FR, (front right) FC, (front center) LFE, (low frequency effect or Sub Woofer) SL, (surround left) SR, (surround right).
- System CPU usage– Probably one of the most important bit of information shown that many overlook. The higher the % the higher the load is on the device, this is a direct cause of buffering/stuttering/freezing. One way to ease this load is to use the Advanced Wizard Settings in Ares Wizard. Enable the recommended settings suggested by the Wizard based on the specs of the device you have it installed in. Keep in mind these settings will differ from one device to another, eg. a PC will have different recommendations than say an Android Box or a FireStick.
CTRL + shift + Letter OThere is another Option while viewing a Movie. At the same time press CTRL + shift + Letter O on the keyboard. This information will always appear in the top left corner of the screen :
- aq 99%- (Audio Queue saturation) Kb/s 1474.29 (current audio bitrate reported by player)
- vq 99%- (Video Queue saturation) Mb/s 3.89 (current video bitrate reported by player) fr:23.976- (frame rate) drop: 0, skip:3 (three frames have been skipped)
- Player: a/v :0.017 (Audio/video sync difference real time)
H.265 HEVCNow lets compare H.264 with H.265. While at first glance both versions appear to be the same, there are some very important figures that will stand out as we move along.
- Audio is 7.1
- AAC (advanced audio coding. comparable to MP3, but much better)
- 1:78:1 ratio
- H.265 or HEVC (High Efficiency Video Coding)
Letter OJust like the other example used, once your movie has started, click the Letter O to acquire the information shown above.
- Video decoder : indicates ff-hevc (SW)
- Video Stream : 3840 x 2160 px which is 4 times 1080p or True 4K Resolution. Most noteworthy is the Video stream shown in the H.264 example, 1920 x 800. Wait a second you say ! I thought I was viewing a 4K stream. This was not done intentionally on my part but felt it was important to include. What has happened is you have selected a stream that is “Up-scaled” 1080p. All of this really only matters if you have a 4K Resolution TV Set. But on a “regular” TV there isn't much of a difference in the quality.
- Audio Stream : Because this is 7.1, compared to the other example there are two more channels added. BL ( back left) and BR (back right). Unless you have a Surround Sound Home Theater Movie System, there's not to much to get excited about….. But if you do ! It does make a difference.
CTRL + shift + Letter OThis is where it gets interesting, especially relevant are the :
- aq 99%- (Audio Queue saturation) Kb/s 270.47 (current audio bitrate reported by player) Compared to the H.264 of 1474.29.
- vq 99%- (Video Queue saturation) Mb/s 1.26 (current video bitrate reported by player) Compared to the H.264 of 3.89.
In ConclusionH.265 will soon be the dominant Compression Standard in the industry. A simple analogy is to imagine you have a Bushel of Apples. You need to fit 100 apples inside. You can do it with more compression (reducing the apples to sauce), or with better compression (finding a better way to make them all fit, but preserving their “appleness”). More compression: applesauce (H.264) Better compression: more apples, same space (H.265) As data-intensive as HD is, 4K is even worse. While most of us were just getting used to the idea of H.264's advantages over MPEG-2 on Blu-ray, the Motion Picture Experts Group and the International Telecommunication Union's Telecommunication Standardization Sector (ITU-T) were already starting work on the next generation of video compression, with an eye on the future. So the next time you have issues with Streaming, make sure the Compression is not H.265, your device may only be designed for H.264. Nothing wrong with Kodi, the Add-on or the Build. Just change to a source that has H.264, most have that information listed and it's easy to read.
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