This text supplies a fast overview of the HEVC codec: what it’s, the way it performs, what it prices, and what it’s good for. We’ll conclude with a bit on what you might want to know to successfully deploy the HEVC codec utilizing the Wowza Streaming Engine software program.

What Is the HEVC Codec?

H.265/Excessive Effectivity Video Coding (HEVC) is the successor codec to H.264, which, like H.264, was collectively developed by the ISO/IEC Shifting Image Consultants Group and ITU-T Video Coding Consultants Group (VCEG). Additionally like H.264, HEVC has two interchangeable names, HEVC from MPEG and H.265 from the ITU. The ITU-T began work on H.265 in 2004, MPEG in 2007, and the usual was permitted by each in January 2013.

HEVC deploys quite a few technical developments over H.264 as mentioned right here. In accordance with the ITU approval doc, H.265 “was developed in response to the rising want for larger compression of shifting photos for numerous functions equivalent to web streaming, communication, video conferencing, digital storage media, and tv broadcasting.”

As a sensible matter, HEVC has loved its most profitable adoption in the lounge, the place it’s seen as an enabler for 4K video, significantly 4K delivered with excessive dynamic vary (HDR). HEVC has additionally achieved important success in contribution and newsgathering markets. In December 2019, LiveU, which manufactures encoders and transcoders for information manufacturing, reported a 65% development in HEVC unit gross sales in 2019. Because of this, 50% of subject models used to stream sports activities had been HEVC-based and LiveU reported a 400% development in HEVC-based periods.

HEVC is a royalty-bearing codec. In distinction with H.264, which had one patent pool with affordable pricing (like an annual cap of ~$9.75 million), HEVC has three patent swimming pools launched as late as 4 years after HEVC was permitted with identified royalties exceeding $65 million per 12 months. The second pool, from HEVC Advance (now Entry Advance), was launched with no cap and with a content material royalty. That is attributed as motivation for Microsoft and Google to type the Alliance for Open Media, which in the end launched the aggressive AV1 codec. Extra on HEVC licensing under.

Compatibility

The web site CanIUse lists HEVC browser compatibility for each desktop and cellular at 18.08% as in comparison with H.264’s 98.23%, VP9’s 96.26%, and AV1’s 74.25%. This comes as no shock provided that market leaders Chrome, Firefox, and Edge are all owned by members of the Alliance for Open Media. Apple can be an Alliance member however began supporting HEVC on iOS, Mac, and Apple TV earlier than becoming a member of the Alliance. Given the low penetration within the browser market, it’s no shock that few publishers are deploying HEVC for browser-based playback.

Within the cellular house, Apple added HEVC playback to iOS, MacOS, and tvOS and debuted {hardware} help on newer Apple gadgets in June 2017. HEVC help is bifurcated on the Android entrance, with Google supporting HEVC in software program however solely as much as predominant profile, stage 3 for cellular gadgets, which suggests help for playback of as much as 960×540@30 fps. To compete with Apple gadgets, nevertheless, many Android cellular gadgets even have HEVC {hardware} decoding; in August 2018, Scientiamobile reported that 57% of Android gadgets had been geared up with {hardware} decoding in comparison with 78% of iOS gadgets. 

HEVC is nearly universally supported on Good TVs and premium OTT gadgets and is the popular format for 4K and excessive dynamic vary movies.

Efficiency

When gauging codec efficiency, you contemplate two features: (1) encoding complexity or pace, and (2) encoding high quality. With most codecs, together with the 4 mentioned on this collection, there’s an inverse relationship between the 2. That’s, the higher the encoding high quality the longer it takes to encode, which interprets to larger encoding and transcoding prices. Since no codec can utterly substitute H.264 at this level, these encoding or transcoding prices are additive to current H.264 encoding-related prices.

When analyzing codec efficiency, keep in mind that there are a number of HEVC implementations, every with its personal efficiency traits. Most HEVC implementations even have presets that allow you to commerce off encoding time for efficiency. For instance, with x265, the HEVC encoder included in FFMpeg, the medium preset encodes in about 11% of the time of the very sluggish preset, and solely delivers about 1% decrease high quality than very sluggish, which is irrelevant for many producers. In fact, H.264, VP9, and AV1 even have a number of implementations with a number of presets, which complicates codec comparisons and is why the encoding pace column in desk 2 exhibits such an in depth vary.

When contemplating encoding high quality, be aware that the determine represents the bitrate discount you must anticipate when evaluating a single full-resolution encode from HEVC, VP9, or AV1, as in comparison with H.264. Clearly, this may differ based mostly upon the codec and preset used.

As well as, any precise estimate of real-world financial savings from adopting a brand new codec should contemplate earlier than and after encoding ladders and the precise distribution of the streams to your viewers. If distribution is top-heavy, as most are within the U.S. and Europe, you must have the ability to harvest a superb little bit of the quantity proven in Desk 2. If you happen to distribute principally within the center vary, bandwidth financial savings will probably be a lot decrease, although video high quality needs to be considerably improved.

Suitability: HEVC vs. H.264, VP9, and AV1

Now let’s look at HEVC’s suitability for a spread of particular encoding functions. HEVC could be very effectively fitted to reside origination as a result of the decrease bitrate drops the outbound bandwidth necessities and since there are numerous inexpensive HEVC hardware-based encoders. There are additionally many HEVC {hardware} transcoders resulting in the wonderful rating for that process.

Whereas most low-latency implementations use the H.264 codec, HEVC is suitable with Low-Latency HLS and is an obtainable format for Low Latency HLS utilizing the Wowza Streaming Engine. Alternatively, HEVC just isn’t suitable with WebRTC and isn’t obtainable in Wowza’s WebRTC implementation.

HEVC’s candy spot is the lounge due to encoding effectivity and compatibility and predominant utilization in all excessive dynamic vary specs, together with Dolby Imaginative and prescient, HDR 10/10+, and HLG.

Royalty Standing: HEVC vs. H.264, VP9, and AV1

HEVC’s royalty standing has been wildly and broadly criticized, together with by MPEG’s founder (after which director) Leonardo Chiariglione, who in a 2018 weblog publish entitled A disaster, the causes and an answer, reviewed HEVC’s fractured royalty coverage and acknowledged “In the end everyone realizes that the previous MPEG enterprise mannequin is now broke, all of the investments (collectively tons of of tens of millions USD) made by the trade for the brand new video codec will go up in smoke and AOM’s royalty-free mannequin will unfold to different enterprise segments as effectively.” About 18 months later, Chiariglione was gone from MPEG, a corporation he had led since its founding in 1988.

Right here’s the image for content material producers, who seemingly comprise the huge bulk of readers of this text. There are three patent swimming pools, MPEG LA, Entry Advance, and Velos. MPEG LA fees no royalties for content material. Entry Advance fees a royalty on industrial content material distribution on bodily digital media, so streaming doesn’t set off a royalty. Velos Media runs the third pool, and over 8 years after the finalization of HEVC, nonetheless states, “Because it pertains to content material, we’ll take our time to completely perceive the dynamics of the ecosystem and be sure that our mannequin greatest helps the development and adoption of HEVC know-how.” Whereas it’s unlikely that Velos will come looking smaller producers for royalties on HEVC-encoded content material, when you’re a really massive producer you actually can’t rule it out.

What You Have to Know to Produce HEVC

Model 1 of the HEVC codec is the predominant model for streaming supply, and it has two video profiles, predominant and predominant 10, which each use the 4:2:0 chroma sampling. Because the title suggests, the latter is ten-bit, which permits for larger colour depth, whereas the previous is 8-bit. If you happen to’re creating HDR content material with HEVC, predominant 10 is most popular, although some producers desire predominant 10 even for 8-bit content material. If you happen to resolve to ship 8-bit content material through predominant 10, make sure that your decoder is suitable with predominant 10 streams.

Each Wowza Streaming Engine and Wowza Streaming Cloud can ingest reside HEVC streams in both profile, although predominant is usually most popular. The Wowza Streaming Cloud can ingest HEVC and go the stream by however can’t transcode different rungs to HEVC.

Wowza Streaming Engine can transcode to HEVC ladder rungs, with each the primary and predominant 10 profiles obtainable, although once more, predominant is most popular. Wowza is within the means of switching from the MainConcept to the Beamr HEVC codec and you may examine find out how to configure your ladder rungs right here.

Like most HEVC codecs, the Beamr codec makes use of presets to outline completely different encoding pace/high quality tradeoffs. The supported values are 98 (slowest, highest video high quality and CPU utilization) to 108 (quickest, lowest video high quality and CPU utilization). Because the Wowza article suggests, “you’ll have to experiment to seek out the suitable worth. If you happen to set this parameter to a price decrease than your obtainable CPU sources can deal with, real-time encoding will lag and finally cease. When this occurs, skip body messages seem within the Wowza Streaming Engine logs.” In my expertise, you must anticipate HEVC transcoding to be about 4-8 instances extra CPU intensive than H.264, although this clearly will relate to the presets that you just use for every.

Total, HEVC needs to be thought of for streaming to cellular and lounge gadgets, however not for normal browser consumption. Within the subsequent article, we’ll talk about the AV1 codec.

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Extra Sources:

• The Streaming Codec Panorama in 2021
• Video Codecs and Encoding: Every thing You Ought to Know
• H.264 Defined
• VP9 Defined

About Jan Ozer

Jan Ozer is a number one professional on H.264, H.265, VP9, and AV1 encoding for reside and on-demand manufacturing. Jan develops coaching programs for streaming media professionals, supplies testing providers to encoder builders, and helps video producers excellent their encoding ladders… View extra