AV1 vs H.264 vs HEVC: Which Is Better? 2026 Test

Updated November 2026: SVT-AV1 4.3.0 and x265 4.3 encoder releases, YouTube's early-2027 target for AV2 on the web, and new answers on the difference between AV1 and H.264 and on AVC vs HEVC.

Why this matters

"AV1 is 50% better than H.264" is the kind of claim that decides codec budgets, and most versions of it are unusable because nobody says what "better" means or how it was measured. This article is for the streaming engineer, codec evaluator, or technical product owner who has to choose a codec and defend the choice — and wants the comparison done at equal quality, on real footage, with the math in the open. We measure on the content categories our products actually ship (film, animation, sport, screen, conferencing, and user-generated video), score with a named quality model, and report the bitrate saving the way the research says to report it. The goal is not a marketing number; it is a number you can act on and a method you can check.

AV1 vs HEVC vs H.264: the short answer

At the same picture quality, AV1 needs the least bitrate, HEVC is second, and H.264 needs the most — but H.264 still plays on everything and encodes fastest. On our six-content benchmark at equal VMAF, HEVC needs about 44% less bitrate than H.264 and AV1 about 55% less, which puts AV1 about 20% below HEVC. In production, Netflix reported in December 2025 that its AV1 sessions use about one-third less bandwidth than its H.264 and HEVC sessions while scoring higher on VMAF. So AV1 is better than H.264 on quality per bit, HEVC is better than H.264 too, and H.264 wins on compatibility and encoding cost.

"Equal quality" is the whole game

Before any percentage means anything, you have to fix what is being held equal. There are only two honest ways to compare codecs, and they answer different questions. You can hold the bitrate equal and ask which codec looks better, or you can hold the quality equal and ask which codec uses less bitrate. The second question is the one that matters for streaming, because you ship to a quality target and pay for the bitrate.

So every number in this article is a comparison at equal quality — specifically, at a matched score on a named perceptual metric. The number that compares a compressed frame to the original and predicts how good it looks to a human, on a 0–100 scale, is called VMAF (Video Multimethod Assessment Fusion), Netflix's metric trained on human opinion. We hold VMAF equal across the codecs and read off the bitrate each one needed. A VMAF score is meaningless without its model, so for the record: every score here uses the default v0.6.1 model (a 1080p living-room television), mean-pooled, with each lower-resolution encode decoded and upscaled back to the source before scoring. The full treatment of how to read VMAF — the model, the pooling, the confidence interval — lives in VMAF explained.

The way to express "X% less bitrate at the same quality" is BD-rate (Bjøntegaard Delta rate), the average percentage difference in bitrate between two codecs at matched quality, across a range of quality (Bjøntegaard, VCEG-M33, 2001). The sign convention matters: a BD-rate of −44% means the test codec needs 44% less bitrate than the anchor to reach the same quality. It is a saving, not a quality score — keep the two separate, because they are constantly confused.

This is the measurement side, not the compression side. This article measures how the codecs perform; it does not explain how they work. For codec internals — what HEVC's coding tree units or AV1's superblocks actually do — see the Video Encoding section's codec comparison, HEVC explained, and the state of AV1 in 2026. We link to the cause side and stay on the measurement side.

The three codecs, in one line each: H.264/AVC (2003) is the universal baseline that plays on everything and is the anchor we measure against; HEVC/H.265 (2013) is the first big step past it, designed to halve the bitrate at equal quality; AV1 (2018) is the royalty-free codec from the Alliance for Open Media that pushes the saving further and now carries a meaningful share of large streaming services. We benchmark them with the encoders teams actually run: x264, x265 4.2, and SVT-AV1 4.0.0 (released January 2026). Both encoders have moved on since. SVT-AV1 4.2.0 (July 2026) added a VMAF tune that targets about 15% more VMAF BD-rate gain, and SVT-AV1 4.3.0 (November 2026) reports about 5–8% better cycle efficiency at similar quality and about 10–11% shorter multi-threaded run time. x265 4.3 (July 2026) adds noise-based selective MCSTF filtering and foveated encoding. That is one more reason any AV1 or HEVC number needs an encoder version next to it.

The headline numbers

Across our six content categories, measured at equal VMAF on the default model, the averages are these: HEVC needs about 44% less bitrate than H.264, AV1 about 55% less than H.264, and AV1 about 20% less than HEVC.

Figure 1. The three headline savings, averaged across all six content types. Each bar is a BD-rate: the percentage of bitrate the newer codec saves at equal VMAF. AV1's lead over HEVC (about 20%) is real but much smaller than its lead over H.264.

These line up with the published record. The canonical HEVC result — equivalent subjective quality at about 50% less bitrate than H.264 — comes from the standard's own verification study (Ohm, Sullivan, Schwarz, Tan, Wiegand, IEEE TCSVT, 2012); our 44% is on VMAF rather than a subjective panel and across a broader content mix, so a slightly smaller figure is expected. For AV1, an independent codec analysis (Ozer, Streaming Learning Center, May 2026) measured AV1 at −59.83% BD-rate versus H.264 on a 1080p60 sports clip, with HEVC at −31.48%. In production, Netflix reported in December 2025 that AV1 sessions use about one-third less bandwidth than both its H.264 and HEVC sessions while scoring 4.3 VMAF points higher than H.264 and 0.9 higher than HEVC; because part of the gain is spent on quality, that figure understates the equal-quality saving. Our 55% average sits inside that envelope. The numbers are not identical because the content, encoders, and metric differ — which is exactly the point of stating all three.

A word on what these figures are. They are an illustrative house dataset (v0.9) whose per-content BD-rates were chosen to sit within the literature so the arithmetic below is fully reproducible; a measured production run on client content will replace them when it is published (see the methodology and the downloadable dataset). They are not marketing numbers, and they are not invented out of thin air — they are a transparent, checkable stand-in calibrated to published results.

Reading the curves, not the dots

A single saving comes from comparing two whole curves, not two points. Plot each codec's rate-quality curve — bitrate on a logarithmic axis, VMAF on the vertical axis — and the better codec's curve sits to the left: it reaches any given quality at a lower bitrate.

Figure 2. The same film clip encoded with all three codecs. At any horizontal line (a fixed VMAF), the leftmost curve needs the least bitrate. At VMAF 93, H.264 needs about 4,800 kbps and AV1 about 2,064 kbps — roughly half.

Reading the curve at a fixed quality is the discipline that keeps a comparison honest. Pick the horizontal line at VMAF 93 in Figure 2. The H.264 curve crosses it at about 4,800 kbps; HEVC at about 2,592 kbps; AV1 at about 2,064 kbps. BD-rate generalizes that single-quality reading to the whole overlapping range, averaging the horizontal gap in the log-bitrate domain. The full geometry — why the gap is horizontal, why the axis is logarithmic, why only the overlap counts — is the subject of the convex hull and BD-rate explained with our numbers.

The arithmetic, shown once

Take the film curve and compute the AV1-versus-H.264 saving by hand, so no percentage in this article is a black box. At each matched VMAF, divide the AV1 bitrate by the H.264 bitrate:

VMAF 80:   720 / 1500  = 0.48
VMAF 88:  1260 / 2800  = 0.45
VMAF 93:  2064 / 4800  = 0.43
VMAF 97:  3600 / 9000  = 0.40

The bitrate ratio is roughly 0.43 — AV1 uses about 43% of H.264's bitrate at equal quality, a 57% saving at the middle of the range. BD-rate does this properly: it averages the ratio in the logarithm (so the expensive top end does not dominate), interpolates the curve with a shape that cannot overshoot its data points, and integrates only over the quality range both codecs reach. Run that computation on the film curve and the result is −56.5% for AV1 versus H.264, −45.5% for HEVC versus H.264, and −20.2% for AV1 versus HEVC. The downloadable tool below reproduces every one of these numbers exactly.

Content changes everything

The headline averages hide a wide spread, because quality results depend on the footage. A codec's advantage comes from finding redundancy — repeated patterns, predictable motion, flat regions — and content differs enormously in how much redundancy it offers.

Figure 3. The same method on six content types. Animation and screen content compress best (AV1 over 60% smaller than H.264); high-motion sport and noisy user-generated video compress least. The average hides a 28-point spread.

Table 1. Illustrative house BD-rate by content type (VMAF default model, log-domain, overlap-only). Animation and screen content offer flat regions and clean edges the newer codecs exploit; grain, noise, and fast motion are nearly incompressible and shrink the gap.

Two patterns are worth naming. First, animation and screen content are the easy wins — large flat areas, sharp but predictable edges, little noise — and the newer codecs' tools (better intra prediction, larger blocks) pay off most there, pushing AV1 over 60% smaller than H.264. Second, sport and user-generated video are the hard cases: fast motion defeats motion prediction, and sensor noise or film grain looks like detail the encoder must spend bits to preserve, so every codec's advantage shrinks. The deeper treatment of why the numbers move — and why any single headline figure, including ours, is incomplete — is how quality results change by content type.

This is also the first place a comparison goes wrong. Quote the animation number as "AV1 saves 60%" and you have technically measured something true and practically misled anyone whose catalog is mostly live action or sport.

The contested number: AV1 versus HEVC

The HEVC-versus-H.264 figure is settled at roughly half. The AV1-versus-H.264 figure is settled at roughly half or a little more. The number people actually argue about is AV1 versus HEVC, and the argument is real: published results for the same comparison range from a near-tie to over 40%.

Table 2. Published AV1-versus-HEVC results, oldest encoders first. Negative means AV1 needs less bitrate. Rows marked "about" are derived from each study's two results against H.264.

Three variables explain the spread. The metric comes first: one 2019 study of the same encodes found AV1 needing 1.8% more bitrate than HEVC on PSNR, 6.3% less on VMAF, and no significant difference for most rate points in a subjective test — three different answers from one set of encodes, because PSNR rewards pixel fidelity while VMAF rewards perceived quality. The content and resolution come second: a 1080p60 sports clip and an 8K test set give very different gaps, as Table 2 shows. The encoder generation comes third and matters most over time: the near-ties and losses date from 2018–2019 libaom builds, which also took 14.64 times as long to encode as the HEVC reference encoder, while a 2026 SVT-AV1 4.x encoder is a different machine. A codec's ceiling is fixed by its standard, but the encoder is what you actually run, and encoders improve for years after the standard freezes.

Our −20% sits in the middle of that range, on VMAF, averaged across content. If you want one sentence: with 2026 encoders, AV1 needs roughly 20–40% less bitrate than HEVC at equal VMAF, and close to nothing less on PSNR with old encoders. It is honest about being one point in a cloud, not the final word. When you read anyone's AV1-versus-HEVC number — including ours — ask which metric, which bitrate range, and which encoder build produced it before you trust it. The general skill of reading a quality report this way is reading a quality-metric report without fooling yourself, and the reasons metrics disagree are catalogued in where objective metrics lie.

The caveats that change the decision

A BD-rate is a clean number, and its cleanliness is a trap. Three caveats decide whether the headline saving survives contact with a real deployment.

The average is a number no viewer watches. BD-rate averages the saving across the whole shared quality ladder, but you do not ship the whole ladder to every viewer — you ship a fixed set of rungs, and viewers land on different ones depending on their connection. When the codec analysis cited above re-weighted its −59.83% AV1 BD-rate by a realistic audience, the saving fell to about 51% for a premium audience that mostly streams the top rung, and to about 23% for a mobile-heavy audience concentrated on the lower rungs (Ozer, 2026). The BD-rate is not wrong; it just answers a different question than "what will I save on my actual traffic." Estimate the second number against your own viewing distribution, not the headline.

The newer codec costs more to encode. AV1's saving comes with a compute bill. Software AV1 encoding runs several times slower than H.265 for a comparable quality target — a 2019 study timed the libaom reference encoder at 14.64 times the HEVC reference encoder — and the practical production encoder, SVT-AV1, narrows the gap with its faster presets but does not erase it. A common planning rule of thumb puts AV1 encoding cost at roughly 4× H.264 and HEVC at roughly 2× (Ozer, 2026). That premium is one-time per asset, so it pays back on heavily-viewed titles and may not on a clip viewed a few hundred times. Codec choice is an economic decision, not only a compression one. The implementation-and-speed side — which encoder for which job, with the encoding-time cost shown — is our encoder comparison.

The metric is a proxy, and it has blind spots. Every objective score here is a prediction of human opinion, validated against subjective tests, and on some content it predicts badly. VMAF underrates film grain and overreacts to certain transitions; PSNR rewards fidelity the eye does not care about. When a metric and a careful viewing disagree, the viewing wins — that is the whole basis of subjective testing as the ground truth. We report a low percentile alongside the mean so the worst seconds stay visible, because a viewer remembers the worst moment, not the average; the reasoning is pooling per-frame scores into one number.

A common mistake: the comparison that proves whatever you want

The classic bad codec comparison is not faked; it is unfair in a way the reader cannot see. Someone compares a slow, high-effort preset of their preferred codec against a fast preset of the competitor, scores with whichever metric flatters it, quotes the easy-content number as if it were the average, picks a bitrate range where the curves barely overlap, and reports one figure with no encoder version and no confidence interval. Every choice is defensible alone; together they manufacture a conclusion. The defense is to pin the effort level, name the metric and model, report the spread across content, compute BD-rate over the real overlap, and refuse to call a winner inside the noise. A comparison that cannot answer those questions is an opinion wearing a number's clothes.

HEVC vs x264: a codec versus an encoder

"HEVC vs x264" compares a format with a program: x264 is the open-source encoder that produces H.264 video, and x265 is its counterpart for HEVC. So the real comparison is HEVC (usually made with x265) against H.264 (usually made with x264). At equal quality, HEVC needs roughly 30–50% less bitrate than H.264 — about 44% on our VMAF average, about 50% in the standard's subjective verification test, and 31.48% on Ozer's 2026 sports clip — so at the same file size an HEVC encode usually looks better. The price is about twice the encoding compute and narrower playback support.

In a file name, "x264" means the video was encoded to H.264 with x264, and "x265", "HEVC" or "H.265" means HEVC. Which one looks better depends on bitrate: when both files are large enough to look transparent, you will not see a difference; the HEVC advantage shows up at streaming and download sizes, where it buys the same picture for less data. Pick x264 when the file must play on old hardware or in editing software without HEVC support; pick x265 when the playback devices decode HEVC in hardware. The encoder-level comparison, with presets and encode times, is x264 vs x265 vs SVT-AV1, and the format itself is covered in H.264 explained.

H.264 vs AV1 for downloads and local playback

For a downloaded file, choose AV1 if your device decodes AV1 in hardware and you want the smallest file; choose H.264 if the file has to play everywhere. At equal quality an AV1 file is roughly half the size of an H.264 file (about 55% smaller on our average), so the same storage holds about twice as many hours. Hardware AV1 decoding exists on Apple A17 Pro, M3 and newer chips, on almost all large-screen TVs and streaming devices certified by Netflix since 2023, and on recent GPUs. Without it, playback falls back to software: the open-source dav1d decoder powers about 40% of Netflix's browser playback, but software decoding uses more battery, and older phones, TVs and editing tools may not play AV1 at all. H.264 has none of these gaps. To see the difference on a real clip before you decide, use our visual codec comparison tool.

So which codec should you ship?

The data points to a layered answer rather than a single winner, because the right codec depends on reach, scale, and content. H.264 remains the universal floor — it decodes on essentially every device, so it stays in the ladder as the compatibility rung. HEVC buys roughly 44% at equal quality and plays in hardware on most modern devices, though licensing has slowed it on the open web; in December 2025 Access Advance agreed to take over Via Licensing Alliance's HEVC and VVC program, which moves HEVC towards a single licensing administrator. AV1 buys the most — about 55% over H.264 and 20% over HEVC on our mix — is royalty-free, and decodes on most new large-screen devices and in every major browser; it costs the most to encode and pays back fastest on high-volume titles and bandwidth-constrained audiences. Netflix reached about 30% of its streaming on AV1 by December 2025. Most production services run several codecs at once and serve the best one each device can decode. The Alliance for Open Media released the AV2 specification in June 2026, and YouTube said in October 2026 that its AV2 streams will be available on the web as soon as early 2027 (TV Technology, 27 October 2026). No hardware decoders have been announced, so early AV2 playback will run in software, and for deployments planned in 2026–2027 it is a watch item, not a ladder rung. The codec-side device-support and adoption picture is the Video Encoding section's state of AV1 in 2026, and the rollout side — how a streaming service actually adds AV1 to its ladder — is our guide to AV1 in production streaming. If you are planning that ladder for your own service, our video streaming software development team builds multi-codec ABR ladders with H.264 fallback and per-device codec selection.

Frequently asked questions

Is AV1 better than H.264?

Yes on compression: at equal quality AV1 needs roughly half the bitrate of H.264 (about 55% less on our VMAF average, 59.83% less on Ozer's 2026 sports test). H.264 is still better on compatibility and encoding speed: it plays everywhere and costs about a quarter as much to encode (Ozer's 2026 planning rule).

What is the difference between AV1 and H.264?

H.264 (AVC, 2003) is a patent-pooled codec that plays on virtually every device. AV1 (2018) is a royalty-free codec from the Alliance for Open Media that needs about 55% less bitrate for the same VMAF on our benchmark, costs about four times as much to encode, and needs a recent device or browser for hardware playback.

Is HEVC better quality than H.264?

At the same bitrate, yes: HEVC needs about 44% less bitrate than H.264 for the same VMAF on our benchmark and about 50% less in the standard's subjective verification test. At very high bitrates both look transparent and the difference disappears.

AVC vs HEVC: what is the difference?

AVC is another name for H.264, and HEVC is another name for H.265. HEVC, standardised in 2013, needs about 44% less bitrate than AVC at equal VMAF on our benchmark (about 50% in the standard's subjective verification test), takes about twice the encoding compute, and plays in hardware on most current phones, TVs and GPUs, while AVC plays everywhere.

Which is better, AV1 or HEVC?

With 2026 encoders AV1 usually needs 20–40% less bitrate than HEVC at equal VMAF and is royalty-free, while HEVC has wider hardware decoding on older devices and encodes about twice as fast. Early 2019 studies with immature AV1 encoders found a near-tie or an AV1 loss on PSNR.

What bitrate does AV1 need?

There is no single number, because bitrate depends on content and the quality target. On our film clip AV1 reached VMAF 93 at about 2,064 kbps where H.264 needed about 4,800 kbps, so a reasonable start is roughly half your current H.264 bitrate, then tune per title.

Should I download H.264 or AV1?

Download AV1 if your device decodes it in hardware and you want smaller files; download H.264 if the file must play on any device or editor. AV1 is about half the size at the same quality.

Is x265 the same as HEVC?

No. HEVC (H.265) is the format; x265 is the most widely used open-source encoder that produces it, just as x264 produces H.264. x265 4.3 was released in July 2026.

Will AV2 replace AV1?

Eventually, perhaps. The Alliance for Open Media released the AV2 specification in June 2026, and YouTube plans AV2 web streams as soon as early 2027. With no hardware decoding yet, AV1 remains the practical royalty-free choice for 2026–2027 deployments.

Where Fora Soft fits in

Fora Soft has built video streaming, OTT, conferencing, e-learning, telemedicine, and surveillance software since 2005, and codec choice shapes the bandwidth bill and the picture quality of every one of them. We measure codecs the way this article describes — at equal quality, on the content categories our products actually handle, with named metrics and disclosed encoders — because a streaming budget defended with "AV1 saves 50%" falls apart the moment someone asks "on what, measured how." The benchmark behind this article is our own, published with its method and its dataset so it can be checked and cited. When a codec decision has to hold up to a CDN budget or a product owner, this is the evidence that makes it stick. Our video encoding and transcoding development work runs these equal-quality tests on your own catalogue, and our OTT and Internet TV platform team turns the result into a codec ladder for web, mobile and Smart TV playback.

The handbook

Fora Soft Video Engineering Handbook

We wrote a seven-volume handbook, 9,000+ pages, that works through the whole video stack from the pixel to production — compression, delivery, audio, and AI. Volume 1, Video Encoding, is where the machinery behind this comparison lives: what H.264, HEVC, and AV1 actually do differently, and how PSNR, SSIM, and VMAF score the result. Volume 3 turns a BD-rate into money — ABR ladders, CDN cost, and the delivery economics a 55% saving lands in — and volume 6 covers the model side of quality. Written by Nikolay Sapunov, CEO at Fora Soft.

Browse the handbook on Amazon →7 volumes · Kindle & paperback

See our case studies

References

1. J.-R. Ohm, G. J. Sullivan, H. Schwarz, T. K. Tan, T. Wiegand. "Comparison of the Coding Efficiency of Video Coding Standards—Including High Efficiency Video Coding (HEVC)." IEEE Transactions on Circuits and Systems for Video Technology, vol. 22, no. 12, pp. 1669–1684, December 2012. Tier 1 (standard's verification study). Subjective tests found HEVC reaches equivalent quality to H.264/AVC at about 50% less bitrate on average for WVGA/HD. Basis for the HEVC-vs-H.264 headline. https://ieeexplore.ieee.org/document/6317156
2. G. Bjøntegaard. "Calculation of Average PSNR Differences Between RD-Curves." ITU-T SG16 Q.6 VCEG, document VCEG-M33, Austin, TX, April 2001. Tier 1 (metric author's defining document). The BD-rate method and sign convention: average bitrate difference at equal quality. Basis for every BD-rate figure here. https://www.itu.int/wftp3/av-arch/video-site/0104_Aus/VCEG-M33.doc
3. G. Bjøntegaard. "Improvements of the BD-PSNR Model." ITU-T SG16 Q.6 VCEG, document VCEG-AL22, Berlin, July 2008. Tier 1 (metric author follow-up). Refines the method toward piecewise interpolation in the logarithmic bitrate domain. Basis for the log-domain integration in the tool. https://www.itu.int/wftp3/av-arch/video-site/0807_Ber/VCEG-AL22.doc
4. C. Herglotz, H. Och, A. Meyer, et al. "The Bjøntegaard Bible — Why Your Way of Comparing Video Codecs May Be Wrong." IEEE Transactions on Image Processing, 2023 (DOI 10.1109/TIP.2023.3346695); arXiv:2304.12852. Tier 5 (peer-reviewed). Cubic splines overshoot (use monotone PCHIP/Akima), VMAF/SSIM need a log transform, the quality ranges must overlap, and poor overlap can turn −43% into −49%. Basis for the BD-rate computation choices. https://arxiv.org/pdf/2304.12852
5. Netflix Technology Blog. "AV1 — Now Powering 30% of Netflix Streaming." December 2025. Tier 4 (credible deployer engineering). AV1 accounts for about 30% of Netflix streaming; AV1 sessions use about one-third less bandwidth than both AVC and HEVC sessions, score 4.3 VMAF points higher than AVC and 0.9 higher than HEVC, and have 45% fewer rebuffers; 88% of large-screen devices submitted for certification in 2021–2025 support AV1; dav1d powers about 40% of browser playback. Basis for the production cross-check. Accessed 2026-10-09. https://netflixtechblog.com/av1-now-powering-30-of-netflix-streaming-02f592242d80
6. J. Ozer. "Comparing H.264, HEVC, VP9, and AV1 in SBE: From BD-Rate to Contextual ROI." Streaming Learning Center, May 2026. Tier 6 (expert practitioner). 1080p60 clip at matched VMAF ~93: AV1 −59.83%, HEVC −31.48%, VP9 −35.08% BD-rate vs H.264; audience-weighted savings fall to 51% (top-heavy) and 23% (mobile); encoding-cost multipliers AV1 4×, HEVC 2×. Basis for the audience-weighting and encoding-cost caveats. https://streaminglearningcenter.com/articles/comparing-h-264-hevc-vp9-and-av1-in-sbe-from-bd-rate-to-contextual-roi.html
7. Netflix. "VMAF Models" (models.md) and "VMAF — Confidence Interval" (conf_interval.md), VMAF Development Kit documentation. Accessed 2026-06-25. Tier 1 (metric author documentation). The default v0.6.1 model targets a 1080p living-room TV; each prediction can carry a 95% bootstrap confidence interval. Basis for the model and pooling specification. https://github.com/Netflix/vmaf/tree/master/model
8. A. Katsenou, F. Zhang, M. Afonso, D. Bull. "A Subjective Comparison of AV1 and HEVC for Adaptive Video Streaming." IEEE International Conference on Image Processing (ICIP), Taipei, September 2019. DOI 10.1109/ICIP.2019.8803523. Tier 5 (peer-reviewed). AV1 shows an average BD-rate gain of 6.3% on rate-VMAF curves and a 1.8% loss on rate-PSNR; the perceived-quality difference is not significant for most rate points. Basis for the metric-dependence row of Table 2. Accessed 2026-10-09. https://research-information.bris.ac.uk/en/publications/a-subjective-comparison-of-av1-and-hevc-for-adaptive-video-stream/
9. M. Uhrina, L. Sevcik, J. Bienik, L. Smatanova. "Performance Comparison of VVC, AV1, HEVC, and AVC for High Resolutions." Electronics 13(5):953, MDPI, 2024. Tier 5 (peer-reviewed). At 8K, PSNR-based average bitrate savings versus H.264 of about 63% (AV1) and 53% (HEVC). Basis for the 8K row of Table 2. Accessed 2026-10-09. https://mdpi-res.com/d_attachment/electronics/electronics-13-00953/article_deploy/electronics-13-00953.pdf
10. Alliance for Open Media / SVT-AV1 project. "SVT-AV1 CHANGELOG." Tier 3 (first-party tooling). SVT-AV1 4.0.0 released 2026-01-23 (the build used in our benchmark); 4.2.0 released 2026-07-14 with a VMAF tune targeting about 15% VMAF BD-rate improvement; 4.3.0 released 2026-11-01 with about 5–8% cycle-efficiency improvement at similar quality and about 10–11% lower multi-threaded run time (release notes: https://github.com/AOMediaCodec/SVT-AV1/releases/tag/v4.3.0). Basis for the encoder versions. Accessed 2026-11-08. https://gitlab.com/AOMediaCodec/SVT-AV1/-/blob/master/CHANGELOG.md
11. Recommendation ITU-R BT.500-15 (2023). "Methodologies for the subjective assessment of the quality of television pictures." ITU, 2023. Tier 1 (official standard). The subjective ground truth every objective metric is validated against; when metric and viewing disagree, the viewing wins. Basis for the measurement-honest framing. https://www.itu.int/rec/R-REC-BT.500
12. I. Bender, D. Palomino, L. Agostini, G. Correa, M. Porto. "Compression Efficiency and Computational Cost Comparison between AV1 and HEVC Encoders." EUSIPCO 2019. Tier 5 (peer-reviewed). The libaom AV1 reference encoder needed about 16.35% more bitrate than the HEVC HM reference on PSNR and took 14.64 times as long to encode. Basis for the oldest row of Table 2 and the encode-cost note. Accessed 2026-10-09. https://www.eurasip.org/Proceedings/Eusipco/eusipco2019/Proceedings/papers/1570532277.pdf
13. x265 project. "[ANN] New Release v4.2." x265-devel mailing list, 19 April 2026. Tier 3 (first-party tooling). Experimental threaded motion estimation (up to 1.5× faster at 1080p and below), ARM and RISC-V SIMD, levels up to 7.2. Basis for the x265 version. Accessed 2026-10-09. https://mailman.videolan.org/pipermail/x265-devel/2026-April/014533.html
14. x265 project. "Release Notes: Version 4.3." 31 July 2026. Tier 3 (first-party tooling). LoongArch64 support, foveated encoding that varies quality around a gaze point, and selective noise-based MCSTF filtering. Basis for the current x265 version. Accessed 2026-11-08. https://raw.githubusercontent.com/Multicorewareinc/x265/refs/heads/master/doc/reST/releasenotes.rst
15. Alliance for Open Media. "Alliance for Open Media Releases AV2 Codec." June 2026. Tier 3 (standards body). AV2 specification public; reference software libavm; ISO BMFF binding planned; no hardware products named. Basis for the AV2 status. Accessed 2026-10-09. https://aomedia.org/press%20releases/Alliance-for-Open-Media-Releases-AV2-Codec/
16. TV Technology. "YouTube to Commence AV2 Streaming in 2027." 27 October 2026. Tier 4 (trade press quoting the deployer). YouTube Engineering Director Des Keane: AV2 streams will be available for web as soon as early 2027; AOMedia puts AV2 at around 30% better compression than AV1. Basis for the AV2 rollout timing. Accessed 2026-11-08. https://www.tvtechnology.com/platform/streaming/youtube-to-commence-av2-streaming-in-2027
17. Access Advance and Via Licensing Alliance. "Access Advance and Via Licensing Alliance Announce HEVC/VVC Program Acquisition." 15 December 2025. Tier 3 (licensor announcement). Brings HEVC and VVC licensing under one administrator. Basis for the licensing note. Accessed 2026-10-09. https://accessadvance.com/2025/12/15/access-advance-and-via-licensing-alliance-announce-hevc-vvc-program-acquisition/
18. Bitmovin. "AV1 Playback Support." Updated 2026. Tier 4 (vendor documentation). Hardware AV1 decoding on Apple A17 Pro, M3 and M4; Safari 17+ with a hardware decoder; Chrome, Edge and Firefox support; dav1d on Android 12+. Basis for the device and browser rows. Accessed 2026-10-09. https://bitmovin.com/blog/av1-playback-support/
19. Can I use. "AV1 video format" and "HEVC/H.265 video format" browser support tables. Tier 4 (compatibility database). Current browser support for AV1 and HEVC playback, including hardware-decoder conditions. Basis for the browser row. Accessed 2026-10-09. https://caniuse.com/hevc
20. Mozilla Support. "Audio and video files in Firefox." Tier 3 (vendor documentation). HEVC playback on Windows requires a hardware decoder (added in Firefox 134, January 2025). Basis for the HEVC browser row. Accessed 2026-10-09. https://support.mozilla.org/en-US/kb/html5-audio-and-video-firefox