Tesla made a lot of improvements in the 2024 Holiday Update, including more than 15 undocumented improvements that were included in the release. One of these was a stealthy performance improvement to the YouTube app.
Several people have mentioned they’ve seen improved performance on YouTube since this year’s Holiday Update - and there’s an interesting reason why.
YouTube Improvements
The improved YouTube performance in Tesla vehicles comes from an unexpected source—Tesla actually rolled back support for YouTube’s newer AV1 video encoding. Instead, vehicles now default to the older VP9 encoding standard.
While AV1 is highly efficient in terms of bandwidth, it requires considerably more processing power to decode and display videos. VP9, on the other hand, is less computationally demanding but uses more bandwidth to achieve the same video quality. This trade-off means smoother playback and better overall performance, even if it comes at the cost of slightly higher data usage.
Intel Inside
The VP9 video codec that the YouTube app is now using is much easier to decode, making it less taxing on the vehicle’s processor. This change is particularly beneficial for Tesla vehicles with Intel processors, which previously struggled to stream video at just 720p. When using AV1, these vehicles often experienced stuttering, sometimes forcing the YouTube app to automatically downgrade playback to 480p.
With this update, Intel-based Teslas should now be able to stream at 1080p smoothly. Streaming at 1440p is also possible, although occasional stutters still occur as the system keeps up with the decoding process.
Intel-based vehicles are the big winners with this change, but this appears to affect AMD Ryzen-based infotainment units as well, providing even smoother playback.
Chromium Web App
Tesla’s Theater apps aren’t native applications; instead, they run as chromeless web apps, leveraging the open-source browser built into Teslas known as Chromium (the open-source version of Chrome). Although this works quite well, there is a severe limitation - Chromium hardware acceleration isn’t supported on Linux, the operating system Tesla uses for their OS.
As a result, Tesla vehicles rely on software decoding instead of hardware decoding, which would otherwise handle video playback far more efficiently. A potential solution could be for Tesla to transition away from Chromium-based web apps in favor of a Mozilla Firefox-based browser, as Firefox does support hardware acceleration on Linux. This switch could also open the door to better streaming performance and the possibility of expanding Tesla’s in-car entertainment options.
However, Tesla’s choice of Chromium likely stems from Digital Rights Management (DRM) requirements for streaming services like Disney+ and Netflix, which rely on DRM-enabled playback. Firefox on Linux has had inconsistent support for DRM due to codec availability and variations in operating system versions.
We’re hopeful that Tesla will either adopt Firefox or develop a fully native application to improve video streaming, rather than continuing with the current web-based Tesla Theater. This shift could also pave the way for additional in-car applications built on Tesla’s native Linux environment—perhaps even reviving the long-rumored Tesla App Store.
Regardless, this update is a welcome improvement, particularly for YouTube, which remains one of the most widely used Theater Mode apps due to its accessibility, free content, and mix of short and long-form videos. It remains to be seen whether similar improvements are made for Netflix, Disney+, or other streaming platforms.
If you’ve noticed improved performance in Theater Mode, now you know why.
Thanks to Brian Zheng for making us aware of these changes.
Tesla’s Cybertruck has officially earned a 5-Star Safety Rating from the NHTSA—an impressive achievement given the vehicle’s design. The achievement demonstrates Tesla’s engineering prowess. As one engineer points out, it wasn’t an easy feat.
Interestingly, the NHTSA only recently disclosed the results, despite the crash tests being completed a while ago. According to Lars Moravy, Tesla’s VP of Vehicle Engineering, the team had been aware of the 5-star rating for quite some time. While the reason for the delay remains unclear, now that the results are public, Tesla’s engineers can finally share how they achieved the rating.
Crumple Zones
Wes Morril, the Cybertruck’s Lead Engineer, wrote about the crash test video on X recently, addressing the claims that the Cybertruck doesn’t have a crumple zone. He also posted a side-by-side video (below) of the engineering analysis and the crash test itself.
Engineered Crash Safety
There’s a lot of engineering precision at play when a Cybertruck is involved in a crash. Unlike traditional crash structures that rely on crash cans and collapse points, the Cybertruck’s front gigacasting is designed to absorb and redirect impact forces in a highly controlled manner.
It all starts with the bumper beam, which crushes within the first few milliseconds of a high-speed impact. At the same time, the vehicle’s sensors rapidly analyze the crash dynamics and determine the optimal deployment of safety restraints, including airbags and seat belt pre-tensioners. These split-second actions are crucial in keeping occupants safe.
As the crash progresses, the vehicle’s structure deforms in a carefully engineered sequence. The drive unit cradle bends, directing the solid drive unit downward and out of the way, allowing the gigacasting to begin absorbing impact forces.
The casting crushes cell by cell, methodically dissipating energy in a controlled manner. This gradual deceleration reduces the g-forces transferred to occupants, making the crash much less severe. As the gigacast begins crushing, the safety restraints are deployed.
As Wes points out in his post - you can see how accurate the virtual analysis and modeling were. The video shows the simulated crash side by side with the real-life crash test and they’re almost identical. All that virtual testing helps provide feedback into the loop to design a better and safer system - one that is uniquely different than any other vehicle on the road.
All the armchair experts claimed the Cybertruck has no crumple zone and I get it, the proportions seem impossible. It was a tough one and there is a lot of engineering that went into it. Let me break it down for you:
Tesla has pioneered the use of single-piece castings for the front and rear sections of their vehicles, thanks to its innovative Gigapress process. Many automakers are now following suit, as this approach allows the crash structure to be integrated directly into the casting.
This makes the castings not only safer but also easier to manufacture in a single step, reducing costs and improving repairability. For example, replacing the entire rear frame of a Cybertruck is estimated to cost under $10,000 USD, with most of the expense coming from labor, according to estimates shared on X after high-speed rear collisions.
These insights come from Sandy Munro’s interview (posted below) with Lars Moravy, Tesla’s VP of Vehicle Engineering, highlighting how these advancements contribute to the improvements in Tesla’s latest vehicles, including the New Model Y.
However, with the new Model Y, Tesla has decided to go a different route and eliminated the front gigacast.
No Front Casting
Tesla’s factories aren’t equipped to produce both front and rear castings for the Model Y. Only Giga Texas and Giga Berlin used structural battery packs, but these were quickly phased out due to the underwhelming performance of the first-generation 4680 battery.
Tesla has gone back to building a common body across the globe, increasing part interchangeability and reducing supply chain complexity across the four factories that produce the Model Y. They’ve instead improved and reduced the number of unique parts up front to help simplify assembly and repair.
There is still potential for Tesla to switch back to using a front and rear casting - especially with their innovative unboxed assembly method. However, that will also require Tesla to begin using a structural battery pack again, which could potentially happen in the future with new battery technology.
Rear Casting Improvements
The rear casting has been completely redesigned, shedding 7 kg (15.4 lbs) and cutting machining time in half. Originally weighing around 67 kg (147 lbs), the new casting is now approximately 60 kg (132 lbs).
This 15% weight reduction improves both vehicle dynamics and range while also increasing the rear structure’s stiffness, reducing body flex during maneuvers.
Tesla leveraged its in-house fluid dynamics software to optimize the design, resulting in castings that resemble organic structures in some areas and flowing river patterns in others. Additionally, manufacturing efficiency has dramatically improved—the casting process, which originally took 180 seconds per part, has been reduced to just 75 seconds, a nearly 60% time reduction per unit.
Advancements in die-casting machines and cooling systems have allowed @Tesla to dramatically reduce cycle times and improve dimensional stability. pic.twitter.com/WB5ji67rvV
Tesla’s new casting method incorporates conformal cooling, which cools the die directly within the gigapress. Tesla has been refining the die-casting machines and collaborating with manufacturers to improve the gigapress process.
In 2023, Tesla patented a thermal control unit for the casting process. This system uses real-time temperature analysis and precise mixing of metal streams to optimize casting quality. SETI Park, which covers Tesla’s manufacturing patents on X, offers a great series for those interested in learning more.
The new system allows Tesla to control the flow of cooling liquid, precisely directing water to different parts of the die, cooling them at varying rates. This enables faster material flow and quicker cooling, improving both dimensional stability and the speed of removing the part from the press for the next stage.
With these new process improvements, Tesla now rolls out a new Model Y at Giga Berlin, Giga Texas, and Fremont every 43 seconds—an astounding achievement in auto manufacturing. Meanwhile, Giga Shanghai operates two Model Y lines, delivering a completed vehicle every 35 seconds.