Posts tagged with mobile
Why it matters: WhatsApp's migration demonstrates that Rust is production-ready for massive-scale, cross-platform applications. It proves memory-safe languages can replace legacy C++ to eliminate vulnerabilities while improving performance and maintainability.
- •WhatsApp replaced its wamedia C++ library with a Rust implementation to mitigate memory-related vulnerabilities in media file processing.
- •The migration reduced the codebase from 160,000 lines of C++ to 90,000 lines of Rust while improving performance and memory efficiency.
- •The Kaleidoscope system performs structural checks on media, detects masquerading file types, and flags high-risk elements like embedded scripts.
- •WhatsApp utilized differential fuzzing and extensive integration testing to ensure compatibility between the legacy C++ and new Rust versions.
- •This deployment represents one of the largest global rollouts of Rust, spanning billions of devices across Android, iOS, Web, and wearables.
Why it matters: This article offers insights into the complex engineering and design challenges of developing advanced wearable AI glasses, providing valuable lessons for hardware and software engineers working on next-gen devices and user interfaces.
- •The Meta Tech Podcast delves into the engineering challenges behind the Meta Ray-Ban Display, Meta's advanced AI glasses.
- •Engineers Kenan and Emanuel discuss unique design hurdles, from display technology to emerging UI patterns for wearable glasses.
- •The episode explores the intersection of particle physics and hardware design in developing cutting-edge wearable tech.
- •It highlights the importance of celebrating incremental wins within a fast-moving development culture for innovative products.
Why it matters: This article demonstrates how Meta leverages secure-by-default mobile frameworks and AI to proactively embed security into development workflows. It's crucial for engineers to understand how to balance security with developer velocity and how AI can scale these efforts.
- •Meta implements secure-by-default mobile frameworks to wrap potentially unsafe OS and third-party functions, ensuring security while maintaining developer speed.
- •These frameworks are designed to closely mimic existing APIs, utilize public interfaces, and reduce complexity to maximize developer adoption.
- •Generative AI and automation significantly accelerate the large-scale adoption of these secure frameworks, enabling consistent security enforcement and efficient code migration.
- •Key design principles include API resemblance to reduce cognitive burden, reliance on stable public APIs, and broad applicability across applications.
- •SecureLinkLauncher (SLL) for Android is an example, preventing intent hijacking by wrapping native intent launching methods with robust security checks.
Why it matters: This article highlights how open video codecs like AV1 drive significant improvements in streaming quality and network efficiency. It showcases a successful large-scale rollout across diverse devices, offering valuable insights into optimizing content delivery and user experience.
- •Netflix's AV1 codec adoption has reached 30% of all streaming, becoming their second most-used codec due to its superior efficiency.
- •AV1 delivers higher video quality (4.3 VMAF points over AVC) with one-third less bandwidth and 45% fewer buffering interruptions.
- •The rollout began with Android mobile in 2020 using the dav1d software decoder, expanding to smart TVs, web browsers, and Apple devices with hardware support.
- •This advanced codec significantly improves network efficiency for Netflix's Open Connect CDN and partner ISPs by reducing overall internet bandwidth consumption.
- •AV1 enables advanced features like HDR10+ streaming and cinematic film grain, enhancing the overall viewing experience for members.
Why it matters: Ensuring mobile accessibility is critical for legal compliance and inclusive user experiences. This post provides practical implementation details for common Android a11y hurdles, like custom actions and semantic announcements, helping engineers build more robust, accessible apps.
- •Slack conducted a VPAT audit in 2024 to identify and fix accessibility (a11y) gaps in their Android app following a major UI redesign.
- •Improved error communication by updating OutlinedTextField and SKBanner to trigger TalkBack announcements when validation fails.
- •Enhanced navigation by explicitly marking headings using semantics { heading() } in Jetpack Compose and accessibilityHeading in XML.
- •Resolved list count inaccuracies for screen readers by implementing CollectionInfo and CollectionItemInfo semantics.
- •Implemented CustomAccessibilityAction to make drag-and-drop functionality in the workspace switcher accessible to non-visual users.
- •Utilized TtsSpan to ensure screen readers announce text formatting like strikethrough, which is otherwise ignored by default.
Why it matters: This article details the intricate process of preserving HDR video metadata (Dolby Vision, AMVE) across a large-scale video pipeline. It's crucial for engineers working on media processing, mobile development, and ensuring high-quality user experiences on global platforms.
- •Instagram for iOS now supports Dolby Vision and Ambient Viewing Environment (AMVE) metadata for enhanced HDR video playback.
- •This involved preserving unique Dolby Vision and AMVE metadata from iPhone-produced HDR videos throughout Meta's video processing pipeline.
- •Previously, FFmpeg-based transcoding systems discarded this metadata, impacting picture consistency, especially at low screen brightness.
- •Meta collaborated with the community to add AMVE support to FFmpeg and adopted Dolby Vision Profile 10 for AV1 delivery.
- •This enhancement makes Instagram the first Meta app to support Dolby Vision video, with future expansion across other Meta platforms.
- •The solution addresses challenges like carrying Dolby Vision metadata in non-HEVC codecs and managing different Dolby Vision profiles.
Why it matters: This article demonstrates how investing in in-house test infrastructure and smart sharding can drastically improve CI/CD efficiency and developer velocity by reducing build times and flakiness. It highlights the benefits of taking control over critical testing environments.
- •Pinterest significantly reduced Android E2E CI build times by 36% by transitioning from Firebase Test Lab to an in-house testing platform, PinTestLab.
- •The core innovation is a runtime-aware sharding mechanism that uses historical test duration and stability data to balance test loads across parallel shards.
- •This in-house solution, running on EC2 bare-metal instances with optimized resource allocation, provided direct control over the testing stack and eliminated third-party flakiness.
- •The new sharding approach decreased the slowest shard's runtime by 55% and drastically reduced the variance between fastest and slowest shards.
- •Building PinTestLab was driven by FTL's high setup overhead, infrastructure instability, and the lack of suitable third-party alternatives for large-scale native emulator support.
Why it matters: This innovation significantly streamlines frontend and mobile development by automating the creation of realistic, type-safe mock data. It frees engineers from tedious manual work, accelerates feature delivery, and improves the reliability of tests and demos.
- •Airbnb introduces @generateMock, a new GraphQL client directive, to automate the creation and maintenance of realistic, type-safe mock data.
- •The solution combines GraphQL schema validation, rich product context, and Large Language Models (LLMs) to generate convincing mock data.
- •Engineers can use @generateMock on any GraphQL operation, fragment, or field, providing optional hints and design URLs to guide the LLM's data generation.
- •Integrated with Airbnb's Niobe CLI tool, it generates JSON mock files and helper functions (TypeScript/Kotlin/Swift) for seamless consumption in tests and demo apps.
- •This approach eliminates the tedious manual process of writing and updating mocks, enabling faster parallel client/server development and ensuring data consistency.
Why it matters: This article details how Cloudflare built a high-performance VPN using Linux networking, offering practical insights into NAT, Netfilter, and conntrack for engineers developing secure, scalable network solutions.
- •Cloudflare's WARP app required building a high-performance, mobile-first VPN solution for secure packet egress from edge machines.
- •The initial WARP implementation functioned as a Layer 3 VPN, encapsulating private IP packets within public ones for secure tunneling.
- •Linux's Netfilter subsystem, configured via nftables, was used to implement Network Address Translation (NAT) for routing VPN client traffic.
- •A key aspect involved setting up source NAT rules to rewrite client IP addresses to the server's public IP for outgoing packets.
- •The conntrack module in Linux Netfilter is crucial for stateful NAT, managing TCP/UDP connections and port reuse efficiently.
Why it matters: This article provides crucial insights into SwiftUI's underlying performance characteristics, especially its view diffing mechanism. Understanding these nuances and implementing strategies like custom Equatable conformance is vital for building high-performance and scalable mobile applications.
- •Airbnb adopted SwiftUI for increased developer productivity but encountered significant performance challenges, particularly with unnecessary view re-evaluations.
- •SwiftUI's default reflection-based diffing algorithm often fails to efficiently compare properties like closures or certain reference types, leading to excessive view body re-evaluations.
- •Integrating SwiftUI with existing unidirectional data flow libraries that use closure-based action handlers exacerbated performance issues, as closures are not reliably diffable by SwiftUI.
- •Explicitly conforming SwiftUI views to the Equatable protocol allows developers to precisely control which property changes trigger a view update, bypassing the default, often inefficient, diffing.
- •While effective, manual Equatable conformance introduces boilerplate code and is prone to errors and maintenance challenges in large-scale applications.