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The conference for video devs

Pack your bags, renew your passports; for the first time, Demuxed is coming to London!

October 29th & 30th
BFI Southbank, London, UK

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Venue & location

BFI Southbank - London
Belvedere Rd, London SE1 SXT

We're hosting Demuxed 2025 at BFI Southbank, which is basically the perfect venue for a bunch of video nerds to gather and argue about codecs. Located right on the Thames with those iconic brutalist concrete vibes, it's been the home of serious film culture since the 1950s.

The BFI has been preserving and celebrating moving images for decades, so there's something beautifully fitting about bringing the Demuxed community to a place that's spent so much time thinking about how to keep video alive for future generations. Plus, the location puts you right in the heart of London's South Bank, with proper pubs and decent coffee within walking distance.

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Speakers

Chaitanya Bandikatla

Chaitanya Bandikatla

TikTok

Talk Overview

Christian Pillsbury

Christian Pillsbury

Mux

Talk Overview

David Payr

David Payr

Mediabunny

Talk Overview

David Springall

David Springall

Yospace

Talk Overview

Farzad Tashtarian

Farzad Tashtarian

University of Klagenfurt

Talk Overview

Hadi Amirpour

Hadi Amirpour

University of Klagenfurt

Talk Overview

Henry McIntyre

Henry McIntyre

Vimeo

Talk Overview

Joanna White

Joanna White

British Film Institute National Archive

Talk Overview

Joey Parrish

Joey Parrish

Talk Overview

Jonathan Lott

Jonathan Lott

AudioShake

Talk Overview

Jordi Cenzano

Jordi Cenzano

Meta

Talk Overview

Julien Zouein

Julien Zouein

Trinity College Dublin

Talk Overview

Karl Shaffer

Karl Shaffer

Google

Talk Overview

Luke Curley

Luke Curley

hang.live

Talk Overview

Matt McClure

Matt McClure

Demuxed

Talk Overview

Mattias Buelens

Mattias Buelens

Dolby Laboratories

Talk Overview

Nicolas Levy

Nicolas Levy

Qualabs

Talk Overview

Nigel Megitt

Nigel Megitt

BBC

Talk Overview

Oli Lisher

Oli Lisher

Talk Overview

Olivier Cortambert

Olivier Cortambert

Yospace

Talk Overview

Pedro Tavanez

Pedro Tavanez

Touchstream

Talk Overview

Prachi Sharma

Prachi Sharma

JioHotstar

Talk Overview

Rafal Leszko

Rafal Leszko

Livepeer

Talk Overview

Ryan Bickhart

Ryan Bickhart

Amazon IVS

Talk Overview

Sam Bhattacharyya

Sam Bhattacharyya

Katana

Talk Overview

Steve Heffernan

Steve Heffernan

Mux

Talk Overview

Ted Meyer

Ted Meyer

Google

Talk Overview

Thasso Griebel

Thasso Griebel

Castlabs

Talk Overview

Thomas Davies

Thomas Davies

Visionular

Talk Overview

Tomas Kvasnicka

Tomas Kvasnicka

CDN77

Talk Overview

Vittorio Giovara

Vittorio Giovara

Vimeo

Talk Overview

Zac Shenker

Zac Shenker

Fastly

Talk Overview

Zoe Liu

Zoe Liu

Visionular

Talk Overview

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The Schedule

09:30 GMT

Matt McClure

Matt McClure

Demuxed

Opening Remarks

09:45 GMT

Jordi Cenzano

Jordi Cenzano

Meta

The media processing pipelines behind AI

In this talk we will be talking about the complex media processing pipelines behind media AI models (translations, lipsyncing, text to video, etc). AI Models are very picky on media specs (resolutions, frame rates, sample rates, colorspace, etc), also most of the times the AI tools that you see that, for instance, generates a fantastic and sharp video from a text prompt are really based on several AI models working in conjunction, each of them with their own constraints. Our team is responsible for ingesting 1 BILLION media assets DAYLY, and delivering 1TRILLION views every 24h, for that we use (highly optimized) typical media processing pipelines. In this talk we will explain how we leveraged all of that experience, and building blocks, and we added media AI inference as another offering of those pipelines, now you can upload an asset and deliver it with ABR encodings + CDN, and ALSO alter the content of that via AI (ex: add a hat to all the dogs in the scene). And all of that trying to NOT break the bank (GPU time is really expensive) We think this talk could be useful to reveal the hidden complexities of delivering AI, specially at scale

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Sam Bhattacharyya

Sam Bhattacharyya

Katana

Why I ditched cloud transcoding and set up a mac mini render farm

There are a number of use cases where you need to tightly integrate video processing with some form of AI processing on the video, like AI Upscaling, real-time lip syncing or gaze-correction, or virtual backgrounds. The killer bottleneck for these tasks is almost always CPU <> GPU communication, making them impractical or expensive for real time applications. The normal approach is setting up a fully GPU pipeline, using GPU video decoder, building your AI processing directly with CUDA (and potentially using custom CUDA kernals) instead of abtracted libraries like Pytorch - it's doable, we did this at Streamyard, but it's very hard to do and high maintenance. I stumbled upon a ridiculous sounding, but actually plausible alternative - writing neural networks in WebGPU, and then using WebCodecs to decode/encode frames, and use WebGPU to directly access and manipulate frame data. When a pipeline like this is run on an Apple M4 chip, it can run AI video processing loads 4-5x faster than an equivalent pipeline on a GPU-enabled instance on a cloud provider, and it's also ~5x cheaper to rent an M4 than an entry-level GPU. I've done a number of tests, and my conclusion is that this is efficient is because the M4 chip (1) has optimizations for encoding in it's hardware, (2) has GPU <> CPU communication much more tightly integrated than a typical GPU + cloud vm setup. All of these technologies are relatively new - the M4 chip, WebGPU, WebCodecs, but those three things together I think present viable alternative AI video processing pipeline compared to traditional processing. Using browser based encoding makes it also much easier to integrate 'simpler' manipulations, like adding 'banners' in live streams, and it's also much easier to integrate with WebRTC workflows. I have a tendency to write my own WebGPU neural networks, but TensorflowJS has improved in the last few years to accommodate importing video-frames from GPU. There are certainly downsides, like working with specialty Mac cloud providers, but it might actually be practical and easier to maintain (at least on the software side).

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10:30 GMT

Break

11:00 GMT

Prachi Sharma

Prachi Sharma

JioHotstar

When Millions Tune In: Server-Guided Ad Insertion for Live Sports Streaming

Delivering targeted ads in live sports streaming is not just an adtech challenge - it’s a streaming engineering problem. At JioHotstar, we serve billions of views across live events, handling concurrency spikes that rank among the largest globally. This talk will explore how we built and scaled our custom Server-Guided Ad Insertion (SGAI) system for live sports, where ad breaks are unpredictable in both timing and duration. We’ll discuss why we moved beyond traditional SSAI, and how we engineered: * Manifest manipulation and segment stitching on the fly * Millisecond-level ad decisioning to insert ads without disrupting playback * Strategies for handling massive concurrency surges during peak moments of live matches. We’ll also share real-world lessons from operating at this scale - where streaming architecture and monetisation must work hand-in-hand. Whether you’re building for ads, scale, or live video, this session will provide practical insights into designing systems that balance playback quality with revenue performance.

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Zac Shenker

Zac Shenker

Fastly

Security Theater: Moving Beyond Performative Content Protection

We contractually implement DRM and forensic watermarking, but how effective are these solutions against modern piracy? This talk dissects common vulnerabilities, from Widevine L3 key extraction to the limitations of A/B segment watermarking against determined adversaries. We'll move beyond checkbox security and detail practical, alternative protection strategies. Topics include implementing short-lived, signed Common Access Tokens(CAT) for token authentication, building rapid revocation systems, and leveraging CDN access logs with player analytics to build real-time anomaly detection for credential sharing and illegal redistribution.

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Zoe Liu

Zoe Liu

Visionular

Thomas Davies

Thomas Davies

Visionular

AI-Driven Real-Time Ball Tracking for Live Sports Streaming

When viewing sports events, audiences typically focus on specific Regions of Interest (ROIs), such as player faces, jersey numbers, or dynamic objects like the ball. Detecting and tracking these ROIs can enhance the user’s Quality of Experience (QoE). These ROIs frequently shift and change dynamically within a scene, making accurate realtime processing challenging. In Live Streaming manual intervention to track this motion may be impractical, and too expensive for many low-cost operations which frequently make use of locked off cameras. Some automatic solutions exist but rely on multi-camera operation. Addressing these limitations, we present an innovative AI-driven real-time ball detection and tracking solution specifically optimized for live-streamed sports events. In this talk we will describe the architecture and the core technology components. Our system employs advanced convolutional neural networks (CNNs), leveraging the efficiency and accuracy of combined YOLO-SORT models for detection and tracking. We integrate these components into an optimised GPU cloud-based architecture, enabling seamless real-time cropping and digital zoom without disruptive visual artifacts like abrupt camera movements. This intelligent content-aware solution significantly improves the QoE by automatically identifying and continuously tracking the ball, adapting smoothly to its movement in real time. Extensive real-world testing demonstrates our system's effectiveness across various sports scenarios, consistently achieving frame rates above 30 fps at 1920x1080 resolution on GPU-equipped cloud instances. Our approach not only reduces operational costs but also enhances viewer satisfaction by delivering a visually comfortable and engaging viewing experience. Future extensions of this work include real-time event detection, enabling further personalized and engaging sports viewing experiences.

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Nigel Megitt

Nigel Megitt

BBC

Which @*!#ing Timed Text format should I use?

The world of Timed Text is esoteric, detailed, full of annoying abbreviations, and full of wildly differing opinions. I'll be giving mine! But also, describing the current state of the most common formats, and some practical and usable advice about which format to adopt for which purpose, and where things are heading in the standards world. If time allows, I will attempt to bring some humour to the topic, as well as a select few nuggets of technical complexity to keep the audience away from their IDE for at least a few minutes.

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12:30 GMT

Lunch

Sponsored by

13:30 GMT

Christian Pillsbury

Christian Pillsbury

Mux

The Great Divorce: How Modern Streaming Broke Its Marriage with HTTP

For over a decade, HTTP Adaptive Streaming was the poster child for how standards should work together. HLS, DASH, and their predecessors succeeded precisely because they embraced HTTP's caching, took advantage of CDNs, and worked within browser security models. But here's the inconvenient truth: many of our newest streaming "innovations" are systematically breaking this symbiotic relationship. Multi-CDN content steering requires parameterizing URLs (for both media requests and content steering polling) and client/server contracts that inherently and literally remove browser cache from the equation. CMCD v2 abandons JSON sidecar payloads for either query parameters that cache-bust every request or custom headers that trigger double the network requests due to CORS preflight checks. Signed URLs with rotating tokens make browser caching impossible. We've become so focused on solving today's edge cases that we're undermining the fundamental advantages that made HTTP streaming successful in the first place. In this session, you'll discover how seemingly innocent streaming standards are creating a hidden performance tax of 2x network requests, cache invalidation, and resource waste. You'll learn why CORS preflight requests and RFC 9111 cache key requirements are putting streaming engineers in impossible positions, forcing them to choose between security and performance. Most importantly, you'll walk away with practical strategies using service workers and cache API to work around these issues client-side, plus concrete recommendations for how we can evolve both streaming and web standards to work together instead of against each other. Because the future of streaming isn't about bypassing the web—it's about making the web work better for streaming.

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Ted Meyer

Ted Meyer

Google

A default HLS player for Chrome (and why I hate the robustness principle)

I'm a chromium engineer who's responsible for launching HLS playback natively in the chromium project (and thus the Google Chrome browser). The talk I plan to give starts by including a brief overview of the history of HLS in browsers, including how we got to the point of launching it in Chrome. Next up is an explanation of how this new player works, and what advantages we can make use of by building it into the browser vs shipping packaged javascript. I haven't yet decided how technical I will get when talking about the chromium pipeline/demuxer/decoder architecture or how MSE works "under the hood". The current version of the talk is intended for the chrome media team, so it covers that stuff, but I haven't yet decided if that's the right fit for the general Demuxed conference. I also plan on adding a section addressing the HLS library folks that isn't in the media-team version of the talk. I want to make it clear that we're not looking to replace those projects, and they will still have a lot of value to offer to site-owners from the perspective of control, telemetry, and spec-extensions. Finally, the talk covers some of the issues I faced when launching the new player, including some stupid bugs I caused including breaking a lot of the Korean web-radio market for an afternoon. I'll have to see exactly what metrics I'm allowed to include in this part of the talk, but I'll give a brief overview of some of the major issues I've cause/found/fixed along the way. Finally, I'll finish up talking about how the "robustness principle" of "Be conservative in what you send, be liberal in what you accept" caused a lot of delay launching the player, and a plea to the community to both produce more spec compliant manifests and for the players to be a bit less liberal in accepting wonky playlists. I think it would be a good talk for Demuxed because (at least from what I saw last year when I first attended), there aren't as many talks from the browser side of things, so it could help add to the breadth of subjects covered.

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David Springall

David Springall

Yospace

Olivier Cortambert

Olivier Cortambert

Yospace

Another talk about ads, but this time what if we talked about the actual ads??

In 2019, the ​​Interactive Advertising Bureau (IAB) released the Secure Interactive Media Interface Definition (SIMID). This format allows Publishers/Advertisers to have a player display an Ad on top or alongside their stream. Two years later, Apple engineers released HLS Interstitial and that’s how Server Guided Ad Insertion (SGAI) was born. Fast forward to 2025, DASH is getting support for SGAI and SGAI is trending. And one of the reasons it is trending is that it allows players to “easily” display new ad formats - in the form of an ad on top of or alongside the stream. Now, we are seeing demos with streams having fancy ads that fade in/out, play alongside content in the corner or take an L-shape part of the screen. But no one is telling you how you sell this space, how you signal a side-by-side ad, what type of media formats the ads need to be etc… Actually, it’s not that no-one talks about it, it’s that no-one in the streaming industry talks about it, but the ad folks (ie. the IAB) are actually working on it. And, *spoiler alert*, they talk about SIMID not SGAI. What if we (the streaming tech world) actually talked to our customers (the ad ecosystem)? What if we actually focused on what really matters: better ads for a better viewer experience? In this talk, we will go through the different cognate words that make it hard for us to understand ad people. We will of course have a couple of words from our marketing friends who are great at finding words that make everything look 100x better. Can you guess what linear means for an ad guy? Or, what’s the difference between an interactive and an immersive ad? (hint: it’s not Virtual Reality!). And what about live rewind ads - how cool do they actually sound in the ad world? We will also review the different standards bodies: on one side, the IAB (for the ads); on the other, Apple, SVTA, CTA-WAVE (for the streaming side). Have you ever met an ad person at one of your Streaming Tech Talks? I don’t mean someone that talks about SSAI or SGAI, but someone that talks about inventory, supply, and demand. Have you ever thought about fill-rates, CPMs, and what affects those metrics? We will look at what we can do to help the ad ecosystem maximise every advertising opportunity, so that generating more revenue does not have to mean more ads on more parts of the screen every time. Finally, we will talk about the trendy ad formats that are floating around and all the challenges they bring (but from an ad tech side, not a streaming tech side). This is going to be the type of talk where we all have an opinion and we all know the challenges (SGAI adoption, device capabilities, player complexity). But it’s time to get out of our bubble and think of the challenges that the ad ecosystem faces and how we can help. How do we avoid showing a cropped ad or worse cropping the most important of the original stream? May our shared love for XML (VAST/DASH) will lead us to a higher fill rate!

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14:45 GMT

Break

15:15 GMT

Julien Zouein

Julien Zouein

Trinity College Dublin

Reconstructing 3D from Compressed Video: An AV1-Based SfM Pipeline

We present an AV1-based Structure from Motion Pipeline repurposing AV1 bitstreams metadata to generate correspondences for 3D reconstruction. The process of creating 3D models from 2D images, known as Structure from Motion (SfM), traditionally relies on finding and matching distinctive features (keypoints) across multiple images. This feature extraction and matching process is computationally intensive, requiring significant processing power and time. We can actually bypass this expensive step using the powerful motion vectors of AV1 encoded videos. We present an analysis of the quality of motion vectors extracted from AV1 encoded video streams. We finally present our full AV1-based Structure from Motion pipeline, re-using motion vectors from AV1 bitstreams to generate correspondences for 3D reconstruction, yielding dense inter-frame matches at a near-zero additional cost. Our method reduces front-end time by a median of 42% and yields up to 8× more 3D points with a median reprojection error of 0.5 px making compressed-domain correspondences a practical route to faster SfM in resource-constrained or real-time settings.

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Chaitanya Bandikatla

Chaitanya Bandikatla

TikTok

Tomas Kvasnicka

Tomas Kvasnicka

CDN77

Improving Video Delivery and Streaming Performance with a "Media-First" Approach for CMAF

In our ongoing effort to enhance live streaming efficiency and viewer experience, we at TikTok partnered with CDN77 to explore a new approach called “Media First” This talk will examine how Media First transforms segment-based video delivery by merging multiple CMAF chunks into unified media objects and leveraging intelligent CDN edge logic. By combining media segments and applying dynamic URL rewriting at the edge, the CDN ensures that each viewer receives the freshest and most cacheable version of the video, even under real-time constraints. By shifting cache logic from “manifest-first” to “media-first,” we observed significant improvements in cache hit ratio, startup time, and stream stability. Specifically, we reduced origin fetches during peak events, improved playback startup predictability across diverse network conditions, and achieved a 2.5% reduction in first-frame delay and a 9% reduction in stalling. This talk highlights the architectural and operational collaboration between TikTok and CDN77 engineering teams, including lessons learned from edge compute deployments, manifest adaptation, and adaptive delivery strategies. Key Takeaways: * Media First Architecture: How merging segment groups and rethinking cache hierarchy enables higher media availability and CDN efficiency. * Edge URL Rewriting: How real-time request rewriting delivers the most current media while minimizing origin MISS traffic. * Performance Gains: Insights into how Media First improves QoE metrics, including startup latency, resolution stability, and playback resilience. * Cross-Team Innovation: Lessons from collaborative development between application logic and CDN infrastructure to advance live streaming capabilities. This talk will be co-presented by engineers from both companies and will include real-world production metrics and implementation details.

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Joanna White

Joanna White

British Film Institute National Archive

FFmpeg's starring role at the BFI National Archive

Ever wondered what happens when 100-year old celluloid cinema film meets digital workflows? Come and hear about the BFI National Archive, where FFmpeg is more than just a tool—it's a vital force in safeguarding Britain's audiovisual heritage. Witness how we seamlessly compress multi-terabyte film frame image scans into preservation video formats, and discover how open source libraries power our National Television Archive's live off-air recording system, capturing an impressive 1TB of British ‘telly’ per day. We’ll look at how vintage hardware digitises broadcast videotape collections, feeding them into automated slicing and transcoding pipelines, with FFmpeg at the heart of our open-source toolkit. This essential technology keeps cultural heritage alive and accessible across the UK through platforms like the BFI Player, UK libraries, and the BFI's Mediatheque. Archives internationally have a growing network of developers working on solutions to challenges like format obsolescence by developing and encoding to open standards like FFV1 and Matroska! With high volumes of digitised and born-digital content flowing into global archives daily, the BFI National Archive embrace the spirit of open-source by sharing our codebase, enabling other archives to learn from our practices. As the Developer who builds many of these workflows, I’m eager to share the code that drives our transcoding processes. I’m passionate about showcasing our work at conferences and celebrating the contributions of open-source developers, like attendees at Demuxed.

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16:15 GMT

Short Break

16:30 GMT

Jonathan Lott

Jonathan Lott

AudioShake

Using AI Audio Separation to Transform A/V Workflows

In video production, audio often plays a supporting role, yet its quality profoundly impacts viewer engagement, distribution, accessibility, and content compliance. Traditional workflows struggle with mixed audio tracks, bleed, and ambient noise, making tasks like isolating and boosting dialogue, removing background noise, or extracting music for rights management cumbersome. This session introduces how AI-powered audio separation can transform A/V workflows. By deconstructing complex audio into distinct components—dialogue, music, effects, and ambient sounds—creators can: - Enhance clarity by isolating and boosting dialogue - Remove or replace music to ensure copyright compliance - Reduce background noise for cleaner sound - Create immersive environments through spatial audio design We'll discuss the technical challenges of source separation, share insights on training models to distinguish audio elements in noisy environments, and demonstrate real-world applications that improve accessibility, localization, enhancement, immersive content, copyright compliance, and content personalization. This talk may be of interest to video devs working in environments such as broadcast, XR, UGC, streaming, post-production, or content creation (traditional or AI).

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Mattias Buelens

Mattias Buelens

Dolby Laboratories

VHS for the streaming era: record and replay for HLS

It’s a quiet day at the office, you’re reviewing your colleague’s latest pull request, when all of a sudden a notification pops up. A new Jira ticket greets you: “This stream is stalling on my machine.” But when you play the stream on your end, everything seems to work just fine. Now what? Is it because of an ad break that only happens once an hour? Is there something wrong with their firewall or ISP? Are you even looking at the same stream, or are you hitting an entirely different CDN? We’ve built a tool to record a part of a live HLS stream, and then replay it later on exactly as recorded. Customers can use the tool on their end until they reproduce the issue once, and then send that recording to our engineers to investigate. This way, these intermittent failures that are difficult to reproduce become fully deterministic and reproduce consistently. This makes debugging much easier and faster, since our engineers no longer have to wait until the problem occurs (no more xkcd #303 situations). In this talk, I’ll show how we’ve built the tool and how we’ve used it to debug issues with our customers’ streams. I’ll also show how we’ve integrated it in our end-to-end tests, so we can prevent regressions even for these tougher issues.

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Vittorio Giovara

Vittorio Giovara

Vimeo

Making sense of all the new VR video formats

Do you believe there is a lot more to Video then generative AI or Ad Insertion? Are you interested in the new and shiny VR ecosystem? Are you confused by all the new video formats, making your head spin like a half-equirectangular 180º 90-fov video without a yaw/pitch/roll set? Well, you've come to the right talk! With a little bit of MV-HEVC magic, a particular projection algorithm, and special metadata, we'll be able to describe how Immersive video works, and how it differs from a classic Spatial video. I'll also go over all the innovations that are happening in the VR field, and introduce you to the plethora of new formats recently released, with a few tips and tricks on how to support them.

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17:45 GMT

Matt McClure

Matt McClure

Demuxed

Closing Remarks

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About Demuxed!

Demuxed is video engineers talking about video technology

Our first meeting was a single day event back in 2015, born out of the SF Video Technology meetup. The video industry had plenty of trade shows and other opportunities for The Business, but our goal was to create a conference and community for the engineers building the technology powering video, from encoding, to delivery, to playback, and beyond. We’ve grown a lot since then, but our goal remains the same.

After creating Demuxed, some of the organizers went on to start and work at Mux. Mux continues to sponsor most of the organizational work behind the scenes (thanks for the salary!), but Demuxed is, at its core, a community-led event.

Every year we get a group together that’s kind enough to do things like schedule planning, help brainstorm cool swag, and, most importantly, argue heatedly over which talk submissions should make the final cut. These folks are the ones hanging out in Video Dev Slack, and they hail from all over the industry.

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