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AI Engineer World's Fair 2026

Building an Agentic Video Editor for Mass Consumer

About this talk

Reelful founder and CEO Ekaterina Deyneka explains how a consumer-facing agentic video editor transforms user-provided photos, footage, and lightweight prompts into polished clips. She compares its architecture with agentic app builders: a remote sandbox runs an agent equipped with tools and skills, but produces a video composition and rendered output instead of an application. The talk emphasizes editing real, sometimes incomplete footage, animating photos, using Remotion for composition, and demonstrates an example edited video.

Chapters

  1. 0:00Why consumer video editing remains difficult
  2. 1:07Introducing Reelful and automated editing
  3. 2:52Agent architecture, sandboxes, and rendered video
  4. 4:17Editing real footage into polished clips
  5. 7:05Photo animation and Remotion composition
  6. 10:08Example video playback and closing

Talk transcript

  1. 0:00

    [upbeat music] Hi, everyone. I think we can start.

  2. 0:15

    Uh, but before we start, I want to ask you a couple of questions. So first of all, how many of you took a photo or video during this conference?

  3. 0:24

    Please raise your hands. Okay. And how many of you actually posted any video content from it online?

  4. 0:37

    Not that many. And, um, to be honest, that was me. I, I was recording a lot of content during conferences, events, trips, meetups, uh, and I never posted them online because video editing is hard.

  5. 0:53

    Uh, it sounds and it is a lot of work, uh, it's tedious, and it's largely still manual. So... And, and it also feels like an art and not really automated.

  6. 1:07

    And that's why we're building Reelful, and we're trying to tackle agentic video editing problem from, uh, video editing problem from the agentic standpoint. I'm Kate. I'm founder and CEO at Reelful.

  7. 1:23

    But let's first talk about what agentic video editing is. So as a user, you just drop in your media photos and videos and provide some context. It can be, uh, the context what happened in these media files, or it can be some directions.

  8. 1:40

    For example, like add captions, add music, add voiceover, and something like that. And then the agent will go understand your media, uh, find the right moments, assemble everything together, generate captions, music, voiceover, B-rolls, uh, and give you a ready-to-share clip.

  9. 2:02

    Uh, and, um, yeah, so basically, um, that's, uh, video... agentic video editing. So agent does everything by itself. Or another example, you recorded, uh, a speak to camera video, and ha-- you have a lot of pauses, unsuccessful shots, and you expect an agent to figure it out, to remove unsuccessful shots, remove

  10. 2:27

    pauses, and give you a ready-to-share clip. Um, and, uh, the, the interesting thing is that a lot of... actually, a lot of the things inside this pipeline can be automated, and this is exactly what we're doing at Reelful.

  11. 2:45

    Oh, this is, um, the example of, uh, video edited.

  12. 2:52

    And, um, since we are at AI engineering conference, I wanted to talk a little bit about infrastructure. And from the infrastructure standpoint, agentic, uh, video editor is very similar to agentic app builder.

  13. 3:08

    Uh, sorry, there is a typo on the slide. So the, uh, second column is agentic video editor. So both of them have a prompt, uh, a UI for prompt, uh, and in the video editor case, it's a media pr-- plus prompt, and usually on back end, what's happening?

  14. 3:26

    There is a remote machine which is called Sandbox, uh, which is spinning up, and inside this machine, there is an agent with tools and skills which is working on, uh, what you're, uh, you're, you're asking it to do.

  15. 3:40

    Uh, in the case of the agentic, uh, app builder, it's a code base. Uh, in the case of the agentic video editor, it's a video, video composition. And as a result, in the a-agentic app builder user get an app preview, and for the video editor users, uh, user get rendered, a rendered video.

  16. 4:03

    And but yes, the, the infrastru-- from infrastructural standpoint, it's pretty similar, but there are a couple of differences. Uh, and, um, this is actually the most interesting to me, generating versus editing.

  17. 4:17

    At Reelful, we are focusing on editing real footage, so we do not generate a lot of content. We are expecting you to provide your real life, your, uh, personal content, and we will edit it for you.

  18. 4:33

    And actually, this is, uh, a more complex problem because if the agent has a blank, blank canvas, it can do whatever they can. But in the editing case, the agent has to figure out, uh, which moments are the best, uh, what to omit, what to use, how to organize everything together.

  19. 4:55

    And also, um, sometimes, uh, fo-footage can be, um, messy or incomplete, and agent still has to deliver a very polished result, professionally made, so that ideally, the viewers of this content don't get if it is, like, AI or, uh, human edited.

  20. 5:17

    So let's actually have a look how we do it, uh, at Reelful. So we start, as I already mentioned, with your media plus a prompt, some directions like how you want it to be edited, and we need to get a polished clip.

  21. 5:35

    So let's go through it step by step. So we are doing first me-media understanding. We need to understand what is, what's actually happening, uh, on those clips and photos, and we also need to transcri-transcribe speech, for example, in the case if you have speak to camera videos.

  22. 5:54

    Then we are providing a creative plan for the user so that they can approve if they like it or not, what they want to change or maybe regenerate, uh, and we create this plan before actually starting editing.

  23. 6:10

    Once the user approve this plan, uh, we spin up a sandbox, the remote, uh, remote machine that we already discussed, and this is an environment for the agent to, uh, execute everything.

  24. 6:24

    So the agent comes with the skills, and in our case, in, in the case of, uh, video editing, our skills are, for example, cut rules, how, for example, how to select the best moments.

  25. 6:37

    Uh, also font pairs, which fonts are, uh, more suitable for this use case, which are not. For example, how to generate B-rolls, and this is where taste and craft, uh, live, actually.

  26. 6:50

    Um, and then also agent, uh, can, um, can initiate some other subprocesses. For example, generating music that will fit this exact composition, generating voiceover, adding sounds, animating images.

  27. 7:05

    Yes, this is actually what we do. Uh, if you provide photos, we can animate your photos to make them more, uh, dynamic and engaging. And then comes Remotion composition.

  28. 7:18

    So here, a little bit of background. What's Remotion? Remotion is a framework, open source, open source framework, uh, to create videos as code, as React code. Uh, so basically it's just like a, a file with, uh, the order with all your assets, uh, and tracks and how they're following each other.

  29. 7:39

    And, um, why it is important, because, uh, agents are really good at writing code, and therefore we can use them to create videos with this Remotion framework. And then, uh, the last thing is the verification layer.

  30. 7:55

    Of course, agent can make mistakes, and that's why we developed this verification layer to make sure that all the, um, the composition is clean, is well-defined, everything will be rendered, and if there, there are some problems, then the agent will, uh, reiterate on the composition.

  31. 8:15

    And this is how we got to a polished clip. [sighs]

  32. 8:19

    So it's a lot, right? Uh, it's like a very complex workflow. Uh, and ideally, we don't want our users to even know anything about it. And this is even maybe a bigger problem, how to deliver this complex agentic workflow to mass consumer.

  33. 8:40

    And this is how we're tackling that at Reelful. So we decided to go mobile first so that users can edit videos, videos while driving, walking, or maybe lifting weights.

  34. 8:53

    Uh, also, I know that prompting videos can sometimes be also challenging. That's why we create directional templates. For example, like speak to camera videos, or maybe you want to add B-rolls or voiceover so that users can just select these directional templates, drop their media, and that's it.

  35. 9:15

    Even without any prompt, it will, it will work. And the third thing is a build-in editor. Uh, why? Because we want to make this experience convenient and familiar for users.

  36. 9:28

    So a lot of people are already sort of, uh, using, uh, regular video editors, and that's why we want to provide this experience as well. So how it works, user first generates a video agentically, but if they want to tweak it, for example, remove a second or maybe, uh, correct some word in the captions, they can go

  37. 9:51

    into build-in editor and edit it a little bit. Um, yeah, and, uh, actually, I have a couple of examples here that I recently created with Reelful. Uh, I will play them, just maybe one of them.

  38. 10:06

    Oh, sorry.

  39. 10:08

    Last week, I was invited-

  40. 10:09

    Do, do you hear? Barely. A little bit. Okay. Y-you just can [laughs] enjoy the video.

  41. 10:15

    Exclusive Cursor Creators Dinner, and honestly, it was one of the best event experiences I've had. First of all, the venue was stunning. It was a custom event space transformed into this tropical sunset feast.

  42. 10:26

    The whole atmosphere felt so warm and cinematic. Second, the food was way beyond my expectations. They brought in private chefs from LA, and we had lobster, wagyu, crab, and this incredible strawberry ice cream that I was still thinking about.

  43. 10:39

    But most importantly, the conversations were so much fun. It was kind of atmosphere it felt really easy to connect with people, talk about what they're working on, and just enjoy the community.

  44. 10:49

    And lastly, we got gifts. One of the highlights-

  45. 10:52

    So, uh, yeah. Basically, all these videos, they were assembled only using agent, no, uh, regular video editor, and I already posting them on social media. And yeah, it-- I, I have a lot of fun with that.

  46. 11:08

    And-

  47. 11:09

    Last week, I was invited-

  48. 11:09

    Oh, sorry. Uh, and exclusively for this conference, we are, uh, giving our beta, uh, which is our new f- new second version. Uh, please give it a try, uh, and, um, let me know if you have any feedback.

  49. 11:28

    Uh, here is my, uh, email. Please, uh, feel free to reach out. Uh, we're still early. We're actively working on it, uh, so we will have-- uh, we will be happy to hear any feedback, and also curious how you use it.

  50. 11:44

    And also, um, some exciting news. We recently got funded by a16z Speedrun, uh, so I'm very excited to, uh, continue working. [audience applauding]

  51. 11:57

    Um, yeah, that's it. Thank you so much. And because it's a presentation about content and how to edit videos, I have to, uh, film a video with you all. [laughs]

  52. 12:12

    Yeah. It's so good. Yay. [upbeat music]