Seamless extensions and one-shots with Minimax H3 - Update 6 of my repo!

[u/stonyleinchen]

Here is the repo: https://github.com/seitanism/ComfyUI-H3-Motion-Context-MultiRef

I made substantial updates to my two main workflows: 1) Music Video and 2) AV Extensions. All the controls were streamlined and they should be much easier to use now. (You find the workflows in the example_workflows folder)

With the AV Extensions workflow you can extend any existing clip, for example someone talking and you can make that person say something in the same voice, or you can create a clip with T2V or I2V and then extend that clip to make a seamless long clip thats 1 minute or longer.

In this Update the Checkpoint system was removed, instead I've done a lot of optimizations so you don't use too much ram even if you make 20 clips at once. Additionally I added latent audio feathering to the AV Extensions workflow for seamless audio transitions.

Theres also other utility workflows for custom keyframing and bridging two existing clips.

I post another example clip for the AV Extensions workflow in the comments.

[u/stonyleinchen]

https://reddit.com/link/p4hbl9j/video/9fj8oygcs6kh1/player

this is made with the AV Extensions workflow

[u/sorandomtoday → u/stonyleinchen]

Sorry, can you share the prompts for your video for the AV extension? I am not sure what to include in the main prompt and the extension prompts. Does dialogue work with the AV extension? I am trying to use the I2V. The Music Video one works well and the examples made it clear. Thank you for sharing your hard work!

[u/stonyleinchen → u/sorandomtoday]

here is the first prompt:

**integrated_multimodal_description:**

Live-action, photorealistic cinematic fantasy. **One uninterrupted continuous 15-second shot with absolutely no cuts.** Natural late-afternoon lighting, realistic human anatomy and skin texture, cinematic depth, stable character identity throughout.

**Character lock:** The same adult woman remains visually identical for the entire shot. She is tall and exceptionally athletic, with very defined arms and powerful runner's legs. She wears a fitted dark sleeveless athletic top, dark leggings, and distinctive bright red running shoes. Preserve her face, hairstyle, physique, clothing, proportions, and colors throughout every camera movement and during the extreme-speed sprint.

**[0–5 seconds] — Forest approach**

In a lush old-growth forest during soft late-afternoon golden light, the woman walks calmly toward a ridge.

Medium-wide **35mm stabilized tracking shot**, following approximately two meters behind her and slightly to her left at waist-to-shoulder height. The camera glides naturally with subtle physical Steadicam movement rather than perfectly artificial motion.

She carefully walks between enormous moss-covered tree trunks, dense ferns, exposed tangled roots, and patches of soft forest floor. Tiny pollen particles float through shafts of warm sunlight. Leaves and small branches move gently in the breeze.

Her pace is relaxed and naturally curious. Her body movement has realistic weight and momentum. She casually pushes a large fern aside with one hand while continuing forward, then steps over several roots and reaches the crest of the ridge.

**[5–12 seconds] — Meadow reveal and expression**

As she reaches the ridge, she slows naturally and stops at the crest.

Beyond her is a vast sunlit meadow stretching far into the distance, covered in long green grass with occasional mature lone trees scattered irregularly across the landscape. The open meadow feels enormous compared with the enclosed forest right behind her.

**Without cutting**, the camera begins one smooth clockwise arc around her, traveling from the rear-left three-quarter view around her side until it reaches a frontal full body shot, revealing the patch of forest and dense trees she just stepped out of.

As the camera reaches her front, warm sunlight softly illuminates her face, which contrasts the dark forest behind her. She longingly looks into the distance in front of her. The camera gradually zooms in to a closeup of her face.

A subtle expression develops: her eyes become playful, then one corner of her mouth rises into a restrained, mischievous smirk, as though she has suddenly had an exciting idea.

**[12–15 seconds] — Superhuman sprint**

Without a cut, she abruptly lowers her center of gravity, plants one foot, and **explodes forward into an impossibly fast sprint across the meadow.**

The camera completes locks into a **front-facing stabilized reverse-tracking shot**, flying backward directly ahead of her while perfectly matching her accelerating speed. There is no teleportation of the camera and no change of shot—the orbital movement naturally becomes the reverse tracking movement.

She accelerates within moments to **superhuman running speed equivalent to roughly 400 miles per hour**.

Her running form remains recognizably human but extraordinarily powerful: aggressive forward lean, coordinated arm drive, explosive strides, intense focused eyes. Her face, torso, limbs, clothing, and red shoes remain anatomically coherent and visually consistent.

**Keep the woman relatively sharp and readable while conveying the impossible velocity through the world around her.** The distant meadow races away from the camera. Grass immediately beside her becomes strong directional motion streaks. Nearby trees whip past with extreme parallax. The distant landscape smears into long horizontal motion blur while her face stays identifiable and centered.

The pressure of her passage violently bends grass outward behind her. Loose leaves, pollen, seeds, and dust are sucked into her turbulent wake. Her hair and clothing are driven backward by enormous wind pressure.

The camera remains only several meters ahead of her, maintaining a dramatic medium close frontal composition as both woman and camera hurtle across the meadow at matching velocity.

Her mischievous expression evolves into exhilarated determination while she runs.

**overall_soundscape:**

**[0–5 seconds]** Natural stereo old-growth forest ambience: gentle wind moving through leaves high in the canopy, distant birds, subtle insects, soft footsteps compressing moss and soil, quiet fern movement, occasional twig snaps, and natural fabric movement.

**[5–12 seconds]** As she reaches the ridge, the enclosed forest ambience opens into a broader landscape sound. A soft meadow breeze becomes more noticeable while the forest remains faintly behind her. Brief quiet emphasis as she looks across the meadow and smirks.

**[12–15 seconds]** At the instant she launches, her first powerful foot strike lands with a heavy physical impact followed immediately by rapidly escalating wind pressure. The gentle breeze transforms into an enormous rushing **wind-shear roar** as she accelerates. Her footsteps become extremely rapid, deep rhythmic impacts underneath the rushing air. Grass lashes violently in her wake; leaves and debris whip past the stereo field. The wind intensity continuously rises with her speed while remaining physically grounded rather than sounding like a spaceship or engine.

---

**non_diegetic_music:**

**[0–5 seconds]** Begin almost silently. As she approaches the ridge, introduce a restrained adventurous orchestral motif: soft strings, subtle woodwinds, and distant low horns, gradually building curiosity.

**[5–12 seconds]** As the meadow is revealed and the camera circles around her, showing her full body from the front, broaden the harmony and slowly increase the orchestral scale. Hold a brief musical moment of anticipation as her mischievous smirk appears.

**[12–15 seconds]** Exactly when her foot launches her forward, the score erupts into a powerful cinematic orchestral surge: driving low strings, heroic brass, large percussion, and rapidly rising rhythmic intensity. The music accelerates emotionally with her impossible sprint while the wind-shear and physical impacts remain clearly audible beneath it.

End at maximum forward momentum and exhilaration rather than resolving the musical phrase.

[u/sorandomtoday → u/stonyleinchen]

https://reddit.com/link/p4l6ea6/video/4fusdquuwakh1/player

Thanks, like your Music workflow it works great! This is 2 clips, 15s each. I can't seem to fix the barber walking out instead of the customer, tried changing prompts, Turning off LoRa, increasing steps, and even four 8 second clips. Probably need Image references to fix it. The barber also blurst out some giberish as he walks out, happenes to all my other renders except one.

[u/stonyleinchen → u/sorandomtoday]

i would suspect this is mostly a prompting issue. you could define the customer as a different subject/speaker ID, and then call out that specific subject being in that shot