Video Combine Encrypt (ShellAgent Plugin)

Video Combine Encrypt is the pack's heavyweight: it stitches a batch of IMAGE tensors into an actual video file - H.264 MP4, H.265, VP9 WebM, MOV, AVI, even GIF or WebP animation - using ffmpeg under the hood, and it can mux in audio and even decode a latent with a VAE for you. It's basically VHS Video Combine reimagined with a much friendlier format menu and a security twist: by default it XOR-encrypts the output file so it can't be played directly, which is the whole point when you're shipping a result to a ShellAgent app rather than watching it yourself.

This is the one node in the pack where the README is a small book in Chinese, and it's worth skimming - the format compatibility table is genuinely useful.

How it works

Feed it an images batch (any image-sequence source - AnimateDiff, video models, frame generation), pick a format, and it shells out to ffmpeg to build the file. The key decision is format:

• video/h264-mp4 - the default pick and the README's loud recommendation. Plays everywhere including Mac and iOS.
• video/h265-mp4 - better compression for 4K, slightly worse compatibility.
• video/vp9-webm - web/streaming-friendly.
• video/mov, video/avi - legacy/QuickTime territory.
• image/gif and image/webp - animated images instead of video (loop with loop_count, and pingpong reverses the frames for a seamless loop).
• video/h264-advanced and video/ffmpeg-manual - the expert modes that unlock advanced_preset, advanced_crf, advanced_pix_fmt, advanced_tune, colorspace, and raw x264 params.

The quality slider (1–100, default 85) maps to ffmpeg quality settings for the simple formats. Connect the optional audio input and it muxes it in, picking a sensible codec. Connect vae and it auto-decodes a latent before encoding - you can skip the separate VAE Decode node.

The gotcha that burns people

encrypt defaults to on. Your shiny MP4 will be XOR-scrambled with the hardcoded key ShellAgentSecretKey2024!, unplayable in any player, un-previewable in ComfyUI. If you just wanted a normal video, flip it off. If you're building the ShellAgent pipeline, leave it on - the app decrypts on its end. Same key is used across the pack's save/load nodes, so files are round-trippable.

Second gotcha: Mac black-screen videos. The advanced_pix_fmt default is yuv420p (plays everywhere), but if you pick yuv444p or yuv444p10le for color fidelity, Mac/iOS players will show black. The README's advice: keep yuv420p unless you're doing professional post-production on Windows/Linux and will convert before publishing.

The output is VHS_FILENAMES - the exact type VHS's Save Video expects, so you can chain this into the pack's Save Video - VHS node to register the file for the app.

Installing it

Same single pack:

cd ComfyUI/custom_nodes
git clone https://github.com/myshell-ai/ComfyUI-ShellAgent-Plugin

restart, or use ComfyUI Manager (search ComfyUI-ShellAgent-Plugin). Video output needs ffmpeg; the pack installs imageio-ffmpeg as a fallback binary, but if you get an "ffmpeg not found" error, install ffmpeg system-wide (sudo apt install ffmpeg, or the Windows build from ffmpeg.org).

Common issues

• "ffmpeg is required for video outputs and could not be found." Install ffmpeg or make sure imageio-ffmpeg survived the install.
• Black video on Mac/iOS. You used yuv444p (or high444 format). Re-encode with video/h264-mp4 / yuv420p.
• File won't play anywhere. encrypt is on - that's expected, decrypt on the receiving end.
• Video is missing audio. The audio input is optional; if nothing's connected there's nothing to mux.