Video Frame Player

Every video workflow in ComfyUI has the same bottleneck: you can't look at your frames without chaining Load → Preview and you can't choose a frame without guessing at an index. VideoFramePlayerMEC is the in-graph answer - a scrubber with a timeline you can drag, an interactive drag-crop overlay with eight handles, trim markers, frame stride, and integrated resize, all in one node. It plays inside the node itself, and it emits the processed batch ready to feed a sampler or a video saver.

The pitch from the author is "one node so you don't have to chain Load → Trim → Crop → Resize → Preview," and that's exactly the workflow it replaces. It's from the ComfyUI-CustomNodePacks pack, an output node, and one of the more polished pieces of the whole suite.

How it works

Feed it frames (the batch), and you get a player: drag the timeline to scrub, hit space to play, set loop mode (once / loop / ping-pong), and mark trim in/out by dragging the green and red markers on the timeline. The frame_index widget tracks your scrub position. Turn on crop_enabled and the preview grows a draggable rectangle - aspect-lockable (1:1, 16:9, 9:16, original, custom, etc.) - with rule-of-thirds guides and a live W×H readout. Then resize_method + target_width/target_height/upscale_factor produce the final output.

The critical design decision is output_mode:

• current_frame (default) - emit only the selected frame. For single-frame work (grab a hero frame, test a prompt on one frame).
• all_frames - apply trim + stride + crop + resize to every frame, producing the processed batch. This is the mode that turns the player into a real preprocessing stage.

The inputs and outputs that matter

• frames (IMAGE) - the batch. frame_start/frame_end/frame_stride - the trim range and sampling step (stride applies in all_frames mode).
• crop_enabled, aspect_ratio, crop_x/y/w/h - the crop, set by dragging on the preview.
• resize_method, target_width, target_height, upscale_factor - the resize stage. lanczos is the quality pick.
• playback_fps, loop_mode - playback controls.

The outputs are where this node earns its keep - it's a control room, not just a preview. The ones you'll actually wire:

• frame (IMAGE) - the full-res frame at the scrubber position (pre-crop/pre-resize, full source precision).
• processed (IMAGE) - the crop+resize result, or the full trimmed/strided batch in all_frames mode.
• frames_trimmed (IMAGE) - the trimmed source batch without crop/resize. This is the one to feed a video saver when you don't want to lose source resolution.
• trimmed_count, out_width, out_height, duration, playback_fps - numbers for downstream automation.
• video_info (STRING) - a JSON blob with all the metadata (width, height, fps, duration, trim/crop values). Wire it to a Show Text node or your own automation.

That's eighteen outputs total, but you'll realistically use frame, processed, frames_trimmed, and video_info. Don't let the long list intimidate you.

Installing it

Standard pack install:

cd ComfyUI/custom_nodes
git clone https://github.com/Code2Collapse/ComfyUI-CustomNodePacks.git

restart ComfyUI or use Manager → "CustomNodePacks". No heavy dependencies - the preview is browser-side; the crop/resize is standard tensor work.

Where people get burned

The most common mistake is leaving output_mode on current_frame and wondering why the "whole video" came out as one frame. If you're processing the clip, switch to all_frames. The second is forgetting that processed applies crop and resize - if you want the clip at source resolution with only a trim, wire frames_trimmed to your saver instead. And the preview_width/preview_format knobs only affect what the browser shows - the IMAGE outputs are always full source precision, so don't fear the JPEG setting.