Simplify H3 beat timing and cleanup

H3_LONG_VIDEOS_GUIDE.md

@@ -10,7 +10,7 @@ The node does two jobs at once:
 Think of it like this:
 
 - `prompt` decides what happens.
-- `shot_seconds`, `per_beat_length`, and beat-level `seconds:` decide how long each beat is allowed to be.
+- `shot_seconds` and beat-level `seconds:` decide how long each beat is allowed to be.
 - `first_frame` and the handoff system decide continuity.
 - `ref_1` to `ref_9` decide identity and location reference conditioning.
 
@@ -375,60 +375,38 @@ This is the most important group to understand.
 These settings work together:
 
 - `shot_seconds`
-- `per_beat_length`
 - beat-level `seconds:` or `duration:`
-- `allow_oversize_shots`
 - `megapixels`
 - `vram_headroom_gb`
 - `allow_res_backoff`
 
 ### The Short Version
 
-`shot_seconds` is a ceiling, not a promise.
+`shot_seconds` is the socket-defined maximum.
 
-A beat-level `seconds:` line is a request, not absolute law.
+A beat-level `seconds:` line wins for that beat.
 
-The final beat length is limited by:
-
-- H3's hard single-shot max
-- the VRAM budget
-- the current resolution and pixel budget
+If a requested length is too much for the hardware, the node keeps it and lets the render fail instead of quietly shrinking it.
 
 ### Exact Decision Order
 
 For each beat, the node decides length like this:
 
 1. If the beat has `seconds:` or `duration:`, use that as the requested length.
-2. Otherwise, if `per_beat_length` is on, estimate the beat length from its content.
-3. Otherwise, use the global shot ceiling.
-4. Clamp that result to the global `shot_seconds` ceiling if one is set.
-5. Clamp again if H3 or VRAM will not allow that size.
-6. Snap the result to H3's frame grid.
+2. Otherwise, estimate the beat length from its content.
+3. Snap the result to H3's frame grid.
 
 ### `shot_seconds`
 
-Global per-shot ceiling.
+Global per-shot maximum.
 
 Important:
 
 - This does not mean every beat will be exactly this long.
-- It means no beat is allowed to be longer than this, unless other limits clamp it first.
+- It means beats are sized against this socket value when the node needs a maximum.
 
 If left unconnected or set to `0`, the node uses the largest safe shot length it can budget automatically.
 
-### `per_beat_length`
-
-When on, the node estimates beat length from the beat content if there is no explicit beat-level `seconds:` line.
-
-That means:
-
-- short simple beats become shorter shots
-- more complex beats become longer shots
-
-When off:
-
-- every beat uses the full global ceiling unless that beat has its own explicit `seconds:` line
-
 ### Beat-Level `seconds:` Or `duration:`
 
 Inside a beat, you can write:
@@ -445,29 +423,7 @@ duration: 8
 
 This has the highest priority for that beat.
 
-But it can still be clamped down if:
-
-- it exceeds the global `shot_seconds` ceiling
-- it exceeds H3's hard max shot length
-- it exceeds the VRAM budget and `allow_oversize_shots` is off
-
-### `allow_oversize_shots`
-
-This only affects forced global `shot_seconds`.
-
-When off:
-
-- too-long requests are clamped down to what fits
-
-When on:
-
-- the node will try to honor the requested global ceiling even if it exceeds the safe VRAM budget
-
-Trade-off:
-
-- slower renders
-- possible spill to system RAM
-- possible OOM
+It is not silently shortened by the node. If you ask for more than your hardware can handle, the render can fail.
 
 This does not bypass H3's hard max shot size.
 
@@ -1287,9 +1243,9 @@ Useful on tighter cards at larger resolutions.
 
 ### `cleanup_between_shots`
 
-Moves completed shot data off the GPU and clears memory between beats.
+The node always moves completed shot data off the GPU and clears memory between beats.
 
-Good default for long chains.
+This is hard-coded for long-chain stability.
 
 ### `upscale`
 
@@ -1313,7 +1269,7 @@ Use them in this order:
 
 1. Get the render stable.
 2. If decode fails, use decode tiling.
-3. If shot length is too short, reduce pixel cost before forcing oversize.
+3. If shot length is too short, reduce pixel cost before forcing a longer shot.
 4. Only upscale after the base render is working.
 
 ## Group 10: Overlay Controls
@@ -1408,7 +1364,7 @@ Recommended pattern:
 - one character ref in `ref_1`
 - `ref_mode = auto ref2v`
 - no explicit `<Picture 1>` tags needed
-- `per_beat_length = on`
+- put `seconds:` on a beat when you want a specific length
 
 ### Two Characters Plus One Location
 
@@ -1422,7 +1378,7 @@ Recommended pattern:
 - use `shot_seconds` as a safe ceiling
 - put `seconds:` inside beats that need exact control
 - check `plan_only` first
-- expect clamping if you ask for more than H3 or VRAM allows
+- expect an OOM if you ask for more than H3 or your hardware allows
 
 ## Best Way To Check What Will Really Happen