Latest version broke animated previews with the Video Helper Suite node.

[Kasr40k]

Hello. I am reporting an error once again. After updating to the latest ComfyUI-bleh version, the animated previews from the VHS node stopped working entirely, and this error is displayed in the console:

!!! Exception during processing !!! Unsupported preview type for VHS animated previews
Traceback (most recent call last):
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\execution.py", line 496, in execute
output_data, output_ui, has_subgraph, has_pending_tasks = await get_output_data(prompt_id, unique_id, obj, input_data_all, execution_block_cb=execution_block_cb, pre_execute_cb=pre_execute_cb, hidden_inputs=hidden_inputs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\execution.py", line 315, in get_output_data
return_values = await _async_map_node_over_list(prompt_id, unique_id, obj, input_data_all, obj.FUNCTION, allow_interrupt=True, execution_block_cb=execution_block_cb, pre_execute_cb=pre_execute_cb, hidden_inputs=hidden_inputs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\execution.py", line 289, in _async_map_node_over_list
await process_inputs(input_dict, i)
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\execution.py", line 277, in process_inputs
result = f(**inputs)
^^^^^^^^^^^
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\custom_nodes\KSamplerAdvancedWithVariationsPrototype.py", line 65, in sample
callback = latent_preview.prepare_callback(model, total_steps)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\latent_preview.py", line 96, in prepare_callback
previewer = get_previewer(model.load_device, model.model.latent_format)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\custom_nodes\comfyui-videohelpersuite\videohelpersuite\latent_preview.py", line 111, in get_latent_video_previewer
return WrappedPreviewer(previewer, rate_setting)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "H:\ComfyUIAPI3-47\ComfyUI_windows_portable\ComfyUI\custom_nodes\comfyui-videohelpersuite\videohelpersuite\latent_preview.py", line 30, in init
raise Exception('Unsupported preview type for VHS animated previews')
Exception: Unsupported preview type for VHS animated previews

The error only occurs when using the high-quality TAESD previews when enabled via the bleh.yaml file. Removing the .yaml file solves the issue with the VHS animated previews.

The previous version of ComfyUI-bleh I had was working correctly with the VHS nodes and the high-quality previews from ComfyUI-bleh, but I don't see any version to roll back to, unfortunately.

[blepping]

Hmm, this is a strange issue. Do you know when the last time you updated ComfyUI-bleh before the time that resulted in this issue? Also, what model are you trying to use when you get this error?

This is also extra weird because the example config files in this repo are just supposed to have the default settings so unless you actually change stuff in the config it should be the same whether or not the config file exists. I will double check to make sure there is no difference from the internal default config.

As for high quality previews for video models like Wan, you basically have to choose between using bleh's previewer (high quality, shows frames like a batch) or VHS's previewer (low quality, but animated). Both node packs try to override ComfyUI's default previewer and can't really both run at the same time. This still shouldn't cause an actual error, you'll just be using one or the other. It should also be possible to do stuff like blacklist video latent formats in the bleh config file if you want to use VHS for animated video previewers and bleh for previews with other non-video models.

[Kasr40k]

Curiously enough, the last bleh version that was working correctly without the "Unsupported preview type for VHS animated previews" issue was the one I was using back in June, when I first posted an issue here xD

So, am I correct to assume that the bleh high-quality previews in the previous version automatically "switched" to the VHS animated previews instead?

[blepping]

So, am I correct to assume that the bleh high-quality previews in the previous version automatically "switched" to the VHS animated previews instead?

It's probably just that Bleh got loaded after VHS and overwrote VHS's previewer with its own. You weren't actually getting previews that animated, right?

Looking closer at the error you pasted above, I can see that there actually isn't anything related to Bleh in those messages. If it was something like bleh delegating to the VHS previewer we'd see it in the traceback. In this case, ComfyUI's previewer handling is directly calling the VHS previewer stuff so this should be the the same as if you just didn't have ComfyUI-bleh installed. In other words, it looks like an issue with VHS, not Bleh which might have been hidden if you were actually just using Bleh's previewer before.

It sounds like you don't update nodes very often, so this problem could be caused by your VHS version being too old if you haven't updated it in a while. If you actually want animated previews instead of Bleh previews, that's what I'd suggest doing. If you want Bleh previews, then you might as well just turn off animated previews in VHS (although keeping it up-to-date is a good idea). You can also force Bleh's previewer to get used with the BlehEnsurePreviewer node. Whenever that node runs, it will make sure Bleh's previewer is the one that's set so you can use it to bridge any input to your sampler and then ComfyUI will have to run it before the sampler. Random example:

I believe VHS won't try to hook the previewer stuff if you have animated previews turned off, so that's probably a better way to do it. BlehEnsurePreviewer is the last resort.

[Kasr40k]

In the VHS github repo, there is a closed issue with the exact error message I was affected with: Kosinkadink/ComfyUI-VideoHelperSuite#560

And I updated VHS to the latest version in my separate ComfyUI portable 0.3.60 install, and I stumbled upon the same " Unsupported preview type for VHS animated previews" issue, so updating the node won't solve the issue in this case.

Unfortunately, it does seem that whatever changed in the latest bleh version caused an incompatibility issue with the VHS animated previews. The problem is that before I updated to the latest bleh version in my 0.3.49 install, I could have the bleh high quality previews enabled via the bleh.yaml file and the animated previews from the VHS node working correctly with the VHS version I'm using (1.7.5), without getting the "Unsupported preview type for VHS animated previews" error when turning on animated previews.

[CABLZ]

@blepping
I’ve investigated the error and found that it was likely introduced in the update on Sep 11 (Commit: 425150b).
The issue seems to be at line 656 in py/better_previews/previewer.py.
The code was changed from:
if format_name == "aceaudio" or (
preview_method == LatentPreviewMethod.Latent2RGB
and latent_format.latent_rgb_factors is not None
):
to:
if format_name == "aceaudio" or latent_format.latent_rgb_factors is not None:
I tested this by reverting to the old code, and the error no longer occurs. I hope this helps in fixing the issue.