Fixed the issue that the generated MP4 file name is not supported under Windows

[manzhizhen]

Fixed the issue that the generated MP4 file name is not supported under Windows:

[2025-03-06 08:41:26,734] INFO: Saving generated video to t2v-1.3B_832480_1_1_Two_anthropomorphic_cats_in_comfy_boxing_gear_and__20250306_084126.mp4
[out#0/mp4 @ 000001bf503857c0] Error opening output E:\t2v-1.3B_832480_1_1_Two_anthropomorphic_cats_in_comfy_boxing_gear_and__20250306_084126.mp4: Invalid argument
Error opening output file E:\t2v-1.3B_832*480_1_1_Two_anthropomorphic_cats_in_comfy_boxing_gear_and__20250306_084126.mp4.
Error opening output files: Invalid argument
cache_video failed, error: result type Float can't be cast to the desired output type Byte

[yingdachen]

lets do this only when windows sys is detected...to be really safe and not break any existing (linux) pipeline.

[manzhizhen]

lets do this only when windows sys is detected...to be really safe and not break any existing (linux) pipeline.

Yes, I have revised it again, what do you think?

[hjj-lmx]

请问一下，windows上i2v多GPU是怎么运行起来的，我运行就报错
RuntimeError: use_libuv was requested but PyTorch was build without libuv support
这是我的命令
torchrun --nnodes=1 --nproc_per_node=2 generate.py --task i2v-14B --ckpt_dir checkpoints/Wan2.1-I2V-14B-720P --image examples/i2v_input.JPG --prompt "Summer beach vacation style, a white cat wearing sunglasses sits on a surfboard. The fluffy-furred feline gazes directly at the camera with a relaxed expression. Blurred beach scenery forms the background featuring crystal-clear waters, distant green hills, and a blue sky dotted with white clouds. The cat assumes a naturally relaxed posture, as if savoring the sea breeze and warm sunlight. A close-up shot highlights the feline's intricate details and the refreshing atmosphere of the seaside." --size 1280*720 --ulysses_size 2 --ring_size 1 --offload_model True --t5_cpu True --dit_fsdp True --sample_steps 40 --sample_shift 5.0 --save_file examples/output.mp4