- fastvideo-kernel/wan22_vae_decode: the Wan2.2 (TI2V-5B) VAE decoder on sm_100a / sm_103a at 704x1248, built on
first use against fastvideo-kernel's CUTLASS submodule. It frees intermediates early and carries 4 latent frames
per pass: a 5 s video peaks at 20.3 GiB, down from 94.6 GiB in the kernel's first version, with the same output.
- WanVAEConfig.decode_kernel routes AutoencoderKLWan.decode through it where it applies (bf16 with fp32
accumulation, about 7x faster than the fp32 decode on a B300, PSNR 61-63 dB, SSIM 0.998 against it);
decode_kernel_parallel splits the decode over the sequence-parallel group (2, 4 or 8 GPUs) and broadcasts the
video, with the ranks agreeing on whether every one of them could build the kernel.
- PAN2's DiT runs fused Triton kernels for Q/K RMSNorm + RoPE and LayerNorm + modulation (pan2_fusions,
set_fused_kernels).
- PAN2PipelineConfig turns all three on (vae_decode_kernel, vae_decode_kernel_parallel, dit_fused_kernels).
- VideoGenerator copies a decoded RGB video's frames to the host once instead of once per frame.
- The PAN2 presets sample at guidance 2.5, the reference launcher's default since 2026-10-23.
VideoGenerator.from_config calls from_fastvideo_args with a log_queue keyword
argument. The StreamingVideoGenerator override did not accept it, so
StreamingVideoGenerator.from_pretrained raised TypeError. The override now
accepts log_queue and passes it to the executor through VideoGenerator.__init__.
A new test covers the call.
MultiprocExecutor created two streaming multiprocessing queues for every
generator, but only StreamingVideoGenerator uses them. Each queue uses POSIX
named semaphores in /dev/shm. When a job epilog deleted these files, spawned
workers failed to start. The executor now creates the queues only when
FastVideoArgs.enable_streaming_ipc_queues is set. StreamingVideoGenerator sets
it on a copy of its arguments in queue mode. Standard generation creates no
streaming semaphores.
For n > 1, the image endpoints returned one preview grid instead of n images.
The endpoints now run one model batch, save each decoded sample as its own file,
and return one URL or base64 item for each image. This applies to generations
and edits.
A keyword-only return_samples field (default False) is added to OutputConfig,
SamplingParam and ForwardBatch. Batched image requests set it and do not build
preview frames. The worker keeps the sample tensor for these requests, and
non-output ranks clear the field. Defaults and positional arguments do not
change.
The image endpoints now validate size, output format and count before they
create output directories, save uploads or start generation. An invalid value
returns HTTP 400. Omitted or null values keep their defaults.
Behavior change: an explicit empty size or output format, and a count outside
1-10, now return HTTP 400. Before, the server replaced them with defaults or
clamped the count.
- create_app reads distributed_executor_backend with getattr(..., None): the MLX
server passes a SimpleNamespace without it, so since #1746 the server could not
start (28 test_openai_video_client failures). An explicit external_launcher
request is still rejected.
- test_cpu_sdpa patches fastvideo.platforms._current_platform instead of
current_platform. monkeypatch restored the real platform as a module attribute
that shadowed the lazy __getattr__, so later tests that fake _current_platform
(gpu_worker dist timeout, ROCm detection, selector role override) failed on
GPU hosts.
GB200 unit lane, A/B on one tray: main 36 failures, this change 0 (2720 passed).
The OpenAI image endpoint defaults to a .jpg output path, but the shared
output-path helper treated every non-PNG image path as a directory, so JPEG and
WebP requests were written somewhere other than where the endpoint read them.
Recognized PNG/JPEG/WebP extensions are now preserved, and existing directories
are checked first so a directory named e.g. renders.jpg still receives its
output inside it. Collision handling and filename sanitization are unchanged.
William Lin