I am too stupid to get ltx-2.3 to produce smooth I2V-videos at larger resolutions....

[martinbu69]

Hi all,

I don't know if this is apropriate to ask here, but I am trying to create I2V videos with ltx-2.3... For a couple of reasons, I wrote/vibe-coded my own python wrapper that auto-generates a python interface around sd.cpp, which works generally nicely and provides an always up-to-date interface. Z-image(-turbo), Flux.2(-dev/9b-klein), ideogram4, ... they all work like a charm. But with ltx-2.3 (/w or /wo distilled LoRA) I am konstantly failing in generating videos. When using smaller resolutions, I keep getting motion, but it starts melting in 90% of the cases for 81, or 121 frames long videos. When using larger resolutions (>= width=960; height=544) pretty much 100% of the time the motion is completely frozen. (while sometimes the audio-track is fine)

I can only think of using parameters in the wrong combinations....
The (flattend) video-parameters are:

---

Video-Parameter:
Bn_compute_blocks: c_int
Fn_compute_blocks: c_int
circular_x: c_bool
circular_y: c_bool
clip_skip: c_int
control_frames: LP_sd_image_t
control_frames_size: c_int
denoising_strength: c_float
end_image: sd_image_t
end_percent: c_float
error_decay_rate: c_float
extra_tiling_args: c_char_p
fps: c_int
height: c_int
high_noise_sample_params__custom_sigmas: LP_c_float
high_noise_sample_params__custom_sigmas_count: c_int
high_noise_sample_params__eta: c_float
high_noise_sample_params__extra_sample_args: c_char_p
high_noise_sample_params__flow_shift: c_float
high_noise_sample_params__guidance__distilled_guidance: c_float
high_noise_sample_params__guidance__img_cfg: c_float
high_noise_sample_params__guidance__slg__layer_count: c_ulong
high_noise_sample_params__guidance__slg__layer_end: c_float
high_noise_sample_params__guidance__slg__layer_start: c_float
high_noise_sample_params__guidance__slg__layers: LP_c_int
high_noise_sample_params__guidance__slg__scale: c_float
high_noise_sample_params__guidance__txt_cfg: c_float
high_noise_sample_params__sample_method: c_int
high_noise_sample_params__sample_steps: c_int
high_noise_sample_params__scheduler: c_int
high_noise_sample_params__shifted_timestep: c_int
hires__custom_sigmas: LP_c_float
hires__custom_sigmas_count: c_int
hires__enabled: c_bool
hires__scale: c_float
init_image: sd_image_t
lora_count: c_uint
loras: LP_sd_lora_t
max_cached_steps: c_int
max_continuous_cached_steps: c_int
max_warmup_steps: c_int
mode: c_int
model_path: c_char_p
moe_boundary: c_float
negative_prompt: c_char_p
prompt: c_char_p
rel_size_x: c_float
rel_size_y: c_float
reset_error_on_compute: c_bool
residual_diff_threshold: c_float
reuse_threshold: c_float
sample_params__custom_sigmas: LP_c_float
sample_params__custom_sigmas_count: c_int
sample_params__eta: c_float
sample_params__extra_sample_args: c_char_p
sample_params__flow_shift: c_float
sample_params__guidance__distilled_guidance: c_float
sample_params__guidance__img_cfg: c_float
sample_params__guidance__slg__layer_count: c_ulong
sample_params__guidance__slg__layer_end: c_float
sample_params__guidance__slg__layer_start: c_float
sample_params__guidance__slg__layers: LP_c_int
sample_params__guidance__slg__scale: c_float
sample_params__guidance__txt_cfg: c_float
sample_params__sample_method: c_int
sample_params__sample_steps: c_int
sample_params__scheduler: c_int
sample_params__shifted_timestep: c_int
scm_mask: c_char_p
scm_policy_dynamic: c_bool
seed: c_long
spectrum_flex_window: c_float
spectrum_lam: c_float
spectrum_m: c_int
spectrum_stop_percent: c_float
spectrum_w: c_float
spectrum_warmup_steps: c_int
spectrum_window_size: c_int
start_percent: c_float
steps: c_int
strength: c_float
target_height: c_int
target_overlap: c_float
target_width: c_int
taylorseer_n_derivatives: c_int
taylorseer_skip_interval: c_int
temporal_tiling: c_bool
tile_size_x: c_int
tile_size_y: c_int
upscale_tile_size: c_int
upscaler: c_int
use_relative_threshold: c_bool
vace_strength: c_float
vae_tiling_params__enabled: c_bool
video_frames: c_int
width: c_int

---

Any hints??