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fix(ltx2): pass actual sequence length to calculate_shift for dynamic timestep shift - #14373
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AloysJehwin wants to merge 1 commit into
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fix(ltx2): pass actual sequence length to calculate_shift for dynamic timestep shift#14373AloysJehwin wants to merge 1 commit into
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… timestep shift LTX2Pipeline passed max_image_seq_len as the first argument to calculate_shift(), which also receives it as the third argument (the maximum). Since calculate_shift returns image_seq_len * m + b, passing the maximum as image_seq_len always returns max_shift — making mu constant regardless of resolution or frame count. The commented-out line below already computed the correct value. Uncommented it and passed video_sequence_length as image_seq_len, matching LTX v1 pipeline (pipeline_ltx.py:725-728) and the LTX reference implementation. Fixeshuggingface#14243 Signed-off-by: Aloys Jehwin <aloysjehwin@gmail.com>
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Fixes#14243
The issue is that
muinLTX2Pipelinewas alwaysmax_shiftregardless of resolution or frame count. Traced it tocalculate_shiftbeing called withmax_image_seq_lenas both the first argument (image_seq_len) and the third (max). Since the function is linear inimage_seq_len, passing the max as input always returns the max output — souse_dynamic_shifting=Truedoes nothing.There was already a commented-out line
# video_sequence_length = latent_num_frames * latent_height * latent_widthright above. Uncommented it and used it as the first arg. Same approach as the LTX v1 pipeline atpipeline_ltx.py:725-728.