Validate CTC capacity from the actual model output shape

Before reducing image width in a PaddleOCR recognition experiment, measure the pinned model's CTC time dimension with a synthetic forward pass. Do not infer it from another architecture's nominal stride or from the configured maximum label length. Require enough output steps for each encoded target plus adjacent repeated-token separators, and fail preparation if any label exceeds capacity. A smaller width may reduce excessive padding but also compress long lines; capacity validation prevents impossible alignments, not distortion or accuracy loss. Validate the exported model using its real serving preprocessing.

Applies when: changing OCR training resize widths while preserving the original label corpus. Keywords: PaddleOCR PaddlePaddle CTC width stride labels repeated tokens capacity preprocessing