Add `tfSamplingMode` universal parameter

[keighrim]

New Feature Summary

mmif-python will provides SamplingMode enum and extract_frames_by_mode() in video_document_helper (mmif-python PR #373). This issue tracks the clams-python side integration.

Changes

• Import SamplingMode, SAMPLING_MODE_DESCRIPTIONS, SAMPLING_MODE_DEFAULT, and _sampling_mode from new mmif.utils.video_document_helper
  • Three modes: representatives (default), single, all
• Add tfSamplingMode to ClamsApp.universal_parameters, built from the imported enum values and descriptions
• In annotate(), pop tfSamplingMode from refined params and set the _sampling_mode context variable before calling _annotate()
  • Uses contextvars for thread-safe propagation — app developers don't need to handle sampling mode;
• Bump mmif-python dependency to the version that includes the new API
  extract_frames_by_mode() reads the mode automatically

Related

No response

Alternatives

No response

Additional context

No response

[keighrim]

Reopening — the code integration is done, but the developer-facing documentation needs updating. The sampling mode selection mechanism is currently only documented in inline code comments. The developer tutorial (documentation/tutorial.md) should explain how tfSamplingMode works, when each mode is useful, and how it interacts with extract_frames_by_mode() so app developers understand it without reading SDK internals.

[keighrim]

re-closed via #280