Fix PTS, DTS and timestamps on frames from clipped videos.#230
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Also change the delta to the first found frame instead of the clip point. This matches the behaviour from ffmpeg's `trim` filter.
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This pull request updates the video decoding logic to rebase the presentation timestamps (PTS), decoding timestamps (DTS), and timestamps of decoded video frames relative to the first emitted frame, ensuring that decoded sub-clips start at 0. It also replaces a custom timestamp helper with PyAV's native frame.time property and adds proper type annotations. Corresponding tests have been updated and added to verify the rebasing behavior. I have no feedback to provide as there are no review comments.
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| frame.pts = max(0, frame.pts - pts_delta) | ||
| if frame.dts is not None: | ||
| # negative dts may be required for proper ordering, can't clamp | ||
| frame.dts -= pts_delta |
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Because the video extra still allows any av version (pyproject.toml:33-35), environments that already have PyAV <13.1 installed can satisfy the dependency; PyAV only added the AVFrame.dts setter in 13.1, so for decoded frames with dts populated this assignment raises instead of yielding the clipped frame. Please either declare a minimum PyAV version or avoid writing dts when the setter is unavailable.
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Replaces #229, as I was not able to edit that PR.
Fixes decoded frame timestamps for clipped
VideoFileinputs so sub-clips use a clip-local clock.iter_frames()now rebases PyAV framepts/dtsto the first emitted frame instead of the requested clip boundary. This keepsDecodedVideoFrame.timestamp_s,DecodedVideoFrame.pts, and the underlying PyAVframe.time/frame.ptsin sync. This matches the ffmpegtrimandsetptsfilters.