A timestamp needs its scale
For an owned recording, a timestamp value is useful only with its time base and stream identity. A number copied from a packet report is not automatically a number of seconds. Keep the original rational value until you need a human-readable display. Premature rounding can turn a consistent relationship into an apparent disagreement between tools.
A hypothetical video timestamp of 180000 with a time base of 1/90000 represents two seconds. An audio position of 96000 samples at 48000 samples per second also represents two seconds. Comparing the raw numbers would suggest a difference where none exists. This arithmetic describes invented values, not the timing of an IPTV Europe stream.
Choose the event you are aligning
Identify the same observable event in both media: a clap visible in the picture and audible on the recording, for example. Record the reference event near the beginning and again later. A stable difference suggests an offset; a changing difference raises a rate or edit question. Neither observation alone identifies the capture component responsible.
FFprobe provides separate packet and frame reports. Select the representation appropriate to the question and retain the stream index. Packet decode timing and frame presentation timing serve different purposes, so a spreadsheet should not silently combine them into one unnamed time column. Include units in exported headings and preserve missing values as missing.
Treat the origin as a separate decision
A source timeline may begin away from zero. Resetting its origin can be reasonable for a standalone deliverable, but another recording, caption sidecar or event log may depend on that original relationship. Decide which timeline the package promises before shifting anything. Keep an unmodified source and a note of the chosen transformation.
For a two-camera edit, make a small synchronisation sheet: source identifier, original clock origin, reference event, offset applied and output timeline. If one camera stops and restarts, give the later section its own observation instead of stretching a single correction across the gap. A discontinuity is not the same as steady drift.
Accept alignment across the finished duration
Review the exported package at several meaningful events, including the last passage and any splice. A correct first clap does not establish the entire hour. Check the delivered file and caption sidecars together; a successful editor preview is only one preparation stage.
Keep the measurement precision proportionate to the source. A visually estimated event should not be reported to six decimal places. Preserve enough technical detail for a later reviewer to reproduce the calculation, while stating which observations were estimated and which came from media metadata.
Questions answered
Does a nonzero first timestamp mean damaged media?
No. Determine how the container and streams define their starting relationship before calling it an error.
Should every stream be reset to zero independently?
Only if that preserves the intended alignment. Independent shifts can remove the relationship you need to keep.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.