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cta-wave / mezzanine

This repo contains scripts that will build annotated test content from specific source content, compatible with the WAVE device playback test suite.
BSD 3-Clause "New" or "Revised" License
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AV sync flashes not in sync for lowest frame rates (e.g. 15fps) #26

Closed nicholas-fr closed 3 years ago

nicholas-fr commented 3 years ago

For the existing 15fps mezzanine streams, AV sync flashes are sometimes not in sync, as the script generates them too close together for the low frame rate.

The script generating the AV sync flashes and beeps was not initially intended for use at such low frame rates. I will look at how it can be updated to resolve this.

As a fallback AV sync could be disabled for the 12.5fps and 15fps streams.

nicholas-fr commented 3 years ago

This was observed during playback of a switching set of test content generated using multiple mezzanine streams. The issue was not caused by the mezzanine, but by the combination of audio from mezzanine of a higher frame rate (e.g. 60fps), with video from mezzanine of a lower frame rate (e.g. 15fps). No changes to mezzanine are needed.

Test content generated for AV-sync testing should always combine audio and video from the same mezzanine stream, to ensure the audio beeps are synced with the flashes.

For discussion in a later stage when addressing AV-sync testing.