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IDProjectCategoryView StatusLast Update
0005575The Dark ModSoundpublic31.03.2021 21:36
ReporterGeep Assigned To 
Status newResolutionopen 
OSWindowsOS Version10 
Product VersionTDM 2.09 
Summary0005575: When Uncapped FPS is Off, Video Cutscene Loses Audio Sync
DescriptionAs reported in stgatilov's [[Time frames and ticks]], when uncapped FPS is off, the game runs slower by 4%, due to integer time issues. This adversely affects playback of video cutscenes. The currently available methodologies for video cutscenes require use of a separate .ogg audio file (even though the video itself contains audio).

In particular, with the "GUI Message Overlay Method" described in my wiki article [[Full-Screen_Video_Cutscenes]], it was observed that synchronization is fine with Video > Advanced > Uncap FPS ON. With Uncap FPS OFF (and Max FPX 60), playback is synchronized at the beginning, but as time goes on the audio increasingly precedes the video. This is consistent with the audio playing at proper speed but the video framerate too slow.

Since the mapper has no control of whether the gamer uncaps FPS or not, this presents a problem.
Steps To ReproduceThe foregoing observation was in my FM WIP.

[TO DO SHORTLY: Create a simplified map with cutscene that demonstrates the problem and can be used as a test of any solution]
Additional InformationIt is not yet known if the other video cutscene method, using a Movie Theatre, represents a viable workaround, or suffers the same problem (but probably).

The best solution would be to no longer require a separate ogg file, but use the audio within the .mp4, presumably enforcing sync. Could the reported special coding applied in TDM 2.06 for video briefings with embedded audio be extended to video cutscenes?
If so, this could be restated as a feature request.

A workaround, at least for an audio track with talk and no music, is to chop it into short segments (under 30 seconds and between sentence boundaries), each of which is then script-started independently after an appropriate wait. These segments would ideally be short enough so that the sloppy sync is not too obvious. Ugly work, though.
TagsNo tags attached.




31.03.2021 17:24

reporter   ~0013823

A test FM with video that demos the problem is available. PM me for a link


31.03.2021 21:36

reporter   ~0013824

Confirmed that the Movie Theatre method exhibits the same bug.

Issue History

Date Modified Username Field Change
31.03.2021 03:13 Geep New Issue
31.03.2021 17:24 Geep Note Added: 0013823
31.03.2021 21:36 Geep Note Added: 0013824