0002994: verify framerate of the subtitle xml

ID	Project	Category	View Status	Date Submitted	Last Update

0002994	DCP-o-matic	Features	public	2025-03-05 23:45	2025-03-08 02:23

Reporter	stereo3d	Assigned To
Priority	normal	Severity	minor	Reproducibility	N/A
Status	confirmed	Resolution	open
Platform	Mac AMD	OS	OS X	OS Version	15.2
Product Version	2.18.12
Target Version	2.18.x

Summary	0002994: verify framerate of the subtitle xml
Description	the SMPTE specs specify a frame rate for the dci subtitles. I noticed this frame rate can be different from the frame rate of the main picture. if the frame rate is different the player cannot find the correct timing with the timecodes. It seems the frame rate of the subtitles is counted in units of the main picture. This also makes it difficult to have the same subtitle files for the same movie with different frame rates. It could be an interesting feature to verify if the framerate matches the main picture or recalculate the TCs if necessary. I guess this affects many downwards compatibility from higher frame rates to lower.
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Branch
Estimated weeks required
Estimated work required	Undecided

stereo3d 2025-03-08 02:23 reporter ~0006866	information Editrate/Framerate for subs 5.8 EditRate Element The EditRate element shall encode the rate at which the virtual timeline progresses. It shall be expressed as a ratio of two integers giving the number of editable units per second of real time. 5.9 TimeCodeRate Element The value of the TimeCodeRate element shall be equal to the value of the EditRate element rounded to the nearest integer. For example: If the value of the EditRate element is “24000 1001”, then the value of the TimeCodeRate element will be 24. If the value of the EditRate element is “200 11”, then the value of the TimeCodeRate element will be 18. In case where the EditRate ratio corresponds exactly to the mid-point of two integer values (e.g., 23.5), then the value of the TimeCodeRate element shall be equal to the value of the EditRate element rounded to the nearest higher integer (e.g., 24 in this example). The TimeCodeRate element shall encode the count of subtitle editable units for each increment of the seconds field (SS) of a subtitle time code — see Section 4.2.5. It shall be expressed as a positive (non- zero) integer value. SMPTE ST 428-7:2014 Revision of SMPTE ST 428-7:2010

Date Modified	Username	Field	Change
2025-03-05 23:45	stereo3d	New Bug
2025-03-06 00:08	carl	Reproducibility	always => N/A
2025-03-06 00:08	carl	Status	new => confirmed
2025-03-06 00:08	carl	Target Version	=> 2.18.x
2025-03-06 00:08	carl	Estimated work required	=> Undecided
2025-03-08 02:23	stereo3d	Note Added: 0006866