On 04/04/2025 15.36, jeremie bergeron wrote:
I'm not trying to edit the subtitle, so no, it doesn't really help me.
I want to know if the player must use the Clock Timestamps or Frame
Timestamps to know when to display the subtitle.
I never gave it a thought before. Thanks for this opportunity.
If you connect to the TV via component cables or HDMI, then the TV gets television, CEA-861 (NTSC or
PAL), and CC (closed captioning), and that's all. Since the video _must_ be in television frames,
I'd say that the subtitles must already be rendered and superimposed over frame images -- except for
CC, television displays content solely in frames.
So I'd say that subtitles must have elapsed-time timestamps that fit them into their intended
frames. Subtitle Edit's Beautify time stamps does that.
Le ven. 4 avr. 2025 à 14:10, Mark Filipak <markfilipak.tr...@gmail.com> a
écrit :
On 04/04/2025 10.16, jeremie bergeron wrote:
Hi,
This is not strictly an FFmpeg question but rather a general video
processing question regarding when subtitles should be rendered.
In this discussion, we are debating whether subtitles should be displayed
based on *clock timestamps* or *frame timestamps (PTS)*.
Let's say I have a video with those timestamps:
-
Frame 0: 0 ms
-
Frame 1: 42 ms
-
Frame 2: 83 ms
... continues
Frame 9: 375 ms
... continues
Frame 20: 834 ms
Now, let's consider a subtitle that starts at *400 ms* and ends at *860
ms*.
Subtitle Edit (https://www.nikse.dk/subtitleedit) has a tool called
"Beautify time codes". The tool
snaps subtitle times to the elapsed-time equivalents of frame PTSes. So
your 0:0.400..0:0.860
subtitle would snap to 0:0.375..0:0.834.
Hope this helps.
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