Bug: Subtitles scale on transitions in custom frame sizes

I get a repeatable bug when using subtitles in v15.0 and v15.1 when working in a custom frame sizes (in this case, 3840x1634). In real-time playback, the subtitles work as expected, but upon rendering the timeline, any transition points (like dissolves or text elements) in the timeline causes the subtitle to jump in scale during that transition. My output preview is 1080 scaled within the Resolve preferences.

As a temporary bandaid, I copy the subtitles to a blank timeline, add black to the video timeline, encode out to a new video file and bring back into Resolve to the original timeline to the top layer with Add composite mode to knock out the black. Not ideal but works for now.

[Shrinivas Ramani]

Hi Marco

I tried some simple testing scenarios and I was not able to observe this behavior.

Could you give us more info about your system, and post a link of your exported project file (.drp) ?

Thanks
Shrinivas

I have just encountered this in version 17.3. Can anyone assist, I have an urgent delivery?

My project resolution in UHD 4K but my custom output is 3840 x 1634 for a 2:35 aspect ratio.

[Shrinivas Ramani]

Hi Misha

I just tried multiple scenarios with UHD to 3840x1634, with different skewed PARs, output mismatches and other settings.

As mentioned above, I'm not able to see this behavior with the usual suspects - so we will need to check what is different about your setup that causes this issue. The more info you provide, the likelier it is that we can catch this issue. Please start with linking an example project (however small), logs and screenshots to show what the scaling is.

For urgent projects, do consider workarounds - like rendering a mezzanine video without subtitles, creating a timeline matching the video's resolution and PAR, and copying the subtitles across for a second pass into the desired format.

Regards
Shrinivas

I get this problem and find that clearing render cache and re cache if necessary seems to fix it

Unfortunately,

While it does fix it for a second or two it usually resorts almost immediatly.

I had to perform a workaround by burning in the subtitles on a 16:9 export. Importing that then re-exporting in 2:35:1.

You need to blow the cache for every resolution change.
V17 is a bit better at it all - not inclined to update?
I have had no trouble working across software updates from V15 across betas for 16 & 17 with no detriment. (A little anxiety but for nought!).
The issues that I have had and still find occasionally are usually around transitions and is probably a reflection of the render cache settings.

Your solution probably fails to take advantage of all the resolution independence.