mark truncated filenames with ellipsis "…" in -o template if length exceeds x bytes

[chrizilla]

DO NOT REMOVE OR SKIP THE ISSUE TEMPLATE

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Checklist

• I'm requesting a feature unrelated to a specific site
• I've looked through the README
• I've verified that I'm running yt-dlp version 2023.03.04 (update instructions) or later (specify commit)
• I've searched known issues and the bugtracker for similar issues including closed ones. DO NOT post duplicates
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Provide a description that is worded well enough to be understood

(Asking here so as not to lead #1136 further off-topic.)

In #1136 (comment) a solution was proposed to mark truncated filenames in -o template:

Add a %(title.201&…|)s - read as "if title.201 (201'th char) exists, then (&) add …, else (|) add nothing"

This works for character count but apparently not for the subsequently discussed byte count (which may be more useful when dealing with unicode chars):

yt-dlp ZYlALC1Pmv4 --skip-download --no-config --print "%(title).50s%(title.51&…|)s"
Hubble Space Telescope, Planet 9, Curiosity Mars R…    # truncates at 50 chars and detects 51st char

yt-dlp ZYlALC1Pmv4 --skip-download --no-config --print "%(title).50B%(title.51B&…|)s"
Hubble Space Telescope, Planet 9, Curiosity Mars R     # truncates at 50 bytes but doesn't detect 51st byte

I guess this is either the wrong syntax or not yet possible to do.
In the latter case, would it be worth considering this new syntax as an enhancement ?

Provide verbose output that clearly demonstrates the problem

• Run your yt-dlp command with -vU flag added (yt-dlp -vU <your command line>)
• If using API, add 'verbose': True to YoutubeDL params instead
• Copy the WHOLE output (starting with [debug] Command-line config) and insert it below

Complete Verbose Output

No response

[mikkovedru]

I confirm your bug report. The format %(title|).160B%(title.161B&…|)s doesn't work on my system either, despite it being suggested in many topics.

[clusterized]

Shouldn't "%(title).50B%(title.51&…|)B" do the trick?

[mikkovedru]

Shouldn't "%(title).50B%(title.51&…|)B" do the trick?

It actually did. Thank you @clusterized !