SOLVED: FFMPEG: Extremely Long Video Output

I was compressing and scaling a collection of videos that had picture-based subtitles, and getting video output that was very long. The input video was less than an hour’s duration; the output was over 1100 hours! I was going to ask a question here, but then I solved the problem thru some forum posts on loosely-related topics that didn’t look likely to help.

It turns out I needed to include “-fix_sub_duration” before specifying the input file:

ffmpeg -fix_sub_duration -i input.mkv etc. etc.

It seems that this causes ffmpeg to take stock of the loose approach to specifying subtitle durations with picture-based subtitles, and in so doing, avoid extending video unnecessarily, potentially for hundreds of hours. See the ffmpeg documentation: ffmpeg.org/ffmpeg.html

HTH