* ffmpeg: a sentence should not begin with an object pronoun.
* img2pdf: fixing a verb tense, and rephrasing to match the original in English.
* java,javac: fix verb tenses.
* mongo: translating a word that doesn't need to stay in English.
* ssh*: translating a word(s) that do(es) not need to stay in English.
* ffmpeg,ssh: updating command accordingly to the English version.