Do you have more details on the Firefox problem?
I have a WebRTC project that is currently in standby (priorities changed) and one issue that I have not been able to troubleshoot was an inability to send audio from Firefox while it somehow worked on Chrome.
Miller (mlr) is now my goto tool for csv/tsv manipulation.
I've used it from time to time during the past year and it's been a joy to use.
I must admit that I did not try any other tool for the purpose so I don't know how it compares.
I did an internship last year which consisted in writing unit tests for a raytracing library that was among other things - I was told - used to determine if buildings were on paper getting enough sunlight according to european standards.
I'm not sure whether they were talking about EU regulations or about the regulations of specific european countries.
I don't know how it compares to xsv, but you might be interested in Miller/mlr (http://johnkerl.org/miller/doc/index.html), I've used it because csvkit was too slow for what I needed to do and was pleasantly surprised by its features.
That's funny because I am a native French speaker and I find German to be a very pleasing language to speak out loud. The sonorities are oddly satisfying to me.
Please note that I am nowhere near fluent in German. It just feels great, especially the way words can agglutinate to form comically long words, while still transporting meaning.