Liệu nó có ý nghĩa để chuyển đổi một tập tin âm thanh thành bitrate cao hơn không?

When a certain file (mp4, flv, etc) has a 95 kbps audio bitrate – does it make sense outputing to a higher bitrate when converting to mp3 or other format (be it lossy or not)?

Would this result in higher audio quality or just in a bigger file?

Yes, it might actually make sense if you are being forced to change formats.

If you have a file with 95kbps in a highly efficient format, to retain the same quality, a relatively inefficient format as mp3 needs a higher bitrate.

Of course you will never get anything back that was lost in the first place. On the contrary, encoding as mp3 will reduce the quality further. Every lossy format uses other means to reduce the amount of data that is stored, by (simplified) throwing away “unneeded” parts of the data. Round trip through a bunch of different formats and there won’t be much left …

So if you want to stay as close a possible to the quality your file has now, you should chose a higher bitrate. 320kbps are probably wasted space, but for mp3 something in the order between 128 and 192 is needed to maintain – or at least come close to – the quality of a more efficient 95kbps file.