When converting audio files, it would make sense to avoid converting into a higher bitrate, as it is commonly understood that you can never recapture data lost in a previous conversion. Read on to see, however, when upgrading the bitrate is just what the digital doctor ordered.
Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.
SuperUser reader Cipricus poses the question:
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?
This is an important consideration; there’s no point in expanding the size of your files by X% if there isn’t an increase in audio quality.
SuperUser contributor Linac offers a practical answer to his question. Despite what popular opinion would have us believe, there are practical reasons for upgrading the bitrate during conversion:
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.
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