Re: Transcoding between lossless formats, bitrates, and preserving lossy content
Reply #3 – 2020-05-29 11:13:43
Would it be best to convert to a lossless format to retain all of the already-lossy audio? To fully keep quality you can only use lossless. But you may get the same perceptual quality by using any lossy format but it depends of many factors.Will you further lose fidelity, and if so how much? 1%, 10% etc You can't precisely quantify in a reliable way the loss. From lossy to lossy you get something different , and not necessary inferior perceptualy. You can even get better subjective quality with reencoding (i.e. if the second lossy encoding removes ringing).And also, if you flip back and forth between two lossy formats, will you ultimately end up with a stable/unchanging file or will every conversion yield more and more and more loss? Each new iteration changes the signal. Depending on the encoder/format and the listener, this change may be audible or not.Specific to MP3 - would a 10-15yr old MP3 at 320k be worse/same/better than a modern MP3 rip at 192k for example? 10…15 years old doesn't mean that much. There were few progress (if any) with MP3 during the last ten years and some 10…15 years encoders are simply excellent. You might keep the same subjective quality if you compare a very old ISO or close to ISO MP3 encoder at 320 kbps (like BLADE MP3) with a modern VBR encoding at ~192 kbps. Again, it depends of the listener. BTW if your old MP3@320 are coming from unknown source it may be a good idea to consider a switch: many files shared on internet were transcoded from inferior bitrate source. Also keep in mind that the opposite way of thinking also work: a bad MP3 encoder can be used to efficiently reduce the size of a 320 kbps LAME 3.100 without subjective loss. Again it depends very much of the listener. In short: try yourself. Depending on your subjectivity, your skills, your music, your sources, and your output format and its settings you might get really good results while re-encoding to a different format at inferior bitrate. But there is no universal answer and what works for someone could sound unacceptable to the other.