Preserve Quality

[sure12345]

Hi,

I would like to take my entire MP3 collection, which are all at different bit rates, and re-encode them so they are all encoded by the same codec. Since they are all encoded at different bit rates, can this program somehow automatically re-encode them using the same bit rate it is already encoded at? If not, is there a program out there that can do this?

[dbample]

Re: Preserve Quality

I would like to take my entire MP3 collection, which are all at different bit rates, and re-encode them so they are all encoded by the same codec.

Actually this is not a very good idea. If you do this, you are guaranteed to get worse sound quality than what you started with no matter what new/higher bitrate you set. Re-encoding files coded in a lossy mp3 format means that they get decoded first, then re-encoded in a lossy mp3 (different bit rate), throwing away whatever the encoder decides (and it will throw out more audio information even if you start with 96kpbs and want to re-code it to 160kpbs, say).

This same argument applies even if you re-encode at the same bit rate - you still lose audio information, thus get lower sound quality.

So if you have the original CDs, better encode (with the same codec) to mp3 from the originals.

[sure12345]

Re: Preserve Quality

no, no original cds. I have a bunch of mp3's that are causing my ipod to restart. It never did that with my creative mp3 player. When a particular mp3 that causes my ipod to restart is re-encoded with a new lame codec it works just fine. So i wanted to do this on all my mp3's so i could stop worrying about this. What if i took all my files, which typically range from 128 to 192 and wrote them to wav then to like 256 or 224?

[ChristinaS]

Re: Preserve Quality

No point in increasing bitrate, you do not gain quality, and in re-encoding you lose quality no matter what settings you pick. A higher bitrate only means the files are bigger.

If you simply want to re-encode in order to use a particular mp3 encoding codec, then re-encode to the same or lower bitrate than what they are.

[sure12345]

Re: Preserve Quality

I see that, but my original question was if there was some way this program could "autodetect" what rate that was and encode at that rate, so I don't have to sit there and do this for my entire mp3 collection. My brute solution was just to choose a higher bitrate so i wouldn't have to worry.

[ChristinaS]

Re: Preserve Quality

Hmm, no it doesn't seem to be possible. Frequency, channels can be set "as source" but no so the bitrate.

I suggest you sort your folder by bitrate (you can show these attribute in Windows Explorer by adding display columns) and select a group at a time to convert using the same bitrate.

[dbample]

Re: Preserve Quality

I suggest you sort your folder by bitrate [...] and select a group at a time to convert using the same bitrate.

I would still caution that re-converting to the same bit rate using a different encoder will result in additional loss of audio quality, mostly because the new encoder does not know or remember what the old encoder did or how it was done.

[sure12345]

Re: Preserve Quality

If i did this to like 10 files, and I was happy with the output, would that be a good enough test? Pretty much what i'm trying to say is, does it vary a lot from mp3 to mp3 as to how much quality i will lose when doing this, or will it remain pretty much the same.

Thanks again for all your help

[dbample]

Re: Preserve Quality

If i did this to like 10 files, and I was happy with the output, would that be a good enough test? Pretty much what i'm trying to say is, does it vary a lot from mp3 to mp3 as to how much quality i will lose when doing this, or will it remain pretty much the same.

Sure, the bottom line is that if your ears cannot perceive a change, and you are happy with the re-encoded files, it would be OK.

As to your second question, it will possibly vary a lot how much quality you lose depending on how different the original encoder and your chosen new mp3 encoder are.

I've also heard reports that even if it is the same encoder, you could end up with less audio info in your re-encoded file because on re-encoding the encoder would throw out slightly different audio bits and therefore throw out not only the filler that the mp3 decoder inserted upon decoding the file to an uncompressed pcm wav-type file, but also some other audio that was into the original mp3-encoded file.

[sure12345]

Re: Preserve Quality

Thanks for your help everyone, you are all very kind. I will be trying it out tonight when I get back from the library and I'll let you know how it turns out.