Converting Quality

[sai]

Does the quality of the music file decrease if you convert it? Of course if you choose a lower bitrate, the song will be of less quality, but I want to know if the conversion permanenty damages the quality of the file.

Example:

I convert a 192kbps mp3 file to a 128kbps wma file and then convert it back to a 192 kbps mp3 file. Will the quality of the song be impaired permanently or will it be the same as before I converted it?

Example 2:

I convert a 192kbps mp3 file to a 128kbps mp3 file and then convert it back to a 192 kbps mp3 file. Will the quality of the song be impaired permanently or will it be the same as before I converted it?

[LtData]

Re: Converting Quality

Your examples look exactly the same.
Anytime you convert from one lossy format to another, in your case mp3 to mp3, you ALWAYS loose quality. You can NEVER gain quality. So in your case, converting a 192kbps file to 128kbps will result in the final 192kbps file sounding like the 128kbps file, but with a higher bitrate and hence wasted space.

[sai]

Re: Converting Quality

I see. As for the conversion quality loss, does it only lose quality due to converting the file/s to a lower bitrate or does it also lose quality from generally converting a file.

[LtData]

Re: Converting Quality

Both. Converting a lossy file to another lossy file results in a quality loss. You also lose quality when you drop the bitrate.

[sai]

Re: Converting Quality

Oh...

With the exception of lossless files....which are unique to ipods only... :(

[LtData]

Re: Converting Quality

Not they aren't... Yes, there is Apple Lossless, but there is also FLAC, Monkeys, and some other formats. If you wanna get particular, you could also include WAV. Now, player support for these formats, except WAV, is few and far between, unfortunately. There are starting to be a few players that support FLAC, though.

[sai]

Re: Converting Quality

Oh. I also heard that mp3pro is something to be concerned about. Reviews suggest that the format is better than a regular mp3, such that you can get a same quality (bitrate) song in half the size?

[Tomb]

Re: Converting Quality

Oh. I also heard that mp3pro is something to be concerned about. Reviews suggest that the format is better than a regular mp3, such that you can get a same quality (bitrate) song in half the size?

Don't you believe it as this 64 k/bits test shows with lame 128 as the high anchor. As you can see MP3 OPro at 64 k/bits is not equal to lame mp3 at 128 k/bits.

Full results here. MP3 Pro seems now to be a dead format as well.

[sai]

Re: Converting Quality

I'm not sure. Technically mp3pro should be equal to half the size of a mp3 at with the same quality as shown here.

http://www.mp3prozone.com/basics.htm

Then again, I'm not sure if it's absolutely true, since the mp3pro technology staff are still developing its product? If I'm wrong please correct me.

[xoas]

Re: Converting Quality

The only real test for any listener is the test of your own ears.
Basically, my experience is that mp3pro is best used for those who want/need the highest compression possible while maintaining a shred of quality. Even then, I believe most users in that situation prefer to use wma.
However, if you want to try mp3pro, give it a try and compare it to the other formats you are interested in. Questions as to what format will be best for you need to be based on yur tastes, your equipment, your choices and your assessment of your own needs.

Best wishes,
Bill

[Tomb]

Re: Converting Quality

I'm not sure. Technically mp3pro should be equal to half the size of a mp3 at with the same quality as shown here.

http://www.mp3prozone.com/basics.htm

Then again, I'm not sure if it's absolutely true, since the mp3pro technology staff are still developing its product? If I'm wrong please correct me.

Commercial propaganda - almost as good as Microsoft claiming that wma at 64 k/bits equalled CD quality although they have now shifted this to 96 k/bits which still a joke to my ears.

Remember if a player does not support mp3pro you will just hear a mp3 file at whatever bitrate you encoded it at.

Bill is right though. Go with what suits you best. If you want to make some PC based tests I used Winabx.

[sai]

Re: Converting Quality

Okay. I should test the formats out myself and utilize my own ear. I was pondering what is the overall most effective format to encode music files regardless of hard drive space limitations. Please, I need logical answers and not "encode everything in 320 kbps mp3!!!" That is a waste of space, even though space is not a factor of what I'm querying.

[xoas]

Re: Converting Quality

I'm afraid that you need to be more specific as to what factors are important to you.
Logically, if quality is the only consideration you would want to choose one of the lossless formats, of which Flac and Ape are the most pre-eminent.
If, however, you are concerned about maintaining quality but economizing on disk space, then you would want to go with one of the lossy formats (mp3, ogg, musepack, wma, mp4/aac) but encoded at a fairly high level. How high that level will be will be determined by your ears alone. My own experience indicates that somewhere around 220-250 kbs appears to be my personal limit beyond which I can no longer distinguish differences in quality. I have not toyed with wma to see if their quality per space advantage would carry over to higher frequencies in which case I met get by with similar quality for about 160-160 kbs.
If space is more of a consideration then go with one of the lossy formats at lower bitrates. If you are satisfied with 128 kbs. mp3 quality then you might want to consider wma or mp3pro where you can get the same quality for about 96 kbs (to my ears). A potential drawback to mp3pro, as has been pointed earlier, is that for highest quality playback you do need to use an mp3pro player, otherwise the file will be read and played (and heard) as an mp3 file so that your 96 kbs mp3pro file will sound like a 96 kbs mp3 file.
Then there's the practical aspects. First, if you have a lot of mp3's or other music encoded at 128 kbs, it makes little sense to re-encode at a higher bitrate (as has been discussed earlier in this thread). Second, if you don't have a player that will play a given format then that format is not a good choice for you. Third, if you have a car mp3 and/or wma player, or if you have a portable musical device (such as an iPod) then you will probably want to consider using a format that is compatible with your portable device. Also, with a car player or a portable player you might often want to use a lower bitrate than you would use at home since the listening environments these are used in are typically not high quality listening environments so more quality will not necessarily be appreciated in those contexts. A big exception to this is with Sony and their Atrac/Atrac 3 format. I would strongly advise against storing all your music in Atrac/Atrac 3 format (which is proprietary) because you will find it extremely difficult to re-encode these files to anything else.
If you wanted to use music (to which you had the rights) to use on an internet web site, then other considerations would come into play as well (and here you might want to consider Realaudio or highly compressed wma or mp3). If you have a cell phone then you need to check what formats are available through the manufacturer and you will undoubtedly want to use a high level of compression.

Anyway, I hope this gives you a feel for what would be logical considerations in choosing a format.
Best wishes,
Bill

[sai]

Re: Converting Quality

You made yourself fairly straight Bill. Thanks for your opinion.

Though I have a few straight questions regarding file converting.

Should I convert a mp3 192+(not equal to 192, but above) file into a 192 kbps mp3 or should I find a file that is originally 192 kbps?

As for my mp3 player, which contains 5 gigabytes, should I encode my mp3s to 128kbps files and keep the 192 kbps files on my computer? (note:I use earphones with my mp3 player and a basic stereo system with my computer)

[xoas]

Re: Converting Quality

Should I convert a mp3 192+(not equal to 192, but above) file into a 192 kbps mp3 or should I find a file that is originally 192 kbps?

Theoretically you will always be better off using a 192 kbs file converted straight from source (like cd) rather than from an already lossy converted file. In practice, I doubt you would find the extra effort to be worthwhile. Again, try it out and see if it makes a difference to you.

As for my mp3 player, which contains 5 gigabytes, should I encode my mp3s to 128kbps files and keep the 192 kbps files on my computer? (note:I use earphones with my mp3 player and a basic stereo system with my computer)

You may find this useful. Many users save files at a higher rate for home use and at a lower rate for portable use. Some prefer to make backup copies in lossless format (which you can do using using dB CD Writer if you don't want to use up hard drive space but are ok with the layout for cd-rom discs) to maintain highest quality backup.

Best wishes,
Bill