Recoding mp3 to ATRAC

[Darkeyed Tormentor]

It is wellknown, that if you encode mp3 to ATRAC (WMA and so on), the sound quality is reducing: mp3 codec compresses the origin in it's way, and ATRAC do the same in another way. So there double compression has a place.

But in the era of Hi-MD we can always use high-quality codec Hi-SP (256). And if we encode low-bitrate mp3's (128-192) by this codec, the result, i believe, is to be near the origin mp3. I hope, i've expressed clear enough.

Am I wrong? Don't you think, that in some degree it solves the problem of direct mp3 playing on MD/Hi-MD units?

[mutant1345]

well my thinking is its playing 256 k/bits per second of the source file so its just taking a bigger chunk of the files quality with it instead of just a little bit

i use hisp when encoding mp3s but for cds directlry from simple burner i spare to use a smallr bitrate as the uncompressed music is going directly to the unit with only one compression

i am still a little angry that simple burner does not alow direct pcm recording to a md when it is a direct transfer but ...whatever

but yes anyways, i dont think i understand what you mean by solving the problem with playing the mp3 directly

i think that if we did play mp3s directly on the units space on the disc would be bad for music i think if encoded in higher bit rates

but and atrac i think sounds better than mp3s

but im known to be crazey when it comes to sound quality

thats my opinion whats yours?

[Darkeyed Tormentor]

Yes, English is not my native, as you see, so i have some problems to describe my question.

Imagine the situation: We have a musical CD(1411kbps, pcm). We encoded it by mp3 codec (128kbps). That was the first compression. The mp3 codec has cut some frequencies, cut some fragments, which are inaudible for human's ears (anyhow codec "considers" so). Then we encoded this mp3 file by ATRAC. So it is the second compression. As ATRAC is not the same as mp3 codec, it has another principle of compression. So ATRAC may cut one more "inaudible" fragments. For example, mp3 codec cut 10 fragments + ATRAC cut 5 fragments more because of other principle. So after second conpression we have 15 cutout fragments versus 10 in case of one compression. I think, i described the effect of double compression visually enough.

But if we use high quality atrac codec (256 for example), the problem of double compression becomes not so sharp (critical). With a high probability mp3 codec (128 or 192) has cut all the fragments which ATRAC (256) was only going to cut, so it wouldn't cut anything (or cut a little) and we would get a sound quality equal to mp3 file. So the double compression effect don't take place.

And when I talked about "direct mp3 downloading on MD unit", i ment there is no double compression and the sound quality is equal to mp3 file, which was downloaded. That's why I said, that "in some degree it solves the problem of direct mp3 playing".

So, the question stays the same: am I wrong?

[skmetal07]

when u say "direct mp3 playing" i think u mean to play mp3s right on the minidc player, i understand everything that u are saying, but it still doesn't solve the mp3 playback limitation because there is still a conversion, yes it is very close to the original mp3 but it still takes time to convert it and that is what people hate. when we mean direct mp3 playback we mean to drag and drop mp3s from the hard drive right on to the minidisc with out the conversion.

i guess using hi-sp to convert mp3s would give u the best quality without taking up too much space

[mutant1345]

well atrac isnt just an encoding to compress and take out certain sounds it was origonaly designed to make the songs you wanted to put on the old mds (with 1/5th the space of a cd) fit because they were not capible of holding music in any other compression and still hold fair quality

but now that sony is measuring in gigs instead f mins due to the extreme increase in amount of minutes it can hold now

the reason sony wishes not to make the players mp3 compatible in the first place is beacause they are in charge of atrac and can control our music with it

atrac started as a great compression to make files fit on the md easier than mp3 but now it is sonys way of restricting our music and making people like marcnet make software themselvs in order to gain back our control

i still think we are able to fit more music on the players now in atrac than if we used mp3

because and average mp3 is about 5 megs give or take 1 or two

and that means that we could fit around 200 songs more or less on the discs

sure if you did this you would get more freedome to do with

but i would rather use atrac and get more space than mp3 and get less space for music

[bjsilva]

mutant1345:

The file size depends on the bit rate (misc info is probably nominal). Therefore, an MP3 file at 256k would be more or less the same size as a 256k (hi-sp) ATRAC file.

I think Sony keeps using ATRAC because they like their product (for various reasons). MP3/AAC/WMA are all capable of using a DRM scheme.

[jadeclaw]

bjsilva, Atrac has something, other codecs don't have: Editability. Sometimes it is that simple...

[dex Otaku]

ATRAC has something that others don't have: editibility. Yes. Main reason being [at least with pre-atrac3+ codecs] that frames of atrac data correspond exactly in length to frames or segments of CD-DA data, which is why things like gapless playback from accurately ripped sources are possible.

Fixed packet-length [and identical source/decoded streams, i.e. sample rate the same] is [/are] crucial to the whole editibility question, and technically any codec that supports fixed packet-length can support editibility as long as the stream can be identified and decoded starting with any arbritrary block.

This doesn't really make ATRAC unique for these qualities. It just means that ATRAC is well-implemented with MD. DRM and editibility are more about carrier design [media format] and container design [file system / file type] than they are about a codec. The codec is actually irrelevant to both when it comes down to it.

That said, Hi-MD andthe new hdd players etc. from Sony that use atrac3+ are built for DRM from the ground up because of built-in encryption. Again, that's an implementation thing, though, and isn't necessarily unique to atrac3+. It would be just as simple to take an mp3 stream and do the same with it [except that the known decoding methods for mp3 would make it much easier to crack the encryption, so it makes good sense for Sony to use their proprietary encoding to discourage this].

Woohoo.

[bjsilva]

jadeclaw and dexOtaku, thanks for the info, I was not aware of that. Very interesting!