bluecrab Posted January 22, 2017 Report Share Posted January 22, 2017 I'm having a hard time finding an answer for this: It seems to me that MD ATRAC1 files don't actually get uncompressed for playback, as they already contain all the data they will ever have. So, they don't have to be uncompressed dynamically for playback. Is that true? How about MP3 (et al.) then? Same as MD or is there a different process used for playback? To give another example, just so I'm being clear, FLAC and ALAC files, while compressed, do contain 100% of their original data; thus, it seems to me that such files are uncompressed/decoded dynamically for playback. Quote Link to comment Share on other sites More sharing options...
NGY Posted January 22, 2017 Report Share Posted January 22, 2017 My understanding is that it is rather decoding than "uncompressing", when it comes to playback. And it is done by the codec of the given format. When "compressing" and audio file, it is actually encoding it (again, by that codec), and in case of certain formats this encoding can reduce the actual file size compared to the original wav audio - either lossy or lossless way, depending on the format. FLAC encoding is lossless, mp3 and ATRAC are lossy. Quote Link to comment Share on other sites More sharing options...
freddyjollo Posted January 22, 2017 Report Share Posted January 22, 2017 the compression only applies to reducing the size of the resulting file, where datas is THROWN AWAY - its not a zip/unzip idea. Atrac codecs used various psycho-acoustic facts like if 2 sounds are of the same frequency with one quieter than the other , you wont hear the quiet one so can be discarded without impairing the sound you hear- maybe a Martian could hear the difference but Humans cant Quote Link to comment Share on other sites More sharing options...
NGY Posted January 22, 2017 Report Share Posted January 22, 2017 7 minutes ago, freddyjollo said: the compression only applies to reducing the size of the resulting file, where datas is THROWN AWAY - its not a zip/unzip idea. Well, in the case of FLAC, it is very close to the zip/unzip idea. WAV is "compressed" to FLAC without throwing away any data, and the exact same WAV can be restored. The FLAC file is resonably smaller, than the original WAV file. Quote Link to comment Share on other sites More sharing options...
freddyjollo Posted January 22, 2017 Report Share Posted January 22, 2017 yes was talking about normal Atrac - I know there are other more modern systems that remove redundant data that can easily be replaced on listening - similar ideas no doubt to how hard discs can be compressed. the op seemed puzzled at why atrac dont need uncompressing and presumably "superior" to eg Flac Quote Link to comment Share on other sites More sharing options...
NGY Posted January 22, 2017 Report Share Posted January 22, 2017 8 minutes ago, freddyjollo said: the op seemed puzzled at why atrac dont need uncompressing Because ATRAC is not compressed. It is encoded. Quote Link to comment Share on other sites More sharing options...
NGY Posted January 22, 2017 Report Share Posted January 22, 2017 14 minutes ago, freddyjollo said: why atrac dont need uncompressing and presumably "superior" to eg Flac We cannot really compare ATRAC and FLAC, a lossy and a lossless format. "Superiority" of ATRAC shows only on the playback side (like 20 bit oversampling etc.), while FLAC "simply" plays back the original audio - but preserves every single bit of it during encoding. Quote Link to comment Share on other sites More sharing options...
freddyjollo Posted January 22, 2017 Report Share Posted January 22, 2017 I dont know why you are taking issue with what I say as I am not saying any of the above which u are taking out of context and misreading Quote Link to comment Share on other sites More sharing options...
NGY Posted January 22, 2017 Report Share Posted January 22, 2017 1 minute ago, freddyjollo said: I dont know why you are taking issue with what I say as I am not saying any of the above which u are taking out of context and misreading Am I? I am very sorry, if you misunderstood what I wrote. Where did I take anything out of context and misread? Quote Link to comment Share on other sites More sharing options...
bluecrab Posted January 23, 2017 Author Report Share Posted January 23, 2017 Let me as the OP just hop in for a second, if you would. I completely understand that ATRAC files are decoded, not uncompressed, for playback. There is really nothing left to uncompress. So I wanted to know if MP3 also works that way. As for ALAC/FLAC, these files are assuredly compressed to begin with; then they have to be decoded for uncompression. So I think, anyway. The reason I thought of any of this at all was that while listening to my JA22ES, I thought it sounded really good. And I wondered if, since an ATRAC file does not need uncompression, that might be a kind of processing benefit (like one less step). Wondered, too, if MP3s are similar to ATRAC files in that way, or not. I really didn't mean to start anything contentious though! Quote Link to comment Share on other sites More sharing options...
freddyjollo Posted January 23, 2017 Report Share Posted January 23, 2017 well one question since Atrac is a discarding codec rather than an zip/unzip one are the resultant files actually decoded on playback unless they are encrypted? Quote Link to comment Share on other sites More sharing options...
punkrockaddict Posted January 23, 2017 Report Share Posted January 23, 2017 one can compare Atrac with mp3 as they work very similar. The decoding is less besides the encoding takes it to the limit. If im not completely wrong the decoding is the same for flac as the compression only takes place when the file gets created. Quote Link to comment Share on other sites More sharing options...
sfbp Posted January 23, 2017 Report Share Posted January 23, 2017 The major difference between ATRAC and MP3 is, if I recall the explanation correctly. one is in the time domain and one in the frequency domain. As well, later versions (ATRAC3/+) take special care with encoding certain recurring frequencies (ie steady notes) in the output by subtracting them out and encoding separately, thereby leaving more bits for the rest of the sound to be encoded (this means for example that pipe organs sound surprisingly good at low bit rates). ATRAC uses fixed frames covering a certain amount of time (i don't recall). All this stuff can be found on minidisc.org. Stephen Quote Link to comment Share on other sites More sharing options...
bluecrab Posted January 24, 2017 Author Report Share Posted January 24, 2017 Thanks one and all. I finally found the right article to read about MP3 and I now understand that, as far as decoding/uncompression, MP3 and ATRAC are more similar than different. Neither is truly compressed in the same sense as a compressed, non-lossy data file. In any case, I intend to go on listening to MD and to avoid MP3 when possible, at least in the realm of lossiness. Pretty happy with ALAC, too, although to my ears, the best digitally sourced sound is still to be had from CD. (Maybe I like my CDP-XA20ES and its bass-heavy DAC a bit too much!) Quote Link to comment Share on other sites More sharing options...
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