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MP4 Question


healium

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A friend of mine downloaded a bunch of MP4 music from iTunes or somewhere at 128kbps - she says that but rate doesn't affect the sound quality of these MP4 - she says since she paid for the whole CD it must be CD quality..

 

Is this true? is 128 MP4 better than 128 MP3?

 

Is iTunes selling music at CD price for download and then offering it at 128?

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A friend of mine downloaded a bunch of MP4 music from iTunes or somewhere at 128kbps - she says that but rate doesn't affect the sound quality of these MP4 - she says since she paid for the whole CD it must be CD quality..

 

Is this true? is 128 MP4 better than 128 MP3?

 

Is iTunes selling music at CD price for download and then offering it at 128?

dont know about mp4 vs mp3, but one thing i know for sure, mp4@128kbps isnt better than wav, flac for example is around 600-1xxx kbps and it still has bit lower bitrate than wav :)
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flac is same quality as wave..

its just kinda zipped up.. but lossless.. google for it :rolleyes:

yes, flac is zipped, but its lossless only when you exctract it back to wave, newly created wave will be as good as it was before compressing to flac, but flac itself when played is a tiny bit lower bitrate than wav, most likely no one could hear the difference tho, couse theres allmost no difference [well, NO difference in music quality anyway :)], perhaps with some software you can "spot" the difference, but music sounds indeed like wav.
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No!

read all of my posts above - when you play flac, it has no fixed bitrate, its variable, but when you play wav, you have one bitrate, and thats what i mean about it.

nor did i say that it loses in audio quality, just some bits that would probably be visible on some spectrograph or smthn, but not the sound itself, as i said, you wont notice any difference from wav and flac, except that flac sounds bit silent than wav.

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Lossless codecs are lossless all the way, not only when you decode them back to wav. If they were, who would and why use them? You have .rar that is better for these purposes :)

 

The cause of difference in sound when playing flac/ape/wv compared to wav is the plug-in.

 

FLAC doesn't have CBR, but VBR instead, why? Because some (more intence?) parts of the track are coded (archived) with the bigger amount of data, some parts (like silence?) don't need that much data. That is done to save space, time, resaurces.

 

I'm not sure, but I think when you play FLAC, your player decodes next 10seconds of the track to wav or something like that.

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Lossless codecs are lossless all the way, not only when you decode them back to wav. If they were, who would and why use them? You have .rar that is better for these purposes :)

 

The cause of difference in sound when playing flac/ape/wv compared to wav is the plug-in.

 

FLAC doesn't have CBR, but VBR instead, why? Because some (more intence?) parts of the track are coded (archived) with the bigger amount of data, some parts (like silence?) don't need that much data. That is done to save space, time, resaurces.

 

I'm not sure, but I think when you play FLAC, your player decodes next 10seconds of the track to wav or something like that.

well thats what im talig about :)

just didnt explain my point of view well enough :ph34r:

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we could agree on this - flac itself chooses how much should the bitrate be for the audio [well, it sets the right amount of bitrate]. while wav has only fixed rate, and thus indeed, silence in wave would take as much place as at peak of the track, while flac gets the best out of it and manages the bitrates the way that each part of the track takes as much space as it needs and not more :)

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dont know about mp4 vs mp3, but one thing i know for sure, mp4@128kbps isnt better than wav, flac for example is around 600-1xxx kbps and it still has bit lower bitrate than wav :)

You know the kbps IS the bitrate, of course 600 kbps is lower bitrate than wav (which is about 1400 i thnk?)

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OT, but there seems to be some misunderstanding regarding digital audio so let's clear things up once and for all :)

 

mp3: compressed, desctructive (the decoded result is not the same as the original format)

flac: compressed, lossless, the ZIP-analogy fits perfect for FLAC.. (the decoded result is exactly the same as the original format)

'Original format' above refers to the format from which the encoded file was encoded.

 

 

To be very specific, you do not play the actual encoded audio file, but you play the decoded version of that audio file..

Not sure if you fully understand this reger, but to me it sounds like you think the actual FLAC is played and FLAC chooses not to play the "unnecessary" bits which would only be seen in a "spectrograph". This is false :)

 

So MP3s or FLAC or any other encoded file for that matter, cannot be played per se. Your media player first decodes the file and plays the result in real-time. Going back to the zip analogy..

Let's say you zip a textfile to "file.txt.zip".. if you open that file in a texteditor it will just be garbage. To actually view it you need to unzip it of course! It sounds super obvious with text files but yes, that applies to flac too! If your media player would play and interpret the flac file as the decoded version it would be just random noise!

 

Lossless formats seem to confuse a lot of people (which is understandable: how can you 'remove' something and still have everything left?). Hope things got a little more clear now :)

 

 

EDIT: and back on topic:

A friend of mine downloaded a bunch of MP4 music from iTunes or somewhere at 128kbps - she says that but rate doesn't affect the sound quality of these MP4..

 

CD quality is a very ambigous term.. it's been used on 192-kbps MP3 and on FLAC as well. Basically it can have the meaning of near "CD quality" (high bitrate MP3), which means if you're not an audiophile you probably wont hear the difference between the MP3 and a CD version (wav) of it. Or it can be just "CD quality", which would apply to an album encoded to FLAC, see above for more details :)

 

- she says since she paid for the whole CD it must be CD quality..

Not sure what you mean but a lot of shops that sell "downloads" pay more for an MP3 encoded version of an album than you would have to pay if you bought the CD in a local shop (for some strange reason). So there are no 'must be' in this case..

 

Is this true? is 128 MP4 better than 128 MP3?

It depends, but it is most likely true yes. But also note that an 128 MP3 can be different from an 128 MP3! You can adjust the quality of the encoding process in most programs to speed up the encoding or increase the quality of the result.

So in the extreme case, very fast but low quality MP4 encoding (128), and very slow but very high quality MP3 encoding (128) the MP3 version could might as well win, but I'm not sure :)

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OT, but there seems to be some misunderstanding regarding digital audio so let's clear things up once and for all :)

 

mp3: compressed, desctructive (the decoded result is not the same as the original format)

flac: compressed, lossless, the ZIP-analogy fits perfect for FLAC.. (the decoded result is exactly the same as the original format)

'Original format' above refers to the format from which the encoded file was encoded.

To be very specific, you do not play the actual encoded audio file, but you play the decoded version of that audio file..

Not sure if you fully understand this reger, but to me it sounds like you think the actual FLAC is played and FLAC chooses not to play the "unnecessary" bits which would only be seen in a "spectrograph". This is false :)

 

So MP3s or FLAC or any other encoded file for that matter, cannot be played per se. Your media player first decodes the file and plays the result in real-time. Going back to the zip analogy..

Let's say you zip a textfile to "file.txt.zip".. if you open that file in a texteditor it will just be garbage. To actually view it you need to unzip it of course! It sounds super obvious with text files but yes, that applies to flac too! If your media player would play and interpret the flac file as the decoded version it would be just random noise!

 

Lossless formats seem to confuse a lot of people (which is understandable: how can you 'remove' something and still have everything left?). Hope things got a little more clear now :)

no baba, i understand what you talig, i was talig about when i play a track on winamp, i see flac going at around 600-1xxx kbps, while wav goes for fixed bitrate, some 1400 or smthn [?], thats what im talig about now :)
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yeah, but your spectrum analyzer talk was wrong :)

 

And yeah, you see the bitrate at around +600 kbps in your win(e)amp, what's your point? :)

It's like... hmm let's say there was a text editor which could automatically open zipped textfiles and display the unzipped version. And in the status bar it said "this was zipped to 80% of it's original size". That's how the bitrate should be interpreted in winamp

 

 

edit: The zipped text file analogy only works on lossless codecs! It doesn't make sense to destructively compress text..

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And yeah, you see the bitrate at around +600 kbps in your win(e)amp, what's your point? :)

It's like... hmm let's say there was a text editor which could automatically open zipped textfiles and display the unzipped version. And in the status bar it said "this was zipped to 80% of it's original size". That's how the bitrate should be interpreted in winamp

edit: The zipped text file analogy on works on lossless codecs! It doesn't make sense to destructively compress text..

then its weird and confusing :D
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Pretty much all the stuff you buy on i-Tunes comes in the MP4 format, which is definetly better then MP3. 128kbs MP4 is the equivalent of 320kbs MP3 or 192kbs WMA, if not better. And most people will never hear the diffenrence between the mp4 and the original cd, thats why we call it cd quality. Personally i think the MP4 format is the best if you want a high quality, but still want to save space on your hard drive or your mp3/mp4 player (128 kbs MP4 is about the same size as 128kbs MP3). If you rip your cds with i-Tunes, by default it should be mp4.

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Pretty much all the stuff you buy on i-Tunes comes in the MP4 format, which is definetly better then MP3. 128kbs MP4 is the equivalent of 320kbs MP3 or 192kbs WMA, if not better. And most people will never hear the diffenrence between the mp4 and the original cd, thats why we call it cd quality. Personally i think the MP4 format is the best if you want a high quality, but still want to save space on your hard drive or your mp3/mp4 player (128 kbs MP4 is about the same size as 128kbs MP3). If you rip your cds with i-Tunes, by default it should be mp4.

I thought you can download songs in AIFF format on Itunes which is uncompressed format essentially equivalent to Wav. You can later convert them to Wav or burn onto CD directly from Itunes.

 

Here is what Wikipedia says:

 

Audio Interchange File Format (AIFF) is an audio file format standard used for storing sound data on personal computers. The format was co-developed by Apple Computer based on Electronic Arts Interchange File Format (IFF) and is most commonly used on Apple Macintosh computer systems. AIFF is also used by Silicon Graphics Incorporated.

The audio data in an AIFF file are uncompressed big-endian pulse-code modulation (PCM) so the files tend to be much larger than files that use lossless compression (such as FLAC) or lossy compression formats such as Vorbis and MP3. Uncompressed AIFF files at compact-disc settings (44.1K samples/sec, 16 bits, 2 channels) thus have a bitrate of 1411.2 kbit/s. The AIFF-Compressed (AIFF-C or AIFC) format supports compression ratios as high as 6:1.

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