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  1. Member
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    Is it better in terms of Quality to convert FLAC files to WAV then convert them into M4U for Itunes, or just simply convert the original Flac files into M4U via an audio converter.

    I have been told the former is the best method in terms of quality, but Im not certain, so I thought id ask the experts, whats your opinion.
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  2. A Member since June, 2004 Keyser's Avatar
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    Both methods produce EXACTLY the same result.
    "The greatest trick the Devil ever pulled was convincing the world he didn't exist."
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  3. FLAC stands for Free Lossless Audio Codec, so being lossless decoding to WAV is an useless step.
    Many converters will do it in the background anyway, so don't bother about doing it yourself except if you want to use a CLI which doesn't accept FLAC as input format, for instance Nero AAC Encoder.
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    Thanks for the CORRECT advice, much appreciated
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  5. Originally Posted by efiste2 View Post
    Is it better in terms of Quality to convert FLAC files to WAV then convert them into M4U for Itunes, or just simply convert the original Flac files into M4U via an audio converter.

    I have been told the former is the best method in terms of quality, but Im not certain, so I thought id ask the experts, whats your opinion.
    Decoding source audio to WAV before compressing it to some other format is advice given by people that know next to nothing about technical aspects of audio compression.

    Two things to know:
    1. WAV is just PCM (uncompressed, raw format) with header (samplerate, no. of channels, ect).
    2. EVERY encoder works with PCM.

    So, when you convert audio from one format to another conversion process goes like this:
    1. Audio is decoded to PCM
    2. PCM is passed to encoder
    3. Encoder compresses that PCM audio into desired format.

    Note: During steps 1 and 2 program can create temporary WAV file or pass PCM audio with WAV header through pipe.

    Note2: Even if your CLI encoder supports input of compressed formats like FLAC it will internaly (in RAM memory) decode FLAC or any other audio to PCM and then compress it to desired format.

    Knowing all this it is pointless to manually decode audio to WAV and then feed that WAV into encoder as program itself MUST do that automatically.

    It also implies that those who recommend decoding manually to WAV have no idea how audio compression works and their advices should not be taken seriously. Especially if they claim to be audiophiles.
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  6. Member Cornucopia's Avatar
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    @Detmek, while you are cognizant of the workings of a FLAC decoder, you are completely disregarding 2 things:
    1. Plenty of apps (whether older, legacy apps or apps in their early formings or specialty apps with few programmer resources) do NOT have capability to read FLAC files. For those apps, one MUST decode & save to WAV (or similar LPCM, such as AIFF) in order to input to them.
    2. Just as in video where there are times that it makes sense to frameserve and other times where it makes sense to have an intermediate file (such as in an environment where there is the possibility of corruption of RAM or where there is very limited RAM but generous HDD capacity or where the FLAC is being converted to multiple outcomes through multiple channels), there are times when it makes sense to decompress & save to WAV prior to final conversion.

    The leap to castigate "audiophiles" (and group them all into one ghetto'd category), particularly when the OP said nothing about the identity of their sources - audiophile or not, seems to be the height of pompous belligerence. Stick to just the facts (or at least the honest subset that you know of them) instead of all the arrogant bullshit.

    The OP was already given the proper answers politely and succinctly (aka Quality=SAME) prior to your diatribe.

    BTW, you are wrong on a few items: some encoders DO NOT work with PCM. They are transcoders and work directly with/on the compressed material without decompression. In the video domain, DVDShrink is a very common app that does just that (in its case, readjusting the quantizer).

    Scott
    Last edited by Cornucopia; 20th Jan 2015 at 03:26.
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  7. 1. I agree. Though I would avoid using such applications if I can. OK, CLI encoders usually work with WAV and you can not avoid that if you want to use CLI. But, if one needs to ask how to convert some audio file it should not be using CLI encoders yet.

    2. Frameserving is done through pipe so no WAV file is created. You can use intermediate WAV file but be aware that a lot of applications have a problem with WAV files lardger then 4GB. For that you need WAV64 which has limited support.

    Keep in mind that OP question was about converting FLAC to M4U to use those in ITunes and I just described that procedure and commented that anyone that makes claims about quality differences doen't know a thing.

    Now about audiophile. There is nothing wrong being true audiophile. But, there is plenty wrong being ignorant audiphile. Reason for that is those guys think that they know everything, when they do not but there is no way you can present any kind of evidence to prove them wrong. Because being ignorant audiophile is a religion and science don't have a place there.

    If you find yourself in my previous post as being audiophile, know that I don't have anything agains you if you use, and relly on science to improve your audio exprerince. But, if you are religios audiophile who only belives in his "golden ears" and every scientific evidence (usually double-blind test, but not limited to) is descarded in advance if does not support his belifes then you and I will have a problem in any thread regarding audio quality that we participate.

    Also, you put that paragraph out of context.

    The OP was given answer but not the detailed explanation why is that way. I just provided more detailed explanation.

    Yes, DVDShrink works directly on MPEG2 stream but in audio world there isn't any audio format and tool that can works directly on audio data without decompression into PCM.
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  8. Nobody has provided the correct answer yet.

    Is it better in terms of Quality to convert FLAC files to WAV then convert them into M4U for Itunes, or just simply convert the original Flac files into M4U via an audio converter.
    Option 1: A google seems to indicate itunes doesn't support flac. Therefore to convert flac to another format with itunes, a conversion to wave is necessary first. I suspect the OP meant convert "with" itunes, not "for" itunes.

    Option 2: Convert flac to another format directly using a program that isn't itunes.

    So it's likely the correct answer is "either method could produce the same result or a completely different result" but it'd be unlikely to have anything do with any conversion to wave first, and everything to do with the encoder used by the conversion program that isn't itunes, and/or any differences in encoder settings.

    The correct answer probably would have pointed out the question was also the wrong in at least one other respect. M4U files are playlists, or cue files, however you'd describe them. They don't contain any audio themselves and can probably be used with a variety of file types.

    efiste2,
    If, for example, you're converting by re-encoding with an AAC encoder (output from itunes would probably be m4a or mp4 files with an accompanying M4U file, or something similar) there's several AAC encoders programs can use. Some programs that aren't itunes are capable of encoding with the Apple encoder, but different settings would still produce different quality. At reasonably decent bitrates though, maybe 128kbps or more for stereo AAC, all the AAC encoders are pretty much "transparent", so in that respect the quality is effectively the same. At bitrates of 192kbps or more, it'd be very unlikely you could pick the source from the original under even ideal listening conditions 99% of the time, so once again, you could consider the quality to be the same for all the commonly used AAC encoders even if technically it isn't.
    I don't know what settings itunes uses for AAC encoding by default or if that's definitely the desired final output codec, but if you're re-encoding to reduce the file size substantially it's fairly likely.
    Last edited by hello_hello; 20th Jan 2015 at 14:33.
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