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View Full Version : Converting FLAC audio to Mp4/AIFF/mp3/m4a/etc for iPhone with minimun quality loss




th3g1z
Dec 16, 2009, 09:04 PM
Any ideas? Itunes won't take FLAC files directly so I have to convert them to something. I was thinking either Apple Lossless (although this made the file size even bigger than FLAC itself), then I tried AIFF (also made file size even bigger than FLAC).. lastly I tried to convert to mp3 (320 kbps) and that reduced the size 66% which was nice so I can fit more onto my iPhone 3Gs.. I usually use it for output into a 5.1 surround sound system or car stereo via optical or aux. so I'd like to lose as minimal quality as possible yet retain the quality of the FLAC.. smaller file size is nice but not my number one priority.. or as close as can be anyway.

I have yet to experiement with other formats such as m4a but didn't know if it would be worth it anyway.

What do you guru's advise? Any input is appreciated. Thank you so much.

~Gizmo



xlii
Dec 16, 2009, 09:12 PM
On the highest end audio system you use can you tell the difference between apple lossless and 320kbs? I think those are your two choices. I would say that on some music you can and some you can't. You're trading off file size for quality, altho 320 kbs is what I encode at and listen to on my ipod and it sounds pretty good to me.

lostless
Dec 17, 2009, 01:04 AM
AAC 320kb/s would be the best as far as matching the original sound. Same file size as Mp3 320, but AAC is newer and more efficient. Now it won't be 100% to the original, but unless you have dog ears, I doubt you'll hear any difference at all.

Doing spectrum analysis on AAC, 192 is where its starts to retain most frequencies above 20kHz, the theoretical max to 99% of all humans. Most don't hear that high anyway. I can't hear past 17.5kHz, and thats barley audible even with it full blast. 256kb/s pretty much reaches the maximum of a CD of 22kHz. 320kb/s would just be extra icing on the cake. Now as I said before, there is loss in possible harmonics, sound field, ect as AAC is throwing tons of sound data out. Let you ears be your guide. I find 192kb/s and above is invisible to me. 160 could also work too for me most of the time. Occasionally I can hear distortion in the high end on 160.

th3g1z
Dec 17, 2009, 08:52 AM
AAC 320kb/s would be the best as far as matching the original sound. Same file size as Mp3 320, but AAC is newer and more efficient. Now it won't be 100% to the original, but unless you have dog ears, I doubt you'll hear any difference at all.

Doing spectrum analysis on AAC, 192 is where its starts to retain most frequencies above 20kHz, the theoretical max to 99% of all humans. Most don't hear that high anyway. I can't hear past 17.5kHz, and thats barley audible even with it full blast. 256kb/s pretty much reaches the maximum of a CD of 22kHz. 320kb/s would just be extra icing on the cake. Now as I said before, there is loss in possible harmonics, sound field, ect as AAC is throwing tons of sound data out. Let you ears be your guide. I find 192kb/s and above is invisible to me. 160 could also work too for me most of the time. Occasionally I can hear distortion in the high end on 160.

thanks for the replies guys. Looks like aac is the way to go perhaps 192 or 320 I'll test that theory out tonite. Aside from that is there any advantge to using mp4 or m4a or aiff at all? Or will aac rock all those off the boat? Just trying to get a clear understanding I guess. I don't understand the point of people ripping to mp3 in 192 when there are all these better options available. My trial for tonite after work is going to be testing aac 192 vs aac 320 vs mp3 320 on my home surround sound (via computer using optica output) and in my car(using iPhone via aux input) and I'll report back with my findings. Thanks again all.

xlii
Dec 17, 2009, 09:15 AM
Comparing 160kbs aac versus 320 kbs aac. I've noticed that if you are listening to busy music (dragonforce example) 320 sounds a lot better to me than 160. If I listen to simple music (one folk guitar, one singer) then 160 and 320 sound about the same.

lostless
Dec 17, 2009, 12:35 PM
Aside from that is there any advantge to using mp4 or m4a or aiff at all? Or will aac rock all those off the boat? Just trying to get a clear understanding I guess. I don't understand the point of people ripping to mp3 in 192 when there are all these better options available.

Mp4 is M4a. Both part of the mpeg 4 standard. Apple just uses .m4a for apple lossless as well. Apple lossless will end up identical to the original CD or FLAC in terms sound reproduction. I find that a well encoded LAME 192 mp3 can sound quite good. Sometimes the encoder has a big impact on sound quality as well. People will use those lower bit rates to put put more music on their playback device. When some people only have 2-4GB players, and people are willing to use, or even notice, lower quality sound, they can put more music on their device. I can fit almost double the amount of music at 192kb/s than 320k/s.