Gapless playback in i-tunes
Mon, Jan 21 2013, 7:51PM
I down-load a lot of music - mainly opera - from the French site Qobuz. I use a mac and the down-loaded files go straight into i-tunes. I have noticed that albums on the Decca label will not play gap-lessly, even when i-tunes is "told" to play them that way. There is a momentary but extremely annoying "drop-out" between index points. Decca is the only label that I have this problem with. Even if I burn a disc directly from the down-loaded files the problem persists. Any ideas, anyone?
Many thanks.
Tue, Jan 22 2013, 4:43PM
#2
RE: Gapless playback in i-tunes
Hi - sorry I'm not familiar with that site but I assume you are buying mp3? - if so and assuming you have a fairly recent version of itunes, the most likely explanation is that the Decca mp3s were supplied a long time ago and do not contain the necessary metadata (extra info in the file) needed to playback gaplessly. (If you have a media player like VLC media player that can display the metadata you would be able to see whether it contains an offset correction.) This problem is not unusual and I have had similar problems.Your options are to (i) ask for a refund; (ii) buy flac versions instead if they are offered or (iii) learn how to manually edit the individual files to correct this problem (but this will be a bit laborious).
My understanding is that more recent versions of Itunes should play gaplessly by default, you should only need to tell it that things are part of a gapless album if by any chance you have the cross-fading option switched on.
Ted
Tue, Jan 22 2013, 6:50PM
#3
RE: Gapless playback in i-tunes
Many thanks for that, Ted... I buy the files in lossless form - MPEG-4. I've done a bit more trawling through my i-tunes library and what I've discovered seems to bear out what you say. The only albums affected are Decca releases, and they do seem to be what you might call "first generation" downloads. Recently released or re-released stuff - even of older material (the Solti/Strauss opera box-set, for example) - don't suffer from the same problem. Presumably, since the original files are the problem, there isn't a way of burning them gaplessly to disc?
It's too late to ask for a refund, so I think I might bite the bullet and look into correcting the problem by editing the files. Any suggestions on editing soft-ware? Thanks again for your help.
Tue, Jan 22 2013, 8:29PM
#4
RE: Gapless playback in i-tunes
There is one more possibility - if the files are very large (as often the case in lossless formats) and your system (computer/etc) a little slow then it may simply take that extra half second to load the file into memory. One way of figuring out if it's that is to create a compressed version of two sample file where you have a gap, i.e., convert them to aac or mp3 at 320 kbps and try playing them again to see if they still have a gap. Just a thought.
One remedy of getting around the possible reason mentioned by others before (which may still be the reason rather than what I say here) might be to re-encode your old files in a lossles format and try again. That might get around the issue.
The only other thing I can think of is that at source they inserted a miniscule gap at the end of a file by giving it a zero volume for a fraction of a seconf. The only way to figure that out is to open the file in an audio editor that shows you the wave form, zoom in and look at the very end of the file if it goes to zero just before the end rather than staying at its full amplitude.
Wed, Jan 23 2013, 6:41PM
#5
RE: Gapless playback in i-tunes
Hi Jeremy - do you really mean the files you have are lossless as opposed to lossy? [The ".mp4" itself is just the "container format" for the file, inside this can be something that is either lossy (e.g. AAC-encoded music) or lossless (ALAC-encoded music)]. If your files are really lossless then there should be no issue at all with gapless playback, so something else might be wrong as for instance the other poster suggested. Check cross-fading is switched off.
If you really have lossy files then I'm not really familiar with Mac options, but if I had e.g. lossy mp3 files on a Windows PC I would try and use Foobar 2000 to convert each file to separate uncompressed wav files. If you look at these wavs in an oscilloscope type editor you will see silence at the beginning and the end. The silence at the beginning is the encoder delay. The silence at end is the padding. Basically you need to figure out how many samples each of these are. You can then go back to the mp3s and use Foobar to add gapless metadata in them with these numbers. Probably they will be same for each track. [Not quite sure but you might need to adjust the real tracklength as well.] I'm sure you can find guides how to do this online.
best wishes
Ted
Wed, Jan 23 2013, 7:31PM
#6
RE: Gapless playback in i-tunes
Thanks for all your help with this, gentlemen. The files are definitely "Lossless - CD Quality" and are delivered as ALAC 16 bit - 44.1 kHz. (I should say immediately that we are now sailing very close to the limits of my technical capabilities!) I think Ted's original theory about the information in the download itself might be the correct one. I tried a relatively inexpensive experiment this morning by buying a second copy - from the same source - of one of the offending Decca albums, but in a later incarnation - i.e., not the original CD release, but a re-release in the mid-price Decca "Opera House" series. No problem at all - it plays gaplessly even without any tweaking within i-tunes. I will try an audio editor for the other albums, as suggested, but I am also going to see whether Qobuz will consider "upgrading" the albums where a later re-release exists.
Once again, thanks for all your help.
Thu, Jan 31 2013, 2:44PM
#7
RE: Gapless playback in i-tunes
I read with your posts and have learned a lot. I am not techical in anyway but Apple has a new system called Match. My understanding is that once you join they take all your music files into thier cloud and upgrade the "old" files into new and improved digital files. Not sure if this is answer to your situation, but be worth investigating.
All the best.
Jerry