Gapless mp3 support [Answered]

Has anyone noted (who may be using mp3 and flac or other files types), that gapless playback in Roon works for flac files but not for mp3? I have noted on my Yamaha network receiver that playback via the Yamaha app from my NAS, results in gaps with mp3 but not flac. I have also noted that on my desktop system using JRiver or iTunes that mp3 files are played gapless (to a NAD D3020 via optical) but with Roon they are not. Files played to the Yamaha via AirPlay and Roon are also not gapless (mp3 files). Any input on this (taking the thread a slightly different direction). I have not been able to test flac gapless playback vs. mp3 in Roon because I have Roon monitor my iTunes library and of course iTunes does not support flac so my files of that type on my NAS are not visible to Roon. I will have to convert to a file format iTunes recognizes for high quality files and see what happens.

EDIT: AIF files made from the non-gapless mp3 files played perfectly gapless in Roon and via the Yamaha over AirPlay. So, what I have noted with a number of devices now and software playback programs is that gapless seems to not be supported in mp3. Is there a technical reason for this?


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Great information, thank you.

I have not been able to test flac gapless playback vs. mp3 in Roon because I have Roon monitor my iTunes library and of course iTunes does not support flac so my files of that type on my NAS are not visible to Roon.

Hi Larry,
can’t help with our original query but was confused by your statement above. Roon can watch multiple folders so why have you not set your FLAC storage folder as a watched folder?

I was about to suggest the same thing…roon can work over many sources just add another location in the storage settings, be it NAS or usb drive or internal folders even a usb stick or multiples of all of the above.

Prior statement was made out of ignorance as to the features of Roon in being able to do that :slight_smile: So, based on your suggestion and wizardofoz comment below this one I did add a second folder and sure enough they appear. Results are the same as I report in the edit of the original post, however, in that the flac files play gapless.

I was intrigued with all the information that was in the links above concerning gapless playback and mp3 or other files and the technical reasons for this. I’m not generally this techie oriented as many of the fundamental principals as to the file types and underlying technology go over my head, but that one I could grasp. Much food for thought.

I have historically ripped all my stuff to 320kb mp3 for convenience purposes (although storage size was a consideration at years ago). This format and kb rate was close enough to RBCD standards that I simply could never hear a difference (or enough of one that concerned me) so I called my files “good enough” and just moved on.

I could just copy the files on the fly to a CD, or take them to my car, or wherever and they just would play with no conversion time or hassle. Of course those arguments are now more moot, but, old habits die hard and I never felt comfortable with a library (5,000+ full albums) of mixed format files (no valid reason for this, just me).

This thread got split off from one where the OP there had been upset about Roon showing a “low quality” light when playing mp3 files, that is how I got involved in this thread. I appreciate the comment about monitoring the extra folders. I suppose I should spend a bit more time learning some of the features, I admit to originally just installing it, clicking the “iTunes monitoring” button and then leaving it alone after that.

Have a great day, thanks.

Thanks for setting me straight on this. I replied to Anthony_Bates about his suggestion and thanked you there as well!

Somehow my comment of last night did not go as a reply to you, so, this one will I think. Thank you for the great links and information, it enlightened me on a number of things concerning the formats. I think I have answered to my satisfaction the original question with your help. Have a great day.

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One more question for you, as it relates to FLAC. Let’s say I have a 320kb mp3 file (which I do, a lot of them, and I do not have access to my original source material for many of them) and I do want to re-encode them to FLAC for purposes of gapless. Obviously if I just use the default encoder to do the conversion I get a large file size, but much of the new file is empty bits (a common complaint with the high-def music site downloads from what I understand).

So, I see I can up the compression on my FLAC encoder to make smaller files sizes but does that do anything? I guess what I was hoping to see was a FLAC setting that pointed to an equivalency to a corresponding mp3 file - for instance “320mp3 = FLAC compression level 8” or something to that effect. Googling this comes up with no such comparison.

Or, am I overthinking?

I suspect (but not 100% sure) no matter what compression level you use FLAC is going to be larger.

If you no longer have the source to re-rip as FLAC, let’s ask @support whether they have any advices for gapless MP3 in Roon, or other alternative approaches.

Thanks Peter. I probably am not going to obsess over this and while I know FLAC was always going to be larger I didn’t think it needed to be 2 - 3 times larger in all cases. With most of what I listen to gapless doesn’t make a difference anyway (studio tracks with defined endpoints). This has been an interesting exercise honestly in understanding how the whole file systems work, I have shared those two links you gave me with a couple of others. If @support doesn’t get back to me no problem going forward I will simply get over my aversion to having multiple file types in my library LOL.

Happy listening.

This link is spot-on, particularly this part:

This issue is technical but also standards-related. The popular MP3 standard, for example, defines no way to record the amount of delay or padding for later removal. Encoder delay may vary from encoder to encoder, making automatic removal difficult. Some encoders use a nonstandard header to store actual encoder delay & padding values, but not all players/decoders support it. More recent (newer than MP3) compressed audio formats have been designed to address this problem, and can therefore produce gapless audio if played back correctly.

Because of MP3’s history with patents, we don’t ship our own MP3 handling code–rather we leverage what comes with the operating system. Because of this, we get whatever behavior we inherit from there.

MP3 patents expired a couple of months ago, so we are investigating moving to a single MP3 codec shipped as part of Roon instead of having multiple operating system specific implementations with slightly different behavior.

If we do this, we will try to use one that supports the unofficial gapless conventions.


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