PDA

View Full Version : Gapless playback



HUEY
2008-10-09, 05:29
I've noticed recently a slight gap between continuous songs on an album. They used to play seemlessly, and now there is a slight gap between songs. I've looked at my settings and nothing seems to have changed.
Rob

MikeekiM
2008-10-09, 09:56
Really? Does SqueezeBox support gapless playback?

I am a relatively new user, and just assumed that gapless playback was not supported...but if it used to work for you, I am becoming optimistic :)

I know that my songs play gapless using iTunes (but not on my iPod)... Listening to live albums and "non-stop" mixes would be great if gapless was supported...

I'll be paying attention to this thread :)

funkstar
2008-10-09, 10:28
Some more information would be appreciated guys.

What format is the music in?
What version of SqueezeCenter are you running?
What OS are you using?
Which player do you have?
How many? and if multiple, are they synced?

Playback for certain formats should be gapless. FLAC, Wav and MP3 are all supported. Transcoded music, such as WMALossless, AAC and ALAC cannot be gapless. Ogg and WMA just can't even though they are decoded natively.

MikeekiM
2008-10-09, 10:31
For me, I am running SC7.2 on Vista-32, streaming mostly 192bit VBR MP3s...

Is there a setting that I need to know about?

Themis
2008-10-09, 10:39
I've noticed recently a slight gap between continuous songs on an album. They used to play seemlessly, and now there is a slight gap between songs. I've looked at my settings and nothing seems to have changed.
RobIf you are streaming MP3 and your Squeeze Center does not transcode MP3 to something else (Settings>Advanced>Audio types : verify that MP3 is set to "Native"), then you probably have performance issues on your PC. Perhaps a background job using 100% of your PC resources ? Please check.

Really? Does SqueezeBox support gapless playback?Of course.

HUEY
2008-10-09, 10:44
After doing a search, which is what I should have done in the first place, I see that sync'd players will have a gap. I'm running a sb3 as the main unit, and duet receiver upstairs, and I might have them sync'd up. BTW, Most of my recordings are either flac(majority) or mp3's.
Rob

schiegl
2008-10-09, 10:52
good news for you in case you haven't found out yet: the next version 7.3 will support gapless playback (for the known formats) even for synchronized players!

kind regards,
Markus

maggior
2008-10-09, 10:54
Something else to note is that it is the tags that LAME adds when encoding mp3s that allows SqueezeCenter (and iTunes for that matter) to play mp3s gaplessly. If your mp3s were made with another encoder, you may not get seamless playback.

andyg
2008-10-09, 11:00
Some more information would be appreciated guys.

What format is the music in?
What version of SqueezeCenter are you running?
What OS are you using?
Which player do you have?
How many? and if multiple, are they synced?

Playback for certain formats should be gapless. FLAC, Wav and MP3 are all supported. Transcoded music, such as WMALossless, AAC and ALAC cannot be gapless. Ogg and WMA just can't even though they are decoded natively.

Ogg is gapless. If you need gapless while synced, please download and try 7.3. I think you will find it is very usable.

funkstar
2008-10-09, 12:23
Ogg is gapless.
It is? cool. I thought the format was gapless, but seemed to thing there was a bug that meant it didn't play gapless.

Noted for the future.

HUEY
2008-10-10, 05:32
Turns out it was because the units were sync'd. All is well now. Thanks for the help.
Rob

ajkidle
2008-10-10, 10:01
Transcoded music, such as WMALossless, AAC and ALAC cannot be gapless.

Dumb question: what does it mean for a format to be "transcoded"? And why can't WMA-lossless be gapless? (Answering the first may answer the second.) All of my lusic is ripped in WMA-lossless and used to play back gapless back when I used WMP -- I guess I haven't paid attention to this since getting my Duet. Now I'm worried...

radish
2008-10-10, 10:11
Transcoding is the process of converting one format to another. In this case it's specifically talking about filetypes which the player itself doesn't support, and which are converted to FLAC (or something else) by the server to allow playback.

WMA lossless is not supported by the players (due, I think, to licensing issues) and so must be transcoded on the server. Currently, that means gapless playback is not possible. I believe the new streaming code in 7.3 should fix that (though I'm not 100% sure of that).

MikeekiM
2008-10-10, 10:55
Turns out it was because the units were sync'd. All is well now. Thanks for the help.
Rob

OK... so gapless is only supported when transcoding is not involved, and when you are not synching with other players... is that correct? And the gapless play is by default (i.e., there is no software "switch" that I need to set to get gapless playback)...

aubuti
2008-10-10, 11:08
OK... so gapless is only supported when transcoding is not involved, and when you are not synching with other players... is that correct? And the gapless play is by default (i.e., there is no software "switch" that I need to set to get gapless playback)...
This is correct, except that I am pretty sure that gapless MP3 is only supported if the encoding was done with a reasonably recent version of LAME (sorry, forget exact version number). Other MP3 encoders and earlier versions of LAME won't play gapless. And yes, there is no software switch for gap/gapless playback.

maggior
2008-10-10, 11:24
Transcoding is the process of converting one format to another. In this case it's specifically talking about filetypes which the player itself doesn't support, and which are converted to FLAC (or something else) by the server to allow playback.

WMA lossless is not supported by the players (due, I think, to licensing issues) and so must be transcoded on the server. Currently, that means gapless playback is not possible. I believe the new streaming code in 7.3 should fix that (though I'm not 100% sure of that).

It would be a waste of bandwidth, but what if it is streamed as WAV rather than FLAC? In that case, it would be a case of decoding on the server and streaming rather than transcode on server, stream, then decode on player.

Mark Lanctot
2008-10-10, 11:35
It would be a waste of bandwidth, but what if it is streamed as WAV rather than FLAC? In that case, it would be a case of decoding on the server and streaming rather than transcode on server, stream, then decode on player.

FLAC -> WAV on the server is still considered transcoding for these purposes, it's just that it's calling one process rather than two.

maggior
2008-10-10, 12:24
This is correct, except that I am pretty sure that gapless MP3 is only supported if the encoding was done with a reasonably recent version of LAME (sorry, forget exact version number). Other MP3 encoders and earlier versions of LAME won't play gapless. And yes, there is no software switch for gap/gapless playback.

From what I've read in Hydrogen Audio forum, gapless support has been in LAME since 3.90, which dates back to late 2001! I've been using version 3.97 since it was released a couple of years ago with success to provide gapless mp3 files for both my squeezebox and iPod.

CatBus
2008-10-10, 13:17
OK... so gapless is only supported when transcoding is not involved, and when you are not synching with other players... is that correct?

Actually, no. Gapless has worked fine with transcoded Ogg->FLAC since I bought my first SB3 in the SlimServer 6.x days. I always transcode my Ogg's because there's a sync bug with native Ogg decoding. You are correct that gapless sync doesn't work unless you're using the 7.3 nightlies though.

If there's a problem with gapless and transcoding, it's limited to specific formats like WMA, but I can't say why that would be.


And the gapless play is by default (i.e., there is no software "switch" that I need to set to get gapless playback)...

Correct.

funkstar
2008-10-10, 15:09
Please someone correct me if I'm wrong again, but I don't think WMA files have any provision for being gappless at all, it's a bad format in that regard.

andyg
2008-10-10, 15:32
I am not entirely sure, see this thread for example: http://www.hydrogenaudio.org/forums/lofiversion/index.php/t18779.html

funkstar
2008-10-10, 16:03
It's a really old thread, and despite reading a few of the posts a few times, i'm still not really sure what the status of gapless playback of WMA is. Woks in some cases, fails in others. Seems a little unpredictable to me.

I would guess that part of the problem is that Miscrosoft are so closed about their audio format. I'm not saying it's broken because it isn't open source, it's just that they don't really tell you anything about the codecs at all, there is a lot of messing around and experimenting. Also seems like things change significnlty between releases.

personally I would file wma as non-gapless until proved otherwise.

CatBus
2008-10-10, 19:38
WMA supports gapless: http://en.wikipedia.org/wiki/Gapless_playback

However, I'd believe that proprietary formats tend to be poorly documented, and therefore there are more likely to be mistakes in encoders and decoders not written specifically by the vendor.

Also, there may be factors where a perfect decoder would require more resources than small devices have, so space-saving compromises may lead to imperfect decoding.

andynormancx
2008-10-10, 23:55
Please someone correct me if I'm wrong again, but I don't think WMA files have any provision for being gappless at all, it's a bad format in that regard.
MP3 has no support for gapless, the Lame gapless support works, but it is a hack rather than anything standard to the MP3 format.

funkstar
2008-10-11, 05:20
MP3 has no support for gapless, the Lame gapless support works, but it is a hack rather than anything standard to the MP3 format.
Oh absolutely, but at least it's documented and developers know how it works :)

autopilot
2008-10-11, 08:53
Please someone correct me if I'm wrong again, but I don't think WMA files have any provision for being gappless at all, it's a bad format in that regard.

That was what i thought too - am sure a number off people on the HydrogenAudio forums mentioned that. But i was also told that it was not the format per-say, but it was because WMP was doing a terrible job of ripping. Not tested much myself though.

andyg
2008-10-11, 09:00
Although I don't really like the WMA format, I'm interested in figuring out if it's really gapless or not and what it would take for us to support it.