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View Full Version : Network demands: flac, wmp, mp3, etc.



RonM
2009-07-19, 18:00
I see in another thread that there has been some suggestion that flac files have the potential of making unseemly network demands under some circumstances (like restricted network capacity). I'm not sure if this is something specific to flac, or if "flac" is being used as a stand-in for all lossless formats.

What are the actual relative bandwidth requirements of flac vs wma lossless vs mp3 lossless? I'd have thought they'd be pretty much the same.

R.

maggior
2009-07-19, 18:40
It depends on the bitrate. A typical FLAC file as I've seen in my collection is between 700 and 1000 kbps. mp3 - it depends on what bitrate you chose for the compression, e.g. a 128kpbs mp3 file will require 128kbps of bandwith to play with no issues.

I think that the best any lossy CODEC is going to do is around 500kbps.

BTW, I've never heard of mp3 lossless. mp3 by definition is a lossy CODEC.

In reality you'll need a little more bandwith to allow for transport overhead - assume 20 or 30% required extra bandwidth as a ballpark figure.

This is the bandwidth required for each player. The server would have to support the sum of the bandwidth of any players playing at the same time. With a wired connection of 100Mbps, this generally isn't an issue. If your server is connected via wireless, then it could be an issue.

I hope that helps.

RonM
2009-07-19, 19:28
BTW, I've never heard of mp3 lossless. mp3 by definition is a lossy CODEC.


. . . but I was apparently in outer space when I wrote my original query.

My question was really about lossless formats, so in reality the question is about Apple lossless, WMA lossless and flac (I know there are others). I was just wondering if the way SC handles the files was different in some way that effects the data transfer rate -- are they generally the same in terms of bandwidth requirements over the network, or are any more efficient?

R.

aubuti
2009-07-19, 20:58
My question was really about lossless formats, so in reality the question is about Apple lossless, WMA lossless and flac (I know there are others). I was just wondering if the way SC handles the files was different in some way that effects the data transfer rate -- are they generally the same in terms of bandwidth requirements over the network, or are any more efficient?
It depends on the format in which you are sending the files across the network. Under SC Settings > Advanced > File types you can choose, for example, to have Apple Lossless (ALAC) transcoded to MP3, FLAC or WAV. Those three choices will chew up network bandwidth in increasing order of severity. The SB players do not support ALAC directly, so some transcoding needs to be done on the server, and that choice determines the bandwith requirements. I think the same is true for WMA Lossless, but I'm not sure as I don't follow those developments closely. A compressed format like FLAC will generally be less demanding of bandwidth than an uncompressed format like WAV or AIFF.

RonM
2009-07-20, 05:11
It depends on the format in which you are sending the files across the network. Under SC Settings > Advanced > File types you can choose, for example, to have Apple Lossless (ALAC) transcoded to MP3, FLAC or WAV. Those three choices will chew up network bandwidth in increasing order of severity. The SB players do not support ALAC directly, so some transcoding needs to be done on the server, and that choice determines the bandwith requirements. I think the same is true for WMA Lossless, but I'm not sure as I don't follow those developments closely. A compressed format like FLAC will generally be less demanding of bandwidth than an uncompressed format like WAV or AIFF.

Since the SB doesn't work directly with WMA files, would it be safe to say that WMA Lossless gets transcoded to FLAC first, then sent down the pipe to the SB? In which case, aside from processor cycles on the computer, the network implications should be identical for the two formats?

Also, I had a look at the file conversion options in SC and found the attached (two screen-shot segments are combined in one image -- the help balloon and the WMA options). Since three conversion options are included for WMA, including "native", I'm wondering which is actually used and how one tells. And does it imply that the SB now handles native WMA format directly?

r.

radish
2009-07-20, 06:26
Since the SB doesn't work directly with WMA files, would it be safe to say that WMA Lossless gets transcoded to FLAC first, then sent down the pipe to the SB? In which case, aside from processor cycles on the computer, the network implications should be identical for the two formats?

Also, I had a look at the file conversion options in SC and found the attached (two screen-shot segments are combined in one image -- the help balloon and the WMA options). Since three conversion options are included for WMA, including "native", I'm wondering which is actually used and how one tells. And does it imply that the SB now handles native WMA format directly?

r.

Lossy WMA is supported natively on the SB (v2+ only I believe), lossless is transcoded (by default to FLAC).

In terms of network usage, FLAC is variable but as stated typically 700-1000kbps, WAV/PCM is ~1400kbps.

aubuti
2009-07-20, 06:27
The SB has handled regular WMA (ie, lossy WMA) natively for some time now. I honestly don't know what the status is with WMA Lossless, but I trust someone who does know will chime in soon.

RonM
2009-07-20, 14:25
Somehow I'd lost track of the fact that the SB supports WMA directly. I'd been sure I'd seen that it didn't.

In any event, there don't seem to be any separate options for WMA lossless, so if it is transcoded it must be to flac without alternatives (not that that would be a bad thing).

Odd that there is no separate listing for the lossless version, though, if it is indeed handled differently than lossy.

May all be moot. I'll shortly be putting all my music on a fit-pc2 (large internal drive), while maintaining my database on the main PC. I may just convert all the lossless files going to the fit to FLAC, in order to reduce the load on the somewhat underpowered processor. That wouldn't be necessary if no transcoding was involved, so if indeed the duet supports WMA lossless this would be a good thing to know.

R.

aubuti
2009-07-20, 14:40
May all be moot. I'll shortly be putting all my music on a fit-pc2 (large internal drive), while maintaining my database on the main PC. I may just convert all the lossless files going to the fit to FLAC, in order to reduce the load on the somewhat underpowered processor. That wouldn't be necessary if no transcoding was involved, so if indeed the duet supports WMA lossless this would be a good thing to know.
I'd trust radish's comment that SBs do not currently support native decoding of WMA Lossless. That's also what it says in the wiki Hardware Comparison (http://wiki.slimdevices.com/index.php/HardwareComparison), and the Duet User's Guide (http://www.logitechsqueezebox.com/attachments/download/13/Squeezebox-Duet-UG-ENG.pdf) (see Appendix D, p. 29).

Note that support for other codecs can be added via firmware updates, such as the recent addition of native AAC support. But I wouldn't hold my breath waiting for WMA Lossless support.