Hello. I'm baffled and looking for help.

I've been trying to play audio over my home wifi :- the backend is a
raspbery pi sending audio out via USB into a DAC, the frontend is a laptop
running Debian 8, sending to a pulseaudio "SMC9514 hub digital stereo
(IEC958) on pi@raspberypi" sink (I find pulseaudio deeply obscure and
offputting, but I haven't found much else that offers the possibility of
doing this at all). This connects, to the extent of getting a noise out of
the speakers, but the sound is useless - broken up, stuttering, as much
silence than sound - it gives the impression that the data's just not being
sent fast enough.

Wifi-wise, the pi is the bottleneck, with 'iwconfig wlan0' giving "Bit
Rate=54 Mb/s" (the rest of the system could go faster). But handwavingly,
this is ~5megabytes/sec, CD-quality sound is ~10megabytes/min, so I'd have
expected that to be plenty.

(I've tried wav and a highly-compressed mp3, doesn't seem to make much
difference, I'm guessing it's decompressed before sending ? But it wouldn't
help anyway, having a DAC and cheap storage I don't want to use a lossy
format).

So what am I missing ? Is there some deep reason why this won't work, am I
doing something stupid, what's going on ?

TIA.

--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html

In article , Richard
Robinson wrote:

Hello. I'm baffled and looking for help.

I've been trying to play audio over my home wifi :- the backend is a
raspbery pi sending audio out via USB into a DAC, the frontend is a
laptop running Debian 8, sending to a pulseaudio "SMC9514 hub digital
stereo (IEC958) on pi@raspberypi" sink (I find pulseaudio deeply obscure
and offputting, but I haven't found much else that offers the
possibility of doing this at all). This connects, to the extent of
getting a noise out of the speakers, but the sound is useless - broken
up, stuttering, as much silence than sound - it gives the impression
that the data's just not being sent fast enough.

I can't comment in detail on the wifi beyond suspecting the obvious, that
it might be slow.

But if you want audio quality you might find you prefer using ALSA.

aplay -L

will list playout devices. I'd hope your system can then find the required
device. Usually Pulse will send out via ALSA anyway.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
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Audio Misc http://www.audiomisc.co.uk/index.html

Bob Latham said:
In article ,
Richard Robinson wrote:

Hello. I'm baffled and looking for help.

I've been trying to play audio over my home wifi :- the backend is a
raspbery pi sending audio out via USB into a DAC, the frontend is a
laptop running Debian 8, sending to a pulseaudio "SMC9514 hub digital
stereo (IEC958) on pi@raspberypi" sink (I find pulseaudio deeply obscure
and offputting, but I haven't found much else that offers the
possibility of doing this at all). This connects, to the extent of
getting a noise out of the speakers, but the sound is useless - broken
up, stuttering, as much silence than sound - it gives the impression
that the data's just not being sent fast enough.

Wifi-wise, the pi is the bottleneck, with 'iwconfig wlan0' giving "Bit
Rate=54 Mb/s" (the rest of the system could go faster). But
handwavingly, this is ~5megabytes/sec, CD-quality sound is
~10megabytes/min, so I'd have expected that to be plenty.

(I've tried wav and a highly-compressed mp3, doesn't seem to make much
difference, I'm guessing it's decompressed before sending ? But it
wouldn't help anyway, having a DAC and cheap storage I don't want to use
a lossy format).

So what am I missing ? Is there some deep reason why this won't work, am
I doing something stupid, what's going on ?

As regards the rip format for music, unless you have extremely good
reasons for not doing so (I'm confident you haven't), use flac. Rip to

Thanks ... and, yes. New stuff comes in as flac. But ...

flac and get your tags sorted from the start rather have to come back
later and sort hundreds of albums.

.... I have a lot of 'historical' mp3s with no proper tagging, from the days
when storage was more of an issue. That's one reason why I'd prefer the
laptop hard disk to be my main storage, rather than put a hard disk behind
the raspbery pi - the laptop software/screen gives a nicer interface than
remotedestopping into the pi (I also have CDs to re-rip, which would be
easier that way). I could do the latter, if all else fails, but I want to
explore the alternative first, it'd just be a bit more convenient if I can
get it to work.

I'm not familiar with the kit you are using but FWIW here is my opinion.

My best guess is that you are trying to push music from a laptop to a
music renderer via wi-fi.

Yes.

I know many people push music via USB from a laptop directly into a dac

Yes. I've been doing that for a while, it works fine through a USB cable.
It's just that a cable stretched across the floor is not a good idea, sooner
or later I _will_ trip over it. I lost a nice pair of headphones that way
once; so wifi would be a better idea.

but I've never seen or heard of it being done with wi-fi in the link too.

I'm suprised; it seemed like the obvious next step, to me. Maybe I'm just
weird (shrug).

Personally, I've never liked the idea of 'push' music systems, it seems to
me that making sure the buffer in the renderer is neither overflowing or
empty is a bit tricky and far worse if you use wi-fi.

I advise using a pull system. The renderer pulls music from the server as
it requires it to keep the buffer just right. There are plenty of these
systems around.

Ah. That's a thing I hadn't taken seriously - I was guessing that given the
throughput numbers above, buffering wouldn't be an issue. Being proud of my
ability to be wrong, I will check out the idea of 'pull'.

To be clear, by a 'pull' system you mean that the music player software
lives on the machine that's wired into the amp (the pi, in my case) and it
sucks the music files down from a remote hard disk somewhere else on the
local network (the laptop, in my case) ?

Using flac I can stream hi-rez 192Khz/24bit music over wireless N all day
without an error but this does depend on how clear your local area is,
have you looked to see how many other wi-fi systems in your area are on
the same channel.

Ah, again. No, I hadn't, but will. I'm new to wifi in general, I've always
only done desktops/ethernet until I started playing with this stuff.

With pull systems, some pull from an SMB share on a PC or NAS eg. Sonos
and Bluesound and other systems pull from a UPnP server. Originally I
preferred the simplicity of the SMB connection but later I've seen the
advantage of UPnP, in particular there is only one central index no matter
how many clients/renderers. MinimServer is easy to setup - not a problem.

For your raspberry pi code Google OpenHome UPnP.

Thank you. This gives me some Things To Try Next.



I know others will not agree but that's life, not everyone will vote
"Leave" today either. :-)

Me, for example :-)




--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html

On Thu, 23 Jun 2016 08:28:04 -0500, Richard Robinson
wrote:

Bob Latham said:
In article ,
Richard Robinson wrote:

Hello. I'm baffled and looking for help.

I've been trying to play audio over my home wifi :- the backend is a
raspbery pi sending audio out via USB into a DAC, the frontend is a
laptop running Debian 8, sending to a pulseaudio "SMC9514 hub digital
stereo (IEC958) on pi@raspberypi" sink (I find pulseaudio deeply obscure
and offputting, but I haven't found much else that offers the
possibility of doing this at all).

Not used a RPi, so can't help much with that at all. BTW, Jim is no
fan of pulse audio - neither am I, so I'm not grumbling - but
pulse audio or not, I suspect the WiFi is the problem, see below.

This connects, to the extent of
getting a noise out of the speakers, but the sound is useless - broken
up, stuttering, as much silence than sound - it gives the impression
that the data's just not being sent fast enough.

What transfer rate do you get if you just copy a file via WiFi from
the laptop to the RPi?

Wifi-wise, the pi is the bottleneck, with 'iwconfig wlan0' giving "Bit
Rate=54 Mb/s" (the rest of the system could go faster).

That sounds like it's telling you the theoretical maximum rate for
802.11g rather than the actual rate being achieved:
802.11b 2.4GHz 11 Mb/s
802.11g 2.4GHz 54 Mb/s
802.11n 2.4GHz 320 Mb/s

But
handwavingly, this is ~5megabytes/sec, CD-quality sound is
~10megabytes/min, so I'd have expected that to be plenty.

5MB/s is approximately equal to 54Mb/s (bytes vs bits), so, even if
you are being told the actual rate being achieved, you could easily be
maxing it out.

So what am I missing ? Is there some deep reason why this won't work, am
I doing something stupid, what's going on ?

I don't think your WiFi can be handling the throughput. You might
wish to investigate the coverage in as scientific a manner as
possible. It is generally accepted that to achieve a stable WiFi
connection, you need a signal-to-noise ratio of around -70dBm or
better. You can get smartphone/tablet apps that measure WiFi signals.
I have used an Android mobile phone app called WiFi Analyser, which I
rate as being pretty good ...
https://play.google.com/store/apps/d....wifi.analyzer
.... while for i* there's this, although I have no experience of it ...
https://itunes.apple.com/gb/app/netw...562315041?mt=8
Use one of these or something similar to check out the WiFi coverage.
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On Thu, 23 Jun 2016 21:24:57 +0100, Java Jive
wrote:

On Thu, 23 Jun 2016 08:28:04 -0500, Richard Robinson
wrote:

Bob Latham said:
In article ,
Richard Robinson wrote:

Hello. I'm baffled and looking for help.

I've been trying to play audio over my home wifi :- the backend is a
raspbery pi sending audio out via USB into a DAC, the frontend is a
laptop running Debian 8, sending to a pulseaudio "SMC9514 hub digital
stereo (IEC958) on pi@raspberypi" sink (I find pulseaudio deeply obscure
and offputting, but I haven't found much else that offers the
possibility of doing this at all).

Not used a RPi, so can't help much with that at all. BTW, Jim is no
fan of pulse audio - neither am I, so I'm not grumbling - but
pulse audio or not, I suspect the WiFi is the problem, see below.

This connects, to the extent of
getting a noise out of the speakers, but the sound is useless - broken
up, stuttering, as much silence than sound - it gives the impression
that the data's just not being sent fast enough.

What transfer rate do you get if you just copy a file via WiFi from
the laptop to the RPi?

Wifi-wise, the pi is the bottleneck, with 'iwconfig wlan0' giving "Bit
Rate=54 Mb/s" (the rest of the system could go faster).

That sounds like it's telling you the theoretical maximum rate for
802.11g rather than the actual rate being achieved:
802.11b 2.4GHz 11 Mb/s
802.11g 2.4GHz 54 Mb/s
802.11n 2.4GHz 320 Mb/s

But
handwavingly, this is ~5megabytes/sec, CD-quality sound is
~10megabytes/min, so I'd have expected that to be plenty.

5MB/s is approximately equal to 54Mb/s (bytes vs bits), so, even if
you are being told the actual rate being achieved, you could easily be
maxing it out.

So what am I missing ? Is there some deep reason why this won't work, am
I doing something stupid, what's going on ?

I don't think your WiFi can be handling the throughput. You might
wish to investigate the coverage in as scientific a manner as
possible. It is generally accepted that to achieve a stable WiFi
connection, you need a signal-to-noise ratio of around -70dBm or
better. You can get smartphone/tablet apps that measure WiFi signals.
I have used an Android mobile phone app called WiFi Analyser, which I
rate as being pretty good ...
https://play.google.com/store/apps/d....wifi.analyzer
... while for i* there's this, although I have no experience of it ...
https://itunes.apple.com/gb/app/netw...562315041?mt=8
Use one of these or something similar to check out the WiFi coverage.

Anyone who lives in a city is lucky if their wifi works at all.
Typically dozens of stations are crammed onto each channel, and the
signal is not the most robust. By London standards, my house is in a
pretty good location, but I still contend with this

http://www.soundthoughts.co.uk/look/wifi.png

d

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[interim followup, I haven't had a lot of time for this].

Java Jive said:
On Thu, 23 Jun 2016 08:28:04 -0500, Richard Robinson

Wifi-wise, the pi is the bottleneck, with 'iwconfig wlan0' giving "Bit
Rate=54 Mb/s" (the rest of the system could go faster).

That sounds like it's telling you the theoretical maximum rate for
802.11g rather than the actual rate being achieved:
802.11b 2.4GHz 11 Mb/s
802.11g 2.4GHz 54 Mb/s
802.11n 2.4GHz 320 Mb/s

I suspected that. Then I shuffled stuff around the network for a while to
make sure it had enough reality to chew on then looked again, and it told
me, variously, 180Mb/s and 216Mb/s. So I think it's real numbers - which I
also don't understand, the card only claiming to be capable of up to
150Mb/s. I have v. little experience of network diagnostics.


But handwavingly, this is ~5megabytes/sec, CD-quality sound is
~10megabytes/min, so I'd have expected that to be plenty.

5MB/s is approximately equal to 54Mb/s (bytes vs bits), so, even if you
are being told the actual rate being achieved, you could easily be maxing
it out.

That's what I don't see, 5 megabytes / second is much faster than 10
megabytes / minute. Bob Latham's comment on buffering may be the answer,
I'll investigate that when my tuits arrive. But not being in an energetic
mood today, I think I'll also look at Volumio.

--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html

On 06/23/2016 12:40 PM, Bob Latham wrote:

For your raspberry pi code Google OpenHome UPnP.

I'm getting good results with MPD in the Pi with the music on another
machice as a file server. OK, sometimes FLAC tracks are a little slow
to start but generally it is good.

If you are handy with scripting and the filenames / directory names are
meaningful could you write a tagging script for those MP3s?

Pete

Peter Chant said:
On 06/23/2016 12:40 PM, Bob Latham wrote:

For your raspberry pi code Google OpenHome UPnP.

I'm getting good results with MPD in the Pi with the music on another
machice as a file server. OK, sometimes FLAC tracks are a little slow
to start but generally it is good.

Yes, that's looking like my next step. I looked at volumio and a couple of
the other dedicated audio distros, but I couldn't get them to even boot and
have reached the point where MPD's looking like a more worthwhile option
than throwing any more time at them.

How does accessing the remote disk work, do you need NFS/Samba, somthing
like that ? I've never needed anything like that before (it's not a problem,
I can do Geek when I have to).

If you are handy with scripting and the filenames / directory names are
meaningful could you write a tagging script for those MP3s?

Kid3 can do that with a button-push. Which is nice, in cases where the
filenames are meaningful. Cue hollow laughter - well, some of them are, but
plenty aren't.

$ find /home/music | egrep '/01.(mp3|flac)' | wc -l
259

Directory names are meaningful, as they more-or-less have to be, I could
script that, but it's not worth it - if I've to be doing the individual
tracks by hand it's hardly any extra nuisance to slap the 'Album' name in at
the same time. I do find Kid3 pretty convenient. And in the meantime, I have
players that'll browse the filesystem as well as the tags.

But I have written a perl script to check for and apply ReplayGain, which
seems to work, and improves things.


Which all reminds me - is there any way of storing tag data outside the
music file ? It's irritating, and slow, having to back up music files in
their entirety when I've only made changes to the tag data.

--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html

On 06/27/2016 01:12 PM, Richard Robinson wrote:
Peter Chant said:
On 06/23/2016 12:40 PM, Bob Latham wrote:

For your raspberry pi code Google OpenHome UPnP.

I'm getting good results with MPD in the Pi with the music on another
machice as a file server. OK, sometimes FLAC tracks are a little slow
to start but generally it is good.

Yes, that's looking like my next step. I looked at volumio and a couple of
the other dedicated audio distros, but I couldn't get them to even boot and
have reached the point where MPD's looking like a more worthwhile option
than throwing any more time at them.


I believe that and others use mpd as a backend.

How does accessing the remote disk work, do you need NFS/Samba, somthing
like that ? I've never needed anything like that before (it's not a problem,
I can do Geek when I have to).

mpd can apparently connect directly to a smb or nfs server. In my
config I mount the nfs director using /etc/fstab. Partly as I did not
realise mpd could connect to the server directly.


Which all reminds me - is there any way of storing tag data outside the
music file ? It's irritating, and slow, having to back up music files in
their entirety when I've only made changes to the tag data.


Don't know. Playlist per album?

Peter Chant said:
On 06/27/2016 01:12 PM, Richard Robinson wrote:
Peter Chant said:
On 06/23/2016 12:40 PM, Bob Latham wrote:

For your raspberry pi code Google OpenHome UPnP.

I'm getting good results with MPD in the Pi with the music on another
machice as a file server. OK, sometimes FLAC tracks are a little slow
to start but generally it is good.

Yes, that's looking like my next step. ...

! I do believe I have it working. And, yes, pull does the job where push didn't.

How does accessing the remote disk work, do you need NFS/Samba, somthing
like that ? I've never needed anything like that before (it's not a problem,
I can do Geek when I have to).

mpd can apparently connect directly to a smb or nfs server. In my
config I mount the nfs director using /etc/fstab. Partly as I did not
realise mpd could connect to the server directly.

I dunno. I did set up nfs, it was so little hassle I don't even know if it
was necessary or not. Fiddling about with alsa/pulseaudio configuration was
nastier, as &^%$! always.

Thanks.

--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html