Fun With Technology – Part IV

So, I blogged back in February about how I was having some problems with the “Play to” feature in the new Windows Media Player that will be part of Windows 7. Since getting the Release Candidate of Windows 7, I’ve been playing around with this feature, and I think I’m beginning to get to the bottom of why it will sometimes work and sometimes fail.

First, a bit of background on the underlying technology specification, which hails from the industry consortium that goes by the pretentious moniker of the Digital Living Networking Alliance, or DLNA for short. As an aside, I note that their motto is “Connect and enjoy”. At this stage of the technology, it’s often felt more like “Connect and tear your hair out”, but I digress…

Their specification defines how a variety of different types of digital devices can connect and share information. This I’ve summarised in the following table:

Device Class What it does Examples
Digital Media Server (DMS) Stores content and makes it available to networked digital media players (DMP) and digital media renderers (DMR). Some digital media servers can also help protect your content once stored. PCs and network attached storage (NAS) devices
Digital Media Player (DMP)
Finds content on digital media servers (DMS) and provides playback and rendering capabilities. TVs, stereos and home theaters, wireless monitors and game consoles
Digital Media Renderer (DMR)
These devices play content received from a digital media controller (DMC), which will find content from a digital media server (DMS). TVs, audio/video receivers, video displays and remote speakers for music.
Digital Media Controller (DMC) These devices find content on digital media servers (DMS) and play it on digital media renderers (DMR). Internet tablets, Wi-Fi® enabled digital cameras and personal digital assistants (PDA).
Digital Media Printer (DMPr) These devices provide printing services to the DLNA home network. Generally, digital media players (DMP) and digital media controllers (DMC) with print capability can print to DMPr. Networked photo printers and networked all-in-one printers.

Table 1: Information drawn from the DLNA web site.

Windows 7 implements a number of these classes as shown here:

Device Class Windows Implementations
Digital Media Server (DMS) When media streaming is enabled, Windows acts as a DMS.
Digital Media Player (DMP)
Windows Media Player and Windows Media Center act as a DMP when browsing shared media libraries
Digital Media Renderer (DMR)
Windows Media Player acts as a DMR when configured to allow remote control of the Player.
Digital Media Controller (DMC) The “Play To” feature from Windows Media Player and Windows Explorer launches a DMC to control the media playback experience

Table 2: Information drawn from the Engineering Windows 7 Blog.

Note that in the above table, Microsoft had planned to have “Play to” added to Windows Explorer in Windows 7. This did not materialise.

At its simplest, just two devices can be involved: a Server and a Player. These can even be running on the same physical device, as in the case where your Windows Media Player on your Desktop PC is streaming music or video stored on the PC itself. The next step up is where the server and player are on separate physical devices. Two typical scenarios are shown in figure 1:

WMP Scenarios
Figure 1: Typical scenarios of simple case of DMP devices accessing DMS devices.

I’ve used the Denon AVR3808 as an example, since this is what I have in my home network. My main DMS is an old headless (no monitor, keyboard or mouse) Dell PC running the Windows Home Server operating system. Actually, to be strictly accurate, the Dell is running two Digital Media Servers. The first is Microsoft’s Windows Media Connector version 2.0, which is built into WHS. The second is the Asset UPnP media server, which is a free piece of third party software installed onto WHS. The fact that I have two DMSes running will prove significant once I get into describing the next set of scenarios.

In my particular case, all flavours of the two scenarios shown above will work, that is, both DMSes running on the Dell box will stream audio to other PCs in the home network, and to the Denon AVR3808. Under the covers, there’s actually some negotiation of streaming formats going on. This is because I have stored all my music files on the Dell server box in Windows Media Audio Lossless (WMAL) format. This presents no problems for the PCs, since the Windows Media Players installed on them can handle WMAL. But the Denon can only handle standard Windows Media Audio, not the Lossless variant. So when I use the Denon to browse my music library on the Dell and select a track to play, the DMS that I’m using sees that the Denon can’t handle WMAL and transcodes the stream into standard PCM (which the Denon can handle) on the fly. Both the Asset and the Windows Media Connect will do this. But this breaks down in the next set of scenarios.

So, the interesting scenarios are where there are three devices linked together: a Digital Media Server, a Digital Media Controller, and a Digital Media Renderer.

WMP Scenarios 2
Figure 2: Typical scenarios of a three device link (DMS-DMC-DMR).

Once again, in my case, all flavours of scenario 3 will work. That is, I can stream from either DMS running on my Dell Windows Home Server using the “Play To” feature of Windows Media Player in Windows 7, and push the stream to either of my PCs that are currently running Windows 7.

But scenario 4 has been giving me all sorts of problems. Sometimes it would seem to work, and other times it wouldn’t. I think I have finally got to the bottom of it.

The issue is that media libraries in Windows Media Player in Windows 7 can be built up in a number of ways. Take a look at this screenshot of the first few albums in my music library:

WMP 12 3

I’ve highlighted the fact that you are looking at the content of my music library in “Album” view. That is shown as part of the “Library” tree (Library – Music – Album). This screenshot has been taken from my Tablet PC, which is running the Windows 7 Release Candidate. Now the interesting part is where these albums are physically stored. There is far more storage required than my Tablet PC can cope with, so in fact these album files are sitting on my Windows Home Server. This next screenshot shows that my music library is in fact being comprised of three storage locations: my own music folders on the Tablet PC, the “Public” music folders on the Tablet PC, and the music folders on Degas – which is my Windows Home Server:

WMP 12 4

But hang on a minute, Windows Media Player is showing two navigation trees on the left hand side of its window: the “Library” tree and another one called “Other Libraries”. The content of the “Other Libraries” tree is populated by other Digital Media Servers which Windows Media Player discovers on the network. Sure enough, it’s found the Windows Media Connect DMS running on the Dell Windows Home Server (Degas), and this next screenshot shows the same album files being seen in the Album view under the “Other Libraries” tree:

WMP 12 6

You’ll notice that just above “User 1 (degas)”, which is the Windows Media Connect DMS, is the Asset UPnP server entry, shown as “Asset UPnP: DEGAS”. So, under scenario 4, I can stream the same album in three different ways:

  1. Using “Play To” to pull from the Tablet PC’s Windows Media Player streaming server and push it out to the Denon.
  2. Using “Play To” to pull from the Windows Media Connect streaming server on the Dell and push it out to the Denon.
  3. Using “Play To” to pull from the Asset UPnP streaming server on the Dell and push it out to the Denon.

What I’ve found is that method (1) and (3) will work, but that method (2) does not. These are illustrated in the following screenshots:

WMP 12 7

WMP 12 8

WMP 12 9

I should just point out that I’ve configured the Asset UPnP server to always stream in PCM format. If I didn’t do this, then while it would work in the simple case of scenario 2, in the case of scenario 4, it would fail just as the Windows Media Connect server does.

The conclusion that I draw from all this is that in these “man-in-the-middle” scenarios, it looks as though end-to-end negotiation of the proper streaming format is not always being done correctly. I suspect that in scenario 4, method 2, the Windows Media Connect server is simply serving up WMAL format to the Denon, which causes it to fail. Now, I don’t know whether this is a shortcoming of the DLNA specification itself, or simply an outcome of how Microsoft have implemented it in the case where there are physically separate servers out on the network. Time will tell.

At least I now know which scenarios work and which will fail. On to the next problem…

About Geoff Coupe

I'm a British citizen, although I have lived and worked in the Netherlands since 1983. I came here on a three year assignment, but fell in love with the country, and one Dutchman in particular, and so have stayed here ever since. On the 13th December 2006 I also became a Dutch citizen.
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26 Responses to Fun With Technology – Part IV

  1. Sean says:

    hey man, i am having a similar problem getting WMP 12 to "play to" my xbox360. here is forum link that i have described the problem in detail. http://windows7forums.com/windows-7-networking/6215-play-xbox-360-media-center-extender-not-working.html long story short though, i get this message "device can not be controlled" any suggestions?????

  2. Geoff says:

    Sean, I suspect that your xbox360 is only implementing version 1.0 of the DLNA spec, not version 1.5 – which seems to be required for full DMR functionality. With version 1.0, the xbox is a DMP – it’s not necessarily a full DMR. I came across a mention of this issue in the Twonky forums (see http://www.twonkyforum.com/viewtopic.php?f=25&t=6124). This may be what’s underlying your issue.Sorry that I can’t help further…

  3. Sean says:

    hey man i got to work by messing with the homegroup settings. even though I don’t have any cpu’s in a homegroup! thanks though!

  4. Geoff says:

    Sean, glad that you got it working, although it seems strange that the homegroup functionality was behind the problem. Still, computers move in mysterious ways for much of the time…

  5. seth says:

    I just recently (3 weeks ago) got myself a brand new desktop PC with Windows 7 Ultimate 64 bit and am having some issues streaming WAV and WMAL files to my Denon AVP-A1HDCI preamp using WMP 12.The main problem is that when I stream either a WAV or WMA Lossless file they display on my Denon AVP-A1HDCI preamp as the wrong file type. Streamed WAV show up as MP3 and WMA Lossless show up as PCM. When I was using Windows XP and WMP 11 on my old PC I never experienced this issue. All file types were streamed and received correctly.One other thing I’ve noticed is that with WMP 12 I have now lost the ability to pause music using my Denon AVP’s remote. I can play, select next track, previous track, and stop, but no pause. Not a major biggie but a bit annoying nonetheless.Any help, tips or advice would be much appreciated.Thanks,Seth

  6. Geoff says:

    Seth,How are you streaming from WMP12 to the Denon – are you using "scenario 2" or "scenario 4" (see figure 1 & 2 above)? Does it make a difference which method you use?If I use scenario 4 to stream WMA Lossless to my Denon, then I also get the PCM indicator lit on the Denon. But I think that this is expected behaviour. Don’t forget that the Denons don’t support WMA Lossless directly, so WMP is transcoding to a LPCM stream on the fly. I don’t know why WAV stremas should be displayed as MP3 on the Denon. I don’t use WAV format, so I can’t test this.I’m afraid I also can’t help you with your remote issue. My Denon remote can pause music streamed from WMP12 with no problem.

  7. seth says:

    Geoff,Thank you for your quick reply. I’m using "scenario 2" I have my Denon preamp connected via CAT 6a to my router, and my desktop PC is the music server.As to my Denon preamp not supporting WMA Lossless directly, well actually it does, along with WAV, AAC and FLAC. And just to rule out that there isn’t something amiss with my Denon AVP preamp, I plugged in a USB stick into my Denon that has WAV and WMA Lossless music on it. It played the files in their correct audio format with no problems (WAV showed up as PCM and WMA Lossless showed up as WMA). So there must be some sort of incompatibility between my Denon preamp and WMP 12.I know that my Denon was designed to be used with WMP 11, and with my previous desktop that used Windows XP and WMP 11 all was well (I could even pause using the Denon remote). So now to find a solution to the issues I’m having. All I know is that if I stream WAV or WMA Lossless, I don’t want to be listening to a different audio format (especially a down resolutioned MP3). If I can’t get WMP 12 to stream things correctly I’m just going to have to find a different media manager to stream my music.Seth

  8. Geoff says:

    Seth, hmmm, interesting. I’ll have to check out a USB stick with WMA lossless files on my Denon to see if it will play. According to the table on page 66 of your manual (and page 53 of mine), the Denons only support WMA formats to bit rates between 48-192 kbps. Since WMA Lossless is using bit rates between 470-940 kbps, then WMA Lossless, according to Denon’s own manuals should not work. And that’s what I see with my AVR-3808. WMA is fine, but WMA Lossless does not work. But I must try a USB stick and see if that makes a difference…

  9. seth says:

    Looks like I was mistaken, you are in fact correct about WMA Lossless. The file type that happened to be on the USB stick was WMA, but not WMA Lossless. I found this out when I was going to add some other music to the USB stick. I went ahead and added some WMA Lossless files to the USB stick, and just like you said, it displayed "file format error". So you are 100% correct that Denon receivers and preamp will not play a WMA Lossless file natively.Thanks for pointing that out. And it’s a good thing that I noticed what was on the USB, as here all this time I thought I had WMA Lossless on it. D’oh!But I still need to get the WAV to MP3 issue resolved.Thank you for help. :)Seth

  10. seth says:

    Hi Geoff,I know that you do not use WAV to stream music to your Denon. But if you could do me a huge favor and add at least one WAV file to your library and see what it shows up as on your Denon when streamed I would really appreciate it. At least this way I would know that the issue indeed stems from either Windows 7 or WMP 12.Only asking as this info would really help me to determine the cause.Thanks,Seth

  11. Geoff says:

    Seth, OK, I scouted through my music collection, and found some WAV files that had been created by Cubase. They are a combination of files recorded at 48 kHz/1536 bps and 44.1 kHz/1411 bps.Now, when I stream these files from WMP12 to the Denon (using either scenario 2 or 4), the Denon MP3 indicator is lit. However, when I put the files onto a USB stick, and play them directly on the Denon, then the PCM indicator is lit. It seems pretty clear then that what is happening is that, in the negotiation that takes place between the Denon and WMP12 over what format to choose for streaming, MP3 is somehow chosen in place of PCM. If this doesn’t happen with WMP11, then it seems that WMP12 makes a bad call on choosing the format for streaming. Something that needs to be reported to Microsoft…

  12. seth says:

    Hi Geoff,Thank you VERY much for testing this out! This verifies that there is indeed something in WMP 12 that is transcoding WAV’s to MP3. You have been a HUGE help for me! :) I will see about contacting Microsoft about this issue and hopefully they will get this resolved and offer an update to fix this very soon.I guess until they correct this, I will use WMA Lossless to stream to my Denon instead of WAV. At least I know that’s getting transcoded to PCM. The only downer now is that at least 90% (over 1,500 songs) of my music library are in WAV format. Is there any way to just convert my library of WAV files to WMA Lossless or will I have to manually re-rip all my CD’s into WMA Lossless?Thank you again for all your help with this. :)Seth

  13. Geoff says:

    Seth, doing a Google for converting WAV to WMA throws up a few possibilities, but I’m afraid I have no personal experience of any of them. So proceed at your own risk, I’m afraid… Good luck.

  14. seth says:

    Hi Geoff,Well for now I have found a excellent solution to my streaming woes. On the recommendation of a friend (and fellow Denon AVP-A1HDCI owner), I downloaded TwonkyMedia Manager. It automatically added all my music (including all my playlists!) to it’s library and found my Denon without me having to do anything. And now when I stream music using TwonkyMedia Manager, WAV’s stream as PCM! Woo hoo! And I can once again pause the music stream via the Denon remote. :)IMO TwonkyMedia Manager is way easier to use than WMP 12. And the best part is that it works right!! Even if Microsoft issues a fix for WMP 12, I may just continue using TwonkyMedia Manager. So it looks like now I will not need to convert my library of WAV’s to WMA Lossless, or re-rip them all.Thank you once again for all your help.Seth

  15. Geoff says:

    Seth,Glad you’ve found a solution in Twonky. Last time I looked at it, it was very buggy – it sounds as though the latest release is much improved.One thing that someone mentioned to me is that the WAV format is actually a file container format – it can contain a variety of compressed or uncompressed audio formats. So it’s possible that WMP12 is choosing what it thinks is the best match for the Codec in the WAV file, and it might be just as good a choice as PCM. The suggestion was to install one of the downloadable Codec packs into WMP12 (e.g. http://download.cnet.com/Media-Player-Codec-Pack/3000-13632_4-11118005.html ) and see if that makes a difference. Since I don’t use WAV in general, I don’t think I’ll bother.

  16. seth says:

    Hi Geoff,Yeah about a year and a half ago I tried using TwonkyMedia Server and I was NOT impressed. But this new Media Manager of theirs actually works quite nicely. Interestingly though, while I can stream WAV’s and MP3’s with not problems, WMA Lossless files for some reason do not stream. No biggie for me as nearly all of my music is WAV, but for others that have a large library of WMA Lossless, this Media Manger will not be a good choice.And after doing a bit of research myself, you’re right, a WAV can contain a variety of different audio formats. But by far the most widespread and common are WAV’s that are fully uncompressed in PCM with a bitrate of 1,411.2 kbit/s. And like you said an MP3 can indeed be contained in a WAV, but even though MP3 can have a non-standard max bit rate of 640 kbit/s, very few devices can play them. And according to the ISO standard, decoders are only required to be able to decode streams up to 320 kbit/s.So it’s quite likely that the WAV’s being transcoded to MP3’s are being played through our Denon’s at 320 kbit/s. Which is a far cry from 1,411.2 uncompressed PCM. I checked out the downloadable codec pack, and it does look promising. It might just do the trick, but in the off chance that it does not, I think I’ll no bother with it either.This is only my second day with using TwonkyMedia Manager, but so far I’m very happy with the results. I’m still going to let Microsoft know about the issue with WMP 12, and hopefully they will offer a fix for it.

  17. John McGinniss says:

    Hi Geoff. I wonder if you can help me as you appear to be a guru on DLNA and WMP12.
    I have set up my WMP12 to share photos, music and video libraries and stream to a Sony BDP-S570 DNLA capable device which connects via HDMI to a Sony Bravia.
    On the Sony BDP menu I can only see photos to play and no music or video libraries although these used to work.
    Any ideas on what I’ve misconfigured?

    Thanks,
    John.

    • Geoff Coupe says:

      Hi John,
      Not being an owner of the Sony BDP-S570, I probably can’t be of much help. I had a quick look through the manual, but I didn’t see a setting that would block music or video, but not photos… I assume that the Sony is seeing your PC?

      The only thing I can think of is that perhaps you’ve turned off sharing of your music and videos on your PC. In WMP12, if you click on the “Stream” menu, and then choose “More streaming options…”, you should see a list of all the DLNA devices in your network. One of them should be the BDP-S570. Click on the “Customize” link, and you should see a window where you can select what medai you want to stream to the player. Now, by default, all media should be streamed, but just in case something is not working right, you could try unchecking the “Use default settings” box and check the “Make all of the media in my library available to this device” box…

      Other than that, I have no idea on what might be going on; sorry…

      • John McGinniss says:

        Thanks, Geoff.
        I’ll check those settings later when I’m home and let you know the results.
        Excellent speedy reply!

  18. John McGinniss says:

    I tried altering streaming options but still no joy.
    I even removed WMP12 and re-installed with no luck.
    I’m beginning to think codec problems or something. Checked Windows firewall, seemed to be OK.
    Eventually installed a trial version of Mezzmo and it showed all folders, Music, Photos and Videos.
    My next move is to try out XBMC which is free.
    Thanks,

    John.

    • Geoff Coupe says:

      Ah, yes, codec issues could be a cause of the problem. You say that at one time music and videos worked. Have you at some point installed a new codec package?

      Also, I went back and looked again at the player specs. I noticed that there were footnotes stating that the player wouldn’t play media files marked with DRM, or play WMA Lossless. I just wonder whether the player has had a firmware upgrade applied that might lock things down a bit more than they were when you first got it?

      Sorry I can’t be of more help…

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