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HELP - MP3 playback using MPD on unslung 6.10

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  • threeeyedtoad
    I m sort of at the end of my rope on this one, and could really use help from some of the seasoned experts... I ve picked up a USB audio dongle (although I
    Message 1 of 5 , Mar 2, 2009
      I'm sort of at the end of my rope on this one, and could really use
      help from some of the seasoned experts...

      I've picked up a USB audio dongle (although I attempted to secure one
      with a C-Media chip, I ended up with "3D SOUND" dongle with a JMTek
      chip in it)... I've managed to configure the dongle with my NSLU2
      running Unslung 6.10 Beta. I abandoned getting it to work with a USB
      2.0 hub, but have met with success using a Texas Instruments
      TUSB2040/2070 USB 1.1 hub. I also have a Western Digital .5 Tb MyBook
      sharing the USB hub, which has all my MP3s on it.

      When I use madplay (0.15.2) to playback an MP3, sound comes out of the
      USB dongle (although it does sound like the MP3 is either downsampled,
      or over-driven) and is delivered to my speakers.

      However, when I attempt to use MPD (0.14.2) with the wymypy web-based
      front-end for playback, the playback is badly stuttered (like, a
      half-second of audio is heard, then a second of silence, then another
      half-second of audio, etc.). Top reveals MPD's CPU utilization is
      pegged at 97%, leading me to believe the stuttering is a side affect
      of the excessive utilization.

      I could go about getting another server-side playback utility running,
      but I was hoping to avoid setting up PHP and/or a web server. Madplay
      reports only using between 5% and 15% CPU utilization, so what's up
      with MPD? Is it using some floating point calculation that can be
      supressed through mpd.conf possibly?

      Also, any ideas on improving the fidelity of the sound sample coming
      out of the USB dongle? I know the dongle is capable of much higher
      quality, having used it with another system...
    • Gregg C Levine
      Hello! If I remember correctly, the NSLU2 processor is one of those unlucky ones to be created without a FPU as part of its design. Technically the processor
      Message 2 of 5 , Mar 2, 2009
        Hello!
        If I remember correctly, the NSLU2 processor is one of those unlucky ones to
        be created without a FPU as part of its design.

        Technically the processor it uses is ideal for file management, and of
        course as it happens working in some routers, and of course the NSLU2.
        Because it does not have this FPU, Linux on it needs to emulate (some how)
        the floating point functions that we take for granted on desktops and full
        size servers, except for IBM's Z Series. So it spends its time physically
        doing that and causes the MP3 players such as that one to produce choppy
        sound. (And the other one to bollix the sampling actions.)

        If you have access to another system running Linux, (your choice of
        distributions), try your MP3s on the same player there.

        Next up: Is this a powered hub? I certainly hope so. You have your disk
        drive there that holds your collection, and the sound device dongle.

        The other issue is why did you abandon using the USB 2.0 hub? Supposedly the
        NSLU2 contains USB 2.0 connectors, so the hub should agree with them.

        The other thing that comes to mind is perhaps your choice of installed
        release, but I don't think it is at fault here.

        --
        Gregg C Levine hansolofalcon@...
        "The Force will be with you always." Obi-Wan Kenobi
         


        > -----Original Message-----
        > From: nslu2-linux@yahoogroups.com [mailto:nslu2-linux@yahoogroups.com] On
        Behalf
        > Of threeeyedtoad
        > Sent: Monday, March 02, 2009 10:47 PM
        > To: nslu2-linux@yahoogroups.com
        > Subject: [nslu2-linux] HELP - MP3 playback using MPD on unslung 6.10
        >
        > I'm sort of at the end of my rope on this one, and could really use
        > help from some of the seasoned experts...
        >
        > I've picked up a USB audio dongle (although I attempted to secure one
        > with a C-Media chip, I ended up with "3D SOUND" dongle with a JMTek
        > chip in it)... I've managed to configure the dongle with my NSLU2
        > running Unslung 6.10 Beta. I abandoned getting it to work with a USB
        > 2.0 hub, but have met with success using a Texas Instruments
        > TUSB2040/2070 USB 1.1 hub. I also have a Western Digital .5 Tb MyBook
        > sharing the USB hub, which has all my MP3s on it.
        >
        > When I use madplay (0.15.2) to playback an MP3, sound comes out of the
        > USB dongle (although it does sound like the MP3 is either downsampled,
        > or over-driven) and is delivered to my speakers.
        >
        > However, when I attempt to use MPD (0.14.2) with the wymypy web-based
        > front-end for playback, the playback is badly stuttered (like, a
        > half-second of audio is heard, then a second of silence, then another
        > half-second of audio, etc.). Top reveals MPD's CPU utilization is
        > pegged at 97%, leading me to believe the stuttering is a side affect
        > of the excessive utilization.
        >
        > I could go about getting another server-side playback utility running,
        > but I was hoping to avoid setting up PHP and/or a web server. Madplay
        > reports only using between 5% and 15% CPU utilization, so what's up
        > with MPD? Is it using some floating point calculation that can be
        > supressed through mpd.conf possibly?
        >
        > Also, any ideas on improving the fidelity of the sound sample coming
        > out of the USB dongle? I know the dongle is capable of much higher
        > quality, having used it with another system...
        >
        >
      • threeeyedtoad
        Thanks for the quick response. I m fully aware that the NSLU2 does not have a FPU. This is well documented in the wiki pages. Also well documented are the
        Message 3 of 5 , Mar 3, 2009
          Thanks for the quick response.

          I'm fully aware that the NSLU2 does not have a FPU. This is well
          documented in the wiki pages. Also well documented are the MP3
          players that only use integer math. Both madplay and MPD are both
          included in the list of supported MP3 players that use integer math.
          As I described, madplay works fine, but (to my knowledge) does not
          support remote server play via a web interface. MPD has many clients
          that support remote play via the web.

          I've read in several places online that replaygain (and possibly
          software volume control - whatever that is) MAY use FP math. My
          question for those who have gotten MPD successfully running on a Slug
          - is there a configuration that can be made in mpd.conf that would
          suppress any functionality that utilizes FPU?

          As for the hub - yes, I'm using a powered USB 1.1 hub. Again, using
          maadplay, everything is hunky dory playing MP3s off a HD plugged into
          the same 1.1 hub. I bailed on a USB 2.0 hub after reading multiple
          places that the USB audio dongle may not play nice with a 2.0 hub - at
          least, not using an unslung distro. The USB 2.0 hub is fine with the
          unslung NSLU to hang HD drives off, but not for the audio.

          So - thoughts on how to get MPD working without FPU math under unslung?


          --- In nslu2-linux@yahoogroups.com, "Gregg C Levine"
          <hansolofalcon@...> wrote:
          >
          > Hello!
          > If I remember correctly, the NSLU2 processor is one of those unlucky
          ones to
          > be created without a FPU as part of its design.
          >
          > Technically the processor it uses is ideal for file management, and of
          > course as it happens working in some routers, and of course the NSLU2.
          > Because it does not have this FPU, Linux on it needs to emulate
          (some how)
          > the floating point functions that we take for granted on desktops
          and full
          > size servers, except for IBM's Z Series. So it spends its time
          physically
          > doing that and causes the MP3 players such as that one to produce choppy
          > sound. (And the other one to bollix the sampling actions.)
          >
          > If you have access to another system running Linux, (your choice of
          > distributions), try your MP3s on the same player there.
          >
          > Next up: Is this a powered hub? I certainly hope so. You have your disk
          > drive there that holds your collection, and the sound device dongle.
          >
          > The other issue is why did you abandon using the USB 2.0 hub?
          Supposedly the
          > NSLU2 contains USB 2.0 connectors, so the hub should agree with them.
          >
          > The other thing that comes to mind is perhaps your choice of installed
          > release, but I don't think it is at fault here.
          >
          > --
          > Gregg C Levine hansolofalcon@...
          > "The Force will be with you always." Obi-Wan Kenobi
          >
          >
          >
          > > -----Original Message-----
          > > From: nslu2-linux@yahoogroups.com
          [mailto:nslu2-linux@yahoogroups.com] On
          > Behalf
          > > Of threeeyedtoad
          > > Sent: Monday, March 02, 2009 10:47 PM
          > > To: nslu2-linux@yahoogroups.com
          > > Subject: [nslu2-linux] HELP - MP3 playback using MPD on unslung 6.10
          > >
          > > I'm sort of at the end of my rope on this one, and could really use
          > > help from some of the seasoned experts...
          > >
          > > I've picked up a USB audio dongle (although I attempted to secure one
          > > with a C-Media chip, I ended up with "3D SOUND" dongle with a JMTek
          > > chip in it)... I've managed to configure the dongle with my NSLU2
          > > running Unslung 6.10 Beta. I abandoned getting it to work with a USB
          > > 2.0 hub, but have met with success using a Texas Instruments
          > > TUSB2040/2070 USB 1.1 hub. I also have a Western Digital .5 Tb MyBook
          > > sharing the USB hub, which has all my MP3s on it.
          > >
          > > When I use madplay (0.15.2) to playback an MP3, sound comes out of the
          > > USB dongle (although it does sound like the MP3 is either downsampled,
          > > or over-driven) and is delivered to my speakers.
          > >
          > > However, when I attempt to use MPD (0.14.2) with the wymypy web-based
          > > front-end for playback, the playback is badly stuttered (like, a
          > > half-second of audio is heard, then a second of silence, then another
          > > half-second of audio, etc.). Top reveals MPD's CPU utilization is
          > > pegged at 97%, leading me to believe the stuttering is a side affect
          > > of the excessive utilization.
          > >
          > > I could go about getting another server-side playback utility running,
          > > but I was hoping to avoid setting up PHP and/or a web server. Madplay
          > > reports only using between 5% and 15% CPU utilization, so what's up
          > > with MPD? Is it using some floating point calculation that can be
          > > supressed through mpd.conf possibly?
          > >
          > > Also, any ideas on improving the fidelity of the sound sample coming
          > > out of the USB dongle? I know the dongle is capable of much higher
          > > quality, having used it with another system...
          > >
          > >
          >
        • Brian Zhou
          I just disabled libsamplerate in mpd configure except on x86 optware target. When libsamplerate is enabled, it does quite a lot of FP calculation. Please give
          Message 4 of 5 , Mar 3, 2009
            I just disabled libsamplerate in mpd configure except on x86 optware target. When libsamplerate is enabled, it does quite a lot of FP calculation. Please give mpd_0.14.2-3 a try and see if it makes any difference.

            -Brian Zhou

            --- In nslu2-linux@yahoogroups.com, "threeeyedtoad" <threeeyedtoad@...> wrote:
            >
            > I'm sort of at the end of my rope on this one, and could really use
            > help from some of the seasoned experts...
            >
            > I've picked up a USB audio dongle (although I attempted to secure one
            > with a C-Media chip, I ended up with "3D SOUND" dongle with a JMTek
            > chip in it)... I've managed to configure the dongle with my NSLU2
            > running Unslung 6.10 Beta. I abandoned getting it to work with a USB
            > 2.0 hub, but have met with success using a Texas Instruments
            > TUSB2040/2070 USB 1.1 hub. I also have a Western Digital .5 Tb MyBook
            > sharing the USB hub, which has all my MP3s on it.
            >
            > When I use madplay (0.15.2) to playback an MP3, sound comes out of the
            > USB dongle (although it does sound like the MP3 is either downsampled,
            > or over-driven) and is delivered to my speakers.
            >
            > However, when I attempt to use MPD (0.14.2) with the wymypy web-based
            > front-end for playback, the playback is badly stuttered (like, a
            > half-second of audio is heard, then a second of silence, then another
            > half-second of audio, etc.). Top reveals MPD's CPU utilization is
            > pegged at 97%, leading me to believe the stuttering is a side affect
            > of the excessive utilization.
            >
            > I could go about getting another server-side playback utility running,
            > but I was hoping to avoid setting up PHP and/or a web server. Madplay
            > reports only using between 5% and 15% CPU utilization, so what's up
            > with MPD? Is it using some floating point calculation that can be
            > supressed through mpd.conf possibly?
            >
            > Also, any ideas on improving the fidelity of the sound sample coming
            > out of the USB dongle? I know the dongle is capable of much higher
            > quality, having used it with another system...
            >
          • threeeyedtoad
            Rock on. Disabling libsamplerate did the trick for me in mpd_0.14.2-3. Now that I know what to search for, there are some threads that have recently spun up
            Message 5 of 5 , Mar 4, 2009
              Rock on. Disabling libsamplerate did the trick for me in mpd_0.14.2-3. Now that I know what to search for, there are some threads that have recently spun up on the linux.debian.bugs.dist Google Group (specifically Bug#517976), complaining about libsamplerate as a CPU hog for machines without FPU. I guess there have been changes to MPD recently that changed how this was implemented.

              Brian, thanks for the quick response and attention in this matter. I'm amazed and grateful for how well the *nix community continues to support the little Slug, five years after it was first introduced to the market. Amazing.


              --- In nslu2-linux@yahoogroups.com, "Brian Zhou" <b88zhou@...> wrote:
              >
              > I just disabled libsamplerate in mpd configure except on x86 optware target. When libsamplerate is enabled, it does quite a lot of FP calculation. Please give mpd_0.14.2-3 a try and see if it makes any difference.
              >
              > -Brian Zhou
              >
              > --- In nslu2-linux@yahoogroups.com, "threeeyedtoad" <threeeyedtoad@> wrote:
              > >
              > > I'm sort of at the end of my rope on this one, and could really use
              > > help from some of the seasoned experts...
              > >
              > > I've picked up a USB audio dongle (although I attempted to secure one
              > > with a C-Media chip, I ended up with "3D SOUND" dongle with a JMTek
              > > chip in it)... I've managed to configure the dongle with my NSLU2
              > > running Unslung 6.10 Beta. I abandoned getting it to work with a USB
              > > 2.0 hub, but have met with success using a Texas Instruments
              > > TUSB2040/2070 USB 1.1 hub. I also have a Western Digital .5 Tb MyBook
              > > sharing the USB hub, which has all my MP3s on it.
              > >
              > > When I use madplay (0.15.2) to playback an MP3, sound comes out of the
              > > USB dongle (although it does sound like the MP3 is either downsampled,
              > > or over-driven) and is delivered to my speakers.
              > >
              > > However, when I attempt to use MPD (0.14.2) with the wymypy web-based
              > > front-end for playback, the playback is badly stuttered (like, a
              > > half-second of audio is heard, then a second of silence, then another
              > > half-second of audio, etc.). Top reveals MPD's CPU utilization is
              > > pegged at 97%, leading me to believe the stuttering is a side affect
              > > of the excessive utilization.
              > >
              > > I could go about getting another server-side playback utility running,
              > > but I was hoping to avoid setting up PHP and/or a web server. Madplay
              > > reports only using between 5% and 15% CPU utilization, so what's up
              > > with MPD? Is it using some floating point calculation that can be
              > > supressed through mpd.conf possibly?
              > >
              > > Also, any ideas on improving the fidelity of the sound sample coming
              > > out of the USB dongle? I know the dongle is capable of much higher
              > > quality, having used it with another system...
              > >
              >
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