[Android Apps and Games] cybermage1:
I just rebooted both, made certain both volumes were set in the middle of the bar, and no better. I just checked adb and here's relevant lines that I found. Note, "Tiny" is the Samsung Player that I use as the renderer:

I/a ( 2718): Tiny: volume range: 0..15
I/a ( 2718): Tiny: protocolInfo: http-get:*:audio/wav:*,http-get:*:audio/wave:*,http-get:*:audio/x-wav:*,http-get:*:audio/mpeg:*,http-get:*:audio/x-mpeg:*,http-get:*:audio/mp1:*,http-get:*:audio/aac:*,http-get:*:audio/flac:*,http-get:*:audio/x-flac:*,http-get:*:audio/m4a:*,http-get:*:audio/mp4:*,http-get:*:audio/x-m4a:*,http-get:*:audio/vorbis:*,http-get:*:audio/ogg:*,http-get:*:audio/x-ogg:*,http-get:*:audio/L16;rate=11025;channels=1:*,http-get:*:audio/L16;rate=22050;channels=1:*,http-get:*:audio/L16;rate=44100;channels=1:*,http-get:*:audio/L16;rate=48000;channels=1:*,http-get:*:audio/L16;rate=88200;channels=1:*,http-get:*:audio/L16;rate=96000;channels=1:*,http-get:*:audio/L16;rate=176400;channels=1:*,http-get:*:audio/L16;rate=192000;channels=1:*,http-get:*:audio/L16;rate=11025;channels=2:*,http-get:*:audio/L16;rate=22050;channels=2:*,http-get:*:audio/L16;rate=44100;channels=2:*,http-get:*:audio/L16;rate=48000;channels=2:*,http-get:*:audio/L16;rate=88200;channels=2:*,http-get:*:audio/L16;rate=96000;channels=2:*,http-get:*:audio/L16;rate=176400;channels=2:*,http-get:*:audio/L16;rate=192000;channels=2:*,http-get:*:video/vnd.dlna.mpeg-tts:*,http-get:*:video/mpeg2:*,http-get:*:video/mp2t:*,http-get:*:video/mpeg:*,http-get:*:video/mp4v-es:*,http-get:*:video/mp4:*,http-get:*:video/quicktime:*,http-get:*:video/x-ms-wmv:*,http-get:*:video/x-ms-asf:*,http-get:*:video/x-msvideo:*,http-get:*:video/x-ms-video:*,http-get:*:video/divx:*,http-get:*:video/x-divx:*,http-get:*:video/x-ms-avi:*,http-get:*:video/avi:*,http-get:*:video/x-mkv:*,http-get:*:video/mkv:*,http-get:*:video/x-matroska:*,http-get:*:video/ogg:*,http-get:*:video/3gpp:*,http-get:*:video/webm:*,http-get:*:video/x-flv:*,http-get:*:video/flv:*,http-get:*:video/wtv:*,http-get:*:image/bmp:*,http-get:*:image/gif:*,http-get:*:image/jpeg:*,http-get:*:image/png:*,http-get:*:image/jpg:*
I/a ( 2718): Tiny: supported mime-types: [audio/wave, application/x-wav, audio/x-wav, application/wave, audio/x-wave, application/wav, application/x-wave, audio/wav, application/x-mp3, audio/x-mpg, audio/mpeg, audio/mpg, application/mpeg3, application/mpeg, audio/x-mp3, audio/mp3, audio/x-mpeg3, application/mp3, audio/x-mpegaudio, audio/x-mpeg, audio/mpeg3, audio/mp1, application/mp1, application/x-mp4, application/mpeg4, audio/3gpp, audio/aac, audio/aacp, audio/x-mp4, audio/mp4, application/x-m4p, audio/x-aac, application/x-m4b, audio/x-m4p, audio/x-m4b, audio/3gpp2, audio/mpeg4, audio/flac, audio/x-flac, application/x-flac, application/flac, audio/m4a, application/x-m4a, audio/x-m4a, application/x-ogg, audio/ogg, application/ogg, audio/x-ogg, audio/vorbis, audio/lpcm, audio/L8, audio/l24, audio/l16, audio/L16, audio/l8, audio/L24, video/vnd.dlna.mpeg-tts, video/mpeg2, video/mp2t, video/mpeg, video/mp4v-es, video/mp4, video/3gpp, video/quicktime, video/x-ms-wmv, video/x-ms-asf, video/x-msvideo, video/x-ms-video, video/divx, video/x-divx, video/x-ms-avi, video/avi, video/x-mkv, video/mkv, video/x-matroska, video/ogg, video/webm, video/x-flv, video/flv, video/wtv, image/bmp, image/gif, image/jpeg, image/jpg, image/png]
I/AndroidUpnpService( 2718): added renderer: Tiny
I/AndroidUpnpService( 2718): active renderer: Tiny

But then later I see:

W/b ( 2718): Tiny: discarding LastChange state variable not in range: Volume=22 (Range Min: 0 Max: 15 Step: 1)

But no log entries seem to correspond directly with me pressing the volume keys on the Nexus. No pop-up display appears either when I press volume. It's weird because I know it worked when I first installed it.

Full log from the Nexus 7 is available for you here: http://dl.dropbox.com/u/17380416/nexus7log.txt

And regarding shuffling:

I'll keep messing with it until I figure out what causes it. It did it again this morning, but after the reboot it's not having trouble. If I figure out more I'll let you know.