Streaming 5.1 Surround Sound files through SSODS

[GerardLardner]

Can this be done?

I would like to stream 5.1-surround-sound files through my Squeezebox. These files are DTS-encoded WAV files, created from Ambisonic original recordings. They play on the PC using the Windows version of MPlayer, so I presume they could play on the version of MPlayer in SSODS; but they do not. I just get a hiss from the speakers.

I guess there needs to be a suitable entry in the custom-convert.conf file, but I do not know what that should be. Can anyone suggest a suitable entry? Or suggest where I can get reasonably clear instructions for creating my own entry?

Gerard Lardner

[GerardLardner]

Further to the question above, there are actually two things I would like to be able to do:

1 Take a DTS-encoded WAV file (say from the Ambisonic surround-sound recording site www.ambisonia.com) and process it to play as stereo through an SB3, and

2 Take a DTS-encoded WAV file (or an AC3 file or an Ambisonic WAVE-EX file) and pass it unprocessed through the SB3, out via the optical or S/PDIF link, to be decoded by a separate hardware decoder.

The server in my case is a Synology DS-207 running SSODS 2.19, SlimServer 6.5.3 and AlienBBC 1.06. Clients are SqueezeBox 3 units.

From various searches through these forums, both of these ideals seem to be possible, but I have not seen how to do them--how to make them work. Can anyone point me in the direction of how to set up these configurations?

Gerard Lardner

[tommypeters]

Yes, it's possible, is surely described several times but surely not in the Hardware forum...

It has nothing to do with Synology, SSODS at all. What most people fail to do, when DTS doesn't work for them, is this:

* Have the Squeezebox set that digital volume shouldn't be affected by volume control. My guess is this in your case.
* Have a Home Theather system that can decode the DTS stream. I believe this is not your problem.

[bpa]

To play DTS in stereo on an SB - the following is what I think will works based on experience with playing AACplus through mplayer (see http://mwiki.slimdevices.com/index.php/AACplus ).

You need to have additions to 3 files - I would suggest making the changes to the ones in AlienBBC as this already.

The following assume creating a new file type DTS which is identified by files with extension DTS. It will appear

1. In custom-convert.conf

dts wav * *     [mplayer]  -really-quiet -vc null -vo null   -af volume=0,resample=44100:0:1,channels=2 -ao pcm:nowaveheader:file=/dev/fd/4 $FILE$ 4>&1 1>/dev/null
dts mp3 * *     [mplayer]  -really-quiet -vc null -vo null   -af volume=0,resample=44100:0:1,channels=2 -ao pcm:nowaveheader:file=/dev/fd/4 $FILE$ 4>&1 1>/dev/null | [lame] --silent -r -x -q $QUALITY$ -b $BITRATE$ - -
dts flc * *      [mplayer] -really-quiet -vc null -vo null   -af volume=0,resample=44100:0:1,channels=2 -ao pcm:nowaveheader:file=/dev/fd/4 $FILE$ 4>&1 1>/dev/null  | [flac] -cs --totally-silent --endian=little --channels=2 --sign=signed --bps=16 --sample-rate=44100 --compression-level-0 -

2. In custom-types.conf

dts     dts              -           audio

3. custom-strings.txt (keep the tabs)

DTS     EN      DTS 5.1 surround

The mplayer lines should be tuned to match SSODS mplayer options as it has a special build of mplayer which may be different.

You may have to play with the mplayer channels to get the right mixing of channel to your taste. Also mixing is CPU intensive - you may not have enough CPU to re-encode into FLac or MP3.

These rules will convert all files with DTS so will prevent pass through. I think you can add a MAC address to end of custom-convert.conf lines to limit the rules to specific players.

[GerardLardner]

Thanks for the suggestion.

I have "tuned" the mplayer lines for mplayer-stdout used by SSODS, but I am still getting just hiss.

Rereading your message, I wondered if it could be to do with the file extensions. They are labelled as .WAV files; it is the content that is DTS-encoded. But when I tried changing the extension of one of them to .DTS it did not play at all - not even a hiss (it still plays correctly using the Windows versions of MPlayer or VLC; just not on version of mplayer on the Diskstation).

More reading needed...

Gerard Lardner

[bpa]

The only way SS will know to use the special mplayer is by having the dts extension. So it must be used.

Have you tested your mplayer command line on the SSODS system but with output to a real file not an fd. Check how long it takes to process - if it is longer than duration of track then CPU overload is happening. Play the WAV file generated to make sure it sounds OK.

Check
1. Settings Filetypes - that all the rules are enabled.
2. When running use d_source to see what rules are being applied to play the file.
3. run from a shell prompt and remove -quiet from mplayer to see what is happening on SSODS.

[GerardLardner]

Yes, it's possible, is surely described several times but surely not in the Hardware forum...

It has nothing to do with Synology, SSODS at all. What most people fail to do, when DTS doesn't work for them, is this:

* Have the Squeezebox set that digital volume shouldn't be affected by volume control. My guess is this in your case.
* Have a Home Theather system that can decode the DTS stream. I believe this is not your problem.

I realise its not strictly a hardware problem. For my first choice (stream 5.1-surround files to a 2-channel stereo decode) I am hoping to use the version of mplayer specially written/modified for SSODS, which is/was originally specific to the Synology hardware. That was why I asked here.

For my second option (streaming to an outboard decoder) I have now found various other threads relating. Thanks for prompting me to search more widely.

Gerard Lardner

[GerardLardner]

Although I think I was beginning to get this working, I have also got enough of the transcoding working to realise that my Synology DS-207 does not have enough processing power, or perhaps memory, for the job, so I am putting this project on the back burner until there is some other reason to replace the DS-207 with a more powerful NAS box.

Thank you to all the people who gave me comments and advice here and off-forum.

Gerard Lardner

[bpa]

If you have a 207 it a 266MHz Freescale processor which has an FPU. The 207+ has an 500Mhz ARM processor but no FPU.

My guess is the relevant mplayer code uses floating point and not Fixed point arithmetic. This means the 207 would probably be faster than the 207+ but it won't be able for much else.

If standalone mplayer can decode a file into WAV in realtime - then make sure SS is not trying to re-encode the WAV into MP3 or Flac.

[GerardLardner]

I had not expected to return to this thread, but your last comment, bpa, has sparked my interest.

My DS-207 is a basic model, around a year old; it has the 266 MHz processor and 64 MB RAM. I had assumed that the newer "plus" model, with its faster clock speed would be more powerful, but from what you write that might not be so for transcoding (and other FP maths ) purposes? Would I be mistaken, therefore, to expect a 500 MHz DS-207+, to be able to manage transcoding better than a 266 MHz DS-207? Or would it be faster only for non-FP functions?

TBH, the whole issue will have to be put aside for the present. I was looking at streaming the DTS files as an exercise while I was unable to work during the past week-and-a-half (I was rather seriously ill, but not confined to bed). As I am somewhat recovered now, I will have less time to play with such ideas for the next few months. Eventually, I do want to take it up again; but my surround sound rigs need a bit more work before they are really ready to play Ambisonic surround music again.

Can you explain how I see if SS is trying to "re-encode the WAV file into MP3 or Flac"? Standalone Windows MPlayer can decode the DTS files, but not the MPlayer from a Windows installation of SqueezeCentre (I set this up today on another PC, by way of a trial); maybe my standalone Windows MPlayer has access to additional codecs? I had forgotten until just now that I had installed the "WIndows-essentials" pack for that version of MPlayer.

Thanks for the interest,

Gerard Lardner