On Sun, 08 Jun 2014 09:44:44 +0100, Jim Lesurf
wrote:

In article , Bob Latham
wrote:
In article , Jim Lesurf
wrote:
[snip]

Oh this is interesting.

I store flac files on a Synology NAS and then use a Sonos box (under
iPad control) to pull the data across the network and play it with spdif
into my pre-amp.

Now my definition of streaming which I assume is wrong, is that chunks
of the file is pulled or pushed just before it is needed with the
minimum amount of data stored at the player, just enough to overcome
blips on the data stream.

So I do consider what I do to be streaming.

From my POV I have a program I've written myself as an example I can use to
illusrate.

The program reads a wave file and shovels data from it to a USB DAC. First
it reads the header of the file so it finds the sample rate, etc. It then
sends to the DAC the value of the sample rate at which to operate.

Then it proceeds by grabbing successive 1-sec 'blocks' of data from the
file and dumping them into an output buffer.

The DAC reads samples from this buffer at a rate the *DAC* now controls. It
reads at regular intervals, each time taking a few samples to allow it to
play at the rate required. Once this buffer-full has been read, this is
detected and the program - which has loaded another buffer-worth ready -
gives that via the buffer.

In effect the software in the computer is just shuffling blocks of data,
and doing each new block when the DAC says it wants it.

This works either from a local hard disc, or something like a NAS or device
like a USB memory stick, say. In each case a filing system makes the file
available to be read.

I *guess* that a 'streamer' is an all-in-one chunk of hardware that
provides its own ability to access files, let the user choose one, and play
it via its own DAC. Thus saving the user the bother of having a computer
run a program to do the job. But I've only deduced this by reading what
people say.

What I don't understand and would love to is, what the blazes is the
point of dlna for audio streaming? What I do does not use dlna at all,
the Sonos just opens the file and pulls data from the NAS using good old
SMB, no dlna server needed or running. It works just fine. What does
dlna do that this doesn't?

I'm also curious about the role and point of dlna.


The point, afaik, is that it provides a searchable database of the
media content placed in its charge on the server for use by a decent
streaming client and can be configured to transcode certain media file
formats to a form that _can_ be recognised and played by the dnla
client being used.

This transcoding feature can take its toll[1] on the server's CPU so
it's best avoided where possible, especially when the server is "cpu
cycles challenged". Unfortunately, this requires that you choose a
client (media streaming box) capable of playing your files in their
native formats.

A few years ago I "Hired" a Medion streaming player from Aldi, set up
the dnla service on the FreeNAS box, drilled the necesary hole through
the basement wall into the kitchen/diner to feed a network cable to
the tiny Medion server box slung under the wall mounted TV stand on
the brackets designed just for such STB support and... was rather
disappointed with the whole experience.

At least two problems became apparent. One, it offered a very klunky
and, as seems to be the way with "TV interfaces", cumbersome/ponderous
explorer style list of the content placed in the charge of the dnla
service on the server box, and two, it couldn't distinguish between
the TV folders stored on the 4 seperate disk volumes under the control
of dnla. I landed up having to rename those folders from "TV Programs"
on each volume to "TV Programs 1" on the first disk through to "TV
Programs 4" on the fourth disk before the Medion stream player would
allow me to access the whole database.

At that point, I did rather wonder what the feckin' point of the 50
quid streaming player box was. I could have just pressed a cheap 2nd
hand laptop into mediaplayer service _without_ the faffing about with
dnla and had a much slicker PC style interface to boot. Needless to
say, I took the gadget back to Aldi for a full refund on the basis of
it not being fit for purpose.

[1] The transcoding won't always be a 'heavy duty' process, sometimes
simply a matter of transcoding the audio stream portion or stripping
out FEC crap from a TS or vice versa for a PS.
--
J B Good