Rockbox as a network media player

[atsakir]

Ok, this may sound a bit far fetched but I've been thinking that this may actually be feasible... bear with me and I'll explain.

1. Since the rockbox firmware is a complete re-write of a player's capabilities and for the players that USB connectivity has been reverse engineered I see no reason why rockbox can't read IP packets over USB.

2. Since most USB based WiFi dongles are based on a handful of chipsets, drivers for those chipsets have been reverse engineered (for linux) and source code for drivers exists it shouldn't be extremely difficult to port at least a driver for one chipset if not for some (as many as can fit in the firmware) drivers in rockbox to connect USB-based WiFi dongles from a large number of vendors on rockboxed players

3. IP stack source code with support for RTP, RTSP or any other realtime streaming protocol exists in linux distributions as well.

4. The database system in Rockbox can trivially be applied to a music collection on a remote host and a media server (database server) can be implemented relatively easily to serve this music over LAN (through wifi)

Unless I have missed something really important, covering these 4 requirements will mean that a rockboxed media player could be used as a wifi-enabled networked media player both for music stored on a host pc but also for internet radio streams. Of course, there would be the downside that battery-time will be significantly less  if the DAP is feeding the wifi dongle with power

Rockbox developers, am I being too optimistic or is this actually feasible?

[Jennifur]

There is a problem with the second part. Most devices that rockbox supports does not have USB host capabilities. Rockbox doesn't support it on the few that have it either. So it would need to be done in software which is quite slow and may not work on most targets, or support the USB host chips on the few targets that have it.

[torne]

USB host can't be implemented in software, you need a controller capable of supporting it.

[Jennifur]

USB host can't be implemented in software, you need a controller capable of supporting it.

Well, I was mistaken then. So this means only the targets with a USB host chip would be supported.

[csavery]

It may also require hardware changes as it isn't a given that the correct signals / terminations have been routed on the board even when a host controller is on the chip. Example circuits I've seen from some chip datasheets indicate different connections for host and client modes. It's probably possible to do a dual mode circuit but the designers may not have chosen to do that.

[Jennifur]

It may also require hardware changes as it isn't a given that the correct signals / terminations have been routed on the board even when a host controller is on the chip. Example circuits I've seen from some chip datasheets indicate different connections for host and client modes. It's probably possible to do a dual mode circuit but the designers may not have chosen to do that.

I would doubt anyone would transfer music to the player while the device was acting as a host at the same time. There is only one connector on the device, and carrying a powered hub around with you doesn't seem like a good idea either.

Now, a dock that did this would be nice. Yet, there wouldn't be much of a point of having the device act as a host either if it was to be done in a dock. You could just use the lineout on the USB/dock connector or the headphone jack.

[atsakir]

since my original post I googled around and done some reading myself and it is very difficult to implement the host controller stack even on devices than carry a usb host adapter on the chipset. I haven't looked into SDIO based wifi yet but something tells me it will be a dead end in that respect too.

it would have been really nice to have that functionality in rockbox though.... oh, well, scratch that idea then

[saratoga]

You're better off getting a WIFI enabled device like an Android phone and developing applications on it.  They provide a network stack and an API to use it with.

[csavery]

Jennifur: I didn't mean to imply being used at the same time but the circuit would have to support changing from host mode to client mode since client mode has pullup resistors to allow the host to detect presence. To attach a usb wifi dongle to Rockbox would be cool but as saratoga says for practical purposes almost certainly out of reach - better to use something like Android. I had other ideas for this and explored it briefly as a way to add high quality usb microphones to Rockbox to enable a portable recording studio. With a host mode stack you could use a hub and a few good mics feeding into Rockbox to be saved giving a multi-track studio. Alas, not to be...

Edit: I take this back. There is a way I can think of to achieve this and still work within normal usb mode on Rockbox devices. Build a special cable with a usb host controller embedded. A device like the NXP LPC2361 (ARM7TDMI) available from Digikey for $8 could be stuck in a usb connector and act as a host controller being directed by commands from software on a plugin in Rockbox. It has internal flash program memory and could be programmed to as a "mirror" controller. This would be possible if someone wanted to develop the supervisor code. It has a usb host mode stack built in I believe. Essentially this would be a "smart hub" that knows how to relay data from one client to another.

Both ends of the cable would be clients and in the middle would be the host acting as a relay directed by commands it gets from one client issued by the plugin software.