Rockbox Development > Feature Ideas

USB PCM streaming to USB soundcard

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Llorean:
Step 1 would be programming USB host architecture and drivers for a USB sound card into Rockbox in the first place. Neither of these exist, so rather than focusing on all the potential targets that could make use of it, why not pick an existing target with the necessary hardware and get to work?

As for Rockbox as an App, wouldn't it be the responsibility of the OS to decide which sound device the audio is sent to? So that's less a Rockbox project if it's going to exist as a hosted app on something with digital out.

Gauss:
Yes and yes Llorean, thanks for your reply.

I found interesting the possibility of step 1. Although it's an early stage as there are not many ports for such mentioned devices as those devices are just starting to grow on the market.

Rockbox as an app maybe would be the one to stay on such market. Either way Rockbox FTW! Any input it's still welcome, I may add the following:

Any external USB soundcard should not be powered directly by the Rockbox device unless it has the specs to give enough power. Either the soundcard should has its dedicated power source or be powered by an USB powered hub (sometimes with a "Y" USB cable).

pixelma:
Just for your interest: while the Iriver H300 and the Iaudio X5 have the USB host hardware, they don't have host drivers (and capabilities) under Rockbox. Development is probably going to be very hard, especially on the X5, because there's no datasheet available. Maybe it would be better to focus on targets that use software USB?

gevaerts:

--- Quote from: pixelma on November 25, 2010, 03:12:07 PM ---Just for your interest: while the Iriver H300 and the Iaudio X5 have the USB host hardware, they don't have host drivers (and capabilities) under Rockbox. Development is probably going to be very hard, especially on the X5, because there's no datasheet available. Maybe it would be better to focus on targets that use software USB?

--- End quote ---

"Software USB" on the device side isn't really relevant. All devices that support USB host do so with a software stack.

The rockbox-running devices I'm aware of that can do host are Gigabeat F, H300 (except the ones sold in the US I believe) , X5, Gigabeat S, and I think some of the Samsungs (the PortalPlayer-based ones). Of those, the Gigabeat F is regular OHCI, the H300 claims to be OHCI but is something else (it's documented though), X5 is undocumented (and therefore unlikely to ever be supported), Gigabeat S and the Samsungs are EHCI (or a close derivative).

If I would happen to be the person working on this, I'd concentrate on the Gigabeat F first, because the specification is available and clear, because the dock has a full-size A connector on it (which makes testing easy without having to look for the right cable all the time), and because this happens to be the player I use most.

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