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Custom MP3 Player

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Zresh:
As the title says I'm considering having a custom MP3 Player built and was wondering if it was possible if Rockbox would work on it as the main OS without the need for side loading and if so what spec's the player should have. If a new player can be built and would work I'd have the plan's made open source so anyone could build there own player if desired.

Here's some details of the player I put together real quick in the attachments.

As this isn't something I'm well versed in I don't know if a GPU is needed or not and the rest is what I thought would make for a good long term player. The ?'s aside from the CPU/GPU are for feature's I'm not sure I'd want but if this is something that might work and can be built would be added if other people wanted.

Any thought's on if this would work, why it wouldn't, if it was built if a new OS would be needed or if Rockbox could be made to work would be greatly appreciated.

speachy:
I wrote this up several years ago.  Updated it a little this morning.

  https://www.shaftnet.org/~pizza/rb-wishlist.txt

Based solely on your specs, I'd eschew large amount of on-device storage for a simple SD card slot.   It also has the advantage of being easily replaceable so you don't have to worry about the on-board flash wearing out.

I'd also strongly caution you about multi-touch screens -- touch is nice to have, but it makes the device unusable if you're not looking at the screen.  Physical buttons are strongly preferred.

The sad truth of the matter is that most modern DAPs, especially the ones built on Android or other touch-first environments, lean in hard to gimmicks and give very little thought to UI/UX.  If you want a smartphone-like UI playing back via bluetooth, then.. why not use the smartphone you already have?

gevaerts:
8GB of RAM is *vastly* more than an mp3 player needs. For Rockbox, something like 8MB might be enough, although a bit more (32MB or 64MB) might be better. Some of this also depends on screen resolution.

I'd recommend having a look at the specifications of some existing players to get a better idea.

Zresh:
Alright here are a few changes to the spec's list and a very rough picture of what I'm planning for the body. Not sure where the micro-sd slot will go yet. The two red spots on the back are where speakers might go if there included, if anyone has a different idea for there placement let me know.

On that note still looking for opinion's on if speakers and Wi-Fi should be included and if it needs a cpu/gpu or something else.

speachy:
...So you're gravitating towards a 6th-gen iPod form factor.

You need to decide if you're going to use something like Android, Rockbox, or something entirely different (do _NOT_ underestimate the level of effort of writing something from scratch!) because that will drive the rest of the fundamental system requirements (ie CPU oomph, GPU, RAM and onboard flash requirements)

If you're intending to run Rockbox on this thing, I recommend using a SoC that has embedded DRAM; something like the Allwinner V3s or Ingenic X1000/X2000.  Alternatively, use an SoC that can stack the DRAM on top (eg the BCM4325? on the RPi series)  Not needing off-chip DRAM will _drastically_ simplify your PCB. 

IMO, Speakers in-device is, like many other things, a mostly useless gimmick, and if they're not complete crap will take away case space from something that matters more, like the battery.

As for WiFi, what's the use case?  Data transfer (via what mechanism/protocol? Consider you'll need server and/or client software to make this happen!) or commercial streaming audio services?  If it's the latter then you'll need a huge bump in specs so the device is capable of running Android reasonably well as these services don't make a habit of allowing 3rd-party clients.

I also don't recommend using a hard power switch; power off needs to be under OS control so we can ensure filesystems are in a safe state and all data has been fully flushed.  Use it as a lock switch instead.   I'd also recommend dedicated volume buttons.

That document I linked above has a lot of details and justifications.

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