Rockbox at FSCONS 2009

www.rockbox.org Göteborg, FSCONS November 14, 2009 Daniel Stenberg <daniel@haxx.se>

Daniel Stenberg
Co-founder of the Rockbox project
Embedded systems developer
Open source hacker

Gadgets Gadgets don't do what we want them to

People like to customize things

Enter portable music players 2001 Not so fancy

How hard can it be? Björn Stenberg Linus Nielsen Feltzing Daniel Stenberg Stockholm Sweden, Dec 2001

more Freedom Games Music formats Speed Customization Applications

And not the least What must not be forgotten...

Sandisk Sansa c100, Onda VX747, SanDisk Sansa Fuze, Sandisk Sansa Clip v1, iAudio M5, Archos FM Recorder, Cowon iAudio 7, iAudio X5, Apple iPod Mini 2nd gen, Apple iPod color/photo, Archos Recorder V2, Onda VX767, Logik Dax, Philips GoGear HDD6300, Samsung YH-925, Olympus M-Robe 500, Apple iPod 3rd gen, SanDisk Sansa c200, Tatung Elio, Archos Ondio FM, iriver H100/H115, Archos Recorder, Apple iPod Nano 2nd gen, iriver H120/H140, Archos Ondio SP, iriver H10 5GB, Philips GoGear SA9200, Philips GoGear HDD1800, Sandisk Sansa m200, Toshiba Gigabeat F/X, SanDisk Sansa e200 v2, Archos Jukebox 5000, Samsung YH-820, Apple iPod Nano 1st gen, iriver H320/H340, Creative ZVM, Apple iPod 4th gen gray, Cowon D2, Meizu M6, Archos Jukebox 6000, Toshiba Gigabeat S, Apple iPod Video 60 GB, Olympus M-Robe 100, Apple iPod 1st and 2nd gen, Samsung YH-920, Apple iPod Video 30 GB, Apple iPod Mini 1st gen, iAudio M3, Sandisk Sansa c200v2, iriver H10 20GB, Philips GoGear HDD1600, SanDisk Sansa e200 52 models and counting

… make great towers!

How to hack an mp3 player Or at least a general description how we've done it so far...

Community involve many people! Time consuming Tedious Lots of work

Physical components
Rip apart
Hi-Res scan PCB and publish
beep connections
Identify components
- used to be less hard
- custom branded chips
SoC is primary

What is inside a typical device?
SoC (sh, ARM, m68k, MIPS, ...)
USB
Sound Codec
RAM (usually 32MB)
Flash (NOR for the program)
Flash (NAND these days for everything)
HDD (for storage)
FM tuner
LCD (greyscale, 16bit color, touch, …)
Remote
Buttons, pads, wheels...
Each device is unique and needs adaptations

Learn how components work
Find data sheets
Not always available
NDAs like crazy
Parts of chips are sublicensed and thus under different licenses/NDAs
Manufacturers like secrets
This is growing harder and harder
Why do graphics chips in the PC world go in the opposite direction?

HW tools
JTAG
BDM
UART
USB

Upgrade format
How is an upgrade done?
How to create a custom upgrade?
Checksums?
Scrambled / encrypted?
Digitally signed?
Analyze! Inspect many variations

Disassemble
Figure out main arch (sh, m68k, arm, MIPS, …)
tricky non-”standard" CPU/DSP cores (calmrisc16)
Objdump is your friend
IDA Pro is expensive

Safe test of own code
“ Unbrickable” devices
Load to RAM
Load with HW tools
Inject into original / binary-patch
Buffer overflow triggered

Write Bootloader
Based on gathered info, write...
LCD code
Button code
Disk/flash access code

Early Rockbox
With a bootloader done
Make it “upgradable” on the device
Try it
Make main Rockbox run:
Sound
USB
Recording
FM tuner
…

All others involved
IRC
Mailing lists
Forums
Talk. Chat. Test. Report. Help. Share knowledge. Describe progress. Distribute wisdom.
Do not expect fast results!

So why not your own player?
Hard and expensive – components, design, manufacture etc
SW is basically done without costs, HW is not
Lyre builds player(s) to run Rockbox

Rockbox the OS
Rockbox is not Linux
Small
Written from scratch
Cooperative multitasking with priorities
Message queues
UI with graphics methods
Loadable plugins
Loadable codecs
Themeable looks

Rockbox Development
Gcc, make, shell, perl
We build our own cross-compiler
SVN
Build your own binary in 30 minutes from scratch
Mostly C, small parts in assembler

Maintain functionality
Simulators – tests high level code without HW access
Distributed build system (150 builds in 4 minutes)
Downloadable binaries after every commit
Bug tracker

Playback
15 Codecs (MP3, Ogg Vorbis, WAV, MPC, AC3, AAC, WMA, ADX, Speex, Cook, ATRAC3, AIFF, FLAC, ALAC, Wavpack, Shorten, Monkey's audio, SID, MOD, NSF, SPC, MIDI, GBS, SAP)
Gapless playback
5-band fully-parametric equalizer, and crossfeed
High-resolution volume control
Advanced crossfading
Cuesheet support
Album Art Support

Accessability
Browse songs with a “tag database” or file system
Unicode support with fonts
Multilingual interface
Optional spoken interface
Target-specific detailed 200+ pages manual!

Non-playback (aka rubbish)
Themes
100 plugins/apps
Games, including Doom
Emulators
MPEG videos
View pictures
… and more!

People like skinning

Standing on the shoulders...
libmad, wavpack, ffmpeg, Ogg Vorbis, liba52, Speex, libfaad, Doom, gnuchess, gnuboy, Pacman Instructional Emulator, Spectemu, libmpeg2, Game_Music_Emu, OpenSPC DSP emulator, ALAC decoder, UCL, iPod Linux, Vision-8 Emulator, robotfindskitten, libmtp, asap, libpng

The Team
80+ committers, 500 named contributors
900K lines of code
IRC
Distributed decisions
Rockbox Steering Board
We meet at devcons!
This is one of the largest open-source teams in the world, and is in the top 2% of all project teams on Ohloh.

Policies
GPL “v2 or later”
Legal
Real name policy
No anonymous contributions
We discourage piracy

Easy to install
Rockbox Utility
Linux, Windows and Mac

It rocks!

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Rockbox at FSCONS 2009

by FSCONS on Nov 17, 2009

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Rockbox at FSCONS 2009 — Presentation Transcript