features.md

neomura > specification > features

video

property	value
resolution	270x180*
orientation	landscape*
aspect ratio	3:2*
pixel aspect ratio	1:1
color depth	24-bit (8-8-8 red/green/blue, interleaved)
color range	full (0 - 255) (not nstc-safe)
color space	gamma (2.2)
refresh rate	60Hz*
vsync	yes
safe area	full frame; no overscan

any values marked with an asterisk are specified by games, and are provided as recommendations.

resolution and scaling notes

the aspect ratio of 3:2 was chosen as a compromise between the retro gaming authenticity of 4:3 and the need to fill 16:9 widescreen monitors.

the virtual display is to be scaled to the largest integer scaling which will fit within physical display without cropping, then centered. any remaining is to be black (rgb 0, 0, 0).

the vertical resolution of 180 is a factor of most common display resolutions, and should therefore fit most displays well with integer scaling:

physical resolution	scale factor	scaled resolution	horizontal padding
1280x720	4x	1080x720	100px
1920x1080	6x	1620x1080	150px
2560x1440	8x	2160x1440	200px
3840x2160	12x	3240x2160	300px

audio

property	value
sample rate	44100hz*
bit depth	32 (ieee floating point)
channels	2 (left/right, interleaved)
buffer length	735 per channel*

any values marked with an asterisk are specified by games, and are provided as recommendations.

timing notes

audio and video generation are to be kept in perfect sync, 735 samples being one buffer per 60hz frame at the sample rate of 44100hz.

the buffer length of 735 is as exposed to the game. in most cases, it will be recommended for performance and compatability reasons to allocate a larger buffer internal to the host which batches several frames' samples together for submission to a system audio api.

input

property	value
maximum simulataneous gamepads	4*
force feedback/rumble	256 intensity levels including deactivated
d-pads per gamepad	1
face buttons per gamepad	4 (arranged like a d-pad)
triggers per gamepad	2 (left/right)
other buttons per gamepad	1 (pause)

any values marked with an asterisk are specified by games, and are provided as recommendations.

suggested layout

    .-------------.----------------------------------------.---------------.
   | left trigger |                                        | right trigger |
 .-'--------------'                                        '----------------'-.
|                                                                              |
|              ^                                             ( )               |
|                                                                              |
|                                  .-------.                                   |
|      <     d-pad     >           | pause |        ( ) face buttons ( )       |
|                                  '-------'                                   |
|                                                                              |
|              v                                             ( )               |
|                                                                              |
 '----------------------------------------------------------------------------'

suggested mappings

these may be tweaked for game-specific hosts, and should generally be remappable in the host's settings.

left joy con (held horizontally with strap attached)

input	mapping
d-pad	left stick
face buttons	directional buttons
left trigger	sl button
right trigger	sr button
pause button	- button

right joy con (held horizontally with strap attached)

input	mapping
d-pad	right stick
face buttons	a/b/x/y buttons
left trigger	sl button
right trigger	sr button
pause button	+ button

joy con pair

input	mapping
d-pad	left stick or directional buttons
face buttons	a/b/x/y buttons
left trigger	l/zl buttons
right trigger	r/zr buttons
pause button	-/+ buttons

dualshock 4

input	mapping
d-pad	directional buttons or left stick
face buttons	cross/square/circle/triangle buttons
left trigger	l1/l2 buttons
right trigger	r1/r2 buttons
pause button	options/touch pad buttons

xbox series controller

input	mapping
d-pad	left stick or directional pad
face buttons	a/b/x/y buttons
left trigger	left bumper/left trigger
right trigger	right bumper/right trigger
pause button	back/start buttons

keyboard (us layout)

input	mapping
d-pad	w/a/s/d keys
face buttons	i/j/k/l keys
left trigger	q/u keys
right trigger	e/o keys
pause button	esc key