README improvements

README.md

@@ -76,6 +76,9 @@ Map file generated by wxmap
 -o <filename>
 Output image filename
 
+-p <filename>
+Path to palette
+
 -r
 Realtime decode. When decoding in realtime it is highly recommended to choose a plain raw image.
 ```
@@ -114,7 +117,7 @@ Decode `audio.wav` with denoise and histogram equalization and save it into the
 
 `aptdec -e d -p palettes/N19-June-High-Vegetation.png -i p audio.wav`
 
-Create a false color image from the `N19-June-High-Vegetation.pn` palette.
+Create a false color image from the `N19-June-High-Vegetation.png` palette.
 
 ## Realtime decoding
 
@@ -126,7 +129,11 @@ aptdec /tmp/aptaudio
 sox -t pulseaudio alsa_output.pci-0000_00_1b.0.analog-stereo.monitor -c 1 -t wav /tmp/aptaudio
 ```
 
-Perform a realtime decode with the audio being played out of `alsa_output.pci-0000_00_1b.0.analog`. To stop the decode kill the `sox` process
+Perform a realtime decode with the audio being played out of `alsa_output.pci-0000_00_1b.0.analog`. To stop the decode kill the `sox` process.
+
+## Palette formatting
+
+Palettes are PNG images that are 256x256 in size with 24bit RGB color. The X axis is the value of Channel A and the Y axis is the value of Channel B
 
 ## Further reading