Android Camera API ISO Setting?
Would anyone know where to control the ISO setting for the camera from in the Android SDK ? It should be possible as the native camera application on the HTC Desire has ISO settings.
Solution 1:
you should take a look at the methods flatten()
, unflatten()
, get(String key)
, set(String key, String value)
in android.hardware.Camera.Parameters
.
Also consider the source code of that class. It might make things clearer.
First you need to obtain the Camera.Parameters
. Unflatten it to a String
and investigate it. I am developing on a HTC Desire as well an get the following String
:
sharpness-max=30;zoom=0;taking-picture-zoom=0;zoom-supported=true;sharpness-min=0;sharpness=10;contrast=5;whitebalance=auto;jpeg-quality=100;preview-format-values=yuv420sp;jpeg-thumbnail-quality=75;preview-format=yuv420sp;preview-size=640x480;focal-length=3.53;iso=auto;meter-mode=meter-center;front-camera-mode=mirror;flash-mode-values=off,auto,on,torch;preview-frame-rate-values=15;preview-frame-rate=15;focus-mode-values=auto,infinity;jpeg-thumbnail-width=640;jpeg-thumbnail-size-values=640x480,512x384,384x288,0x0;zoom-ratios=100,114,131,151,174,200;saturation-def=5;preview-size-values=1280x720,800x480,768x432,720x480,640x480,576x432,480x320,400x240,384x288,352x288,320x240,272x272,240x240,240x160,176x144,160x120;smart-contrast=off;picture-size-values=2592x1952,2592x1456,2592x1936,2592x1728,2592x1552,2048x1536,2048x1360,2048x1216,2048x1152,1600x1200,1584x1056,1280x960,1280x848,1280x768,1280x720,1024x768,640x480,640x416,640x384,640x368,512x384,400x400,272x272;contrast-min=0;min-exposure-compensation=-4;brightness-min=0;antibanding=auto;taking-picture-zoom-min=0;saturation-min=1;contrast-max=10;vertical-view-angle=42.5;taking-picture-zoom-max=21;contrast-def=5;brightness-max=6;horizontal-view-angle=54.8;brightness=3;jpeg-thumbnail-height=480;cam-mode=0;focus-mode=auto;sharpness-def=10;front-camera-mode-values=mirror,reverse;picture-format-values=jpeg;saturation-max=10;max-exposure-compensation=4;exposure-compensation=0;exposure-compensation-step=0.5;flash-mode=off;effect-values=none,mono,negative,solarize,sepia,posterize,aqua;meter-mode-values=meter-average,meter-center,meter-spot;picture-size=2592x1952;max-zoom=5;effect=none;saturation=5;whitebalance-values=auto,incandescent,fluorescent,daylight,cloudy-daylight;picture-format=jpeg;brightness-def=3;iso-values=auto,deblur,100,200,400,800,1250;enable-caf=off;antibanding-values=off,50hz,60hz,auto
So basically there is a key called iso-values
to retrieve the supported values and a key iso
which holds the current value.
You can do the following:
Camera cam = Camera.open();
Camera.Parameters camParams = cam.getParameters();
String supportedIsoValues = camParams.get("iso-values"); //supported values, comma separated String
camParams.set("iso", (String)newValue);
cam.setParameters(camParams);
And with reference to the unflattened parameters I would assume that there is a difference between the iso and exposure compensation settings.
Solution 2:
By now (KK 4.4.2) android has no official APIs to manage ISO.
ISO management is a totally device dependant matter, and 8/18 devices i tested so far doesn't support ISO settings at all.
Investigate Camera.getParameters().flatten()
String to check valid keywords, every device can use different keywords!!
Most devices use "iso-values" keyword to define a comma separated list-of-possible-values to use with "iso" keyword, like this:
param.set("iso", valid_value_from_list);
Some other devices uses "iso-mode-values" and "iso" keywords (Galaxy Nexus).
I found also a device that uses "iso-speed-values" and "iso-speed" (Micromax A101).
Another one that make me sad is "nv-picture-iso-values" -> "nv-picture-iso" (LG dual P990).
Follow szia answer on how to use these keywords.
Here's some code i use to get a list of valid values using known keywords:
String flat = param.flatten();
String[] isoValues = null;
String values_keyword=null;
String iso_keyword=null;
if(flat.contains("iso-values")) {
// most used keywords
values_keyword="iso-values";
iso_keyword="iso";
} else if(flat.contains("iso-mode-values")) {
// google galaxy nexus keywords
values_keyword="iso-mode-values";
iso_keyword="iso";
} else if(flat.contains("iso-speed-values")) {
// micromax a101 keywords
values_keyword="iso-speed-values";
iso_keyword="iso-speed";
} else if(flat.contains("nv-picture-iso-values")) {
// LG dual p990 keywords
values_keyword="nv-picture-iso-values";
iso_keyword="nv-picture-iso";
}
// add other eventual keywords here...
if(iso_keyword!=null) {
// flatten contains the iso key!!
String iso = flat.substring(flat.indexOf(values_keyword));
iso = iso.substring(iso.indexOf("=")+1);
if(iso.contains(";")) iso = iso.substring(0, iso.indexOf(";"));
isoValues = iso.split(",");
} else {
// iso not supported in a known way
}
Solution 3:
since I had the same problem of finding if the device has an ISO
parameter I looked at this answer https://stackoverflow.com/a/23567103/3976589 and saw that @j.c had solved the problem for 8/18 devices by listing some parameters that he had found on different devices. Based on that listing I found that each paramter contains the words iso
and values
(sometimes only those words, sometimes something additional).
So if I list all of the camera parameters and search for a strings that contain both words I will know what is the name of the ISO
parameter, if it exists. Furthermore if the parameter exists I can take the supported ISO
values and if I want to set one of those values i.e. change the camera parameter, I can just remove the -values
at the end of the iso-values
parameter and then I can change the ISO
value successfully.
I will now share my code for this task. First a snippet that retrieves a list with supported ISO
values.
private String ISOValuesParameter = null;
private String ISOParameter = null;
private String ISOValues = null;
private void initCamera() {
Camera mCamera = Camera.open();
// this will list supported values
String ISOvalues = getISOValues();
textViewISO = (TextView) findViewById(R.id.viewISO);
textViewISO.setText(ISOvalues);
// setting Minimum ISO value
if(ISOValuesParameter != null) {
Camera.Parameters params = mCamera.getParameters();
ISOParameter = ISOValuesParameter.replace("-values", "");
params.set(ISOParameter, getMinISO());
mCamera.setParameters(params);
// get the updated ISO value
params = mCamera.getParameters();
String ISO = params.get(ISOParameter);
Toast.makeText(this,"ISO set to: " + ISO, Toast.LENGTH_SHORT).show();
}
}
// returns a list with supported ISO values
private String getISOValues() {
ISOValuesParamter = getISOValuesParameter();
Camera.Parameters params = mCamera.getParameters();
ISOValues = params.get(ISOValuesParamter);
return ISOValues!=null ? ISOValues : "ISO not supported";
}
// this will return the name of the ISO parameter containing supported ISO values
private String getISOValuesParameter() {
Camera.Parameters params = mCamera.getParameters();
String flatten = params.flatten();
String[] paramsSeparated = flatten.split(";");
for(String cur : paramsSeparated) {
if(cur.contains("iso") && cur.contains("values")) {
return cur.substring(0,cur.indexOf('='));
}
}
return null;
}
This snippet only lists the supported ISO
values. In my application I needed to pick the lowest ISO. Here is my solution:
private String getMinISO() {
if(ISOValues == null) {
return null;
}
String[] ISOarray = ISOValues.split(",");
Arrays.sort(ISOarray, myComparator);
String minISO = ISOarray[ISOarray.length-1];
return minISO;
}
Here myComparator
is a class that compares two strings and sorts the array in descending order. All alphabet words are at the beginning and all numbers are at the end. Here is my implementation:
// Singelton class
public class MyComparator implements Comparator<String> {
private static MyComparator myComparator = null;
private MyComparator() {}
@Override
public int compare(String a, String b) {
return compareString(a,b);
}
public static int compareString(String a, String b) {
if (a.length() > b.length())
return -1;
if (a.length() == b.length()) {
if (a.compareTo(b) > 0)
return -1;
else if (a.compareTo(b) == 0)
return 0;
}
return 1;
}
public static synchronized MyComparator getInstance() {
if(myComparator==null) {
myComparator = new MyComparator();
}
return myComparator;
}
}
I hope my answer helps other people. :)
Cheers! @ee3509