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Commit 3fc21ef7 authored by Eino-Ville Talvala's avatar Eino-Ville Talvala
Browse files

DngCreator: Fix calculation of date/time stamps 

Converting the sensor timestamp to date/time requires checking
what the timebase of those timestamps is; getting it wrong will
create drift that increases with device uptime.

Test: android.hardware.camera2.cts.
      DngCreatorTest#testSingleImageThumbnail
Bug: 30125412
Change-Id: Ia5db86012bc9e1c06463b8dc4434d3e063f62cf5
parent 492450c8

core/java/android/hardware/camera2/DngCreator.java

+22 −5
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ import android.location.Location; 
import android.media.ExifInterface;

import android.media.Image;

import android.os.SystemClock;

import android.util.Log;

import android.util.Size;



import java.io.IOException;
@@ -89,17 +90,33 @@ public final class DngCreator implements AutoCloseable { 
            throw new IllegalArgumentException("Null argument to DngCreator constructor");

        }



        // Find current time

        // Find current time in milliseconds since 1970

        long currentTime = System.currentTimeMillis();



        // Find boot time

        long bootTimeMillis = currentTime - SystemClock.elapsedRealtime();

        // Assume that sensor timestamp has that timebase to start

        long timeOffset = 0;



        int timestampSource = characteristics.get(

                CameraCharacteristics.SENSOR_INFO_TIMESTAMP_SOURCE);



        if (timestampSource == CameraCharacteristics.SENSOR_INFO_TIMESTAMP_SOURCE_REALTIME) {

            // This means the same timebase as SystemClock.elapsedRealtime(),

            // which is CLOCK_BOOTTIME

            timeOffset = currentTime - SystemClock.elapsedRealtime();

        } else if (timestampSource == CameraCharacteristics.SENSOR_INFO_TIMESTAMP_SOURCE_UNKNOWN) {

            // This means the same timebase as System.currentTimeMillis(),

            // which is CLOCK_MONOTONIC

            timeOffset = currentTime - SystemClock.uptimeMillis();

        } else {

            // Unexpected time source - treat as CLOCK_MONOTONIC

            Log.w(TAG, "Sensor timestamp source is unexpected: " + timestampSource);

            timeOffset = currentTime - SystemClock.uptimeMillis();

        }



        // Find capture time (nanos since boot)

        Long timestamp = metadata.get(CaptureResult.SENSOR_TIMESTAMP);

        long captureTime = currentTime;

        if (timestamp != null) {

            captureTime = timestamp / 1000000 + bootTimeMillis;

            captureTime = timestamp / 1000000 + timeOffset;

        }



        // Format for metadata