3 files changed, 39 insertions, 24 deletions
diff --git a/media/java/android/media/AudioDeviceInfo.java b/media/java/android/media/AudioDeviceInfo.java
index 09b382ee46d0..a186566aec0b 100644
--- a/media/java/android/media/AudioDeviceInfo.java
+++ b/media/java/android/media/AudioDeviceInfo.java
@@ -25,7 +25,6 @@ import android.util.SparseIntArray;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
 import java.util.TreeSet;
@@ -515,29 +514,7 @@ public final class AudioDeviceInfo {
      * For forward compatibility, applications should ignore entries it does not recognize.
      */
     public @NonNull int[] getEncodings() {
-        final int[] encodings = AudioFormat.filterPublicFormats(mPort.formats());
-        boolean hasFloat = false;
-        boolean hasExtendedIntegerPrecision = false;
-
-        for (int encoding : encodings) {
-            if (AudioFormat.isEncodingLinearPcm(encoding)) {
-                if (encoding == AudioFormat.ENCODING_PCM_FLOAT) {
-                    hasFloat = true;
-                } else if (AudioFormat.getBytesPerSample(encoding) > 2) {
-                    hasExtendedIntegerPrecision = true;
-                }
-            }
-        }
-        if (hasExtendedIntegerPrecision && !hasFloat) {
-            // R and earlier compatibility - add ENCODING_PCM_FLOAT to the end
-            // (replacing the zero pad). This ensures pre-S apps that look
-            // for ENCODING_PCM_FLOAT continue to see that encoding if the device supports
-            // extended precision integers.
-            int[] encodingsPlusFloat = Arrays.copyOf(encodings, encodings.length + 1);
-            encodingsPlusFloat[encodings.length] = AudioFormat.ENCODING_PCM_FLOAT;
-            return encodingsPlusFloat;
-        }
-        return encodings;
+        return AudioFormat.filterPublicFormats(mPort.formats());
     }
 
     /**
diff --git a/media/java/android/media/MediaCodec.java b/media/java/android/media/MediaCodec.java
index cc05ecd3f18e..8b9153621165 100644
--- a/media/java/android/media/MediaCodec.java
+++ b/media/java/android/media/MediaCodec.java
@@ -72,6 +72,37 @@ import java.util.concurrent.locks.ReentrantLock;
  Finally, you request (or receive) a filled output buffer, consume its contents and release it
  back to the codec.
 
+ <h3 id=qualityFloor><a name="qualityFloor">Minimum Quality Floor for Video Encoding</h3>
+ <p>
+ Beginning with {@link android.os.Build.VERSION_CODES#S}, Android's Video MediaCodecs enforce a
+ minimum quality floor. The intent is to eliminate poor quality video encodings. This quality
+ floor is applied when the codec is in Variable Bitrate (VBR) mode; it is not applied when
+ the codec is in Constant Bitrate (CBR) mode. The quality floor enforcement is also restricted
+ to a particular size range; this size range is currently for video resolutions
+ larger than 320x240 up through 1920x1080.
+
+ <p>
+ When this quality floor is in effect, the codec and supporting framework code will work to
+ ensure that the generated video is of at least a "fair" or "good" quality. The metric
+ used to choose these targets is the VMAF (Video Multi-method Assessment Function) with a
+ target score of 70 for selected test sequences.
+
+ <p>
+ The typical effect is that
+ some videos will generate a higher bitrate than originally configured. This will be most
+ notable for videos which were configured with very low bitrates; the codec will use a bitrate
+ that is determined to be more likely to generate an "fair" or "good" quality video. Another
+ situation is where a video includes very complicated content (lots of motion and detail);
+ in such configurations, the codec will use extra bitrate as needed to avoid losing all of
+ the content's finer detail.
+
+ <p>
+ This quality floor will not impact content captured at high bitrates (a high bitrate should
+ already provide the codec with sufficient capacity to encode all of the detail).
+ The quality floor does not operate on CBR encodings.
+ The quality floor currently does not operate on resolutions of 320x240 or lower, nor on
+ videos with resolution above 1920x1080.
+
  <h3>Data Types</h3>
  <p>
  Codecs operate on three kinds of data: compressed data, raw audio data and raw video data.
diff --git a/media/java/android/media/MediaRecorder.java b/media/java/android/media/MediaRecorder.java
index 341bb8d5309a..7d80e931c943 100644
--- a/media/java/android/media/MediaRecorder.java
+++ b/media/java/android/media/MediaRecorder.java
@@ -1096,6 +1096,13 @@ public class MediaRecorder implements AudioRouting,
      * clipped internally to ensure the video recording can proceed smoothly based on
      * the capabilities of the platform.
      *
+     * <p>
+     * NB: the actual bitrate and other encoding characteristics may be affected by
+     * the minimum quality floor behavior introduced in
+     * {@link android.os.Build.VERSION_CODES#S}. More detail on how and where this
+     * impacts video encoding can be found in the
+     * {@link MediaCodec} page and looking for "quality floor" (near the top of the page).
+     *
      * @param bitRate the video encoding bit rate in bits per second.
      */
     public void setVideoEncodingBitRate(int bitRate) {