Merge "media: clarify MediaFormat.KEY_FRAME_RATE for video encoders" into tm-dev am: 42e8a2285c am: 32caee0675

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18605610

Change-Id: I5c8e57917b0b2e2a15d1581216c2de741e6ac652
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
This commit is contained in:
Lajos Molnar
2022-05-26 07:58:41 +00:00
committed by Automerger Merge Worker

View File

@@ -456,17 +456,27 @@ public final class MediaFormat {
/**
* A key describing the frame rate of a video format in frames/sec.
* <p>
* The associated value is normally an integer when the value is used by the platform,
* but video codecs also accept float configuration values.
* Specifically, {@link MediaExtractor#getTrackFormat MediaExtractor} provides an integer
* value corresponding to the frame rate information of the track if specified and non-zero.
* Otherwise, this key is not present. {@link MediaCodec#configure MediaCodec} accepts both
* float and integer values. This represents the desired operating frame rate if the
* float and integer values.
* <p>
* This represents the desired operating frame rate if the
* {@link #KEY_OPERATING_RATE} is not present and {@link #KEY_PRIORITY} is {@code 0}
* (realtime). For video encoders this value corresponds to the intended frame rate,
* although encoders are expected
* to support variable frame rate based on {@link MediaCodec.BufferInfo#presentationTimeUs
* buffer timestamp}. This key is not used in the {@code MediaCodec}
* (realtime). Otherwise, this is just informational.
* <p>
* For video encoders this value corresponds to the intended frame rate (the rate at which
* the application intends to send frames to the encoder, as calculated by the buffer
* timestamps, and not from the actual real-time rate that the frames are sent to
* the encoder). Encoders use this hint for rate control, specifically for the initial
* frames, as encoders are expected to support variable frame rate (for rate control) based
* on the actual {@link MediaCodec.BufferInfo#presentationTimeUs buffer timestamps} of
* subsequent frames.
* <p>
* This key is not used in the {@code MediaCodec}
* {@link MediaCodec#getInputFormat input}/{@link MediaCodec#getOutputFormat output} formats,
* nor by {@link MediaMuxer#addTrack MediaMuxer}.
*/