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CodecDbLite is a repository of chipset-specific codec recommendations.
Initially, these recommendations will focus on video encoders,
specifically choosing the right encoder to use on a given chipset
and the B-frame configuration to use with that encoder.

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Googler 2025-03-20 12:16:44 -07:00 committed by Copybara-Service
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libraries/transformer/src/main/java/androidx/media3/transformer/CodecDbLite.java Normal file
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/*
* Copyright 2025 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.media3.transformer;
import androidx.annotation.IntDef;
import androidx.media3.common.util.UnstableApi;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Repository of chipset-specific recommendations and/or optimizations for using Android platform
* provided {@linkplain android.media.MediaCodec video codecs}.
*
* <p>Recommendations made by this class are based on Google-collected benchmark data collected on
* production devices leveraging the chipsets represented.
*/
@UnstableApi
public final class CodecDbLite {
private CodecDbLite() {}
/**
* Internal entry in CodecDB Lite which represents a single codec and the recommended B-frame
* configuration for that codec.
*/
private static final class VideoEncoderEntry {
/**
* The MIME type of the recommended video encoder to use.
*
* <p>This value can be passed into Transformer via {@link
* Transformer.Builder#setVideoMimeType(String)}.
*/
private final String mimeType;
/**
* The recommended value for {@link android.media.MediaFormat#KEY_MAX_B_FRAMES}, where any value
* greater than 0 indicates that B-Frames should be used.
*
* <p>If a non-zero value is recommended, enabling B-frames will generally result in a gain in
* user-perceived video quality versus not enabling them.
*/
private final int maxBFrames;
/**
* A composite spatial resolution (width x height) indicating where B-frames should be disabled.
*
* <p>In general, B-frame encoding for hardware-encoders in the Android ecosystem tend to
* perform better at lower-resolutions. This resolution indicates a cutoff above which B-frames
* should not be enabled.
*/
private final int bFrameResolutionCutoff;
/**
* Flags that indicate other optimizations that should be performed on the video encoder
* specified by this recommendation.
*/
private final @VideoEncoderEntry.FormatOptimization int formatOptimizations;
private VideoEncoderEntry(
String mimeType,
int maxBFrames,
int bFrameResolutionCutoff,
@VideoEncoderEntry.FormatOptimization int formatOptimizations) {
this.mimeType = mimeType;
this.maxBFrames = maxBFrames;
this.bFrameResolutionCutoff = bFrameResolutionCutoff;
this.formatOptimizations = formatOptimizations;
}
/**
* Flags that indicate a specific optimization should be made to the {@link
* android.media.MediaFormat} used to configure a specific video encoder.
*/
@Documented
@Retention(RetentionPolicy.SOURCE)
@Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
@IntDef(
flag = true,
value = {
VideoEncoderEntry.FormatOptimization.FORMAT_OPTIMIZATION_NONE,
VideoEncoderEntry.FormatOptimization
.FORMAT_OPTIMIZATION_SET_TEMPORAL_LAYERING_FOR_B_FRAMES
})
private @interface FormatOptimization {
/** Flag indicating that no additional optimizations need to be made to the encoder. */
int FORMAT_OPTIMIZATION_NONE = 0;
/**
* Flag indicating that to enable B-frames on a given device, that {@link
* android.media.MediaFormat#KEY_TEMPORAL_LAYERING} must also be set.
*/
int FORMAT_OPTIMIZATION_SET_TEMPORAL_LAYERING_FOR_B_FRAMES = 1;
}
}
}