Android MediaCodec设置H264 Profile到High
H264 High Profile压缩率高，能降低码率，这里记录下MediaCodec Profile设置到High遇到的一些问题。
Android 4.1 就引入了MediaCodecInfo.CodecProfileLevel类，下面截取H264(AVC)的Profile和Level定义:
/** Copyright (C) 2012 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 android.media;public final class MediaCodecInfo {/*** Encapsulates the profiles available for a codec component.*/public static final class CodecProfileLevel {// These constants were originally in-line with OMX values, but this// correspondence is no longer maintained.// Profiles and levels for AVC Codec, corresponding to the definitions in// "SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS,// Infrastructure of audiovisual services – Coding of moving video// Advanced video coding for generic audiovisual services"// found at// https://www.itu.int/rec/T-REC-H.264-201704-I/*** AVC Baseline profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileBaseline = 0x01;/*** AVC Main profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileMain = 0x02;/*** AVC Extended profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileExtended = 0x04;/*** AVC High profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileHigh = 0x08;/*** AVC High 10 profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileHigh10 = 0x10;/*** AVC High 4:2:2 profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileHigh422 = 0x20;/*** AVC High 4:4:4 profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileHigh444 = 0x40;/*** AVC Constrained Baseline profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileConstrainedBaseline = 0x10000;/*** AVC Constrained High profile.* See definition in* <a href="https://www.itu.int/rec/T-REC-H.264-201704-I">H.264 recommendation</a>,* Annex A.*/public static final int AVCProfileConstrainedHigh = 0x80000;public static final int AVCLevel1 = 0x01;public static final int AVCLevel1b = 0x02;public static final int AVCLevel11 = 0x04;public static final int AVCLevel12 = 0x08;public static final int AVCLevel13 = 0x10;public static final int AVCLevel2 = 0x20;public static final int AVCLevel21 = 0x40;public static final int AVCLevel22 = 0x80;public static final int AVCLevel3 = 0x100;public static final int AVCLevel31 = 0x200;public static final int AVCLevel32 = 0x400;public static final int AVCLevel4 = 0x800;public static final int AVCLevel41 = 0x1000;public static final int AVCLevel42 = 0x2000;public static final int AVCLevel5 = 0x4000;public static final int AVCLevel51 = 0x8000;public static final int AVCLevel52 = 0x10000;public static final int AVCLevel6 = 0x20000;public static final int AVCLevel61 = 0x40000;public static final int AVCLevel62 = 0x80000;}
}其中AVCProfileConstrainedBaseline 和 AVCProfileConstrainedHigh 是安卓8.1 引入的; AVCLevel52 是安卓5.0 引入的; AVCLevel6, AVCLevel61, AVCLevel62 是安卓10 引入的；
AVC High profile 和 AVC Constrained High profile的区别: 1. 从名字就可以看出Constrained High是High的子集; 2. Constrained High 不支持B slice(B帧)； 3. Constrained High 只支持帧编码，不支持场编码和帧场自适应编码;
另外Level也要选择合适的, GB28181-2016要求本地录像帧率不低于25fps, 网络传输时重要图像帧率宜25fps. GB28181-2022要求一类视频监控点、二类视频监控点的本地录像和网络传输的最大视频帧率应不低于25fps. 这里以视频30fps为例, 安卓摄像头常用的几个分辨率最小支持的Level如下:
| 分辨率 | 最小支持的Level |
| 640*480 | 3 |
| 1280*720(720p) | 3.1 |
| 1920*1280(1080p) |
4 |
| 3840*2160(4k) | 5.1 |
虽然安卓5.0已引入android.media.MediaFormat.KEY_PROFILE, 安卓6.0 引入android.media.MediaFormat.KEY_LEVEL. 但安卓7.0及以上AVC Profile设置才有效, 并且要求Profile和Level必须一起设置.
我的代码也提供了Mediacode编码参数设置接口, Java 和 NDK 两种MediaCodec接口方式都支持:
// Copyright (C) 1130758427@qq.com/*** 设置视频硬编码是否使用Native Media NDK, 默认是不使用, 安卓5.0以下设备不支持* @param handle* @param is_native: 0表示不使用, 1表示使用, sdk默认是0.* @return {0} if successful*/public native int SetNativeMediaNDK(long handle, int is_native);/** 设置视频硬编码码率控制模式* @param hw_bitrate_mode: -1表示使用默认值,不设置也会使用默认值, 0:CQ, 1:VBR, 2:CBR, 3:CBR_FD, 请参考:android.media.MediaCodecInfo.EncoderCapabilities* 注意硬编码和手机硬件有关，多数手机只支持部分码率模式, 另外硬编码设备差异很大，不同设备同一码率控制模式效果可能不一样* @return {0} if successful*/public native int SetVideoHWEncoderBitrateMode(long handle, int hw_bitrate_mode);/** 设置视频硬编码质量, 安卓9及以上支持, 仅当硬编码器码率控制模式(BitrateMode)是CQ(constant-quality mode)时才有效* @param hw_quality: -1表示不设置, 请参考:android.media.MediaFormat.KEY_QUALITY* 注意硬编码和手机硬件有关，部分手机可能不支持此设置* @return {0} if successful*/public native int SetVideoHWEncoderQuality(long handle, int hw_quality);/** 设置H.264硬编码Profile, 安卓7及以上支持* @param hw_avc_profile: 0表示使用默认值, 0x01: Baseline, 0x02: Main, 0x08: High, 0x10000: ConstrainedBaseline, 0x80000: ConstrainedHigh;* 注意: ConstrainedBaseline 和 ConstrainedHigh 可能多数设备不支持,* H.264推荐使用 High 或者 ConstrainedHigh, 如果您使用的手机硬解码解不了，那还是设置Baseline* 如果设置的Profile硬编码器不支持，应编码器会使用默认值* 具体参考:android.media.MediaCodecInfo.CodecProfileLevel* @return {0} if successful*/public native int SetAVCHWEncoderProfile(long handle, int hw_avc_profile);/** 设置H.264硬编码Level, 这个只有在设置了Profile的情况下才有效, 安卓7及以上支持* @param hw_avc_level: 0表示使用默认值, 0x100: Level3, 0x200: Level3.1, 0x400: Level3.2,* 0x800: Level4, 0x1000: Level4.1, 0x2000: Level4.2,* 0x4000: Level5, 0x8000: Level5.1, 0x10000: Level5.2,* 0x20000: Level6, 0x40000: Level6.1, 0x80000: Level6.2,* 如果设置的level太高硬编码器不支持，SDK内部会做相应调整* 注意: 640*480@25fps最小支持的是Level3, 720p最小支持的是Level3.1, 1080p最小支持的是Level4* 具体参考:android.media.MediaCodecInfo.CodecProfileLevel* @return {0} if successful*/public native int SetAVCHWEncoderLevel(long handle, int hw_avc_level);/** 设置视频硬编码最大码率, 安卓没有相关文档说明, 所以不建议设置,* @param hw_max_bitrate: 每秒最大码率, 单位bps* @return {0} if successful*/public native int SetVideoHWEncoderMaxBitrate(long handle, long hw_max_bitrate);经测试MTK、 海思(鸿蒙系统)、 三星、全志、晶晨、瑞芯微等编码器AVC Profile设置都可以成功。