一、简介
Codec HDI（Hardware Device Interface）对上层媒体服务提供视频编解码的驱动能力接口，主要功能有获取组件编解码能力，创建、销毁编解码器对象，启停编解码器操作，编解码处理等。
Codec HDI 2.0接口依赖OpenMax IL的标准接口，Codec HDI通过调用封装好的libOMX_Core.z.so获取支持的编解码器组件并创建组件运行。
本文主要介绍OpenHarmony 5.x版本视频硬件编解码Codec HDI的适配方法。
注：5.x版本的AVPlayer播放器histreamer引擎调用的视频硬件编解码框架和AVCodec视频硬件编解码框架都会调用到av_codec_service系统服务，通过IPC与Codec HDI通信。
二、适配流程
配置codec_host 服务
vendor/{company}/{product}/hdf_config/uhdf/device_info.hcs 文件配置codec_host服务
以rk3568为例，配置如下文件：vendor/hihope/rk3568/hdf_config/uhdf/device_info.hcs
codec :: host {
hostName = "codec_host";
priority = 50;
gid = ["codec_host", "uhdf_driver", "vendor_mpp_driver"];
codec_omx_idl_device :: device {
device0 :: deviceNode {
policy = 2;
priority = 100;
moduleName = "libcodec_driver.z.so";
serviceName = "codec_component_manager_service";
deviceMatchAttr = "media_codec_capabilities";
}
}
...
}codec_component_manager_service 服务被视频硬件编解码服务调用，重点是这个服务的配置。
配置codec_capabilities hcs文件
添加 vendor/{company}/{product}/hdf_config/uhdf/media_codec/media_codec_capabilities.hcs文件，该文件主要描述芯片支持的硬件编解码组件的能力集。
根据codec_component_manager_service 服务配置的deviceMatchAttr，media_codec_capabilities.hcs文件的match_attr字段为media_codec_capabilities。
以rk3568为例，添加 vendor/hihope/rk3568/hdf_config/uhdf/media_codec/media_codec_capabilities.hcs 文件
root {
module = "master";
codec_config {
match_attr = "media_codec_capabilities";
use_openmax = true;
// capsMask: 0x01, Adaptive playback; 0x02, Secure playback; 0x04, Tunnel playback.
// allocateMask: 0x01, Input buffer allocated within the Codec module;
// allocateMask: 0x02, Input buffer allocated by an external user;
// allocateMask: 0x04, Output buffer allocated within the Codec module;
// allocateMask: 0x08, Output buffer allocated by an external user.
VideoHwEncoders {
/* node name explanation -- HDF_video_hw_enc_avc_rk：
**
** HDF____________video_________hw___________________enc_________avc____rk
** | | | | | |
** HDF or OMX video or audio hardware or software encoder or decoder mime vendor
*/
HDF_video_hw_enc_avc_rk {
role = 1;
type = 1;
name = "OMX.rk.video_encoder.avc";
supportProfiles = [1, 32768, 2, 32768, 8, 32768];
maxInst = 4;
isSoftwareCodec = false;
processModeMask = [];
capsMask = [0x01];
minBitRate = 1;
maxBitRate = 40000000;
minWidth = 144;
minHeight = 144;
maxWidth = 4096;
maxHeight = 4096;
widthAlignment = 2;
heightAlignment = 2;
minBlockCount = 99;
maxBlockCount = 8160;
minBlocksPerSecond = 99;
maxBlocksPerSecond = 489600;
blockSizeWidth = 16;
blockSizeHeight = 16;
supportPixelFmts = [28, 24, 20, 12];
measuredFrameRate = [320, 240, 165, 165, 720, 480, 149, 149, 1280, 720, 73, 73, 1920, 1080, 18, 18];
bitRateMode = [1, 2];
minFrameRate = 1;
maxFrameRate = 60;
canSwapWidthHeight = true;
}
...
}
VideoHwDecoders {
HDF_video_hw_dec_avc_rk {
role = 1;
type = 0;
name = "OMX.rk.video_decoder.avc";
supportProfiles = [1, 32768, 2, 32768, 8, 32768];
maxInst = 6;
isSoftwareCodec = false;
processModeMask = [];
capsMask = [0x01];
minBitRate = 1;
maxBitRate = 10000000;
minWidth = 144;
minHeight = 144;
maxWidth = 4096;
maxHeight = 4096;
widthAlignment = 2;
heightAlignment = 2;
minBlockCount = 99;
maxBlockCount = 34560;
minBlocksPerSecond = 99;
maxBlocksPerSecond = 2073600;
blockSizeWidth = 16;
blockSizeHeight = 16;
supportPixelFmts = [24, 12, 20];
measuredFrameRate = [320, 240, 617, 617, 720, 480, 559, 559, 1280, 720, 276, 276, 1920, 1080, 164, 164, 3840, 2160, 30, 30];
bitRateMode = [];
minFrameRate = 1;
maxFrameRate = 60;
canSwapWidthHeight = true;
}
...
}
}
}该文件需根据实际芯片能力配置，name组件名根据OMX组件层的定义配置，其他参数尽量按实际配置，否则系统服务层可能因检验参数失败导致编解码异常。
编解码能力配置文件添加编译
vendor/{company}/{product}/hdf_config/uhdf//hdf.hcs 引入media_codec_capabilities.hcs
以rk3568为例，vendor/hihope/rk3568/hdf_config/uhdf/hdf.hcs 添加
+ #include "media_codec/media_codec_capabilities.hcs"OMX Wrapper的封装
封装实现libOMX_Core.z.so，供Codec HDI通过dlopen调用。
不同厂商OMX组件层的实现是不同的，这里不再详细赘述。
三、适配验证
适配完成后可以通过应用调用AVPlayer播放码流验证。
开机后首次播放视频或kill av_codec_service进程后首次播放视频时，如果可以获取到可用的编解码组件会有如下打印：
I C02b32/HCODEC: [GetManager xxx] need to get ICodecComponentManager
I C02b32/HCODEC: [GetCapList xxx] GetComponentCapabilityList return xxx components
I C02b32/HCODEC: [HdiCapToUserCap xxx] ----- codecName: xxx.encoder.avc -----
I C02b32/HCODEC: [HdiCapToUserCap xxx] codecType: 0, mimeType: video/avc, maxInstance x
...
I C02b32/HCODEC: [HdiCapToUserCap xxx] ----- codecName: xxx.decoder.avc -----
I C02b32/HCODEC: [HdiCapToUserCap xxx] codecType: 1, mimeType: video/avc, maxInstance x硬件解码组件创建成功，正常解码播放会有如下打印：
I C02b32/HCODEC: [0][dec.avc][Uninitialized][OnAllocateComponent xxx] create omx node xxx.decoder.avc succ
I C02b32/HCODEC: [ChangeStateTo xxx] Uninitialized -> Initialized
I C02b32/HCODEC: [ChangeStateTo xxx] Starting -> Running