前一篇文章已經(jīng)把捕獲屏幕的功能實(shí)現(xiàn)卿城，現(xiàn)在我們要把捕獲的視頻數(shù)據(jù)編碼成264為后面保存成文件，或者通過(guò)流媒體的形式分發(fā)做準(zhǔn)備

鴻蒙avcodec kit編碼的關(guān)系圖如下

編碼調(diào)用關(guān)系官方圖

下面實(shí)現(xiàn)整個(gè)編碼過(guò)程

1唆姐，在CMake腳本中鏈接動(dòng)態(tài)庫(kù)

target_link_libraries(entry PUBLIC libace_napi.z.so                                    libnative_avscreen_capture.so                                    libhilog_ndk.z.so                                    libnative_media_core.so                                    libnative_buffer.so                                    libnative_media_codecbase.so                                    libnative_media_venc.so                                    libnative_media_acodec.so)        

2，新建video_encoder類廓八，并實(shí)現(xiàn)相關(guān)函數(shù)

視頻編碼器類中包括創(chuàng)建編碼器奉芦，配置編碼器，啟動(dòng)編碼器剧蹂，停止二號(hào)釋放編碼器

int32_t Create(const std::string &videoCodecMime);int32_t Config(VideoSampleInfo &sampleInfo, AVCodecUserData *codecUserData);int32_t Start();int32_t Stop();int32_t Release();

1声功，根據(jù)mine type創(chuàng)建編碼器，這里我們用的mine type是OH_AVCODEC_MIMETYPE_VIDEO_AVC就是h264

int32_t VideoEncoder::Create(const std::string &videoCodecMime){       // 通過(guò) MIME TYPE 創(chuàng)建編碼器宠叼，系統(tǒng)會(huì)根據(jù)MIME創(chuàng)建最合適的編碼器先巴。//     OH_AVCapability *capability = OH_AVCodec_GetCapability(OH_AVCODEC_MIMETYPE_VIDEO_AVC, true);//     const char *codecName = OH_AVCapability_GetName(capability);//     codec = OH_VideoEncoder_CreateByName(codecName);    encoder_ = OH_VideoEncoder_CreateByMime(videoCodecMime.c_str());    CHECK_AND_RETURN_RET_LOG(encoder_ != nullptr, AVCODEC_SAMPLE_ERR_ERROR, "Create failed");    return AVCODEC_SAMPLE_ERR_OK;}

2，配置編碼器车吹，主要包括色彩格式筹裕，視頻寬度，視頻高度窄驹，視頻幀率朝卒，關(guān)鍵幀間隔，和編碼回調(diào)等

int32_t VideoEncoder::Config(VideoSampleInfo &sampleInfo, AVCodecUserData *codecUserData){    CHECK_AND_RETURN_RET_LOG(encoder_ != nullptr, AVCODEC_SAMPLE_ERR_ERROR, "Encoder is null");    CHECK_AND_RETURN_RET_LOG(codecUserData != nullptr, AVCODEC_SAMPLE_ERR_ERROR, "Invalid param: codecUserData");    // Configure video encoder    int32_t ret = Configure(sampleInfo);    CHECK_AND_RETURN_RET_LOG(ret == AVCODEC_SAMPLE_ERR_OK, AVCODEC_SAMPLE_ERR_ERROR, "Configure failed");    // GetSurface from video encoder    ret = GetSurface(sampleInfo);    CHECK_AND_RETURN_RET_LOG(ret == AVCODEC_SAMPLE_ERR_OK, AVCODEC_SAMPLE_ERR_ERROR, "Get surface failed");        // SetCallback for video encoder    ret = SetCallback(codecUserData);    CHECK_AND_RETURN_RET_LOG(ret == AVCODEC_SAMPLE_ERR_OK, AVCODEC_SAMPLE_ERR_ERROR,                             "Set callback failed, ret: %{public}d", ret);    // Prepare video encoder    ret = OH_VideoEncoder_Prepare(encoder_);    CHECK_AND_RETURN_RET_LOG(ret == AV_ERR_OK, AVCODEC_SAMPLE_ERR_ERROR, "Prepare failed, ret: %{public}d", ret);    return AVCODEC_SAMPLE_ERR_OK;}

這里寫(xiě)了兩個(gè)輔助函數(shù)乐埠，

創(chuàng)建surface模式對(duì)應(yīng)的窗口

int32_t VideoEncoder::GetSurface(VideoSampleInfo &sampleInfo){    int32_t ret = OH_VideoEncoder_GetSurface(encoder_, &sampleInfo.window);    CHECK_AND_RETURN_RET_LOG(ret == AV_ERR_OK && sampleInfo.window, AVCODEC_SAMPLE_ERR_ERROR,        "Get surface failed, ret: %{public}d", ret);    (void)OH_NativeWindow_NativeWindowHandleOpt(sampleInfo.window, SET_BUFFER_GEOMETRY, sampleInfo.videoWidth,                                                sampleInfo.videoHeight);    (void)OH_NativeWindow_NativeWindowHandleOpt(sampleInfo.window, SET_USAGE, 16425); // 16425: Window usage    (void)OH_NativeWindow_NativeWindowHandleOpt(sampleInfo.window, SET_FORMAT,        ToGraphicPixelFormat(sampleInfo.pixelFormat, sampleInfo.isHDRVivid));    return AVCODEC_SAMPLE_ERR_OK;}

配置編碼器的相關(guān)回調(diào)：編碼錯(cuò)誤回調(diào)抗斤，編碼格式更新回調(diào)囚企，編碼輸入緩存回調(diào)（這是surface模式，未使用）瑞眼，編碼輸出緩存回調(diào)

int32_t VideoEncoder::SetCallback(AVCodecUserData *codecUserData){    int32_t ret = OH_VideoEncoder_RegisterCallback(encoder_,    {VideoSampleCallback::OnCodecError, VideoSampleCallback::OnCodecFormatChange,        VideoSampleCallback::OnNeedInputBuffer, VideoSampleCallback::OnNewOutputBuffer},        codecUserData);    CHECK_AND_RETURN_RET_LOG(ret == AV_ERR_OK, AVCODEC_SAMPLE_ERR_ERROR, "Set callback failed, ret: %{public}d", ret);    return AVCODEC_SAMPLE_ERR_OK;}

3龙宏，啟動(dòng)編碼器

int32_t VideoEncoder::Start(){    CHECK_AND_RETURN_RET_LOG(encoder_ != nullptr, AVCODEC_SAMPLE_ERR_ERROR, "Encoder is null");    int ret = OH_VideoEncoder_Start(encoder_);    CHECK_AND_RETURN_RET_LOG(ret == AV_ERR_OK, AVCODEC_SAMPLE_ERR_ERROR, "Start failed, ret: %{public}d", ret);    return AVCODEC_SAMPLE_ERR_OK;}

然后改造screen_capture

引入視頻編碼類，額外啟動(dòng)一個(gè)線程用來(lái)接受編碼后的數(shù)據(jù)伤疙，并寫(xiě)入文件

在CreateAndInitWithSurfaceMode函數(shù)中實(shí)例化視頻編碼器

在StartWithSurfaceMode函數(shù)中加入

在StopAndReleaseWithSurfaceMode添加停止編碼相關(guān)邏輯

這里我們把視頻保存成h264文件了银酗，文件地址如下

運(yùn)行測(cè)后會(huì)在手機(jī)報(bào)名目錄下生成文件

用ffplay播放文件顯示如下信息