技术背景

我们在做无纸化同屏的时候，好多开发者采集到屏幕、麦克风|扬声器数据，除了需要推RTMP出去，或者启动个轻量级RTSP服务，对外提供个拉流的RTSP URL，别的终端过来拉流（小并发场景），还有个技术需求，就是需要本地实时录像。本文主要介绍屏幕采集的过程中，如何实现推送端录像。

技术实现

实际上，Android同屏，需要录像的话，和采集摄像头数据录像一样，只是数据源不同而已，鉴于不管什么格式的video数据，我们都是投递到模块底层做转换编码，所以本质上没啥差别。

本地录像，我们界面上没有做展示，如果实现，很简单，就是加个开始录像|停止录像按钮即可。

对外提供了二次封装设计如下：

/** NTStreamMediaEngine.java* Author: daniusdk.com* WeChat: xinsheng120** Copyright © 2014~2024 DaniuSDK. All rights reserved.*/public interface NTStreamMediaEngine {void register_callback(Callback callback);void unregister_callback(Callback callback);void set_resolution_level(int level);int get_resolution_level();/** 启动媒体投影*/boolean start_video_capture(int token_code, android.content.Intent token_data);boolean is_video_capture_running();void stop_video_capture();/** 启动麦克风*/boolean start_audio_record(int sample_rate, int channels);boolean is_audio_record_running();void stop_audio_record();/**  Android 10及以上支持, Android10以下设备调用直接返回false*  需要有RECORD_AUDIO权限*  要开启媒体投影*/boolean start_audio_playback_capture(int sample_rate, int channels);boolean is_audio_playback_capture_running();void stop_audio_playback_capture();/** 输出的音频类型*  0: 不输出音频*  1: 输出麦克风*  2: 输出audio playback(Android 10及以上支持)*/boolean set_audio_output_type(int type);int get_audio_output_type();void set_fps(int fps);void set_gop(int gop);boolean set_video_encoder_type(int video_encoder_type);int get_video_encoder_type();..../** 启动本地录像*/boolean start_stream_record(String record_directory, int file_max_size);boolean is_stream_recording();void stop_stream_record();boolean is_stream_running();
}

开始录像实现如下：

/** NTStreamMediaProjectionEngineImpl.java* Author: daniusdk.com* WeChat: xinsheng120** Copyright © 2014~2024 DaniuSDK. All rights reserved.*/
@Override
public boolean start_stream_record(String record_directory, int file_max_size) {if (stream_publisher_.is_recording()) {Log.e(TAG, "start_stream_record already recording");return false;}if (!is_video_capture_running()) {Log.e(TAG, "start_stream_record please start_video_capture first");return false;}if (is_null_or_empty(record_directory)) {Log.e(TAG, "start_stream_record record_directory is null");return false;}if (file_max_size < 5) {Log.e(TAG, "start_stream_record file_max_size:" + file_max_size + " error");return false;}Runnable r = new Runnable() {private String record_directory_;private int file_max_size_;@Overridepublic void run() {if (!start_record_internal(this.record_directory_, this.file_max_size_)) {// notify .....}}Runnable set(String record_directory, int file_max_size) {this.record_directory_ = record_directory;this.file_max_size_ = file_max_size;return this;}}.set(record_directory, file_max_size);post_or_execute(r);Log.i(TAG, "start_stream_record record_directory:" + record_directory + ", file_max_size:" + file_max_size);return true;
}@Override
public boolean is_stream_recording() {return stream_publisher_.is_recording();
}

start_record_internal()实现如下：

private boolean start_record_internal(String record_directory, int file_max_size) {if (stream_publisher_.is_recording()) {Log.e(TAG, "start_record_internal already recording");return false;}if (!test_and_create_sdk_instance()) {Log.e(TAG, "start_record_internal create sdk instance failed");return false;}if (!config_record(record_directory, file_max_size)) {Log.e(TAG, "start_record_internal config_record failed");stream_publisher_.try_release();return false;}if (!stream_publisher_.StartRecorder()) {Log.e(TAG, "start_record_internal call sdk start failed");stream_publisher_.try_release();return false;}switch_audio_output_type(audio_output_type_);return true;
}

这里调用的录像设置config_record()实现如下：

private boolean config_record(String record_directory, int file_max_size) {if (is_null_or_empty(record_directory))return false;if (file_max_size < 5)return false;if (null == this.lib_publisher_)return false;String directory = record_directory;int ret = lib_publisher_.SmartPublisherCreateFileDirectory(directory);if (ret != 0) {Log.e(TAG, "try create record directory failed, dir:" + directory);return  false;}if (!stream_publisher_.SetRecorderDirectory(directory)) {Log.e(TAG, "set record directory failed, dir:" + directory);return false;}if (!stream_publisher_.SetRecorderFileMaxSize(file_max_size)) {Log.e(TAG, "set record file max size failed, size:" + file_max_size);return false;}return true;
}

停止录像：

@Override
public void stop_stream_record() {if (!stream_publisher_.is_recording())return;Runnable r = new Runnable() {@Overridepublic void run() {stream_publisher_.StopRecorder();stream_publisher_.try_release();test_and_disable_post_audio();}};post_or_execute(r);
}

总结

Android平台无纸化同屏，如果需要本地录像的话，实现难度不大，只要复用之前开发的录像模块的就可以，对我们来说，同屏采集这块，只是数据源不同而已，如果是自采集的其他数据，我们一样可以编码录像。以上是Android同屏录像设计，感兴趣的开发者，可以跟我单独沟通交流。