背景

1. 当涉及App内部视频的时候，我们不希望被别人以抓包的形式来爬取我们的视频
2. 大视频文件以文件方式整个加密的话需要完全下载后才能进行解密
3. 当前m3u8格式虽然支持加密，但是ts格式的小视频可以独立播放的，也就是ts文件本身没有被加密，或者加密方法过于复杂

根据以上，我通过修改ExoPlayer的源代码实现以下功能，这里不讨论其他视频流加密解密的方法

1. 大文件分段加密后应用分段解密（m3u8）
2. 高度自定义，你可以实现任何你需要的加密方法，甚至每一个ts都有自己的解码方式
3. ts加密，不允许独立播放

加密流程

PS：使用ffmpeg进行音视频分割后使用Java代码进行加密

1. 音视频分割
   代码就是通过java执行ffmpeg的命令即可，请确保环境变量中安装了ffmpeg，内部的代码可以自己通过需求来修改，其中音频与视频的分割方式差不多

 private static String encryptVideoWithFFmpeg(String videoFilePath, String outputDirPath) {File outputDir = new File(outputDirPath);if (!outputDir.exists()) {outputDir.mkdirs();}String outputFileName = "output"; // 输出文件名，这里可以根据需要自定义String tsOutputPath = outputDirPath + File.separator + outputFileName + ".ts";String m3u8OutputPath = outputDirPath + File.separator + outputFileName + ".m3u8";try {ProcessBuilder processBuilder = new ProcessBuilder("ffmpeg","-i", videoFilePath,"-c:v", "libx264","-c:a", "aac","-f", "hls","-hls_time", "5","-hls_list_size", "0","-hls_segment_filename", outputDirPath + File.separator + "output%03d.ts",m3u8OutputPath);// 设置工作目录，可以防止某些情况下找不到 ffmpeg 命令的问题Process process = processBuilder.start();// 获取 ffmpeg 命令执行的输出信息（可选，如果需要查看 ffmpeg 执行日志）BufferedReader reader = new BufferedReader(new InputStreamReader(process.getErrorStream()));String line;while ((line = reader.readLine()) != null) {System.out.println(line);}int exitCode = process.waitFor();if (exitCode == 0) {System.out.println("FFmpeg command executed successfully.");} else {System.err.println("Error executing FFmpeg command. Exit code: " + exitCode);}} catch (IOException | InterruptedException e) {e.printStackTrace();}return tsOutputPath;}
private static String splitAudioWithFFmpeg(String audioFilePath, String outputDirPath) {File outputDir = new File(outputDirPath);if (!outputDir.exists()) {outputDir.mkdirs();}String outputFileName = "output"; // 输出文件名，这里可以根据需要自定义String tsOutputPath = outputDirPath + File.separator + outputFileName + ".ts";String m3u8OutputPath = outputDirPath + File.separator + outputFileName + ".m3u8";try {ProcessBuilder processBuilder = new ProcessBuilder("ffmpeg","-i", audioFilePath,"-c:a", "aac","-f", "hls","-hls_time", "10","-hls_list_size", "0","-hls_segment_filename", outputDirPath + File.separator + "output%03d.ts",m3u8OutputPath);Process process = processBuilder.start();BufferedReader reader = new BufferedReader(new InputStreamReader(process.getErrorStream()));String line;while ((line = reader.readLine()) != null) {System.out.println(line);}int exitCode = process.waitFor();if (exitCode == 0) {System.out.println("FFmpeg command executed successfully.");} else {System.err.println("Error executing FFmpeg command. Exit code: " + exitCode);}} catch (IOException | InterruptedException e) {e.printStackTrace();}return tsOutputPath;}

2. 音视频加密
   这里的视频加密使用的是AES加密，是将ts结尾的所有文件进行加密，后面的方法是解密，一般用不到

 private static void encryptTSSegmentsWithAES(String outputDirPath, String aesKey) {File outputDir = new File(outputDirPath);File[] tsFiles = outputDir.listFiles((dir, name) -> name.endsWith(".ts"));if (tsFiles != null) {try {byte[] keyBytes = aesKey.getBytes();Key aesKeySpec = new SecretKeySpec(keyBytes, AES_ALGORITHM);Cipher cipher = Cipher.getInstance(AES_ALGORITHM);cipher.init(Cipher.ENCRYPT_MODE, aesKeySpec);for (File tsFile : tsFiles) {byte[] tsData = Files.readAllBytes(Paths.get(tsFile.getPath()));byte[] encryptedData = cipher.doFinal(tsData);Files.write(Paths.get(tsFile.getPath()), encryptedData);}} catch (Exception e) {e.printStackTrace();}}}public static void decryptTSSegmentsWithAES(String outputDirPath, String aesKey) {File outputDir = new File(outputDirPath);File[] tsFiles = outputDir.listFiles((dir, name) -> name.endsWith(".ts"));if (tsFiles != null) {try {byte[] keyBytes = aesKey.getBytes();Key aesKeySpec = new SecretKeySpec(keyBytes, "AES");Cipher cipher =  Cipher.getInstance(AES_ALGORITHM);cipher.init(Cipher.DECRYPT_MODE, aesKeySpec);for (File tsFile : tsFiles) {byte[] tsData = Files.readAllBytes(Paths.get(tsFile.getPath()));byte[] encryptedData = cipher.doFinal(tsData);Files.write(Paths.get(tsFile.getPath()), encryptedData);}} catch (Exception e) {e.printStackTrace();}}}

加密完成之后将m3u8放在服务器上，并且分割的文件也要在同一目录，或者切片的时候手动设置，保证切片后的视频可以正常播放即可

音视频解密

这里使用的是修改ExoPlayer的源代码来实现的，因为在Android手机上面播放视频的选择有很多，大家也可以根据我的方法修改其他播放器，本次按照ExoPlayer进行演示教学
PS:因为Google把ExoPlayer整合到MediaPlayer3里了，所以如果不使用纯源代码来修改的话，也会跟我的演示一样有删除线，但是无伤大雅

1. 引入依赖，直接在App层的Build.gradle引入ExoPlayer2的依赖，其中我们要使用的视频流为hls格式，所以需要引入hls模块

	implementation 'com.google.android.exoplayer:exoplayer-core:2.19.0'implementation 'com.google.android.exoplayer:exoplayer-dash:2.19.0'implementation 'com.google.android.exoplayer:exoplayer-ui:2.19.0'implementation 'com.google.android.exoplayer:exoplayer-hls:2.19.0'

2. 准备修改代码，我们需要修改的类如下

• DefaultDataSource
• DefaultDataSourceFactory
• DefaultHttpDataSource
• HttpDataSource

我们只需要复制其源码然后进行修改后，使用ExoPlayer播放视频的时候，使用我们自己的类即可，如果你不想这样，那么可以直接下载ExoPlayer2的源代码进行修改，这样的话还能去除废弃的表示，没有那么多删除线，接下来我们正式开始修改
修改类“DefaultHttpDataSource”
我将以注释的方式来讲解代码，注意这里只是演示一个简单的自定义加解密的切入方式，所以按照文件名末尾为ts的文件进行暴力判断，精细化的处理方式可以有很多拓展，比如仅加密视频的中间部分作为会员视频，这样只需要单一视频流就可以解决试看的问题，而且不怕应用内部修改VIP标志位（对于修改源码等暴力破解的方法无效，毕竟源码都给你扒出来了）

//定义解密流，主要使用此流来进行解密
private CipherInputStream cipherInputStream;
//修改open方法代码，最后的try代码块中增加如下内容用来解密流
@Override
public long open(DataSpec dataSpec) throws HttpDataSourceException {
....
try {inputStream = connection.getInputStream();if (isCompressed) {inputStream = new GZIPInputStream(inputStream);}//新增代码块，这里的解密方法可以按照自己的需求编写----------------------------------if (dataSpec.uri.getPath().endsWith(".ts")) {Cipher cipher;try {cipher = Cipher.getInstance("AES");} catch (NoSuchAlgorithmException | NoSuchPaddingException e) {throw new RuntimeException(e);}Key aesKeySpec = new SecretKeySpec("1234567890abcdef".getBytes(), "AES");try {cipher.init(Cipher.DECRYPT_MODE, aesKeySpec);} catch (InvalidKeyException e) {throw new RuntimeException(e);}cipherInputStream = new CipherInputStream(inputStream, cipher);}//新增代码块结束------------------------------} catch (IOException e) {closeConnectionQuietly();throw new HttpDataSourceException(e,dataSpec,PlaybackException.ERROR_CODE_IO_UNSPECIFIED,HttpDataSourceException.TYPE_OPEN);}....
}//修改read方法如下，如果判断是需要解密的文件则走cipherInputStream@Overridepublic final int read(byte[] buffer, int offset, int length) throws IOException {if (dataSpec.uri.getPath().endsWith(".ts")) {Assertions.checkNotNull(cipherInputStream);int bytesRead = cipherInputStream.read(buffer, offset, length);if (bytesRead < 0) {return C.RESULT_END_OF_INPUT;}return bytesRead;} else {try {return readInternal(buffer, offset, length);} catch (IOException e) {throw HttpDataSourceException.createForIOException(e, castNonNull(dataSpec), HttpDataSourceException.TYPE_READ);}}}
//最后释放资源@Overridepublic void close() throws HttpDataSourceException {try {@Nullable InputStream inputStream = this.inputStream;if (inputStream != null) {long bytesRemaining =bytesToRead == C.LENGTH_UNSET ? C.LENGTH_UNSET : bytesToRead - bytesRead;maybeTerminateInputStream(connection, bytesRemaining);try {inputStream.close();} catch (IOException e) {throw new HttpDataSourceException(e,castNonNull(dataSpec),PlaybackException.ERROR_CODE_IO_UNSPECIFIED,HttpDataSourceException.TYPE_CLOSE);}}if (cipherInputStream != null) {cipherInputStream.close();}} catch (IOException e) {throw new HttpDataSourceException(e,castNonNull(dataSpec),PlaybackException.ERROR_CODE_IO_UNSPECIFIED,HttpDataSourceException.TYPE_CLOSE);} finally {inputStream = null;cipherInputStream = null;closeConnectionQuietly();if (opened) {opened = false;transferEnded();}}}

修改类“DefaultDataSourceFactory”
此类只需要修改一点，那就是将DefaultDataSource的create过程引导到我们自己写的DefaultDataSource，也就是删除原来的ExoPlayer2的依赖引入，引入刚刚讲到的DefaultHttpDataSource，不需要修改代码，只需要切换依赖即可

 public DefaultDataSourceFactory(Context context, @Nullable String userAgent, @Nullable TransferListener listener) {this(context, listener, new DefaultHttpDataSource.Factory().setUserAgent(userAgent));} 

音视频播放

因为ExoPlayer2同时支持音频和视频的播放，所以均可使用下列方式完成

public class PlayerActivity extends AppCompatActivity {private PlayerView playerView;private SimpleExoPlayer player;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_player);// Initialize PlayerViewplayerView = findViewById(R.id.player);// Create a DefaultTrackSelector to enable tracksDefaultTrackSelector trackSelector = new DefaultTrackSelector(this);// Create an instance of ExoPlayerplayer = new SimpleExoPlayer.Builder(this).setTrackSelector(trackSelector).build();// Attach the player to the PlayerViewplayerView.setPlayer(player);String userAgent = Util.getUserAgent(this, "ExoPlayerDemo");DefaultDataSourceFactory dataSourceFactory = new DefaultDataSourceFactory(this, userAgent);String videoUrl = "http://zhangzhiao.top/missit/aa/output.m3u8";// Create an HlsMediaSourceHlsMediaSource mediaSource = new HlsMediaSource.Factory(dataSourceFactory).createMediaSource(MediaItem.fromUri(Uri.parse(videoUrl)));// Prepare the player with the media sourceplayer.prepare(mediaSource);}@Overrideprotected void onDestroy() {super.onDestroy();// Release the player when the activity is destroyedplayer.release();}
}

源码下载

结语

代码里给大家提供了一个小视频，如果按照流程编写应该是可以顺利播放的，如果需要还可以把m3u8文件进行加密处理，一切处理方法都可以实现，如果对您有帮助不妨点个赞