AVPlayer停止在线模式下播放AES加密的离线HLS视频 [英] AVPlayer Stops Playing AES encrypted offline HLS Video in online mode
问题描述
我写了一个代码来下载HLS视频并以离线模式播放。
此代码对编码视频有效。现在，我有一个经过AES加密的视频，并且我们为其具有自定义的加密密钥。下载AES加密的HLS视频后，我使用下面给出的代码提供视频解密的密钥。
I have written a code to download HLS video and play it in offline mode. This code works fine for encoded video. Now I have a video which is AES encrypted and we are having custom encryption key for it. After downloading AES encrypted HLS video I am using below given code to supply key for decryption of video.
- (BOOL)resourceLoader:(AVAssetResourceLoader *)resourceLoader shouldWaitForLoadingOfRequestedResource:(AVAssetResourceLoadingRequest *)loadingRequest {
NSString *scheme = loadingRequest.request.URL.scheme;
if ([scheme isEqualToString:@"ckey"]) {
NSString *request = loadingRequest.request.URL.host;
NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:request];
if (data) {
[loadingRequest.dataRequest respondWithData:data];
[loadingRequest finishLoading];
} else {
// Data loading fail
}
}
return NO; }
我正在拦截对密钥的请求，并传递存储在UserDefaults中的密钥以进行解密。
I am intercepting a request for a key and passing key stored in UserDefaults for decryption.
当我的设备的wifi或数据连接关闭时，带有自定义密钥的AES加密HLS视频可以很好地播放。
如果在启用设备的wifi或数据连接后开始播放此视频，或者
在播放视频时启用设备的wifi或数据连接；视频立即停止播放，没有任何错误，并且再也不会播放。
我已经检查了playerItem的accessLog和errorLog，但没有发现任何帮助。
I have checked accessLog and errorLog of playerItem but haven't found anything helpful.
要在下载HLS内容后提供自定义URL密钥，我将通过替换
To provide a custom URL key after downloading of HLS content I am updating a content of .m3u8 file by replacing
URI = ...
URI="..."
带有
URI = ckey：// ...
URI="ckey://..."
是为AES加密视频提供密钥的正确方法？
Is this a correct way to provide key for AES encrypted video?
，可能是此行为的原因以及如何解决此问题？
and what could be the reason of this behaviour and how to solve this issue?
请先感谢。
推荐答案
最后，我设法解决了这个问题。下载的HLS视频的大致包结构如下所示：
Finally I managed to solve this issue. Rough package structure of downloaded HLS video is like given below:
HLS.movpkg
|_ 0-12345
|_ 123.m3u8
|_ StreamInfoBoot.xml
|_ StreamInfoRoot.xml
|_ <>.frag
|_ boot.xml
- boot.xml包含HLS的网络URL（基于https：）
- StreamBootInfo.xml包含HLS URL（基于https :）与本地下载的.frag文件之间的映射。
在离线模式下，HLS视频可以完美播放。但是启用网络连接后，它是指https：URL而不是本地.frag文件。
In offline mode HLS video was playing perfectly. But when network connection was enabled it was referring to https: URL instead of local .frag files.
我用自定义方案（fakehttps :）替换了这些文件中的https：方案。限制AVPlayer联机获取资源。
I replaced https: scheme in these files with custom scheme (fakehttps:) to restrict AVPlayer going online for resources.
这件事解决了我的问题，但我不知道其背后的确切原因以及AVPlayer如何播放HLS。
This thing solved my issue but I don't know the exact reason behind it and how HLS is played by AVPlayer.
我提到了> ，并且有了一些想法，因此尝试了一些尝试。
I referred this and got some idea so tried something .
我正在进一步更新此答案，以说明如何在离线模式下播放加密的视频。
-
获取视频解密所需的密钥。
Get the key required for video decryption.
将该键保存在某个位置。
Save that key some where.
您可以将该键另存为 NSData 或<$ UserDefault 中的c $ c> Data 对象我正在使用视频文件名作为密钥，将密钥数据保存在UserDefaults中。
You can save that key as NSData or Data object in UserDefault I am using video file name as key to save key data in UserDefaults.
-
使用
FileManagerAPI遍历<$ c $中的所有文件c> .movpkg 。
获取每个 .m3u8 的内容文件，然后将 URI = some key url 替换为URI = ckey：// keyusedToSaveKeyDataInUserDefaults
Get the content of each .m3u8 file and replace URI="some key url" with URI="ckey://keyusedToSaveKeyDataInUserDefaults"
您可以参考下面给出的此过程代码。
You can refer code given below for this process.
if let url = asset.asset?.url, let data = data {
let keyFileName = "\(asset.contentCode!).key"
UserDefaults.standard.set(data, forKey: keyFileName)
do {
// ***** Create key file *****
let keyFilePath = "ckey://\(keyFileName)"
let subDirectories = try fileManager.contentsOfDirectory(at: url,
includingPropertiesForKeys: nil, options: .skipsSubdirectoryDescendants)
for url in subDirectories {
var isDirectory: ObjCBool = false
if fileManager.fileExists(atPath: url.path, isDirectory: &isDirectory) {
if isDirectory.boolValue {
let path = url.path as NSString
let folderName = path.lastPathComponent
let playlistFilePath = path.appendingPathComponent("\(folderName).m3u8")
if fileManager.fileExists(atPath: playlistFilePath) {
var fileContent = try String.init(contentsOf: URL.init(fileURLWithPath: playlistFilePath))
let stringArray = self.matches(for: "URI=\"(.+?)\"", in: fileContent)
for pattern in stringArray {
fileContent = fileContent.replacingOccurrences(of: pattern, with: "URI=\"\(keyFilePath)\"")
}
try fileContent.write(toFile: playlistFilePath, atomically: true, encoding: .utf8)
}
let streamInfoXML = path.appendingPathComponent("StreamInfoBoot.xml")
if fileManager.fileExists(atPath: streamInfoXML) {
var fileContent = try String.init(contentsOf: URL.init(fileURLWithPath: streamInfoXML))
fileContent = fileContent.replacingOccurrences(of: "https:", with: "fakehttps:")
try fileContent.write(toFile: streamInfoXML, atomically: true, encoding: .utf8)
}
} else {
if url.lastPathComponent == "boot.xml" {
let bootXML = url.path
if fileManager.fileExists(atPath: bootXML) {
var fileContent = try String.init(contentsOf: URL.init(fileURLWithPath: bootXML))
fileContent = fileContent.replacingOccurrences(of: "https:", with: "fakehttps:")
try fileContent.write(toFile: bootXML, atomically: true, encoding: .utf8)
}
}
}
}
}
userInfo[Asset.Keys.state] = Asset.State.downloaded.rawValue
// Update download status to db
let user = RoboUser.sharedObject()
let sqlDBManager = RoboSQLiteDatabaseManager.init(databaseManagerForCourseCode: user?.lastSelectedCourse)
sqlDBManager?.updateContentDownloadStatus(downloaded, forContentCode: asset.contentCode!)
self.notifyServerAboutContentDownload(asset: asset)
NotificationCenter.default.post(name: AssetDownloadStateChangedNotification, object: nil, userInfo: userInfo)
} catch {
}
}
func matches(for regex: String, in text: String) -> [String] {
do {
let regex = try NSRegularExpression(pattern: regex)
let nsString = text as NSString
let results = regex.matches(in: text, range: NSRange(location: 0, length: nsString.length))
return results.map { nsString.substring(with: $0.range)}
} catch let error {
print("invalid regex: \(error.localizedDescription)")
return []
}
}
这将更新您的下载包结构，以便在离线模式下播放加密的视频。
现在最后要做的就是在AVAssetResourceLoader类的给定方法下实现如下
- (BOOL)resourceLoader:(AVAssetResourceLoader *)resourceLoader shouldWaitForLoadingOfRequestedResource:(AVAssetResourceLoadingRequest *)loadingRequest {
NSString *scheme = loadingRequest.request.URL.scheme;
if ([scheme isEqualToString:@"ckey"]) {
NSString *request = loadingRequest.request.URL.host;
NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:request];
if (data) {
loadingRequest.contentInformationRequest.contentType = AVStreamingKeyDeliveryPersistentContentKeyType;
loadingRequest.contentInformationRequest.byteRangeAccessSupported = YES;
loadingRequest.contentInformationRequest.contentLength = data.length;
[loadingRequest.dataRequest respondWithData:data];
[loadingRequest finishLoading];
} else {
// Data loading fail
}
}
return YES;
}
此方法将在播放视频时提供视频解密的密钥。
This method will provide key to video while playing to decrypt it.
这篇关于AVPlayer停止在线模式下播放AES加密的离线HLS视频的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
