iOS 边下边播的实现代码
时间：2021-01-22 12:24:13|栏目：iOS代码|点击： 次
项目中之前使用的是AVPlayer直接播放URL地址，但是不知道是相机的wifi不够稳定还是代码的问题，app总是出现缓冲卡顿，就考虑改写成边下边播的模式，查过了许多资料，发现大部分都是用的同一种方法
AVAssetResourceLoaderDelegate 代理方法，来看看如何实现
首先要实现两个必须的代理方法
AVAssetResourceLoaderDelegateObjective-C
#pragma mark - AVAssetResourceLoaderDelegate
//开始加载
- (BOOL)resourceLoader:(AVAssetResourceLoader *)resourceLoader shouldWaitForLoadingOfRequestedResource:(AVAssetResourceLoadingRequest *)loadingRequest {
[self addLoadingRequest:loadingRequest];
return YES;
}
//取消加载
- (void)resourceLoader:(AVAssetResourceLoader *)resourceLoader didCancelLoadingRequest:(AVAssetResourceLoadingRequest *)loadingRequest {
[self removeLoadingRequest:loadingRequest];
}
#pragma mark - AVAssetResourceLoaderDelegate
//开始加载
- (BOOL)resourceLoader:(AVAssetResourceLoader *)resourceLoader shouldWaitForLoadingOfRequestedResource:(AVAssetResourceLoadingRequest *)loadingRequest {
[self addLoadingRequest:loadingRequest];
return YES;
}
//取消加载
- (void)resourceLoader:(AVAssetResourceLoader *)resourceLoader didCancelLoadingRequest:(AVAssetResourceLoadingRequest *)loadingRequest {
[self removeLoadingRequest:loadingRequest];
}
然后要定义一个下载类，其实就是分段下载数据的下载器
AVAssetResourceLoaderDelegateObjective-C
- (void)start {
NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:[self.requestURL originalSchemeURL] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:RequestTimeout];
if (self.requestOffset > 0) {
[request addValue:[NSString stringWithFormat:@"bytes=%ld-%ld", self.requestOffset, self.fileLength - 1] forHTTPHeaderField:@"Range"];
}
self.session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
self.task = [self.session dataTaskWithRequest:request];
[self.task resume];
}
#pragma mark - NSURLSessionDataDelegate
//服务器响应
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler {
if (self.cancel) return;
SRQLog(@"response: %@",response);
completionHandler(NSURLSessionResponseAllow);
NSHTTPURLResponse * httpResponse = (NSHTTPURLResponse *)response;
NSString * contentRange = [[httpResponse allHeaderFields] objectForKey:@"Content-Range"];
NSString * fileLength = [[contentRange componentsSeparatedByString:@"/"] lastObject];
self.fileLength = fileLength.integerValue > 0 ? fileLength.integerValue : response.expectedContentLength;
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidReceiveResponse)]) {
[self.delegate requestTaskDidReceiveResponse];
}
}
//服务器返回数据 可能会调用多次
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
if (self.cancel) return;
//SRQLog(@"收到响应了: %@",data);
self.cacheLength += data.length;
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidUpdateCache)]) {
[self.delegate requestTaskDidUpdateCache];
}
}
//请求完成会调用该方法，请求失败则error有值
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
if (self.cancel) {
SRQLog(@"下载取消");
}else {
if (error) {
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidFailWithError:)]) {
[self.delegate requestTaskDidFailWithError:error];
}
}else {
//可以缓存则保存文件
if (self.cache) {
[FileHandle cacheTempFileWithFileName:[NSString fileNameWithURL:self.requestURL]];
}
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidFinishLoadingWithCache:)]) {
[self.delegate requestTaskDidFinishLoadingWithCache:self.cache];
}
}
}
}
- (void)start {
NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:[self.requestURL originalSchemeURL] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:RequestTimeout];
if (self.requestOffset > 0) {
[request addValue:[NSString stringWithFormat:@"bytes=%ld-%ld", self.requestOffset, self.fileLength - 1] forHTTPHeaderField:@"Range"];
}
self.session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
self.task = [self.session dataTaskWithRequest:request];
[self.task resume];
}
#pragma mark - NSURLSessionDataDelegate
//服务器响应
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler {
if (self.cancel) return;
SRQLog(@"response: %@",response);
completionHandler(NSURLSessionResponseAllow);
NSHTTPURLResponse * httpResponse = (NSHTTPURLResponse *)response;
NSString * contentRange = [[httpResponse allHeaderFields] objectForKey:@"Content-Range"];
NSString * fileLength = [[contentRange componentsSeparatedByString:@"/"] lastObject];
self.fileLength = fileLength.integerValue > 0 ? fileLength.integerValue : response.expectedContentLength;
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidReceiveResponse)]) {
[self.delegate requestTaskDidReceiveResponse];
}
}
//服务器返回数据 可能会调用多次
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
if (self.cancel) return;
//SRQLog(@"收到响应了: %@",data);
self.cacheLength += data.length;
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidUpdateCache)]) {
[self.delegate requestTaskDidUpdateCache];
}
}
//请求完成会调用该方法，请求失败则error有值
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
if (self.cancel) {
SRQLog(@"下载取消");
}else {
if (error) {
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidFailWithError:)]) {
[self.delegate requestTaskDidFailWithError:error];
}
}else {
//可以缓存则保存文件
if (self.cache) {
[FileHandle cacheTempFileWithFileName:[NSString fileNameWithURL:self.requestURL]];
}
if (self.delegate && [self.delegate respondsToSelector:@selector(requestTaskDidFinishLoadingWithCache:)]) {
[self.delegate requestTaskDidFinishLoadingWithCache:self.cache];
}
}
}
}
最后将拿到的数据塞进AVAssetResourceLoaderDelegate代理中，交还给AVPlayer，就可以播放了
AVAssetResourceLoaderDelegateObjective-C
- (BOOL)finishLoadingWithLoadingRequest:(AVAssetResourceLoadingRequest *)loadingRequest {
//填充信息
CFStringRef contentType = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, (__bridge CFStringRef)(MimeType), NULL);
loadingRequest.contentInformationRequest.contentType = CFBridgingRelease(contentType);
loadingRequest.contentInformationRequest.byteRangeAccessSupported = YES;
loadingRequest.contentInformationRequest.contentLength = self.requestTask.fileLength;
//读文件，填充数据
NSUInteger cacheLength = self.requestTask.cacheLength;
NSUInteger requestedOffset = loadingRequest.dataRequest.requestedOffset;
if (loadingRequest.dataRequest.currentOffset != 0) {
requestedOffset = loadingRequest.dataRequest.currentOffset;
}
NSUInteger canReadLength = cacheLength - (requestedOffset - self.requestTask.requestOffset);
NSUInteger respondLength = MIN(canReadLength, loadingRequest.dataRequest.requestedLength);
//SRQLog(@"好不容易填充一次");
[loadingRequest.dataRequest respondWithData:[FileHandle readTempFileDataWithOffset:requestedOffset - self.requestTask.requestOffset length:respondLength]];
//如果完全响应了所需要的数据，则完成
NSUInteger nowendOffset = requestedOffset + canReadLength;
NSUInteger reqEndOffset = loadingRequest.dataRequest.requestedOffset + loadingRequest.dataRequest.requestedLength;
if (nowendOffset >= reqEndOffset) {
[loadingRequest finishLoading];
return YES;
}
return NO;
}
- (void)player{
self.resouerLoader = [[ResourceLoader alloc] init];
self.asset = [AVURLAsset URLAssetWithURL:[self.videoUrl customSchemeURL] options:nil];
[self.asset.resourceLoader setDelegate:self.resouerLoader queue:dispatch_get_main_queue()];
_playerItem = [AVPlayerItem playerItemWithAsset:self.asset];
_players = [AVPlayer playerWithPlayerItem:_playerItem];
}
- (BOOL)finishLoadingWithLoadingRequest:(AVAssetResourceLoadingRequest *)loadingRequest {
//填充信息
CFStringRef contentType = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, (__bridge CFStringRef)(MimeType), NULL);
loadingRequest.contentInformationRequest.contentType = CFBridgingRelease(contentType);
loadingRequest.contentInformationRequest.byteRangeAccessSupported = YES;
loadingRequest.contentInformationRequest.contentLength = self.requestTask.fileLength;
//读文件，填充数据
NSUInteger cacheLength = self.requestTask.cacheLength;
NSUInteger requestedOffset = loadingRequest.dataRequest.requestedOffset;
if (loadingRequest.dataRequest.currentOffset != 0) {
requestedOffset = loadingRequest.dataRequest.currentOffset;
}
NSUInteger canReadLength = cacheLength - (requestedOffset - self.requestTask.requestOffset);
NSUInteger respondLength = MIN(canReadLength, loadingRequest.dataRequest.requestedLength);
//SRQLog(@"好不容易填充一次");
[loadingRequest.dataRequest respondWithData:[FileHandle readTempFileDataWithOffset:requestedOffset - self.requestTask.requestOffset length:respondLength]];
//如果完全响应了所需要的数据，则完成
NSUInteger nowendOffset = requestedOffset + canReadLength;
NSUInteger reqEndOffset = loadingRequest.dataRequest.requestedOffset + loadingRequest.dataRequest.requestedLength;
if (nowendOffset >= reqEndOffset) {
[loadingRequest finishLoading];
return YES;
}
return NO;
}
- (void)player{
self.resouerLoader = [[ResourceLoader alloc] init];
self.asset = [AVURLAsset URLAssetWithURL:[self.videoUrl customSchemeURL] options:nil];
[self.asset.resourceLoader setDelegate:self.resouerLoader queue:dispatch_get_main_queue()];
_playerItem = [AVPlayerItem playerItemWithAsset:self.asset];
_players = [AVPlayer playerWithPlayerItem:_playerItem];
}
注意：此方法服务器端最好支持Range头，这样才是分段下载。
总结
