记录一个iOS实现视频分片缓存拖拽快进不能播放的问题

代码现状

首先来看一下我们将视频数据塞给请求的代码

- (void)finishLoadingWithLoadingRequest:(IdiotResourceTask *)task {// printf("哈哈执行到这里执行到到这里\n");printf("哈哈哈数量数量%ld\n", self.taskList.count);//填充信息task.loadingRequest.contentInformationRequest.contentType = @"video/mp4";task.loadingRequest.contentInformationRequest.byteRangeAccessSupported = YES;task.loadingRequest.contentInformationRequest.contentLength = task.resource.fileLength;if (task.resource.fileLength <= 0) {NSLog(@"requestTask.fileLength <= 0");}printf("哈哈哈1111执行执行执行%lld点 %lld 一 %lld %p  %p\n", task.loadingRequest.dataRequest.requestedOffset,task.loadingRequest.dataRequest.currentOffset, task.resource.requestOffset, task.loadingRequest, task);//读文件，填充数据long long cacheLength = task.resource.cacheLength;long long requestedOffset = task.loadingRequest.dataRequest.requestedOffset;if (task.loadingRequest.dataRequest.currentOffset != 0) {requestedOffset = task.loadingRequest.dataRequest.currentOffset;}if (requestedOffset < task.resource.requestOffset) {/*这里是说明视频请求对象的offset小于当前任务的resouce 的offset注意：task.resouce,是一开始播放创建的resouce或者拖拽之后创建的resouce即一段连续不中断的资源对应一个resouce,如果当前当前视频请求的offset小于task.resouce.offset,说明该resouce 和当前request没有重合部分，要返回注意这里不能加上 请求的.dataRequest.requestedLength 然后和task.resouce.requestoffset比较，因为填充数据要从请求的开头就是offset开始填充*/printf("哈哈哈返回111111 \n");return;}long long paddingOffset = requestedOffset - task.resource.requestOffset;long long canReadLength = cacheLength - paddingOffset;if (canReadLength <= 0) {printf("哈哈哈返回222222 %lld\n", canReadLength);return;}long long respondLength = MIN(canReadLength, task.loadingRequest.dataRequest.requestedLength);NSFileHandle * handle = [IdiotFileManager fileHandleForReadingAtPath:task.resource.cachePath];[handle seekToFileOffset:paddingOffset];[task.loadingRequest.dataRequest respondWithData:[handle readDataOfLength:[[NSNumber numberWithLongLong:respondLength] unsignedIntegerValue]]];
//    printf("哈哈哈匹配到匹配到的长度%lld %lld %lld  %lld  %lld\n",respondLength,task.loadingRequest.dataRequest.requestedLength, task.loadingRequest.dataRequest.requestedOffset, task.loadingRequest.dataRequest.currentOffset, task.resource.requestOffset);[handle closeFile];//如果完全响应了所需要的数据，则完成long long nowendOffset = requestedOffset + canReadLength;long long reqEndOffset = task.loadingRequest.dataRequest.requestedOffset + task.loadingRequest.dataRequest.requestedLength;printf("哈哈哈哈差别差别%lld\n",reqEndOffset - nowendOffset);if (nowendOffset >= reqEndOffset) {[task.loadingRequest finishLoading];printf("哈哈哈主动删除%lld %lld %p\n",nowendOffset, reqEndOffset, task);[self removeLoadingRequest:task.loadingRequest];return;}}

遇到的问题

拖拽之后的操作

- (void)seekToTime:(NSTimeInterval)time completionHandler:(void (^ __nullable)(BOOL finished))completionHandler {if (self.totalTime > 0) {CMTime seekTime = CMTimeMake(time, 1);WEAKSELF[_player seekToTime:seekTime toleranceBefore:kCMTimeZero toleranceAfter:CMTimeMake(1, 1) completionHandler:^(BOOL finished) {// 视频跳转回调[weakSelf play];} else {self.seekTime = time;}
}

操作之后的结果发现视频不能播放了
查看执行的流程如下

后来经过多次调试发现，是我们seek的时候没有暂停，造成原来的请求还在，就会获取一个offset很小的请求，从而移除拖动之后的请求，造成无法播放

解决方法

修改之后的代码
就是seek之前 pause

- (void)seekToTime:(NSTimeInterval)time completionHandler:(void (^ __nullable)(BOOL finished))completionHandler {self.resourceLoader.seek = YES;if (self.totalTime > 0) {[self.player pause];CMTime seekTime = CMTimeMake(time, 1);WEAKSELF[_player seekToTime:seekTime toleranceBefore:CMTimeMake(1,1) toleranceAfter:CMTimeMake(1,1) completionHandler:^(BOOL finished) {[weakSelf play];}];} else {self.seekTime = time;}
}

表现

拖拽之后，视频可以正常播放