AVAssetWriter多个会话和status属性 [英] AVAssetWriter multiple sessions and the status property

问题描述

我正在尝试使用AVAssetWriter创建多个串行写入会话。一旦我成功完成一个（在调用finishWriting之后）状态设置为2（AVAssetWriterStatusCompleted）。

I am attempting to create multiple, serial writing sessions with AVAssetWriter. Once I've completed one successfully (after calling finishWriting) the status is set to 2 (AVAssetWriterStatusCompleted).

尝试创建另一个会话，我调用startWriting，但是我得到了错误：

Trying to create another session, I call startWriting, but I get the error:

[AVAssetWriter startWriting] cannot call method when status is 2

似乎我无法创建写入会话，除非我配置了什么。我是否必须再次重新创建AVAssetWriter？我必须遗漏一些东西，而且文档没有帮助。

Seems I cannot create a writing session unless I configure something. Do I have to recreate the AVAssetWriter again? I must be missing something, and the docs aren't helping.

谢谢。

推荐答案

作家完成后就没有了更长的可用。您必须创建一个新的。来自文档：

After the writer has completed it is no longer usable. You must create a new one. From the docs:

您只能使用给定的AVAssetWriter实例一次写入单个文件。
如果你想多次写文件，你每次都必须使用
AVAssetWriter的新实例。

You can only use a given instance of AVAssetWriter once to write to a single file. If you want to write to files multiple times, you must use a new instance of AVAssetWriter each time.

我有一个应用程序我在哪里使用两个AVAssetWriters。我创建了两个编写器，其中一次只有一个是活动的。当达到某个时间增量时，我将活动的writer写入GCD队列以完成和重新创建，并将活动的writer指针设置为另一个writer。

I have an app where I use two AVAssetWriters. I create two writers where only one is active at a time. When some time delta is reached I push the active writer onto a GCD queue for completion and recreation, and set the active writer pointer to the other writer.

if(time > delta)
  dispatch( ^{ finish writer, create new one })
  active_writer = next writer

这在使用捕获队列时效果很好。您可以设置一个开关来执行给定状态的操作。

This works well when using a capture queue. You can setup a switch to perform the operations given the state of the writer.

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