在设备上导出时AVAssetExportSession缺少音轨 [英] AVAssetExportSession missing audio track when exporting on device

问题描述

我在模拟器上运行了导出，并且一切正常.我在设备上运行它，视频被导出，但是没有音频.这使我相信，我必须使用设备不支持但OS X支持的音频格式，因为模拟器使用OS X所使用的格式.我尝试过m4a，aiff和aifc，但没有运气！有什么想法吗?

I run the export on the simulator and everything works great. I run it on the device and the video gets exported but there's no audio. This leads me to believe that I must be using an audio format that the device doesn't support but OS X does, as the simulator uses what OS X uses. I've tried m4a, aiff, and aifc and have had no luck! Any ideas??

推荐答案

我有一个非常相似的问题.它似乎与编解码器无关，因为我制作了一个单独的测试用例，可以很好地处理相同的视频.有一个相关问题，说明问题可能出在使用MPMoviePlayerController播放相同的资产.那使我走上了正确的轨道.

I have a very similar problem. It does not seem to do with codecs, as I made a separate test case that runs fine with the same video. There’s a related question that says the problem might be in playing the same assets using MPMoviePlayerController. That got me on the right track (sort of).

在我的情况下，问题出在导出期间使用了AVPlayer中的资产.我无法找到导致导出丢失音轨的确切组合–在单独的测试项目中，即使资产同时在AVPlayer中播放，导出也可以正常运行.在尝试寻找确切原因几个小时之后，我放弃了，只是在导出过程中使用replaceCurrentItemWithPlayerItem:nil从播放器中弹出了资产.这是一种骇客，但行之有效.

In my case the trouble stem from using the assets in an AVPlayer during the export. I was not able to find the exact combination that causes the export to drop the audio track – in the separate test project the export runs fine even though the asset plays in AVPlayer at the same time. After several hours of trying to find the exact cause I gave up and simply popped the asset out of the player using replaceCurrentItemWithPlayerItem:nil during export. It’s a hack, but it works.

AVFoundation是一个非常强大的框架，但是上帝，我希望它不是那么挑剔，或者至少记录了更多的错误，而不是无声地产生垃圾.

AVFoundation is a very powerful framework, but God I wish it wasn’t so finicky or at least logged more errors instead of silently producing garbage.

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