iOS custom camera output crash resolution +[avcapturestillimageoutput Jpegstillimagensdatarepresentation:]-NULL Sample BUF

When using a custom camera, when you output a photo,

Sometimes it will crash in nsdata*jpegdata = [Avcapturestillimageoutputjpegstillimagensdatarepresentation:imagedatasamplebuffer]; This place, and prompted "+[avcapturestillimageoutput Jpegstillimagensdatarepresentation:]--NULL sample buffer." The bug may be that you took the photo too quickly.

The possible reason is that you put the output code in the main thread, which is wrong, because capturestillimageasynchronouslyfromconnection this method writes "Clients should not assume" Completion handler is called on a specific thread. So you can't call it in the main thread.

If you just call this problem with normal calls, there are two solutions:

1. To judge the problem

Method one code

2. Put execution in the global, if it is synchronous execution will not appear this problem