RTSP stream hangs on camera going offline

[magistrser]

Also when camera returns stream still hangs. I debugged it a little and find out that for

avcodec_decode_video2(this->video_dec_ctx, this->frame, &got_frame, &(this->packet));

got_frame still be 1 even if avcodec_decode_video2 returns 0. It leads to infinity loop in grab function.
I hope this fix is good enough, or may be you know the right way to fix it

[LukasBommes]

Thanks a lot for your contribution, @magistrser! Due to limited time available I did not include this in the 1.1.0 release but will hopefully find the time to have a look at this soon and included it in the next release.

[LukasBommes]

I never merged this because I could not accurately reproduce the issue du to lack of a real RTSP source. If anyone runs into the same issue and finds that this PR correctly solves the issues please leave a comment. I can then merge it more confidently.