We have had exactly the same problem during a few of our past gigs. We use the most up to date version of VMix.
These are some of the log files:
17/01/2015 21:17:30, Version: 14.0.0.112 x64
17/01/2015 21:17:30, Size: 1280x720
17/01/2015 21:17:30, System: PAL 50i
17/01/2015 21:17:30, Codec: Microsoft MPEG-2 Encoder
17/01/2015 21:17:30, Format: UYVY 16 1498831189
17/01/2015 21:17:30, AudioDevice: vMix Audio
17/01/2015 21:17:30, AudioFormat: 44100 Hz 16 Bit 2 Channels
17/01/2015 21:17:30, AudioDelay: 0
17/01/2015 21:17:30, RestartInterval: 0
17/01/2015 21:17:30, Buffers: 50
17/01/2015 21:17:30, BitRate: 12
17/01/2015 21:17:31, StartRecording
17/01/2015 21:24:39, StopRecording
17/01/2015 21:24:39, Duration: 00:07:07
17/01/2015 21:24:39, Frames: 10679
17/01/2015 21:24:39, DroppedFrames: 0
17/01/2015 21:24:39, DueToSourceFrameRate: 0
17/01/2015 21:24:39, DueToHardDiskOrCPU: 0
17/01/2015 21:24:39, DroppedSamples: 0
17/01/2015 21:24:39, MissedSamples: 0
17/01/2015 21:24:39, SyncedSamples: 0
17/01/2015 21:24:39, AudioOffset: 20
17/01/2015 21:24:39, AudioDelay: 0
17/01/2015 21:24:39, AudioEngine
17/01/2015 21:24:39, Running: True
17/01/2015 21:24:39, SampleRate: 44100hz 16 Bit
17/01/2015 21:24:39, MixingErrors: 0
17/01/2015 21:24:39, Streams
17/01/2015 21:24:39, Mixer
17/01/2015 21:24:39, Samples: 26188
17/01/2015 21:24:39, Dropped: Read 0 Write 0
17/01/2015 21:24:39, Latency: 0 ms
17/01/2015 21:24:39, Errors: 0
17/01/2015 21:24:39, Headphones
17/01/2015 21:24:39, Samples: 26188
17/01/2015 21:24:39, Dropped: Read 0 Write 0
17/01/2015 21:24:39, Latency: 10 ms
17/01/2015 21:24:39, Errors: 0
17/01/2015 21:13:57, Version: 14.0.0.112 x64
17/01/2015 21:13:57, Size: 1280x720
17/01/2015 21:13:57, System: PAL 50i
17/01/2015 21:13:57, Codec: Microsoft MPEG-2 Encoder
17/01/2015 21:13:57, Format: UYVY 16 1498831189
17/01/2015 21:13:57, AudioDevice: vMix Audio
17/01/2015 21:13:57, AudioFormat: 44100 Hz 16 Bit 2 Channels
17/01/2015 21:13:57, AudioDelay: 0
17/01/2015 21:13:57, RestartInterval: 0
17/01/2015 21:13:57, Buffers: 50
17/01/2015 21:13:57, BitRate: 12
17/01/2015 21:13:59, StartRecording
17/01/2015 21:15:54, StopRecording
17/01/2015 21:15:54, Duration: 00:01:55
17/01/2015 21:15:54, Frames: 2884
17/01/2015 21:15:54, DroppedFrames: 0
17/01/2015 21:15:54, DueToSourceFrameRate: 0
17/01/2015 21:15:54, DueToHardDiskOrCPU: 0
17/01/2015 21:15:54, DroppedSamples: 0
17/01/2015 21:15:54, MissedSamples: 0
17/01/2015 21:15:54, SyncedSamples: 0
17/01/2015 21:15:54, AudioOffset: 0
17/01/2015 21:15:54, AudioDelay: 0
17/01/2015 21:15:54, AudioEngine
17/01/2015 21:15:54, Running: True
17/01/2015 21:15:54, SampleRate: 44100hz 16 Bit
17/01/2015 21:15:54, MixingErrors: 0
17/01/2015 21:15:54, Streams
17/01/2015 21:15:54, Mixer
17/01/2015 21:15:54, Samples: 11591
17/01/2015 21:15:54, Dropped: Read 0 Write 0
17/01/2015 21:15:54, Latency: 0 ms
17/01/2015 21:15:54, Errors: 0
17/01/2015 21:15:54, Headphones
17/01/2015 21:15:54, Samples: 11591
17/01/2015 21:15:54, Dropped: Read 0 Write 0
17/01/2015 21:15:54, Latency: 20 ms
17/01/2015 21:15:54, Errors: 0
17/01/2015 22:09:28, Version: 14.0.0.112 x64
17/01/2015 22:09:28, Size: 1920x1080
17/01/2015 22:09:28, System: PAL 50i
17/01/2015 22:09:28, Codec: Microsoft MPEG-2 Encoder
17/01/2015 22:09:28, Format: UYVY 16 1498831189
17/01/2015 22:09:28, AudioDevice: vMix Audio
17/01/2015 22:09:28, AudioFormat: 44100 Hz 16 Bit 2 Channels
17/01/2015 22:09:28, AudioDelay: 0
17/01/2015 22:09:28, RestartInterval: 0
17/01/2015 22:09:28, Buffers: 50
17/01/2015 22:09:28, BitRate: 12
17/01/2015 22:09:31, StartRecording
17/01/2015 22:11:56, StopRecording
17/01/2015 22:11:56, Duration: 00:02:25
17/01/2015 22:11:56, Frames: 3318
17/01/2015 22:11:56, DroppedFrames: 252
17/01/2015 22:11:56, DueToSourceFrameRate: 0
17/01/2015 22:11:56, DueToHardDiskOrCPU: 252
17/01/2015 22:11:56, DroppedSamples: 0
17/01/2015 22:11:56, MissedSamples: 0
17/01/2015 22:11:56, SyncedSamples: 0
17/01/2015 22:11:56, AudioOffset: 0
17/01/2015 22:11:56, AudioDelay: 0
17/01/2015 22:11:56, AudioEngine
17/01/2015 22:11:56, Running: True
17/01/2015 22:11:56, SampleRate: 44100hz 16 Bit
17/01/2015 22:11:56, MixingErrors: 0
17/01/2015 22:11:56, Streams
17/01/2015 22:11:56, Mixer
17/01/2015 22:11:56, Samples: 127328
17/01/2015 22:11:56, Dropped: Read 0 Write 0
17/01/2015 22:11:56, Latency: 0 ms
17/01/2015 22:11:56, Errors: 0
17/01/2015 22:11:56, Headphones
17/01/2015 22:11:56, Samples: 127328
17/01/2015 22:11:56, Dropped: Read 0 Write 0
17/01/2015 22:11:56, Latency: 50 ms
17/01/2015 22:11:56, Errors: 0
17/01/2015 22:11:56, AV
17/01/2015 22:11:56, Samples: 127082
17/01/2015 22:11:56, Dropped: Read 257 Write 0
17/01/2015 22:11:56, Latency: 100 ms
17/01/2015 22:11:56, TargetLatency: 80 ms
17/01/2015 22:11:56, Resampled: 5120/120
17/01/2015 22:11:56, Errors: 0
17/01/2015 22:11:56, AV
17/01/2015 22:11:56, Samples: 127054
17/01/2015 22:11:56, Dropped: Read 236 Write 0
17/01/2015 22:11:56, Latency: 80 ms
17/01/2015 22:11:56, TargetLatency: 80 ms
17/01/2015 22:11:56, Resampled: 4680/180
17/01/2015 22:11:56, Errors: 0
17/01/2015 22:11:56, AV
17/01/2015 22:11:56, Samples: 127048
17/01/2015 22:11:56, Dropped: Read 472 Write 0
17/01/2015 22:11:56, Latency: 60 ms
17/01/2015 22:11:56, TargetLatency: 80 ms
17/01/2015 22:11:56, Resampled: 9420/140
17/01/2015 22:11:56, Errors: 0
17/01/2015 22:11:56, AV
17/01/2015 22:11:56, Samples: 127042
17/01/2015 22:11:56, Dropped: Read 365 Write 0
17/01/2015 22:11:56, Latency: 100 ms
17/01/2015 22:11:56, TargetLatency: 80 ms
17/01/2015 22:11:56, Resampled: 7260/160
17/01/2015 22:11:56, Errors: 0
17/01/2015 22:11:56, DirectShow
17/01/2015 22:11:56, Samples: 127033
17/01/2015 22:11:56, Dropped: Read 4 Write 0
17/01/2015 22:11:56, Latency: 80 ms
17/01/2015 22:11:56, TargetLatency: 80 ms
17/01/2015 22:11:56, Resampled: 0/60
17/01/2015 22:11:56, Errors: 0
17/01/2015 22:11:56, FFMpeg
17/01/2015 22:11:56, Samples: 2733
17/01/2015 22:11:56, Dropped: Read 1 Write 0
17/01/2015 22:11:56, Latency: 60 ms
17/01/2015 22:11:56, Errors: 0
We solved it by running FMLE seperate from Vmix and by switching from a SSD to a normal harddisk and not using the ts but the Mpeg codec. From then on everything ran smooth.
We always have this while recording shows that are using a complex light setup (fast lights), combined by a slightly unstable internet connection.
No idea what is actually causing this problem in our case, but we sometimes faced this problem several times in a few minutes.
Since our streaming is not as important as our recordings, we really would love to see this problem solved.