Non monotonically increasing dts to muxer in stream

Question

I'm just trying to save same frames on video from a buffer, where I properly saved the Bitmap Frame, and the Time Stamp, of the frame.

writer1 = new VideoFileWriter();
this.writer1.Width = this.videoSourceEndo.VideoResolution.FrameSize.Width;
this.writer1.Height = this.videoSourceEndo.VideoResolution.FrameSize.Height;
this.writer1.VideoCodec = VideoCodec.H264;
this.writer1.BitRate = (this.videoSourceEndo.VideoResolution.FrameSize.Height * this.videoSourceEndo.VideoResolution.FrameSize.Width * 30);

this.writer1.VideoOptions["preset"] = "superfast";
this.writer1.VideoOptions["tune"] = "zerolatency";

writer1.Open("test_HDMI.mp4");

(...)

writer1.WriteVideoFrame(endoFrameBuffer[endoFrameBuffer.Tail],endoFrameBuffer.getframetime(endoFrameBuffer.Tail));

But on visual studio (not on the first frame) I'm getting this error: Accord.Video.VideoException: 'Error while writing video frame. Error -22: Invalid argument. See console output for more details.'

And on console: Application provided invalid, non monotonically increasing dts to muxer in stream 0: 512 >= 512

I don't know the reason for that because on debug all values seems right. (Please let me know if you need more code)

I'm assuming you set codec/stream time_base's correctly (which I don't see here). So your problem lies here endoFrameBuffer.getframetime(endoFrameBuffer.Tail) let's see the code — the kamilz
endoFrameBuffer is just a RingBuffer with Bitmap Images and the proper timespan : public TimeSpan getframetime(int index) { return _timeBuffer[index]; } — Eduardo Preto
to set the values I just add a new element, like this: endoFrameBuffer.Enqueue(eventArgs.Frame,DateTime.Now - _firstFrameTime.Value); when the newframe event is fired. Then On the other thread I'm just recording each frame from the RingBuffer. — Eduardo Preto
Let me ask you directly, what fps is that video stream (because pts=512 is unusual to me). Is getFrameTime method returns pts value ?. — the kamilz
the video stream is about aprox. 30fps. getFrameTime return the TimeSpan (diference of time between the frame and the first frame received) — Eduardo Preto

the kamilz the kamilz · Accepted Answer · 2018-03-08T13:28:30

Ok, I'll put here. 1st thing where does VideoStream->time_base: 1/15360 comes from, this should be 1000/30000 for 30fps or 1001/30000 for 29.97 fps.

2nd something wrong with your pts/dts and frame duration calculation. As you see last two pts/dts values are same.

For packet duration (I'm assuming fps is constant as normally should) use these pre-calculated values (or check with yours as reference):

fps     duration (same unit as AVPacket::duration)
23.98   2086
24.00   2000
25.00   2000
29.97   2068
30.00   2000
50.00   1000
59.94   1016
60.00   1000

As for manually calculating pts/dts: this is my C++ function that I use:

static void write_video_pts(EncoderContext *ectx, AVPacket *pkt)
{
    pkt->pts          = ectx->video_pts; /* this is to keep next pts value, same unit as AVPacket::pts */
    ectx->video_pts  += ectx->frame_duration; /* check above table for ectx->frame_duration value */
    pkt->dts          = pkt->pts;
    pkt->duration     = ectx->frame_duration; /* check above table for ectx->frame_duration value */
    pkt->stream_index = ectx->VideoStream->index; /* AVStream */
}

These definitely works when manually encode from RAW source, like yours. Not for transcoding of course.

Hope that helps.

Non monotonically increasing dts to muxer in stream

1 Answers