GStreamer Can someone explain this video recording behaviour?

[madstrum]

I'm using GStreamer with CM-FX6 to record from the video-in analog source.

Initially, the command I used was :

Recording

gst-launch tvsrc fps-n=30 ! queue ! vpuenc codec=6 bitrate=4000000 ! matroskamux ! filesink location=output3.mkv sync=false

After 1 minute or so, there was a error saying

ERROR: from element /GstPipeline:pipeline0/MFWGstTVSRC:mfwgsttvsrc0: Internal data flow error

Aditional debug info

gstbasesrc.c(2582): gst_base_src_loop (): /GstPipeline:pipeline0/MFWGstTVSRC:mfwgsttvsrc0:

streaming task paused, reaosn error (-5)

But when I changed this to

gst-launch tvsrc fps-n=30 ! queue max-size-buffers=1 max-size-bytes=0 max-size-time=0 ! vpuenc codec=6 bitrate=4000000 ! matroskamux ! filesink location=output3.mkv sync=false

The error goes away. I can keep recording and play back the file using playbin2.

Can someone explain this to me? Even though it's working now for me, I don't really understand it.

Thanks.

[madstrum]

To add on, there's a strange thing.

I am now using the setup with a dual-core imx6, instead of quad-core as previously.

Now,

gst-launch tvsrc fps-n=30 ! queue ! vpuenc codec=6 bitrate=4000000 ! matroskamux ! filesink location=output3.mkv sync=false

works.

I don't have to do the number of buffers thing for queue anymore. What gives?