decklink plugin

[Krzysztof Borowczyk]

[...]

 

Try turning on debug for the decklinksrc:

 

    GST_DEBUG=decklinksrc:6 gst-launch-1.0 ...

 

That will tell you if it is having to drop frames because the pipeline

isn't receiving them fast enough. If that's the case try adding a queue

after decklinksrc (?).

 

I tried with these logs, and decklink doesn’t say anything about dropping frames – quite the opposite, it reports Valid Frame (log.txt):


:00:02.684938080  2552  0x8163120 DEBUG            decklinksrc capture.cpp:114:VideoInputFrameArrived:<decklinksrc0> Frame received [No timecode] - Valid Frame - Size: 4147200 bytes

0:00:02.688372967  2552  0x815dbb0 DEBUG            decklinksrc gstdecklinksrc.cpp:746:gst_decklink_src_task:<decklinksrc0> task

0:00:02.718353360  2552  0x8163120 DEBUG            decklinksrc capture.cpp:114:VideoInputFrameArrived:<decklinksrc0> Frame received [No timecode] - Valid Frame - Size: 4147200 bytes

0:00:02.721746566  2552  0x815dbb0 DEBUG            decklinksrc gstdecklinksrc.cpp:746:gst_decklink_src_task:<decklinksrc0> task



although, I’m not sure if the “No timecode” is expected here? Maybe that’s the reason for drops?

 

You could also try "autovideosink sync=false" and see what happens (you

probably don't want to do that in practice, but trying it might give some

insight as to what's causing your low framerate).

 

Setting the sync to false helps. The playback is not 100% smooth, but it’s much better.

 

Maybe also try with fakesink, to eliminate videoconvert and your video

sink from the equation: gst-launch-1.0 decklinksrc mode=... ! fakesink

 

This also seems to help, there are no messages about dropped buffers.

 

I don’t know if the queue solution would help, because GStreamer does not want to connect it (log2.txt):

 

WARNING: erroneous pipeline: could not link queue0 to videoconvert0

 

Any idea why it would do so?

 

-- 

Best regards,
Krzysztof Borowczyk

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