[FFmpeg-user] Decklink input buffer overrun

[Flávio Pontes]

Thx for the quick reply.

I can encode two streams fine when I input them from files. I managed to
encode 3 at a time, even.
I tried encoding one from the Decklink card and another from a file and it
worked flawlessly, so I'm assuming it's some parameter inside ffmpeg.
I looked into libavdevices decklink files and in decklink_dec.cpp and found
a queue size limit.
I'll try to increase the limit and see if that fixes the problem.

thx!

Em qua, 23 de set de 2015 às 19:51, Marton Balint <cus at passwd.hu> escreveu:

>
> On Wed, 23 Sep 2015, Ricardo Kleemann wrote:
>
> > On Wed, Sep 23, 2015 at 12:47 PM, Flávio Pontes <flaviocpontes at gmail.com
> >
> > wrote:
> >
> >> Hi,
> >>
> >> I need to stream the 2 inputs from a DeckLink Duo card in FHD.
> >> So far I could compile ffmpeg with decklink support and capture one
> input
> >> at a time without problems.
> >>
> >> When I try to capture from the 2 inputs I start getting the following
> >> message repeatedly on both terminals:
> >> [decklink @ 0x32287e0] Decklink input buffer overrun!
> >>
> >> I use these commands in the terminals:
> >>
> >> /opt/ffmpeg_build/bin/ffmpeg -f decklink -re -i 'DeckLink SDI (1)@7' -g
> 90
> >> -s hd1080 -profile:v baseline -pix_fmt yuv420p -preset veryfast -c:v
> >> libx264 -b:v 2000k -bufsize 1400k -minrate 2000k -maxrate 2000k -c:a
> >> libfdk_aac -b:a 96k -threads 4 -f flv rtmp://10.12.20.62/myapp/tvines
> >>
> >> /opt/ffmpeg_build/bin/ffmpeg -f decklink -re -i 'DeckLink SDI (2)@7' -g
> 90
> >> -s hd1080 -profile:v baseline -pix_fmt yuv420p -preset veryfast -c:v
> >> libx264 -b:v 2000k -bufsize 1400k -minrate 2000k -maxrate 2000k -c:a
> >> libfdk_aac -b:a 96k -threads 4 -f flv rtmp://10.12.20.62/myapp/tvescola
> >>
> >> I tried many combinations but couldn't get it to work.
> >> I wonder if the input buffer is shared between the 2 inputs.
> >> Is there any way to set an input buffer size independently for each
> >> command?
> >>
> >> Thx in advance!
> >> Flávio.
> >> _______________________________________________
> >> ffmpeg-user mailing list
> >> ffmpeg-user at ffmpeg.org
> >> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >>
> >
> > Hi Flávio,
> >
> > I'm not sure if this directly addresses your problem, but have you tried
> > using the -thread_queue_size parameter? I believe having a deeper queue
> > might help, the default value is only 8. I've used much larger values,
> even
> > 2048 for example.
>
> Thread queue size only has an effect if multiple input sources are used.
> If a single input is used then reading from it is not threaded in the
> current ffmpeg.c implementation.
>
> Regards,
> Marton
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