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Blackscreen on CVBS output

Posted: Tue May 28, 2019 8:39 am
by lleri
Hi!

I try to enable CVBS output as specified in Wiki but see only blackscreen. Is it correct? TV detected that a signal is available (without cable attached it show "No signal" warning).
Do some tests:
1. Power on the board and see blackscreen on CVBS after load. TV set detected signal.
2. Enter commands from Wiki:
media-ctl -l '"Main-PIP":1->"analog_hdout0":0[0]'
media-ctl -l '"Main-PIP":1->"analog_sdout0":0[1]'
and nothing is changed.

Use Raspbian image.

Thanks in advance!

Re: Blackscreen on CVBS output

Posted: Tue May 28, 2019 1:10 pm
by attie
Hi lleri,

The CVBS output operates on `/dev/fb1`.
The HDMI output works with `/dev/fb0`, which is where the Raspbian Desktop is rendered.

If you use the following, you should be able to see random colors on the CVBS output:

dd if=/dev/urandom of=/dev/fb1 bs=4M

You should also be able to play media to the CVBS output.

Attie

Re: Blackscreen on CVBS output

Posted: Wed May 29, 2019 9:58 am
by lleri
attie wrote:
Tue May 28, 2019 1:10 pm
If you use the following, you should be able to see random colors on the CVBS output:

dd if=/dev/urandom of=/dev/fb1 bs=4M

You should also be able to play media to the CVBS output.
Thank you, Attie!
When I enter dd if=/dev/urandom of=/dev/fb1 bs=4M I see mosaic on CVBS output. Enter the command several times - mosaic is changed so it seems it's working!

According to your advise: I try to start simple test on /dev/fb1:
gst-launch-1.0 videotestsrc ! videoconvert ! stdisplaysink . After stdisplaysink should be something like device=/dev/fb1 but stdisplaysink doesn't have the property 'device' There are only 'dev-id' (doesn't work) and 'plane-name' ("Main-PIP" doesn't working either). Could you or anyone be so kind to help me with correct command for output video on /dev/fb1?

Re: Blackscreen on CVBS output

Posted: Wed May 29, 2019 3:14 pm
by attie
Hi lleri,

No problem!

You can play media on the CVBS output using the "Aux-GDP2" plane.

You'll need to run the following media-ctl commands first (I'll update the Wiki):

Code: Select all

media-ctl -l '"Main-VID":1->"analog_hdout0":0[0]' # disconnect Main-VID from HDMI
media-ctl -l '"Main-VID":1->"analog_sdout0":0[1]' # connect Main-VID to CVBS
media-ctl -l '"Main-PIP":1->"analog_hdout0":0[0]' # disconnect Main-PIP from HDMI
media-ctl -l '"Main-PIP":1->"analog_sdout0":0[1]' # connect Main-PIP to CVBS
stfbset -f /dev/fb1 -a 0                          # set fb1 to fully transparent

Code: Select all

gst-launch-1.0 videotestsrc ! videoconvert ! stdisplaysink plane-name="Aux-GDP2"
For example:

Code: Select all

gst-launch-1.0 filesrc location=Sintel.2010.720p.mkv ! matroskademux name=x \
    x.video_0 ! stvideo ! stdisplaysink plane-name="Aux-GDP2"

Re: Blackscreen on CVBS output

Posted: Thu May 30, 2019 8:15 am
by lleri
Hi attie,

Thank you very much, everything is working fine!
For playing video I use TS file with program 1030 and video pid 1031 (0x407):

Code: Select all

gst-launch-1.0 filesrc location=1.ts ! tsdemux program_number=1030 name=x \
          x.video_0_0407 ! stvideo ! stdisplaysink plane-name="Aux-GDP2"
It seems there is an error in Wiki in description of 'video' pad in TS Demux section:
SRC template: video_%04d

but, in fact, it correspond to description in gstreamer's TS demux:
video_%01x_%05x
Thank you again! Solved!