Blackmagic Forum

Hello,
Has anybody managed to capture SD video (PAL) with a deckling duo/quad or any other decklink device on Linux ?
We now manage to capture SDI full HD video without any problem with media express and bmdcapture, but when we try with a SD/PAL video, changing bmdcapture "m" parameter to "2" (or settings in the Black Magic Control Panel + Media Express), we didn't manage to get any signal

Code: Select all

./bmdcapture -C 0 -m 2 -A 2 -V 0 -F nut -f pipe:1 | ffmpeg -y -i - -f v4l2 /dev/video10

strangely, I manage to get the ref image with -V 0 whereas with -V 1 (composite), I got :

Code: Select all

./bmdcapture -C 0 -m 2 -V 1 -F nut -f pipe:1 | ffmpeg -y -i - -f v4l2 /dev/video10
...
Failed to set video input - result 80000001
pipe:: Invalid data found when processing input

thanks for any help
++benjamin

do you use bmdtools ?

u need to specifi right video mode ..

yes we use bmdtools as bmdcapture is part of it :

Code: Select all

./bmdcapture -h
Usage: bmdcapture -m <mode id> [OPTIONS]
 
    -m <mode id>:
-> DeckLink SDI (-C 0 )
 
Supported video output display modes and pixel formats:
         0:   NTSC                     720 x 486       29.97 FPS
         1:   NTSC 23.98               720 x 486      23.976 FPS
         2:   PAL                      720 x 576          25 FPS
         3:   HD 1080p 23.98           1920 x 1080      23.976 FPS
         4:   HD 1080p 24              1920 x 1080          24 FPS
         5:   HD 1080p 25              1920 x 1080          25 FPS
         6:   HD 1080p 29.97           1920 x 1080       29.97 FPS
         7:   HD 1080p 30              1920 x 1080          30 FPS
         8:   HD 1080i 50              1920 x 1080          25 FPS
         9:   HD 1080i 59.94           1920 x 1080       29.97 FPS
        10:   HD 1080i 60              1920 x 1080          30 FPS
        11:   HD 720p 50               1280 x 720          50 FPS
        12:   HD 720p 59.94            1280 x 720     59.9401 FPS
        13:   HD 720p 60               1280 x 720          60 FPS
 
    -v                   Be verbose (report each 25 frames)
    -f <filename>        Filename raw video will be written to
    -F <format>          Define the file format to be used
    -c <channels>        Audio Channels (2, 8 or 16 - default is 2)
    -s <depth>           Audio Sample Depth (16 or 32 - default is 16)
    -p <pixel>           PixelFormat Depth (8 or 10 - default is 8)
    -n <frames>          Number of frames to capture (default is unlimited)
    -M <memlimit>        Maximum queue size in GB (default is 1 GB)
    -C <num>             number of card to be used
    -S <serial_device>   data input serial
    -A <audio-in>        Audio input:
                         1: Analog (RCA or XLR)
                         2: Embedded Audio (HDMI/SDI)
                         3: Digital Audio (AES/EBU)
    -V <video-in>        Video input:
                         1: Composite
                         2: Component
                         3: HDMI
                         4: SDI
                         5: Optical SDI
                         6: S-Video

So I supposed that this command :

Code: Select all

./bmdcapture -C 0 -m 2 -A 2 -V 1 -F nut -f pipe:1 | ffmpeg -y -i - -f v4l2 /dev/video10

should capture on the first input (-C 0) PAL video (-m 2) with Analog audio (-A 2) from a Composite source (-V 1)
The source is a DV Camera which output PAL video with a RCA cable (source tested on a Tv set)
This command worked with other parameters (-m 8 - A 2 -V 4) with a SDI source
did I missed anything ?

++Benjamin

analog audio is -A 1 .. no -A 2 (whitch is embeded SDI/HDMI) ..

Pytkin wrote:analog audio is -A 1 .. no -A 2 (whitch is embeded SDI/HDMI) ..

ah, yes, sorry mistake while writing the post, but the result is the same :

Code: Select all

 ./bmdcapture -C 0 -m 2 -A 1 -V 1 -F nut -f pipe:1
Failed to set audio input - result = 80000001
./bmdcapture -C 0 -m 2 -V 1 -F nut -f pipe:1
Failed to set video input - result 80000001


I tried also with gstreamer / plugin-bad with the same result, a linux driver limitation ?

thks for your help
++Benjamin

uhh .. topic is Decklink DUO/QUAD .. both have only digital SDI signal I/O ... no analog audio/video .. so what declink card do U use ?

We use a decklink Quad which : "Includes four SDI inputs and four 4 SDI outputs that can be independently switched between SD and HD video formats" and the Connection Reference Guide says "HD/SD-SDI In" so I thought it was possible to switch beetween HD-SDI and SD-Composite, am I wrong ?
thks
benjamin

Labomedia wrote:We use a decklink Quad which : "Includes four SDI inputs and four 4 SDI outputs that can be independently switched between SD and HD video formats" and the Connection Reference Guide says "HD/SD-SDI In" so I thought it was possible to switch beetween HD-SDI and SD-Composite, am I wrong ?
thks
benjamin

SD-SDI can be selected. There is no provision on the Quad card for composite signals.
You may need to use mini-converters.

Labomedia : its SDI only inputs/outputs .. BTW : where U was put Analog AUDIO ? on QUAD cards there is 4x SDI IN , and 4x SDI OUT ..

ah, ok, I understand now that there is no way to acquire directly composite signal but it is possible to get an SD video threw SDI (which works well here with bmdcapture)
we didn't really care about audio as we get audio with an external soundcard and we remux audio and video with the software we are developping (and will publish it under an open source licence)
thanks you very much for the answers, it really helped us to understand how we could use this card under linux
best++
benjamin

yes .. U can normalny capture SD signal via SDI input ..

and be carefull .. if U capture video thru Decklink ,and AUDIO thru another audio card , than U will get desynchron between AUDIO and VIDEO stram , because your cards (decklink and soundcard) are not synchronised .. best way for you is BMD Analog to SDI converter .. I connect Analog composite (or svideo/component) video + analog audio to it , and SDI dignal put into decklink input .. And everything will be in SYNC ..

Thanks for the advice
The audio and video sources are in our case independent, so we'll have anyway to resynchronize them with the software we are developing, hoping that the desynchron remains the same (we capture 2-4 video signals from cameras threw SDI and a stereo audio signal from 2 microphones), I keep in mind the BMD Analog to SDI converter which is a good option to capture an analog composite signal.
++Benjamin

ah soo .. then it will work

Hello,

I am facing similar issue, I brought a brand new BlackMagic Declink Quad 2. SDI cables are plugged and it has video feed with audio embedded in it.

Trying to capture using the bmdcapture tools. I got the video but there is no audio.


Can someone help me on this?

Following is the command I am using:

bmdcapture -C 1 -m 1 -F nut -A 2 -c 2 -s 32 -V 4 -f pipe:1

Different combinations of options and values are already tried and none of them work. Please let me know where could be the issue then?


Thanks a lot.

U capturing 32bit audio .. try 16 bit