Re: How do you capture (raw) VBI on Linux?

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You're quite welcome, and I'm so glad it works for you too!  I spent a
lot of time, and documented every new lead, back then.  I doubt these
three simple commands appear consolidated until now, so when I saw
your question I felt I had to share my experience.

Good luck in the future!

On Mon, Jul 12, 2021 at 10:39 PM Steven Zakulec <spzakulec@xxxxxxxxx> wrote:
>
> This worked exactly as you described- I had to install the libzvbi
> devel headers, then a simple make of zvbi2raw let me use the program
> with the exact command you provided.
>
> Thank you so much for this!
> I spent a ton of time searching and I just didn't have the right keywords.
>
> On Mon, Jul 12, 2021 at 9:30 PM Lucas <jaffa225man@xxxxxxxxx> wrote:
> >
> > I pieced this together myself, from Internet searches, in 2013:
> >
> > Since (at that time at least) zvbi-ntsc-cc was ignoring null bytes the
> > time codes ended up being "significantly off," according to my
> > findings and those of the author of the program I've been using, I
> > switched completely to using it: https://github.com/codeman38/zvbi2raw
> >
> > To use it to capture the raw VBI information, here's the command I use:
> > zvbi2raw -d /dev/vbi0 > file.vbi
> >
> > Then, I convert it to a .srt file with ccextractor as you expected:
> > ccextractor -in=raw ./file.vbi -o ./file.srt
> >
> > If you want to change the time offset in the .srt file, you can use a
> > program from the libsubtitles-perl package in debian (I didn't find it
> > in debian back then, so I compiled the source in its "subtitles-1.00"
> > directory).  The program is subs, and here's how it can be used to
> > subtract five minutes from every time in the .srt file (with -i, it
> > edits in-place, but keeps a (.bak) backup file of the previous
> > version, but I think repeating the command will lose your initial
> > version):
> > subs -i -b -5:00 file.srt
> >
> > It took me a lot longer to figure out than it probably will with this
> > for you, but I didn't ask the mailing list. ;)
> >
> > I hope that helps,
> >
> >   Lucas
> >
> >
> > On Mon, Jul 12, 2021 at 6:21 PM Steven Zakulec <spzakulec@xxxxxxxxx> wrote:
> > >
> > > HI, I am writing to the Linux-media mailing list in hopes that someone
> > > can share how the /dev/vbi device can be captured from under Linux to
> > > disk so it can be processed back into captions.
> > >
> > > I've tried a long list of items (listed below), and the only success
> > > I've had under Linux is using old Hauppauge PVR (150 & 250) PCI cards,
> > > and extracting the embedded VBI data from those captures.
> > >
> > > I can successfully display closed captions on my Hauppauge HVR-950q
> > > USB device with "zvbi-ntsc-cc -d /dev/vbi0 -c" as long as I start a
> > > capture first in one terminal, then run that command in a second
> > > terminal, so I know that card works.
> > >
> > > With my Hauppauge HVR-950q, I've tried the following items:
> > > cat /dev/vbi (both before, during, and after a capture is started on the card
> > >
> > > Trying to use ffmpeg to capture /dev/vbi - unclear if this is even
> > > supposed to work, and if so, what the proper commands are
> > >
> > > I've tried using zvbi to capture the captions- at best, I can get the
> > > text dumped to a file, but no timestamps, or raw/sliced VBI that I
> > > could convert using ccextractor into a subtitle file.
> > > I had thought one of the commands below should work based on the
> > > descriptions from --help.
> > > zvbi-ntsc-cc -d /dev/vbi0 -r -C vbi.bin
> > > zvbi-ntsc-cc -d /dev/vbi0 -r -R -C vbi.bin
> > >
> > > I've tried some of the test tools in the zvbi source code test folder,
> > > but it's not entirely clear if they work with NTSC closed captions.
> > >
> > > I'm on Kubuntu 20.04 with kernel 5.4.0-77-generic.
> > >
> > > If anyone knows an application/device combination (any Linux OS),
> > > please let me know- this seems totally possible, I just can't figure
> > > out how to make it happen.
> > > Thank you in advance for any insights or guidance you can provide here.
> >
> >
> >
> > --
> > Protect your digital freedom and privacy, eliminate DRM, learn more at
> > http://www.defectivebydesign.org/what_is_drm
> > On a related note, also see https://www.fsf.org/campaigns/surveillance



-- 
Protect your digital freedom and privacy, eliminate DRM, learn more at
http://www.defectivebydesign.org/what_is_drm
On a related note, also see https://www.fsf.org/campaigns/surveillance



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