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

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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



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