advice on Easycap dongles and VBI interface..

[Andrea Venturi <a.venturi@avalpa.com>]

i'm working on a project for legacy support of a teletext server with 
composite output interface.

i supposed to "ingest" teletext using the /dev/vbi support on linux so 
i've got an Easycap dongle

Bus 001 Device 008: ID 05e1:0408 Syntek Semiconductor Co., Ltd STK1160 
Video Capture Device

AFAIK (i didn't open) it's using a video decoder SC7113 supposed to be a 
clone of SAA7113.

this device is supposed to work on an Ubuntu 12.04 with old kernel 3.2 
so i had to blacklist the stock "RE" kernel module easycap and install 
the "retrofit" from here:

   https://github.com/ezequielgarcia/stk1160-standalone

i see the saa7115 is loaded and i can also see audio and video through 
mplayer..

  $ lsmod
  Module                  Size  Used by
  saa7115                18447  1
  stk1160                27732  0
  videobuf2_core         28148  1 stk1160
  snd_ac97_codec        110213  1 stk1160
  ....

  but in the dev fs there's no sign of /dev/vbi interface..

so my questions are:

- are these SAA7113 clones really copycat with all the features supported?

- has the SAA711x driver ever been used for /dev/vbi feature? i used to 
work with Bt878 cards for that feature.

- is the stock 3.x mainline kernel of the stk1160 really 
improved/different/VBI enabled?

- is there a way to extract VBI lines on /dev/video0?

- is there an easy way to enable or at least test (directly on the USB 
interface) the VBI interface?

- finally which approach do you suggest for supporting this ancient 
feature, if feasibiliy tests are ok:
   - a libusb quick hack?
   - an implementation of the bindings between user level /dev/vbi and 
underlying SAA711x routines?

bests

andrea venturi