Hi all, new to the list, hope this is an appropriate place to ask this. Quick question: I can extract NTSC analog closed captions with the Hauppauge 950Q as follows: 1. Run v4l2-ctl -i 1 ## Set input to composite 2. In a test application, open file /dev/video0 3. Read 1 byte from the file ** Note: This seems to be sufficient to "start" the device ** Calling VIDIOC_STREAMON ioctl is *not* sufficient 4. Run: zvbi-ntsc-cc -c -d /dev/vbi0 ## Prints the closed captions 5. Close file handle to /dev/video0 when finished. Device "stops". My question: Is opening the device and reading 1 byte a good/ok way to start the device? I'm only interested in closed captions, and want this to be as small a footprint as possible. I'm worried that this method may break in future driver versions. ----- More details: I'm involved in an automation project where we need to extract CEA-608 Closed Caption data (NTSC/VBI line 21) from an analog (RF and/or composite) input stream. I am evaluating the Hauppauge 950Q for this purpose. The one I've received uses the xc5000c firmware. I've found I can use mplayer/vlc to configure and start the device, and zvbi-ntsc-cc to extract the data. But I need to make this as simple and lightweight as possible (may want this to run with multiple devices connected, or run on something like a Raspberry Pi). So I figured out that reading 1 byte works as I detailed above works, just not sure if this will suddenly break one day. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
