Problems w/ OR and PVR-500

[Kit Peters]

I've now managed to compile the important (to me) parts of OR:  sdl_gui, playoutd, v4l2_ingest.  Now, when I try and ingest:

./v4l2_ingest /dev/video33 /root/openreplay.buffer

I get: "memory-mapped streaming I/O not available. Bailing..."

Thoughts?


--
Kit Peters, W0KEH
GPG public key fingerpint: 1A12 04B6 0C80 306A B292  14FD 2C7A 1037 F666 46A7

[Andrew Armenia]

The message is indicating that your capture card (or its driver) does not support memory-mapped streaming I/O... this is used for maximum efficiency in data transfer. There are a number of low-cost 4-input cards designed for CCTV video capture... in my experience these work well. I had purchased one from DealExtreme (of all places) that contained four independent capture chips; these are often advertised as "120fps". I believe mine was supported by the "saa7134" video4linux driver. That specific card is unfortunately no longer available from DealExtreme.

This card appears to be the same one I bought from DealExtreme: http://www.ebay.com/itm/H-264-Real-time-4CH-100-120FPS-PCI-DVR-Capture-Card-/230419087392?pt=PCC_Video_TV_Cards&hash=item35a60c4020 - but I have no connection with this seller so I can't make any promises. However these cards tend to be so inexpensive (under $50) that there is little risk in picking one up to see what happens. I found this by searching eBay for "120fps capture card", there seem to be plenty of low-cost buying options.

If you must use the card you already have, you'll want to modify the v4l2_ingest program so that it uses the read()/write() I/O method instead of memory-mapped I/O. Depending on your hardware, this may or may not be able to keep up with the realtime video. If you're a programmer or know of someone who would be willing to rewrite the code, they'll want to check out chapter 3 of the Video4Linux2 specification: http://v4l2spec.bytesex.org/spec/. You mentioned you were at a university... I know RPI had a program where comp sci students would get credit for producing improvements to open source software, maybe that could be an angle to pursue?

Our system at RPI TV consisted of one of the DealExtreme cards for input, and a Blackmagic DeckLink Studio for output, running 64-bit Arch Linux; this is the system most of this code was developed on. Now that we've upgraded to an HD-SDI environment, we use a system with 2 DeckLink Quad SDI cards, and the DealExtreme card for SD inputs. 

Hope this helps...

-Andrew