Header files and libraries

The video capture framework uses common and board-specific header files and libraries.

Header files

To use video capture your application needs to include the following header files:

the common header file vcapture/capture.h
the vcapture/capture-*-ext.h header file(s) for:
- the SOC (system-on-a-chip) on your board (e.g., vcapture/capture-j5-ext.h for a Jacinto 5 board)
- the decoder on your board (e.g., vcapture/capture-adv-ext.h for an ADV* decoder

Libraries

Video capture is shipped with an empty implementation of the video capture library libcapture.so. To link with this library use the -lcapture command.

Figure 1. Overview of video capture libraries

At startup, you need to create an appropriate symbolic link (often a proc link) that points to the actual implementation of this library for your board. For example:

ln –sP /usr/lib/libcapture-board-j5-evm.so /usr/lib/libcapture.so

The board DLL will pull in the board-specific decoder(s), the SOC, and all required shared libraries.

Video capture uses board-specific versions of the following libraries:

libcapture-board-*-*.so: Mandatory library with knowledge of the board's SOC and decoder chip, and the number of capture devices and sources available on the board. This library redirects the video capture functions to libcapture-soc-*.so and libcapture-decoder-*.so.
libcapture-decoder-*.so: Optional library that initializes and applies properties to decoders (e.g. libcapture-decoder-tvp5158.so for the TI TVP5158 decoder). This library implements only the context and property related capture_*_context() and capture_*_property_*() functions. The source code for the functions in this library is in decoder.c.; On some boards, the video capture framework doesn't include a libcapture-decoder-*.so library, leaving control of the decoder to the decoder utility. In this case, a special board DLL (e.g. libcapture-board-*-no-decoder.so), which only pulls in a libcapture-soc-*.so library is used.
libcapture-soc-*.so: Mandatory library for the board's SOC.

Every board-specific library has the definition of the entire API set, as defined in capture.h. See Video Capture API Library Reference for more information.