/* Work around a MythTV oddity: if you're in the UK, you need to be able to set
 * the TV standard to PAL-I in order to get audio to work, but MythTV only lets
 * you pick plain PAL. This is a preloadable library that'll rewrite PAL to
 * PAL-I in the appropriate ioctl.
 *
 * Compile this with:
 *   gcc -shared -o palifier.so palifier.c -ldl
 * And add this to the top of /etc/init.d/mythtv-backend (or equivalent):
 *   export LD_PRELOAD=/wherever/palifier.so
 *
 * Adam Sampson <ats@offog.org> */

#include <stdio.h>
#define __USE_GNU
#include <dlfcn.h>
#include <asm/ioctl.h>
#include <linux/videodev2.h>

int ioctl(int d, unsigned long int request, void *arg) {
	static int (*real)(int d, unsigned long int request, void *arg) = NULL;

	if (real == NULL)
		real = dlsym(RTLD_NEXT, "ioctl");

	if (request == VIDIOC_S_STD) {
		unsigned long long int *std = arg;

		/* This matches any of the PAL standards. */
		if (*std & 0xFFF) {
			*std = V4L2_STD_PAL_I;
			fprintf(stderr, "palifier: rewrote PAL* to PAL_I\n");
		}
	}

	return real(d, request, arg);
}