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use libv4l2 (https://github.com/philips/libv4l) for local USB cameras . #3733

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use libv4l2 (https://github.com/philips/libv4l) for local USB cameras . #3733

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64a2729
use libv4l2 (https://github.com/philips/libv4l) for local USB cameras .
Jul 2, 2023
a97dbc0
Merge branch 'ZoneMinder:master' into libv4l2
sletteland Jul 24, 2023
2825e90
Update src/zm_local_camera.cpp
connortechnology Mar 10, 2026
5ec3012
Update CMakeLists.txt
connortechnology Mar 10, 2026
f17a8cf
Update src/zm_local_camera.cpp
connortechnology Mar 10, 2026
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24 changes: 15 additions & 9 deletions src/zm_local_camera.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,10 @@
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#if ZM_HAS_V4L2
#include <libv4l2.h>
#endif // ZM_HAS_V4L2


#if ZM_HAS_V4L2

Expand All @@ -38,13 +42,15 @@
static unsigned int BigEndian;
static bool primed;

#if ZM_HAS_V4L2
static int vidioctl(int fd, int request, void *arg) {
int result = -1;
do {
result = ioctl(fd, request, arg);
result = v4l2_ioctl( fd, request, arg );
} while( result == -1 && errno == EINTR );
return result;
}
#endif // ZM_HAS_V4L2
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Copilot AI Mar 10, 2026

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#if ZM_HAS_V4L2 is currently based on finding linux/videodev2.h, but this patch unconditionally includes/uses libv4l2 (<libv4l2.h>, v4l2_open/ioctl/mmap/...) under the same macro. Systems with V4L2 headers but without libv4l2 installed will now fail to compile/link. Consider adding a separate CMake check for the V4L2::libv4l2 component and guarding the libv4l2 include/calls behind a dedicated macro, with a fallback to open/ioctl/mmap/close when libv4l2 is unavailable.

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@connortechnology connortechnology Mar 10, 2026

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@copilot open a new pull request to apply changes based on this feedback


static _AVPIXELFORMAT getFfPixFormatFromV4lPalette(int v4l_version, int palette) {
_AVPIXELFORMAT pixFormat = AV_PIX_FMT_NONE;
Expand Down Expand Up @@ -481,7 +487,7 @@ int LocalCamera::Close() {

void LocalCamera::Initialise() {
Debug(3, "Opening video device %s", device.c_str());
if ((vid_fd = open(device.c_str(), O_RDWR, 0)) < 0)
if ( (vid_fd = v4l2_open( device.c_str(), O_RDWR, 0 )) < 0 )
Fatal("Failed to open video device %s: %s", device.c_str(), strerror(errno));

struct stat st;
Expand Down Expand Up @@ -672,7 +678,7 @@ void LocalCamera::Initialise() {
Fatal("Unable to query video buffer: %s", strerror(errno));

v4l2_data.buffers[i].length = vid_buf.length;
v4l2_data.buffers[i].start = mmap(nullptr, vid_buf.length, PROT_READ|PROT_WRITE, MAP_SHARED, vid_fd, vid_buf.m.offset);
v4l2_data.buffers[i].start = v4l2_mmap(nullptr, vid_buf.length, PROT_READ|PROT_WRITE, MAP_SHARED, vid_fd, vid_buf.m.offset);

if (v4l2_data.buffers[i].start == MAP_FAILED)
Fatal("Can't map video buffer %u (%u bytes) to memory: %s(%d)",
Expand Down Expand Up @@ -737,12 +743,12 @@ void LocalCamera::Terminate() {
for ( unsigned int i = 0; i < v4l2_data.reqbufs.count; i++ ) {
capturePictures[i] = nullptr;

if ( munmap(v4l2_data.buffers[i].start, v4l2_data.buffers[i].length) < 0 )
if ( v4l2_munmap(v4l2_data.buffers[i].start, v4l2_data.buffers[i].length) < 0 )
Error("Failed to munmap buffer %d: %s", i, strerror(errno));
}
}

close(vid_fd);
v4l2_close(vid_fd);
primed = false;
} // end LocalCamera::Terminate

Expand All @@ -757,7 +763,7 @@ uint32_t LocalCamera::AutoSelectFormat(int p_colours) {
int enum_fd;

/* Open the device */
if ( (enum_fd = open(device.c_str(), O_RDWR, 0)) < 0 ) {
if ( (enum_fd = v4l2_open(device.c_str(), O_RDWR, 0)) < 0 ) {
Error("Automatic format selection failed to open video device %s: %s",
device.c_str(), strerror(errno));
return selected_palette;
Expand Down Expand Up @@ -841,7 +847,7 @@ uint32_t LocalCamera::AutoSelectFormat(int p_colours) {
}

/* Close the device */
close(enum_fd);
v4l2_close(enum_fd);

return selected_palette;
} //uint32_t LocalCamera::AutoSelectFormat(int p_colours)
Expand All @@ -866,7 +872,7 @@ bool LocalCamera::GetCurrentSettings(
queryDevice = stringtf("/dev/video%d", devIndex);
}

if ((vid_fd = open(queryDevice.c_str(), O_RDWR)) <= 0) {
if ((vid_fd = v4l2_open(queryDevice.c_str(), O_RDWR)) < 0) {
if (!device.empty()) {
Error("Failed to open video device %s: %s", queryDevice.c_str(), strerror(errno));
if (verbose) {
Expand Down Expand Up @@ -1149,7 +1155,7 @@ bool LocalCamera::GetCurrentSettings(
*(output_ptr-1) = '\n';
}

close(vid_fd);
v4l2_close(vid_fd);
if (!device.empty()) {
break;
}
Expand Down