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webcam: 2 captures works

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This commit is contained in:
Thomas Farstrike
2025-05-13 17:32:32 +02:00
parent 53d37e7265
commit 62943cf175
1 changed files with 84 additions and 47 deletions
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c_mpos/src/webcam.c
+84 -47
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@@ -23,13 +23,17 @@
#define CAPTURE_HEIGHT 480
#define OUTPUT_WIDTH 240 // Resize to 240x240
#define OUTPUT_HEIGHT 240
#define NUM_BUFFERS 2 // Use 2 buffers for robust streaming
// Webcam object type
typedef struct _webcam_obj_t {
mp_obj_base_t base;
int fd; // File descriptor for the webcam
void *buffer; // Memory-mapped buffer
size_t buffer_length; // Length of the buffer
struct {
void *start; // Memory-mapped buffer
size_t length; // Buffer length
} buffers[NUM_BUFFERS]; // Array of buffers
size_t num_buffers; // Number of allocated buffers
bool streaming; // Streaming state
} webcam_obj_t;
@@ -72,13 +76,27 @@ static mp_obj_t webcam_capture_grayscale(mp_obj_t self_in) {
struct v4l2_buffer buf = {0};
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = 0;
// Queue the buffer
WEBCAM_DEBUG_PRINT("webcam: Queuing buffer (index=%d)\n", buf.index);
if (ioctl(self->fd, VIDIOC_QBUF, &buf) < 0) {
WEBCAM_DEBUG_PRINT("webcam: Failed to queue buffer for capture (errno=%d)\n", errno);
mp_raise_OSError(errno);
// Find an available buffer
for (size_t i = 0; i < self->num_buffers; i++) {
buf.index = i;
// Query buffer state to ensure it’s not already queued
WEBCAM_DEBUG_PRINT("webcam: Querying buffer state (index=%zu)\n", i);
if (ioctl(self->fd, VIDIOC_QUERYBUF, &buf) < 0) {
WEBCAM_DEBUG_PRINT("webcam: Failed to query buffer state (index=%zu, errno=%d)\n", i, errno);
mp_raise_OSError(errno);
}
// Queue the buffer
WEBCAM_DEBUG_PRINT("webcam: Queuing buffer (index=%zu)\n", i);
if (ioctl(self->fd, VIDIOC_QBUF, &buf) == 0) {
break; // Successfully queued
}
WEBCAM_DEBUG_PRINT("webcam: Failed to queue buffer (index=%zu, errno=%d)\n", i, errno);
if (i == self->num_buffers - 1) {
mp_raise_OSError(errno); // No buffers available
}
}
// Start streaming if not already started
@@ -92,16 +110,16 @@ static mp_obj_t webcam_capture_grayscale(mp_obj_t self_in) {
self->streaming = true;
}
// Dequeue the buffer (capture frame)
memset(&buf, 0, sizeof(buf)); // Clear buffer for dequeue
// Dequeue a buffer (capture frame)
memset(&buf, 0, sizeof(buf));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = 0;
WEBCAM_DEBUG_PRINT("webcam: Dequeuing buffer\n");
if (ioctl(self->fd, VIDIOC_DQBUF, &buf) < 0) {
WEBCAM_DEBUG_PRINT("webcam: Failed to dequeue captured frame (errno=%d)\n", errno);
mp_raise_OSError(errno);
}
size_t buf_index = buf.index;
// Convert YUYV to grayscale (640x480)
size_t capture_size = CAPTURE_WIDTH * CAPTURE_HEIGHT;
@@ -110,7 +128,7 @@ static mp_obj_t webcam_capture_grayscale(mp_obj_t self_in) {
WEBCAM_DEBUG_PRINT("webcam: Failed to allocate memory for grayscale buffer (%zu bytes)\n", capture_size);
mp_raise_OSError(ENOMEM);
}
yuyv_to_grayscale((uint8_t *)self->buffer, grayscale_buf, CAPTURE_WIDTH, CAPTURE_HEIGHT);
yuyv_to_grayscale((uint8_t *)self->buffers[buf_index].start, grayscale_buf, CAPTURE_WIDTH, CAPTURE_HEIGHT);
// Resize to 240x240
size_t output_size = OUTPUT_WIDTH * OUTPUT_HEIGHT;
@@ -129,14 +147,14 @@ static mp_obj_t webcam_capture_grayscale(mp_obj_t self_in) {
// Clean up
free(resized_buf);
// Re-queue the buffer for the next capture
memset(&buf, 0, sizeof(buf)); // Clear buffer for re-queue
// Re-queue the buffer
memset(&buf, 0, sizeof(buf));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = 0;
WEBCAM_DEBUG_PRINT("webcam: Re-queuing buffer (index=%d)\n", buf.index);
buf.index = buf_index;
WEBCAM_DEBUG_PRINT("webcam: Re-queuing buffer (index=%zu)\n", buf_index);
if (ioctl(self->fd, VIDIOC_QBUF, &buf) < 0) {
WEBCAM_DEBUG_PRINT("webcam: Failed to re-queue buffer after capture (errno=%d)\n", errno);
WEBCAM_DEBUG_PRINT("webcam: Failed to re-queue buffer after capture (index=%zu, errno=%d)\n", buf_index, errno);
mp_raise_OSError(errno);
}
@@ -159,13 +177,16 @@ static mp_obj_t webcam_deinit(mp_obj_t self_in) {
self->streaming = false;
}
// Unmap buffer
if (self->buffer != NULL && self->buffer != MAP_FAILED) {
WEBCAM_DEBUG_PRINT("webcam: Unmapping buffer\n");
munmap(self->buffer, self->buffer_length);
self->buffer = NULL;
self->buffer_length = 0;
// Unmap buffers
for (size_t i = 0; i < self->num_buffers; i++) {
if (self->buffers[i].start != NULL && self->buffers[i].start != MAP_FAILED) {
WEBCAM_DEBUG_PRINT("webcam: Unmapping buffer %zu\n", i);
munmap(self->buffers[i].start, self->buffers[i].length);
self->buffers[i].start = NULL;
self->buffers[i].length = 0;
}
}
self->num_buffers = 0;
// Close device
if (self->fd >= 0) {
@@ -183,9 +204,12 @@ static mp_obj_t webcam_init(void) {
webcam_obj_t *self = m_new_obj(webcam_obj_t);
self->base.type = &webcam_type;
self->fd = -1;
self->buffer = NULL;
self->buffer_length = 0;
self->num_buffers = 0;
self->streaming = false;
for (size_t i = 0; i < NUM_BUFFERS; i++) {
self->buffers[i].start = NULL;
self->buffers[i].length = 0;
}
// Open the webcam device
WEBCAM_DEBUG_PRINT("webcam: Opening device %s\n", VIDEO_DEVICE);
@@ -209,37 +233,50 @@ static mp_obj_t webcam_init(void) {
mp_raise_OSError(errno);
}
// Request one buffer
// Request buffers
struct v4l2_requestbuffers req = {0};
req.count = 1;
req.count = NUM_BUFFERS;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
WEBCAM_DEBUG_PRINT("webcam: Requesting one memory-mapped buffer\n");
WEBCAM_DEBUG_PRINT("webcam: Requesting %d memory-mapped buffers\n", NUM_BUFFERS);
if (ioctl(self->fd, VIDIOC_REQBUFS, &req) < 0) {
WEBCAM_DEBUG_PRINT("webcam: Failed to request memory-mapped buffer (errno=%d)\n", errno);
WEBCAM_DEBUG_PRINT("webcam: Failed to request memory-mapped buffers (errno=%d)\n", errno);
close(self->fd);
mp_raise_OSError(errno);
}
self->num_buffers = req.count;
// Query and map the buffer
struct v4l2_buffer buf = {0};
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = 0;
WEBCAM_DEBUG_PRINT("webcam: Querying buffer properties\n");
if (ioctl(self->fd, VIDIOC_QUERYBUF, &buf) < 0) {
WEBCAM_DEBUG_PRINT("webcam: Failed to query buffer properties (errno=%d)\n", errno);
close(self->fd);
mp_raise_OSError(errno);
}
// Query and map buffers
for (size_t i = 0; i < self->num_buffers; i++) {
struct v4l2_buffer buf = {0};
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i;
WEBCAM_DEBUG_PRINT("webcam: Querying buffer %zu properties\n", i);
if (ioctl(self->fd, VIDIOC_QUERYBUF, &buf) < 0) {
WEBCAM_DEBUG_PRINT("webcam: Failed to query buffer %zu properties (errno=%d)\n", i, errno);
for (size_t j = 0; j < i; j++) {
if (self->buffers[j].start != NULL) {
munmap(self->buffers[j].start, self->buffers[j].length);
}
}
close(self->fd);
mp_raise_OSError(errno);
}
self->buffer_length = buf.length;
WEBCAM_DEBUG_PRINT("webcam: Mapping buffer of length %zu\n", self->buffer_length);
self->buffer = mmap(NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, self->fd, buf.m.offset);
if (self->buffer == MAP_FAILED) {
WEBCAM_DEBUG_PRINT("webcam: Failed to map buffer memory (errno=%d)\n", errno);
close(self->fd);
mp_raise_OSError(errno);
self->buffers[i].length = buf.length;
WEBCAM_DEBUG_PRINT("webcam: Mapping buffer %zu of length %zu\n", i, buf.length);
self->buffers[i].start = mmap(NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, self->fd, buf.m.offset);
if (self->buffers[i].start == MAP_FAILED) {
WEBCAM_DEBUG_PRINT("webcam: Failed to map buffer %zu memory (errno=%d)\n", i, errno);
for (size_t j = 0; j < i; j++) {
if (self->buffers[j].start != NULL) {
munmap(self->buffers[j].start, self->buffers[j].length);
}
}
close(self->fd);
mp_raise_OSError(errno);
}
}
// Create a tuple to hold the webcam object and method references