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camera: framerate support.

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This commit is contained in:
Ryan C. Gordon
2023-12-17 13:38:36 -05:00
parent 9ae39d52de
commit 0b5875825e
3 changed files with 122 additions and 10 deletions
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51
src/camera/SDL_camera.c
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@@ -224,6 +224,21 @@ static int SDLCALL CameraSpecCmp(const void *vpa, const void *vpb)
return 1;
}
// still here? We care about framerate less than format or size, but faster is better than slow.
if (a->interval_numerator && !b->interval_numerator) {
return -1;
} else if (!a->interval_numerator && b->interval_numerator) {
return 1;
}
const float fpsa = ((float) a->interval_denominator)/ ((float) a->interval_numerator);
const float fpsb = ((float) b->interval_denominator)/ ((float) b->interval_numerator);
if (fpsa > fpsb) {
return -1;
} else if (fpsb > fpsa) {
return 1;
}
return 0; // apparently, they're equal.
}
@@ -276,13 +291,21 @@ SDL_CameraDevice *SDL_AddCameraDevice(const char *name, int num_specs, const SDL
for (int i = 0; i < num_specs; i++) {
SDL_CameraSpec *a = &device->all_specs[i];
SDL_CameraSpec *b = &device->all_specs[i + 1];
if ((a->format == b->format) && (a->width == b->width) && (a->height == b->height)) {
if (SDL_memcmp(a, b, sizeof (*a)) == 0) {
SDL_memmove(a, b, sizeof (*specs) * (num_specs - i));
i--;
num_specs--;
}
}
#if DEBUG_CAMERA
SDL_Log("CAMERA: Adding device ('%s') with %d spec%s:", name, num_specs, (num_specs == 1) ? "" : "s");
for (int i = 0; i < num_specs; i++) {
const SDL_CameraSpec *spec = &device->all_specs[i];
SDL_Log("CAMERA: - fmt=%s, w=%d, h=%d, numerator=%d, denominator=%d", SDL_GetPixelFormatName(spec->format), spec->width, spec->height, spec->interval_numerator, spec->interval_denominator);
}
#endif
device->num_specs = num_specs;
device->handle = handle;
device->instance_id = SDL_GetNextObjectID();
@@ -734,6 +757,28 @@ static void ChooseBestCameraSpec(SDL_CameraDevice *device, const SDL_CameraSpec
SDL_assert(bestfmt != SDL_PIXELFORMAT_UNKNOWN);
closest->format = bestfmt;
// We have a resolution and a format, find the closest framerate...
const float wantfps = spec->interval_numerator ? (spec->interval_denominator / spec->interval_numerator) : 0.0f;
float closestfps = 9999999.0f;
for (int i = 0; i < num_specs; i++) {
const SDL_CameraSpec *thisspec = &device->all_specs[i];
if ((thisspec->format == closest->format) && (thisspec->width == closest->width) && (thisspec->height == closest->height)) {
if ((thisspec->interval_numerator == spec->interval_numerator) && (thisspec->interval_denominator == spec->interval_denominator)) {
closest->interval_numerator = thisspec->interval_numerator;
closest->interval_denominator = thisspec->interval_denominator;
break; // exact match, stop looking.
}
const float thisfps = thisspec->interval_numerator ? (thisspec->interval_denominator / thisspec->interval_numerator) : 0.0f;
const float fpsdiff = SDL_fabs(wantfps - thisfps);
if (fpsdiff < closestfps) { // this is a closest FPS? Take it until something closer arrives.
closestfps = fpsdiff;
closest->interval_numerator = thisspec->interval_numerator;
closest->interval_denominator = thisspec->interval_denominator;
}
}
}
}
SDL_assert(closest->width > 0);
@@ -770,7 +815,9 @@ SDL_Camera *SDL_OpenCameraDevice(SDL_CameraDeviceID instance_id, const SDL_Camer
ChooseBestCameraSpec(device, spec, &closest);
#if DEBUG_CAMERA
SDL_Log("CAMERA: App wanted [(%dx%d) fmt=%s], chose [(%dx%d) fmt=%s]", spec ? spec->width : -1, spec ? spec->height : -1, spec ? SDL_GetPixelFormatName(spec->format) : "(null)", closest.width, closest.height, SDL_GetPixelFormatName(closest.format));
SDL_Log("CAMERA: App wanted [(%dx%d) fmt=%s interval=%d/%d], chose [(%dx%d) fmt=%s interval=%d/%d]",
spec ? spec->width : -1, spec ? spec->height : -1, spec ? SDL_GetPixelFormatName(spec->format) : "(null)", spec ? spec->interval_numerator : -1, spec ? spec->interval_denominator : -1,
closest.width, closest.height, SDL_GetPixelFormatName(closest.format), closest.interval_numerator, closest.interval_denominator);
#endif
if (camera_driver.impl.OpenDevice(device, &closest) < 0) {