[PATCH v1] media: vivid: Add webcam parameter for (un)limited bandwidth
From: Max Staudt
Date: Mon Apr 10 2023 - 02:35:35 EST
This adds an option for higher frame rates from a simulated webcam.
Currently, vivid emulates (amongst other things) a webcam with somewhat
limited bandwidth - higher resolutions deliver fewer frames per second:
$ yavta --enum-formats -c /dev/video0
Device /dev/video0 opened.
Device `vivid' on `platform:vivid-000' (driver 'vivid') supports video, capture, without mplanes.
- Available formats:
Format 0: YUYV (56595559)
Type: Video capture (1)
Name: YUYV 4:2:2
Frame size: 320x180 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40, 1/50, 1/60)
Frame size: 640x360 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40)
Frame size: 640x480 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25)
Frame size: 1280x720 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25)
Frame size: 1920x1080 (1/1, 1/2, 1/4, 1/5)
Frame size: 3840x2160 (1/1, 1/2)
In some test cases, it is useful to allow for higher frame rates, as
configurations such as 720p@30 FPS have become commonplace now.
With `webcam_bandwidth_limit=0` we get more options:
$ yavta --enum-formats -c /dev/video0
Device /dev/video0 opened.
Device `vivid' on `platform:vivid-000' (driver 'vivid') supports video, capture, without mplanes.
- Available formats:
Format 0: YUYV (56595559)
Type: Video capture (1)
Name: YUYV 4:2:2
Frame size: 320x180 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40, 1/50, 1/60)
Frame size: 640x360 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40, 1/50, 1/60)
Frame size: 640x480 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40, 1/50, 1/60)
Frame size: 1280x720 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40, 1/50, 1/60)
Frame size: 1920x1080 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40, 1/50, 1/60)
Frame size: 3840x2160 (1/1, 1/2, 1/4, 1/5, 1/10, 2/25, 1/15, 1/25, 1/30, 1/40, 1/50, 1/60)
Passes v4l2-compliance 1.25.0-5039 from v4l-utils git ccc08732823f
Signed-off-by: Max Staudt <mstaudt@xxxxxxxxxxxx>
---
Documentation/admin-guide/media/vivid.rst | 25 +++++++++++++++++++
drivers/media/test-drivers/vivid/vivid-core.c | 8 ++++++
drivers/media/test-drivers/vivid/vivid-core.h | 1 +
.../media/test-drivers/vivid/vivid-vid-cap.c | 18 ++++++++++---
4 files changed, 48 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/media/vivid.rst b/Documentation/admin-guide/media/vivid.rst
index 58ac25b2c385..e65067550efc 100644
--- a/Documentation/admin-guide/media/vivid.rst
+++ b/Documentation/admin-guide/media/vivid.rst
@@ -110,6 +110,28 @@ all configurable using the following module options:
num_inputs=8 input_types=0xffa9
+- webcam_bandwidth_limit:
+
+ whether a simulated webcam offers fewer frames per second for higher
+ resolutions. This only affects webcam inputs as selected in input_types
+ and is ignored for all other inputs. It affects all webcam inputs of
+ a vivid instance.
+
+ - 0: All predefined frame intervals available for all
+ predefined resolutions
+ - 1: Simulate limited bandwidth by removing two FPS rates
+ for each step up in resolution
+
+ The default is for all webcams to cap their FPS at high resolutions.
+ This maintains the behaviour known from earlier versions of vivid.
+
+ To enable all frame rates across all resolutions on webcam inputs, load
+ vivid with this option set to 0:
+
+ .. code-block:: none
+
+ webcam_bandwidth_limit=0
+
- num_outputs:
the number of outputs, one for each instance. By default 2 outputs
@@ -336,6 +358,9 @@ supports frames per second settings of 10, 15, 25, 30, 50 and 60 fps. Which ones
are available depends on the chosen framesize: the larger the framesize, the
lower the maximum frames per second.
+The FPS limit for higher resolutions can be disabled by passing the
+`webcam_bandwidth_limit=0` parameter.
+
The initially selected colorspace when you switch to the webcam input will be
sRGB.
diff --git a/drivers/media/test-drivers/vivid/vivid-core.c b/drivers/media/test-drivers/vivid/vivid-core.c
index f28440e6c9f8..720ffe470709 100644
--- a/drivers/media/test-drivers/vivid/vivid-core.c
+++ b/drivers/media/test-drivers/vivid/vivid-core.c
@@ -143,6 +143,11 @@ MODULE_PARM_DESC(input_types, " input types, default is 0xe4. Two bits per input
"\t\t bits 0-1 == input 0, bits 31-30 == input 15.\n"
"\t\t Type 0 == webcam, 1 == TV, 2 == S-Video, 3 == HDMI");
+/* Default: limited webcam bandwidth */
+static bool webcam_bandwidth_limit[VIVID_MAX_DEVS] = { [0 ... (VIVID_MAX_DEVS - 1)] = true };
+module_param_array(webcam_bandwidth_limit, bool, NULL, 0444);
+MODULE_PARM_DESC(webcam_bandwidth_limit, " for webcam inputs, cap FPS at higher frame sizes (default: true).");
+
/* Default: 2 outputs */
static unsigned num_outputs[VIVID_MAX_DEVS] = { [0 ... (VIVID_MAX_DEVS - 1)] = 2 };
module_param_array(num_outputs, uint, NULL, 0444);
@@ -940,6 +945,9 @@ static int vivid_detect_feature_set(struct vivid_dev *dev, int inst,
v4l2_info(&dev->v4l2_dev, "using %splanar format API\n",
dev->multiplanar ? "multi" : "single ");
+ /* Are "webcam" type inputs of this instance rate limited? */
+ dev->webcam_bandwidth_limit = webcam_bandwidth_limit[inst];
+
/* how many inputs do we have and of what type? */
dev->num_inputs = num_inputs[inst];
if (node_type & 0x20007) {
diff --git a/drivers/media/test-drivers/vivid/vivid-core.h b/drivers/media/test-drivers/vivid/vivid-core.h
index 473f3598db5a..aa38988384e4 100644
--- a/drivers/media/test-drivers/vivid/vivid-core.h
+++ b/drivers/media/test-drivers/vivid/vivid-core.h
@@ -186,6 +186,7 @@ struct vivid_dev {
unsigned int num_hdmi_outputs;
u8 output_type[MAX_OUTPUTS];
u8 output_name_counter[MAX_OUTPUTS];
+ bool webcam_bandwidth_limit;
bool has_audio_inputs;
bool has_audio_outputs;
bool has_vid_cap;
diff --git a/drivers/media/test-drivers/vivid/vivid-vid-cap.c b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
index c0999581c599..347c51f36386 100644
--- a/drivers/media/test-drivers/vivid/vivid-vid-cap.c
+++ b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
@@ -79,6 +79,14 @@ static const struct v4l2_fract webcam_intervals[VIVID_WEBCAM_IVALS] = {
{ 1, 60 },
};
+static inline unsigned webcam_ival_count(const struct vivid_dev *dev,
+ unsigned frmsize_idx)
+{
+ return dev->webcam_bandwidth_limit ?
+ 2 * (VIVID_WEBCAM_SIZES - frmsize_idx) :
+ 2 * (VIVID_WEBCAM_SIZES);
+}
+
static int vid_cap_queue_setup(struct vb2_queue *vq,
unsigned *nbuffers, unsigned *nplanes,
unsigned sizes[], struct device *alloc_devs[])
@@ -773,14 +781,16 @@ int vivid_s_fmt_vid_cap(struct file *file, void *priv,
compose->height /= factor;
}
} else if (vivid_is_webcam(dev)) {
+ unsigned ival_sz = webcam_ival_count(dev, dev->webcam_size_idx);
+
/* Guaranteed to be a match */
for (i = 0; i < ARRAY_SIZE(webcam_sizes); i++)
if (webcam_sizes[i].width == mp->width &&
webcam_sizes[i].height == mp->height)
break;
dev->webcam_size_idx = i;
- if (dev->webcam_ival_idx >= 2 * (VIVID_WEBCAM_SIZES - i))
- dev->webcam_ival_idx = 2 * (VIVID_WEBCAM_SIZES - i) - 1;
+ if (dev->webcam_ival_idx >= ival_sz)
+ dev->webcam_ival_idx = ival_sz - 1;
vivid_update_format_cap(dev, false);
} else {
struct v4l2_rect r = { 0, 0, mp->width, mp->height };
@@ -1908,7 +1918,7 @@ int vidioc_enum_frameintervals(struct file *file, void *priv,
break;
if (i == ARRAY_SIZE(webcam_sizes))
return -EINVAL;
- if (fival->index >= 2 * (VIVID_WEBCAM_SIZES - i))
+ if (fival->index >= webcam_ival_count(dev, i))
return -EINVAL;
fival->type = V4L2_FRMIVAL_TYPE_DISCRETE;
fival->discrete = webcam_intervals[fival->index];
@@ -1935,7 +1945,7 @@ int vivid_vid_cap_s_parm(struct file *file, void *priv,
struct v4l2_streamparm *parm)
{
struct vivid_dev *dev = video_drvdata(file);
- unsigned ival_sz = 2 * (VIVID_WEBCAM_SIZES - dev->webcam_size_idx);
+ unsigned ival_sz = webcam_ival_count(dev, dev->webcam_size_idx);
struct v4l2_fract tpf;
unsigned i;
--
2.40.0.577.gac1e443424-goog