* [PATCH v3] media: vivid: Improve timestamping
@ 2018-11-11 22:39 Gabriel Francisco Mandaji
2018-11-16 14:12 ` Hans Verkuil
0 siblings, 1 reply; 2+ messages in thread
From: Gabriel Francisco Mandaji @ 2018-11-11 22:39 UTC (permalink / raw)
To: Hans Verkuil, Mauro Carvalho Chehab, linux-media, linux-kernel; +Cc: lkcamp
Simulate a more precise timestamp by calculating it based on the
current framerate.
Signed-off-by: Gabriel Francisco Mandaji <gfmandaji@gmail.com>
---
Changes in v2:
- fix spelling
- end of exposure is offset by 90% of the frame period
- fix timestamp calculation for FIELD_ALTERNATE (untested)
- timestamp is now calculated and set from vivid_thread_cap_tick()
- capture vbi uses the same timestamp as non-vbi, but offset by 5%
- timestamp stays consistent even if the FPS changes
- tested with dropped frames
Changes in v3:
- fix calculating offset for 'End of Frame'
- fix changing 'Timestamp Source' mid-capture
- change order of operation when calculating the VBI's offset
---
drivers/media/platform/vivid/vivid-core.h | 3 ++
drivers/media/platform/vivid/vivid-kthread-cap.c | 47 +++++++++++++++++-------
drivers/media/platform/vivid/vivid-vbi-cap.c | 4 --
3 files changed, 36 insertions(+), 18 deletions(-)
diff --git a/drivers/media/platform/vivid/vivid-core.h b/drivers/media/platform/vivid/vivid-core.h
index 1891254..f7b2a0b 100644
--- a/drivers/media/platform/vivid/vivid-core.h
+++ b/drivers/media/platform/vivid/vivid-core.h
@@ -392,6 +392,9 @@ struct vivid_dev {
/* thread for generating video capture stream */
struct task_struct *kthread_vid_cap;
unsigned long jiffies_vid_cap;
+ u64 cap_stream_start;
+ u64 cap_frame_period;
+ u64 cap_frame_eof_offset;
u32 cap_seq_offset;
u32 cap_seq_count;
bool cap_seq_resync;
diff --git a/drivers/media/platform/vivid/vivid-kthread-cap.c b/drivers/media/platform/vivid/vivid-kthread-cap.c
index eebfff2..f97cb6a 100644
--- a/drivers/media/platform/vivid/vivid-kthread-cap.c
+++ b/drivers/media/platform/vivid/vivid-kthread-cap.c
@@ -425,12 +425,6 @@ static void vivid_fillbuff(struct vivid_dev *dev, struct vivid_buffer *buf)
is_loop = true;
buf->vb.sequence = dev->vid_cap_seq_count;
- /*
- * Take the timestamp now if the timestamp source is set to
- * "Start of Exposure".
- */
- if (dev->tstamp_src_is_soe)
- buf->vb.vb2_buf.timestamp = ktime_get_ns();
if (dev->field_cap == V4L2_FIELD_ALTERNATE) {
/*
* 60 Hz standards start with the bottom field, 50 Hz standards
@@ -554,14 +548,6 @@ static void vivid_fillbuff(struct vivid_dev *dev, struct vivid_buffer *buf)
}
}
}
-
- /*
- * If "End of Frame" is specified at the timestamp source, then take
- * the timestamp now.
- */
- if (!dev->tstamp_src_is_soe)
- buf->vb.vb2_buf.timestamp = ktime_get_ns();
- buf->vb.vb2_buf.timestamp += dev->time_wrap_offset;
}
/*
@@ -667,10 +653,25 @@ static void vivid_overlay(struct vivid_dev *dev, struct vivid_buffer *buf)
}
}
+static void vivid_cap_update_frame_period(struct vivid_dev *dev)
+{
+ u64 f_period = dev->timeperframe_vid_cap.numerator * 1000000000 /
+ dev->timeperframe_vid_cap.denominator;
+ if (dev->field_cap == V4L2_FIELD_ALTERNATE)
+ f_period /= 2;
+ /*
+ * If "End of Frame", then offset the exposure time by 0.9
+ * of the frame period.
+ */
+ dev->cap_frame_eof_offset = f_period * 9 / 10;
+ dev->cap_frame_period = f_period;
+}
+
static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
{
struct vivid_buffer *vid_cap_buf = NULL;
struct vivid_buffer *vbi_cap_buf = NULL;
+ u64 f_time = 0;
dprintk(dev, 1, "Video Capture Thread Tick\n");
@@ -702,6 +703,11 @@ static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
if (!vid_cap_buf && !vbi_cap_buf)
goto update_mv;
+ f_time = dev->cap_frame_period * dev->vid_cap_seq_count +
+ dev->cap_stream_start + dev->time_wrap_offset;
+ if (!dev->tstamp_src_is_soe)
+ f_time += dev->cap_frame_eof_offset;
+
if (vid_cap_buf) {
v4l2_ctrl_request_setup(vid_cap_buf->vb.vb2_buf.req_obj.req,
&dev->ctrl_hdl_vid_cap);
@@ -721,9 +727,13 @@ static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
dprintk(dev, 2, "vid_cap buffer %d done\n",
vid_cap_buf->vb.vb2_buf.index);
+
+ vid_cap_buf->vb.vb2_buf.timestamp = f_time;
}
if (vbi_cap_buf) {
+ u64 vbi_period;
+
v4l2_ctrl_request_setup(vbi_cap_buf->vb.vb2_buf.req_obj.req,
&dev->ctrl_hdl_vbi_cap);
if (dev->stream_sliced_vbi_cap)
@@ -736,6 +746,10 @@ static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
dprintk(dev, 2, "vbi_cap %d done\n",
vbi_cap_buf->vb.vb2_buf.index);
+
+ /* If capturing a VBI, offset by 0.05 */
+ vbi_period = dev->cap_frame_period * 5 / 100;
+ vbi_cap_buf->vb.vb2_buf.timestamp = f_time + vbi_period;
}
dev->dqbuf_error = false;
@@ -767,6 +781,8 @@ static int vivid_thread_vid_cap(void *data)
dev->cap_seq_count = 0;
dev->cap_seq_resync = false;
dev->jiffies_vid_cap = jiffies;
+ dev->cap_stream_start = ktime_get_ns();
+ vivid_cap_update_frame_period(dev);
for (;;) {
try_to_freeze();
@@ -779,6 +795,9 @@ static int vivid_thread_vid_cap(void *data)
dev->jiffies_vid_cap = cur_jiffies;
dev->cap_seq_offset = dev->cap_seq_count + 1;
dev->cap_seq_count = 0;
+ dev->cap_stream_start += dev->cap_frame_period *
+ dev->cap_seq_offset;
+ vivid_cap_update_frame_period(dev);
dev->cap_seq_resync = false;
}
numerator = dev->timeperframe_vid_cap.numerator;
diff --git a/drivers/media/platform/vivid/vivid-vbi-cap.c b/drivers/media/platform/vivid/vivid-vbi-cap.c
index 903cebe..17aa4b0 100644
--- a/drivers/media/platform/vivid/vivid-vbi-cap.c
+++ b/drivers/media/platform/vivid/vivid-vbi-cap.c
@@ -95,8 +95,6 @@ void vivid_raw_vbi_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf)
if (!VIVID_INVALID_SIGNAL(dev->std_signal_mode))
vivid_vbi_gen_raw(&dev->vbi_gen, &vbi, vbuf);
-
- buf->vb.vb2_buf.timestamp = ktime_get_ns() + dev->time_wrap_offset;
}
@@ -119,8 +117,6 @@ void vivid_sliced_vbi_cap_process(struct vivid_dev *dev,
for (i = 0; i < 25; i++)
vbuf[i] = dev->vbi_gen.data[i];
}
-
- buf->vb.vb2_buf.timestamp = ktime_get_ns() + dev->time_wrap_offset;
}
static int vbi_cap_queue_setup(struct vb2_queue *vq,
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v3] media: vivid: Improve timestamping
2018-11-11 22:39 [PATCH v3] media: vivid: Improve timestamping Gabriel Francisco Mandaji
@ 2018-11-16 14:12 ` Hans Verkuil
0 siblings, 0 replies; 2+ messages in thread
From: Hans Verkuil @ 2018-11-16 14:12 UTC (permalink / raw)
To: Gabriel Francisco Mandaji, Mauro Carvalho Chehab, linux-media,
linux-kernel
Cc: lkcamp
On 11/11/2018 11:39 PM, Gabriel Francisco Mandaji wrote:
> Simulate a more precise timestamp by calculating it based on the
> current framerate.
>
> Signed-off-by: Gabriel Francisco Mandaji <gfmandaji@gmail.com>
Something is still wrong: the frame period calculation is fine for
input 0 (webcam), but if I switch to another input (S-Video/TV/HDMI),
then it is totally wrong: for input 3 (HDMI) the fps seems to be off
by a factor of 10000 (i.e. I see a framerate of over 60000 where I
expected to see 60 Hz), and for inputs 2 and 3 I get 7000 fps for
PAL and 110000 for NTSC.
v4l2-ctl -P (== VIDIOC_G_PARM) returns the right thing here.
This calculation is the problem:
u64 f_period = dev->timeperframe_vid_cap.numerator * 1000000000 /
dev->timeperframe_vid_cap.denominator;
You need to cast dev->timeperframe_vid_cap.numerator to a u64
first otherwise the multiplication overflows the u32 if numerator is > 4.
Also note that you cannot divide 64 bit values: not all architectures
support that. Use do_div instead.
With that change it should work.
Regards,
Hans
> ---
> Changes in v2:
> - fix spelling
> - end of exposure is offset by 90% of the frame period
> - fix timestamp calculation for FIELD_ALTERNATE (untested)
> - timestamp is now calculated and set from vivid_thread_cap_tick()
> - capture vbi uses the same timestamp as non-vbi, but offset by 5%
> - timestamp stays consistent even if the FPS changes
> - tested with dropped frames
> Changes in v3:
> - fix calculating offset for 'End of Frame'
> - fix changing 'Timestamp Source' mid-capture
> - change order of operation when calculating the VBI's offset
> ---
> drivers/media/platform/vivid/vivid-core.h | 3 ++
> drivers/media/platform/vivid/vivid-kthread-cap.c | 47 +++++++++++++++++-------
> drivers/media/platform/vivid/vivid-vbi-cap.c | 4 --
> 3 files changed, 36 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/media/platform/vivid/vivid-core.h b/drivers/media/platform/vivid/vivid-core.h
> index 1891254..f7b2a0b 100644
> --- a/drivers/media/platform/vivid/vivid-core.h
> +++ b/drivers/media/platform/vivid/vivid-core.h
> @@ -392,6 +392,9 @@ struct vivid_dev {
> /* thread for generating video capture stream */
> struct task_struct *kthread_vid_cap;
> unsigned long jiffies_vid_cap;
> + u64 cap_stream_start;
> + u64 cap_frame_period;
> + u64 cap_frame_eof_offset;
> u32 cap_seq_offset;
> u32 cap_seq_count;
> bool cap_seq_resync;
> diff --git a/drivers/media/platform/vivid/vivid-kthread-cap.c b/drivers/media/platform/vivid/vivid-kthread-cap.c
> index eebfff2..f97cb6a 100644
> --- a/drivers/media/platform/vivid/vivid-kthread-cap.c
> +++ b/drivers/media/platform/vivid/vivid-kthread-cap.c
> @@ -425,12 +425,6 @@ static void vivid_fillbuff(struct vivid_dev *dev, struct vivid_buffer *buf)
> is_loop = true;
>
> buf->vb.sequence = dev->vid_cap_seq_count;
> - /*
> - * Take the timestamp now if the timestamp source is set to
> - * "Start of Exposure".
> - */
> - if (dev->tstamp_src_is_soe)
> - buf->vb.vb2_buf.timestamp = ktime_get_ns();
> if (dev->field_cap == V4L2_FIELD_ALTERNATE) {
> /*
> * 60 Hz standards start with the bottom field, 50 Hz standards
> @@ -554,14 +548,6 @@ static void vivid_fillbuff(struct vivid_dev *dev, struct vivid_buffer *buf)
> }
> }
> }
> -
> - /*
> - * If "End of Frame" is specified at the timestamp source, then take
> - * the timestamp now.
> - */
> - if (!dev->tstamp_src_is_soe)
> - buf->vb.vb2_buf.timestamp = ktime_get_ns();
> - buf->vb.vb2_buf.timestamp += dev->time_wrap_offset;
> }
>
> /*
> @@ -667,10 +653,25 @@ static void vivid_overlay(struct vivid_dev *dev, struct vivid_buffer *buf)
> }
> }
>
> +static void vivid_cap_update_frame_period(struct vivid_dev *dev)
> +{
> + u64 f_period = dev->timeperframe_vid_cap.numerator * 1000000000 /
> + dev->timeperframe_vid_cap.denominator;
> + if (dev->field_cap == V4L2_FIELD_ALTERNATE)
> + f_period /= 2;
> + /*
> + * If "End of Frame", then offset the exposure time by 0.9
> + * of the frame period.
> + */
> + dev->cap_frame_eof_offset = f_period * 9 / 10;
> + dev->cap_frame_period = f_period;
> +}
> +
> static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
> {
> struct vivid_buffer *vid_cap_buf = NULL;
> struct vivid_buffer *vbi_cap_buf = NULL;
> + u64 f_time = 0;
>
> dprintk(dev, 1, "Video Capture Thread Tick\n");
>
> @@ -702,6 +703,11 @@ static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
> if (!vid_cap_buf && !vbi_cap_buf)
> goto update_mv;
>
> + f_time = dev->cap_frame_period * dev->vid_cap_seq_count +
> + dev->cap_stream_start + dev->time_wrap_offset;
> + if (!dev->tstamp_src_is_soe)
> + f_time += dev->cap_frame_eof_offset;
> +
> if (vid_cap_buf) {
> v4l2_ctrl_request_setup(vid_cap_buf->vb.vb2_buf.req_obj.req,
> &dev->ctrl_hdl_vid_cap);
> @@ -721,9 +727,13 @@ static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
> VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
> dprintk(dev, 2, "vid_cap buffer %d done\n",
> vid_cap_buf->vb.vb2_buf.index);
> +
> + vid_cap_buf->vb.vb2_buf.timestamp = f_time;
> }
>
> if (vbi_cap_buf) {
> + u64 vbi_period;
> +
> v4l2_ctrl_request_setup(vbi_cap_buf->vb.vb2_buf.req_obj.req,
> &dev->ctrl_hdl_vbi_cap);
> if (dev->stream_sliced_vbi_cap)
> @@ -736,6 +746,10 @@ static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
> VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
> dprintk(dev, 2, "vbi_cap %d done\n",
> vbi_cap_buf->vb.vb2_buf.index);
> +
> + /* If capturing a VBI, offset by 0.05 */
> + vbi_period = dev->cap_frame_period * 5 / 100;
> + vbi_cap_buf->vb.vb2_buf.timestamp = f_time + vbi_period;
> }
> dev->dqbuf_error = false;
>
> @@ -767,6 +781,8 @@ static int vivid_thread_vid_cap(void *data)
> dev->cap_seq_count = 0;
> dev->cap_seq_resync = false;
> dev->jiffies_vid_cap = jiffies;
> + dev->cap_stream_start = ktime_get_ns();
> + vivid_cap_update_frame_period(dev);
>
> for (;;) {
> try_to_freeze();
> @@ -779,6 +795,9 @@ static int vivid_thread_vid_cap(void *data)
> dev->jiffies_vid_cap = cur_jiffies;
> dev->cap_seq_offset = dev->cap_seq_count + 1;
> dev->cap_seq_count = 0;
> + dev->cap_stream_start += dev->cap_frame_period *
> + dev->cap_seq_offset;
> + vivid_cap_update_frame_period(dev);
> dev->cap_seq_resync = false;
> }
> numerator = dev->timeperframe_vid_cap.numerator;
> diff --git a/drivers/media/platform/vivid/vivid-vbi-cap.c b/drivers/media/platform/vivid/vivid-vbi-cap.c
> index 903cebe..17aa4b0 100644
> --- a/drivers/media/platform/vivid/vivid-vbi-cap.c
> +++ b/drivers/media/platform/vivid/vivid-vbi-cap.c
> @@ -95,8 +95,6 @@ void vivid_raw_vbi_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf)
>
> if (!VIVID_INVALID_SIGNAL(dev->std_signal_mode))
> vivid_vbi_gen_raw(&dev->vbi_gen, &vbi, vbuf);
> -
> - buf->vb.vb2_buf.timestamp = ktime_get_ns() + dev->time_wrap_offset;
> }
>
>
> @@ -119,8 +117,6 @@ void vivid_sliced_vbi_cap_process(struct vivid_dev *dev,
> for (i = 0; i < 25; i++)
> vbuf[i] = dev->vbi_gen.data[i];
> }
> -
> - buf->vb.vb2_buf.timestamp = ktime_get_ns() + dev->time_wrap_offset;
> }
>
> static int vbi_cap_queue_setup(struct vb2_queue *vq,
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-11-11 22:39 [PATCH v3] media: vivid: Improve timestamping Gabriel Francisco Mandaji
2018-11-16 14:12 ` Hans Verkuil
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