| Message ID | 20220920-resend-hwtimestamp-v1-6-e9c14b258404@chromium.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v1,1/8] media: uvc: Extend documentation of uvc_video_clock_decode() | expand |
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 75c32e232f5d..7c7fb478aef7 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -742,10 +742,10 @@ void uvc_video_clock_update(struct uvc_streaming *stream, spin_lock_irqsave(&clock->lock, flags); - if (clock->count < clock->size) + if (clock->count < 2) goto done; - first = &clock->samples[clock->head]; + first = &clock->samples[(clock->head - clock->count) % clock->size]; last = &clock->samples[(clock->head - 1) % clock->size]; /* First step, PTS to SOF conversion. */
With UVC 1.5 we get as little as one clock sample per frame. Which means that it takes 32 frames to move from the software timestamp to the hardware timestamp method. This results in abrupt changes in the timestamping after 32 frames (~1 second), resulting in noticeable artifacts when used for encoding. With this patch we modify the update algorithm to work with whatever amount of values are available. Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>