diff options
| author | Jean-François Moine <moinejf@free.fr> | 2012-01-04 13:44:02 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-01-06 08:52:54 -0200 |
| commit | 18bef42c2d9a63e028261b88e9202b6d0d34292b (patch) | |
| tree | 554e1518e9d117c47b56c61efd818f50ef48b857 | |
| parent | 965b37a477915b75ec09cd38d077d0eee9e71abf (diff) | |
[media] gspca - main: Change the bandwidth estimation of isochronous transfer
Having:
- a mean image size of 0.375 time the max compressed image size and
- a frame rate of 30 fps for small images or with USB 2.0/3.0
seems more realistic and gives less image freezes.
Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
| -rw-r--r-- | drivers/media/video/gspca/gspca.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c index 5ce3557bde8..cdd43ff4aa0 100644 --- a/drivers/media/video/gspca/gspca.c +++ b/drivers/media/video/gspca/gspca.c @@ -633,13 +633,14 @@ static u32 which_bandwidth(struct gspca_dev *gspca_dev) u32 bandwidth; int i; + /* get the (max) image size */ i = gspca_dev->curr_mode; bandwidth = gspca_dev->cam.cam_mode[i].sizeimage; - /* if the image is compressed, estimate the mean image size */ + /* if the image is compressed, estimate its mean size */ if (bandwidth < gspca_dev->cam.cam_mode[i].width * gspca_dev->cam.cam_mode[i].height) - bandwidth /= 3; + bandwidth = bandwidth * 3 / 8; /* 0.375 */ /* estimate the frame rate */ if (gspca_dev->sd_desc->get_streamparm) { @@ -649,7 +650,14 @@ static u32 which_bandwidth(struct gspca_dev *gspca_dev) gspca_dev->sd_desc->get_streamparm(gspca_dev, &parm); bandwidth *= parm.parm.capture.timeperframe.denominator; } else { - bandwidth *= 15; /* 15 fps */ + + /* don't hope more than 15 fps with USB 1.1 and + * image resolution >= 640x480 */ + if (gspca_dev->width >= 640 + && gspca_dev->dev->speed == USB_SPEED_FULL) + bandwidth *= 15; /* 15 fps */ + else + bandwidth *= 30; /* 30 fps */ } PDEBUG(D_STREAM, "min bandwidth: %d", bandwidth); |