Low frame rate problems have been seen with at least 5 UVC cameras on
multiple computers. It isn't low light, USB bandwidth, etc. In the
past, I have assumed the cameras were being dishonest about their
performance, now I am pretty sure it is the UVC driver's fault. On a
newer, faster, computer performance has even gone down on some cameras.
I just got a new Logitech C910 UVC webcam. This camera has a 5MP
(2592x1944) sensor and can do 1920x1080/30P, 720x1280/30P, and
640x480/60P. It works right out of the box with guvcview except for:
- The crippling frame rate problems described here
- uvcvideo doesn't support still picture capture (this is a real 5MP
bayer resolution webcam).
- Exposure mode can be set to Manual or Aperature Priority. Auto or
Shutter priority produce an error.
- Video in MJPG mode is badly corrupted when recording (any program) or
when
displayed in some programs.
Other than that, auto/manual exposure, digital zoom, digital pan/tilt
(zoom first), auto/manual focus, etc. seem to work. Sound not tested.
It does support still image.
However, streaming to disk or using a number of other applications fails
badly:
Tests were done on this camera, except where otherwise noted.
As we will see below, mplayer is the only one that admits to dropping 3/4
of the video frames at 60fps but the other programs (or the driver) are
doing it.
Because of the large number of video modes, less interesting modes have
been deleted and only 480P, 720P, 1080P, and full sensor resolution shown
in YUYV and MJPG:
Init. UVC Camera (046d:0821) (location: usb-0000:00:13.2-3)
{ pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' }
{ discrete: width = 640, height = 480 }
Time interval between frame: 1/30, 1/24, 1/20, 1/15, 1/10, 2/15,
1/5,
{ discrete: width = 1280, height = 720 }
Time interval between frame: 1/10, 2/15, 1/5,
{ discrete: width = 1920, height = 1080 }
Time interval between frame: 1/2,
{ discrete: width = 2592, height = 1944 }
Time interval between frame: 1/2,
{ pixelformat = 'MJPG', description = 'MJPEG' }
{ discrete: width = 640, height = 480 }
Time interval between frame: 1/60, 1/30, 1/24, 1/20, 1/15, 1/10,
2/15, 1/5,
{ discrete: width = 1280, height = 720 }
Time interval between frame: 1/30, 1/24, 1/20, 1/15, 1/10, 2/15,
1/5,
{ discrete: width = 1920, height = 1080 }
Time interval between frame: 1/30, 1/24, 1/20, 1/15, 1/10, 2/15,
1/5,
{ discrete: width = 2592, height = 1944 }
Time interval between frame: 1/10, 2/15, 1/5,
{ pixelformat = 'RGB3', description = 'RGB3' }
...
{ pixelformat = 'BGR3', description = 'BGR3' }
...
vid:046d
pid:0821
driver:uvcvideo
Adding control for Pan (relative)
UVCIOC_CTRL_ADD - Error: File exists
checking format: 1196444237
VIDIOC_G_COMP:: Invalid argument
compression control not supported
fps is set to 1/30
drawing controls
fps is set to 1/30
guvcview gets max 12-14fps in any video mode down to 160x120.
Yes, I am using MJPG not YUYV. No the camera exposure should not be
knocking down the frame rate as this occurs even when pointed at a light.
No the CPU isn't overloaded; Phenom II 1060T X6 and none of the cores are
heavily loaded. No, I am not plugged into a 12Mbps port. No, the USB
bus isn't loaded (unplugged another webcam). luvcview does a little
better, getting 30fps at 160x120. But if you run guvcview as root, now
all of a sudden it can run 30fps up to 1920x1080. This continues when
you switch back to a normal user. Until it breaks. Which happened
when I tried to read full sensor resolution. After that, I was stuck at
<=15fps in all modes as root and ordinary user. Removing both copies of
.guvcviewrc didn't help. Unpluging the camera doesn't fix it.
Unplugging the camera and rmmoding uvcvideo (which takes videodev with it)
and replugging the camera didn't fix it. Plugging into USB 3.0
superspeed port didn't help (not that the camera supports superspeed, just
trying to change the USB controller). "shutdown -h now" didn't fix it.
Sound is disabled.
At one point during the brief time that it was working as root, I got
58fps 640x480 and it did not slow down even when I lowered frame rate to
30fps. Don't know if it actually had anything to do with being root.
It did work just long enough to indicate that the camera can deliver on
its promised specifications.
It does appear guvcview frame rate display is somewhat unreliable. I get
different results if I turn it off and on, and they vary depending on how
long it was off, like the title bar only gets updated once. But on
different cameras that do slow the frame rate in low light, the title bar
fps is updated when I cover the lens. The changing numbers when turning
off/on the title bar fps readout may reflect resetting the boxcar
averaging. The low numbers do seem to reflect reality. When I record
files using various programs, I only get 25fps according to ffprobe.
Bad video looks like typically less than half of frame (varies how much
frame to frame) with some errors of 1/4 to 1/2 width of frame in the
section that is displayed. Like there is a race condition between
grabbing the video and playback or one of the errors encountered is bad
enough to kill the rest of the frame. I have played back with "mplayer
-vo x11" to disable any hardware accelleration on my video card and the
results are the same.
- Cheese - works but very limited
- guvcview record video - you get less than half a video frame and other
errors.
- ffmpeg -f video4linux2 -s 640x480 -r 60 -vcodec mjpeg -i /dev/video0 -r
60 -vcodec copy /tmp/test1.mjpeg
You get the same unusable video as guvcview
These errors reported before recording starts, then none during
recording.
[mjpeg @ 0x1a0c900]mjpeg_decode_dc: bad vlc: 0:0 (0x1a297c0)
[mjpeg @ 0x1a0c900]error dc
[mjpeg @ 0x1a0c900]error y=2 x=11
[video4linux2 @ 0x1a0b660]Estimating duration from bitrate, this may be
inaccurate
then playing back recorded stream with ffplay gives the
[mjpeg @ 0xf95850]mjpeg_decode_dc: bad vlc: 0:0 (0xfe2240)
[mjpeg @ 0xf95850]error dc
[mjpeg @ 0xf95850]error y=1 x=21
[mjpeg @ 0xf95850]mjpeg_decode_dc: bad vlc: 0:0 (0xfe2240) 0B f=0/0
[mjpeg @ 0xf95850]error dc
[mjpeg @ 0xf95850]error y=2 x=9
[mjpeg @ 0xf95850]mjpeg_decode_dc: bad vlc: 0:0 (0xfe2240)f=0/1
[mjpeg @ 0xf95850]error dc
[mjpeg @ 0xf95850]error y=2 x=9
[mjpeg @ 0xf95850]error count: 64
[mjpeg @ 0xf95850]error y=0 x=30
[mjpeg @ 0xf95850]mjpeg_decode_dc: bad vlc: 0:0 (0xfe2240)
[mjpeg @ 0xf95850]error dc
[mjpeg @ 0xf95850]error y=3 x=21
The bad vlc lines originate from libavcodec/mjpegdec.c
- vlc
vlc v4l2:///dev/video0:width=640:height=480:fps=60:chroma=MJPG
--sout=file/ogg:/tmp/test3.mjp
vlc v4l2:///dev/video0:width=640:height=480:fps=60:chroma=MJPG
you get the same unusable video (<1/2frame) whether you are playing or
recording. No errors reported on record. When simply watching cam,
looks like this:
[0x9ebdb0] signals interface error: signal 17 overriden (0x7f41629c9450)
[0x9ebdb0] signals interface error: /usr/lib/libQtCore.so.4(?)[(nil)]
error dc
error y=0 x=29
error dc
error y=6 x=1
error dc
error y=6 x=1
error dc
error y=1 x=8
vlc does display the image ok if you use YUYV instead of MJPG but then
you are severly limited in resolution/frame rate.
- mplayer
time mplayer tv:// -tv driver=v4l2:width=640:height=240:fps=60
v4l2: 159 frames successfully processed, 475 frames dropped.
real 0m10.939s
I.E. about 58fps from camera but 14.5fps after frames dropped.
time mplayer tv:// -tv driver=v4l2:width=640:height=240:fps=30
v4l2: 149 frames successfully processed, 144 frames dropped.
real 0m10.101s
I.E. about 29fps from camera but about 14.75fps after frames dropped
Setup time may affect results slightly.
Note that if you request more frames than camera supports, it will report
more frames dropped.
- luvcview -s 640x480 -r 60 -f MJPG &
prints "find DRI" repeatedly
reports 14, 16, and 20fps on subsequent runs when camera set to 60.
title bar updated at least twice as it initially reports 0.0 fps.
luvcview -s 640x480 -r 60 -f MJPG -C -o /tmp/test4.avi &
xine, mplayer, and vlc are unable to read the file.
Using read method instead of mmap doesn't seem to make a difference, tried
with various programs.
Same problem on netbook running ubuntu 9.04.
It may be a bug where uvcvideo gives you the next frame received after you
request a frame instead of giving you the next frame stored in the queue.
No uvcvideo syslog messages
Other UVC cameras:
- 230X USB microscope UVC eb1a:1760 (real 1.3MP)
v4l2: 132 frames successfully processed, 199 frames dropped. real
12.252s
i.e. 10.77fps out of 27fps.
{ discrete: width = 640, height = 480 }
Time interval between frame: 1/30,
looking at video monitor or overhead light. guvcview says 17fps but
will drop to 3.5fps in low light when fps reported set to 30.
http://www.freelabs.com/~whitis/reviews/230X_USB_Microscope/
On a previous computer I was able to get 27 out of 30fps at 640x480
and 7fps out of 15fps at 1280x1024 in bright light.
- deal extreme sku #25948 $6.40 camera 18ec:3299 Arkmicro Technologies
Inc. (0.3MP)
http://www.dealextreme.com/p/compact-usb-pc-webcam-300k-pixel-25948
{ pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' }
{ discrete: width = 640, height = 480 }
Time interval between frame: 1/30, 1/15, 1/10, 1/5,
...
guvcview reports 20fps looking at overhead light
v4l2: 245 frames successfully processed, 74 frames dropped. real
0m10.706s
i.e. 22.88fps out of 29.79fps
pressing snapshot button changes color instead, cycling between
different colors
- 0c45:62c0 Microdia Sonix USB 2.0 Camera (0.3MP)
{ pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' }
{ discrete: width = 640, height = 480 }
Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5,
...
guvcview reports 21.5fps looking at light, 9fps lens blocked
v4l2: 311 frames successfully processed, 24 frames dropped. real
0m11.514s
i.e. 27fps out of 29fps
ebay cubeternet USB 2 WEBCAM Camera 5M, Mic, 6 Infrared LED PC/Mac UVC
claimed 1.3MP sensor, it was only 0.3MP.
- Built-in netbook camera 064E:A102 Suyin Corp
Different computer: Acer Aspire One 532h-2588 netbook
{ pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' }
{ discrete: width = 640, height = 480 }
Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5,
(hand typed)
...
guvcview reports 7.00fps looking at overhead light/7.00fps lens
covered
ditto for luvcview.
- Logitech quickcam fusion. Now broken, but I recall similar results a
few years ago. Other cameras were tested now.
Ubuntu 11.04
Linux cervantes 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC
2011 x86_64 x86_64 x86_64 GNU/Linux
AMD Phenom(tm) II X6 1090T Processor
ASUS Crosshair IV Formula
Radeon HD 6950
luvcview 0.2.6
guvcview 1.4.1
Cheese 2.32.0
FFmpeg version 0.6.2-4:0.6.2-1ubuntu1
VLC media player 1.1.9 The Luggage (revision exported)
MPlayer 1.0rc4-4.5.2 (C) 2000-2010 MPlayer Team
This is xine (X11 gui) - a free video player v0.99.6.
ii libavcodec-extra-52 4:0.6.2-1ubuntu2
Libav codec library
rc libavcodec52 4:0.6.2-1ubuntu1
Libav codec library
ii libv4l-0 0.8.3-1
Collection of video4linux support libraries
ii libgstreamer0.10-0 0.10.32-3ubuntu3
Core GStreamer libraries and elements
My video monitors are running at: 60hz (DVI), 60.3hz (VGA over
DisplayPort), 60hz (DVI). ATI proprietary driver 11-5.
lsusb -v -d 046d:0821 is 1770 lines, so I won't include it. The guvcview
exceprts include some of the more pertinent details. Someone else has
posted the lsusb output here for same model camera:
http://pastebin.ca/raw/1967260
Wireshark:
guvcview -s 640x480 -r 30 -f YUYV
used YUYV since it is hard to infer info about number of frames from
compressed video.
guvcview reports 16fps
Over 10 seconds, with guvcview already running:
125Mbit/second (all traffic)
640*480*2*8bits*30 = 147.456 megabits
640*480*2*8bits*16 = 78.6432 megabits
2629 packets of size>=5120bytes, typically 62016
This indicates less than 30 frames actually making it onto the wire in
this mode or data is being lost within frames.
guvcview -s 1920x1080 -r 30 -f MJPG
13.50fps
125MBit/second over 10.941 seconds
2736 big packets, typically 62016 bytes from camera to host Same number
of small (320-639) packets, typically 576 bytes host to camera. 4
smaller packets (40-159 bytes).
Oddly, the highest MaxBit rate on this camera is 995328000 which exceeds
the capacity of USB High Speed. That is for 1920*1080 30fps MJPEG and is
actually the uncompressed bitrate. The bitrate for that resolution
FRAME_UNCOMPRESSED is given as 165888000 which is for 2fps. Most of the
tests were done at 640x480 compressed or uncompressed and adequate
bandwidth should be available.
lsusb -t
/: Bus 08.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
/: Bus 07.Port 1: Dev 1, Class=root_hub, Driver=ohci_hcd/4p, 12M
/: Bus 06.Port 1: Dev 1, Class=root_hub, Driver=ohci_hcd/2p, 12M
/: Bus 05.Port 1: Dev 1, Class=root_hub, Driver=ohci_hcd/5p, 12M
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=ohci_hcd/5p, 12M
|__ Port 3: Dev 3, If 0, Class=HID, Driver=usbhid, 1.5M
|__ Port 3: Dev 3, If 1, Class=HID, Driver=usbhid, 1.5M
|__ Port 4: Dev 4, If 0, Class=HID, Driver=usbhid, 1.5M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=ehci_hcd/4p, 480M
|__ Port 3: Dev 2, If 0, Class=stor., Driver=usb-storage, 480M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci_hcd/5p, 480M
|__ Port 3: Dev 13, If 0, Class=audio, Driver=snd-usb-audio, 480M
|__ Port 3: Dev 13, If 1, Class=audio, Driver=snd-usb-audio, 480M
|__ Port 3: Dev 13, If 2, Class='bInterfaceClass 0x0e not yet
handled', Driver=uvcvideo, 480M
|__ Port 3: Dev 13, If 3, Class='bInterfaceClass 0x0e not yet
handled', Driver=uvcvideo, 480M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci_hcd/5p, 480M
Windows users have reported getting 30fps.
http://forums.quickcamteam.net/showthread.php?tid=1345&page=2
Sometimes I get a little more than 15fps, for no apparent reason. For
example, now guvcview reports 18.00fps at 640x480/30P-MJPG and when I tell
guvcview to capture video, it gives 24.18fps:
Duration: 00:00:05.54, start: 0.000000, bitrate: 16494 kb/s
Stream #0.0: Video: mjpeg, yuvj422p, 640x480, 24.18 tbr, 24.18 tbn,
24.18 tbc
http://ffmpeg-users.933282.n4.nabble.com/What-does-the-output-of-ffmpeg-mean-tbr-tbn-tbc-etc-td941538.html
The video is corrupted.
_______________________________________________
Linux-uvc-devel mailing list
Linux-uvc-devel@lists.berlios.de
https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
