cyberic schrieb:
Hello

I am following this group since a while ago, because I have bought a
webcam that works perfectly on a USB2 port, but I needed USB1 support
as well.

After seeing improvements related to USB1/huffman/jpeg compression, I
tested the development tree from yesterday on a PCengine's WRAP. It is
a geode-based PC with an USB1 port.

I am glad to report that it works! thanks to everyone developing or
testing this driver!

Now some info:

My webcam is a 6270 which has an switch to capture infrared.

My lsusb gives:
Bus 001 Device 003: ID 0c45:6270 Microdia PC Camera (SN9C201 + MI0360/
MT9V011 or MI0360SOC/MT9V111) U-CAM PC Camera NE878, Whitcom
WHC017, ...
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

I tested it on voyage linux 0.6 beta.

The maximum resolution I could capture (with mplayer) was 320x200 or
(nonstandard) 320x230, at framerates from 1 to 25.

If I go above, I got some:
libv4lconvert: Error decompressing JPEG: fill_nbits error: need 4 more
bits

My cmd line was:

when plugging in the cam, I got:
[ 1175.006133] microdia: Microdia USB 2.0 webcam driver loaded
[ 1175.007179] microdia: Microdia USB 2.0 Webcam - 0C45:6270 plugged-
in.
[ 1175.015003] microdia: Detected SN9C20X Bridge
[ 1175.228256] microdia: I2C slave 0x5d returned error during write to
address 0xff
[ 1175.284240] microdia: Detected MT9V111 Sensor
[ 1176.003677] microdia: Microdia USB 2.0 Webcam is now controlling
video device /dev/video0
[ 1176.028549] usbcore: registered new interface driver
usb_microdia_driver
[ 1176.033665] microdia: v2008.11 : Microdia USB 2.0 Webcam Driver

LD_PRELOAD=/usr/local/lib/libv4l/v4l2convert.so mencoder  tv:// -tv
driver=v4l2:width=320:height=230:fps=10:device=/dev/video0 -nosound -
o /tmp/t.avi -ovc lavc

After quitting mplayer, I gots tons of these in dmesg:
[  430.264304] microdia: Iso frame 1 of USB has error -18
[  430.264304] microdia: Iso frame 2 of USB has error -18
[  430.264304] microdia: Iso frame 3 of USB has error -18
[  430.264304] microdia: Iso frame 4 of USB has error -18
...
...

so I commented in in the source.



So to summarize:
++ OK with USB1 up to 320,240, 25fps
- : I2c error when plugging in, not sure if it is important
- : the built in microphone does not seem to be recognized
- cannot go above 320x230 ;-)

And now I have questions:
- Is the resolution limitation due to USB total bandwidth, or only to
the size of a picture? In fact I'd like to get bigger resolution if
possible, even at 1fps (I do not need to use it as a real webcam but
rather as a 'screenshotter')
- What is the 'bulk' parameter in the module?
- How do I choose between huffman and jpeg compresson, and why?

I am at your disposal if you want more tests, and thank you for this
driver!

Eric


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That's great news.

You're right to ignore all the error's that showed up (including the I2C error). They can't be solved anyway it seems.

The bulk parameter was also introduced for low bandwidth situations like USB1 - you can use it like this:
# insmod microdia.ko bulk=1
Bulk is a different transfer method from the standard isochronous pipe. Just try if it helps you in anyway. If not - don't use it ;) .

The microphone is handled by another driver. We try to leave their stuff alone but maybe the two couldn't share the bandwidth properly.

The huffman algorithm is part of the JPEG compression. No choosing.

I'd really like to help you with the framerate but I'm not so sure about it either.

How do you measure the framerate?
Does the infrareed stuff work, too?

GWater

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