Hello Laurent
> > Just to give you an update on something that I realized:
> > > What bothers me in the trace is
> > >
[snip] (and saved to a file called payload_header_info)
...
[unsnip]
> If the camera doesn't set the EOF bit and doesn't toggle the FID bit
> there's very little I can do. Without any frame boundary information
> the driver can't synchronize itself to the video stream. I'm really
> puzzled by how this camera can work at all. Your last e-mail showed
> that it toggled the FID bit once from 0 to 1 and left it at 1 forever
> after. Is my understanding correct ?
100% correct. But don't despair of the republic just yet. Right now
the best you can do is just give me your insights and suggestions. I'm
going to continue working on this thing. I currently believe that it
is a UVC-compliant device (complete with working FID and EOF bits) but
that it is not being set up correctly and is streaming in a mode that
is for diagnostics or some undocumented mode. I spent a couple of days
documenting the lsusb listing and everything points to it being
UVC-compliant. Now what I would really like to know is if I'm right
about the following:
If there is a stream of mjpeg payloads coming in, whether or not
we can sync them, we still should be able to detect things like
M_SOF0, M_SOI, M_EOI ...
in the stream, yet when I scan the packets I get messages like
lapsystemx kernel: uvcvideo: doing scan
lapsystemx last message repeated 4360 times
"scan" just searches any packet greater than the header size
(typically 12) and if it finds 0xff it prints out the preceding
and following byte. (in case there is some endianess lurking about)
I can't believe that 4360 payloads come in whithout any jpeg
information at all. If this is the case what are these packets?
Are there other quick tests that I could try in case the device
is saying that it is putting out mjpeg packets but is really putting
out another format? The other thing I am wondering is what is the
format of the *.raw files that luvcview creates. Are they more or
less jpeg files (assuming this particular case of a webcam doing
mjepg streaming ) If I toggle the video->last_fid every time a packet
comes in it gives me a convenient way of sending this data to
user-land and luvcview then can write the *.raw files which I can
the examine so currently information on these files is helpful.
Regards Bruce
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