Re: so sick of vendors who advertise linux compatibility but no real support

On Thu, 28 Dec 2006 20:36:26 -0500, noone wrote:

Thanks for the followups.

I've managed to reverse engineer enough of the driver functions in the
video encoder to make use of it but I stick by my original comment.
Eurotech/Parvus should not be advertising the product for linux use with
the current driver that they make available. It is not documented well
enough nor well tested.

The support chips are Phillips SAA so they have publicly available
datasheets but the actual MPEG4 encoder is the INTUNE6400 and it has no
publicly available API documentation for the firmware. I was only able to
reverse engineer the register values by trial and error to get proper
keyframe insertion and bitrate values. It also does not do a proper I/O
wait while waiting for the next available frame to go into the PCI memory
buffer so I end up with a really annoying CPU hog polling the (frame
available) status. I also get a sporatic (unstable TSC error) when
loading the driver. To fix it I have to remove and reinsert the driver.
This is not acceptable or the final product. I'm also seeing too many
MPEG4 frames that seem to be non-conforming: macroblock errors show up
while decoding in mplayer or ffplay and they show up with the same
macroblock numbers within the frame. This leads me to believe an error
exists in the MPEG4 encoder firmware..

I will be evaluating the Sensoray 314 product as a possible replacement.
I've been in contact with their tech folks, who seem to know a bit more
about linux and it sounds like they are willing to look at fixing the
shortcomings I've identified in their driver: no support for the poll() or
select() syscalls, and the addition of mmap() to map the MPEG frame
directly to user-land space. Again, they don't include real documentation
for the linux driver either: just an example RTP server program.

The only other comparable product I've seen is marketed in the UK and I've
got concerns about USA availability, lead times, and support.

Why does it have to be this hard? Oh yeah, it's because linux is all
about "choices" :^P

OK. 4AM...Time to sleep.


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