Re: libv4l2 and the Hauppauge HVR1600 (cx18 driver) not working well together

[Simon Farnsworth <simon.farnsworth@onelan.com>]

Simon Farnsworth wrote:
> Hans de Goede wrote:
>> Ok,
>> 
>> That was even easier then I thought it would be. Attached is a
>> patch (against libv4l-0.6.1), which implements 1) and 3) from
>> above.
>> 
> I applied it to a clone of your HG repository, and had to make a
> minor change to get it to compile. I've attached the updated patch.
> 
> It looks like the read() from the card isn't reading entire frames
> ata a time - I'm using a piece of test gear that I have to return in
> a couple of hours to send colourbars to it, and I'm seeing bad
> colour, and the picture moving across the screen. I'll try and chase
> this, see whether there's something obviously wrong.
> 
There is indeed something obviously wrong; at line 315 of libv4l2.c, we
expand the buffer we read into, then ask for that many bytes.

diff -r c51a90c0f62f v4l2-apps/libv4l/libv4l2/libv4l2.c
--- a/v4l2-apps/libv4l/libv4l2/libv4l2.c        Tue Sep 01 10:03:27 2009 +0200
+++ b/v4l2-apps/libv4l/libv4l2/libv4l2.c        Thu Sep 03 11:32:40 2009 +0100
@@ -326,7 +326,7 @@
   }

   do {
-    result = SYS_READ(devices[index].fd, devices[index].readbuf, buf_size);
+    result = SYS_READ(devices[index].fd, devices[index].readbuf, devices[index].dest_fmt.fmt.pix.sizeimage);
     if (result <= 0) {
       if (result && errno != EAGAIN) {
        int saved_err = errno;

fixes it for me.

I appear to lose colour after a few seconds of capture, which I shall chase
further.
-- 
Simon Farnsworth