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
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