Hi Mauro,
On 07/14/2011 12:35 AM, Mauro Carvalho Chehab wrote:
> Em 28-06-2011 11:23, Michael Jones escreveu:
>> There is an assumption that the format coming from the device
>> needs 2 bytes per pixel, which is not the case when the device
>> delivers e.g. V4L2_PIX_FMT_GREY. This doesn't manifest itself with
>> IO_METHOD_MMAP because init_mmap() (the default) doesn't take
>> sizeimage as an argument.
>>
>> Signed-off-by: Michael Jones <[email protected]>
>> ---
>>
>> This same issue would apply to other formats which have 1 byte per pixel,
>> this patch only fixes it for GREY. Is this OK for now, or does somebody
>> have a better suggestion for supporting other formats as well?
>
> Well, just rely on the bytesperline provided by the driver should be enough.
> Devices should be returning it on a consistent way.
>
> Regards,
> Mauro
So you would rather remove the "Buggy driver paranoia" altogether and
just trust the bytesperline from the driver? That's fine with me, but I
presumed the paranoia was there for a reason. Would you accept a patch
then that just removes the 7 lines which fiddle with bytesperline?
-Michael
>
>>
>> contrib/test/capture-example.c | 4 +++-
>> 1 files changed, 3 insertions(+), 1 deletions(-)
>>
>> diff --git a/contrib/test/capture-example.c b/contrib/test/capture-example.c
>> index 3852c58..0eb5235 100644
>> --- a/contrib/test/capture-example.c
>> +++ b/contrib/test/capture-example.c
>> @@ -416,6 +416,7 @@ static void init_device(void)
>> struct v4l2_crop crop;
>> struct v4l2_format fmt;
>> unsigned int min;
>> + unsigned int bytes_per_pixel;
>>
>> if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) {
>> if (EINVAL == errno) {
>> @@ -519,7 +520,8 @@ static void init_device(void)
>> }
>>
>> /* Buggy driver paranoia. */
>> - min = fmt.fmt.pix.width * 2;
>> + bytes_per_pixel = fmt.fmt.pix.pixelformat == V4L2_PIX_FMT_GREY ? 1 : 2;
>> + min = fmt.fmt.pix.width * bytes_per_pixel;
>> if (fmt.fmt.pix.bytesperline < min)
>> fmt.fmt.pix.bytesperline = min;
>> min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
>
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