IMX Scaler / CSC m2m driver.

[Nicolas Dufresne]

Le mardi 24 mars 2015 à 12:35 +0000, Ian Molton a écrit :
> 0:00:00.284476334  1216   0xd01e30 ERROR          v4l2transform
> gstv4l2transform.c:239:gst_v4l2_transform_set_caps:<v4l2video0convert0> failed to set output caps: video/x-raw, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive, framerate=(fraction)24/1, format=(string)BGRx, width=(int)473, height=(int)272
> ERROR: from
> element /GstPipeline:pipeline0/v4l2video0convert:v4l2video0convert0:
> Device '/dev/video0' cannot capture at 473x272
> Additional debug info:
> gstv4l2object.c(2967): gst_v4l2_object_set_format
> (): /GstPipeline:pipeline0/v4l2video0convert:v4l2video0convert0:
> Tried to capture at 473x272, but device returned size 472x272
> ERROR: pipeline doesn't want to preroll.

This is a famous case. The driver rounds middle, where only rounding up
can be managed by application. There is an RFC to add some flags to VB2
to let the driver decide what's ideal. When you crop, you want to round
down, when you allocate space, you want to round up (so one can crop on
top). The middle rounding is usually not very useful. I think this
discussion should move to linux-media ML.

Nicolas