Hi,
we have image conversion code for scaling and colorspace conversion in
the IPUv3 base driver for a while. Since the IC hardware can only write
up to 1024x1024 pixel buffers, it scales to larger output buffers by
splitting the input and output frame into similarly sized tiles.
This causes the issue that the bilinear interpolation resets at the tile
boundary: instead of smoothly interpolating across the seam, there is a
jump in the input sample position that is very apparent for high
upscaling factors. This can be avoided by slightly changing the scaling
coefficients to let the left/top tiles overshoot their input sampling
into the first pixel / line of their right / bottom neighbors. The error
can be further reduced by letting tiles be differently sized and by
selecting seam positions that minimize the input sampling position error
at tile boundaries.
This is complicated by different DMA start address, burst size, and
rotator block size alignment requirements, depending on the input and
output pixel formats, and the fact that flipping happens in different
places depending on the rotation.
This series implements optimal seam position selection and seam hiding
with per-tile resizing coefficients and adds a scaling mem2mem device
to the imx-media driver.
regards
Philipp
Philipp Zabel (16):
gpu: ipu-v3: ipu-ic: allow to manually set resize coefficients
gpu: ipu-v3: image-convert: prepare for per-tile configuration
gpu: ipu-v3: image-convert: calculate per-tile resize coefficients
gpu: ipu-v3: image-convert: reconfigure IC per tile
gpu: ipu-v3: image-convert: store tile top/left position
gpu: ipu-v3: image-convert: calculate tile dimensions and offsets
outside fill_image
gpu: ipu-v3: image-convert: move tile alignment helpers
gpu: ipu-v3: image-convert: select optimal seam positions
gpu: ipu-v3: image-convert: fix debug output for varying tile sizes
gpu: ipu-v3: image-convert: relax tile width alignment for NV12 and
NV16
gpu: ipu-v3: image-convert: relax input alignment restrictions
gpu: ipu-v3: image-convert: relax output alignment restrictions
gpu: ipu-v3: image-convert: fix bytesperline adjustment
gpu: ipu-v3: image-convert: add some ASCII art to the exposition
gpu: ipu-v3: image-convert: disable double buffering if necessary
media: imx: add mem2mem device
drivers/gpu/ipu-v3/ipu-ic.c | 52 +-
drivers/gpu/ipu-v3/ipu-image-convert.c | 865 +++++++++++++---
drivers/staging/media/imx/Kconfig | 1 +
drivers/staging/media/imx/Makefile | 1 +
drivers/staging/media/imx/imx-media-dev.c | 11 +
drivers/staging/media/imx/imx-media-mem2mem.c | 953 ++++++++++++++++++
drivers/staging/media/imx/imx-media.h | 10 +
include/video/imx-ipu-v3.h | 6 +
8 files changed, 1760 insertions(+), 139 deletions(-)
create mode 100644 drivers/staging/media/imx/imx-media-mem2mem.c
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2.17.1
