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media: uapi: Add PiSP Compressed RAW Bayer formats
Add Raspberry Pi compressed RAW Bayer formats. The compression algorithm description is provided by Nick Hollinghurst <nick.hollinghurst@raspberrypi.com> from Raspberry Pi. Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com> Reviewed-by: Naushir Patuck <naush@raspberrypi.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
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Jacopo Mondi
Hans Verkuil
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8f6c220222
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d260c12247
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@ -20,6 +20,7 @@ orders. See also `the Wikipedia article on Bayer filter
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:maxdepth: 1
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pixfmt-srggb8
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pixfmt-srggb8-pisp-comp
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pixfmt-srggb10
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pixfmt-srggb10p
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pixfmt-srggb10alaw8
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@ -0,0 +1,74 @@
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.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
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.. _v4l2-pix-fmt-pisp-comp1-rggb:
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.. _v4l2-pix-fmt-pisp-comp1-grbg:
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.. _v4l2-pix-fmt-pisp-comp1-gbrg:
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.. _v4l2-pix-fmt-pisp-comp1-bggr:
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.. _v4l2-pix-fmt-pisp-comp1-mono:
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.. _v4l2-pix-fmt-pisp-comp2-rggb:
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.. _v4l2-pix-fmt-pisp-comp2-grbg:
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.. _v4l2-pix-fmt-pisp-comp2-gbrg:
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.. _v4l2-pix-fmt-pisp-comp2-bggr:
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.. _v4l2-pix-fmt-pisp-comp2-mono:
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**************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
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V4L2_PIX_FMT_PISP_COMP1_RGGB ('PC1R'), V4L2_PIX_FMT_PISP_COMP1_GRBG ('PC1G'), V4L2_PIX_FMT_PISP_COMP1_GBRG ('PC1g'), V4L2_PIX_FMT_PISP_COMP1_BGGR ('PC1B), V4L2_PIX_FMT_PISP_COMP1_MONO ('PC1M'), V4L2_PIX_FMT_PISP_COMP2_RGGB ('PC2R'), V4L2_PIX_FMT_PISP_COMP2_GRBG ('PC2G'), V4L2_PIX_FMT_PISP_COMP2_GBRG ('PC2g'), V4L2_PIX_FMT_PISP_COMP2_BGGR ('PC2B), V4L2_PIX_FMT_PISP_COMP2_MONO ('PC2M')
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**************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
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================================================
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Raspberry Pi PiSP compressed 8-bit Bayer formats
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================================================
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Description
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===========
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The Raspberry Pi ISP (PiSP) uses a family of three fixed-rate compressed Bayer
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formats. A black-level offset may be subtracted to improve compression
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efficiency; the nominal black level and amount of offset must be signalled out
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of band. Each scanline is padded to a multiple of 8 pixels wide, and each block
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of 8 horizontally-contiguous pixels is coded using 8 bytes.
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Mode 1 uses a quantization and delta-based coding scheme which preserves up to
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12 significant bits. Mode 2 is a simple sqrt-like companding scheme with 6 PWL
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chords, preserving up to 12 significant bits. Mode 3 combines both companding
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(with 4 chords) and the delta scheme, preserving up to 14 significant bits.
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The remainder of this description applies to Modes 1 and 3.
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Each block of 8 pixels is separated into even and odd phases of 4 pixels,
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coded independently by 32-bit words at successive locations in memory.
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The two LS bits of each 32-bit word give its "quantization mode".
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In quantization mode 0, the lowest 321 quantization levels are multiples of
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FSD/4096 and the remaining levels are successive multiples of FSD/2048.
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Quantization modes 1 and 2 use linear quantization with step sizes of
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FSD/1024 and FSD/512 respectively. Each of the four pixels is quantized
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independently, with rounding to the nearest level.
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In quantization mode 2 where the middle two samples have quantized values
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(q1,q2) both in the range [384..511], they are coded using 9 bits for q1
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followed by 7 bits for (q2 & 127). Otherwise, for quantization modes
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0, 1 and 2: a 9-bit field encodes MIN(q1,q2) which must be in the range
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[0..511] and a 7-bit field encodes (q2-q1+64) which must be in [0..127].
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Each of the outer samples (q0,q3) is encoded using a 7-bit field based
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on its inner neighbour q1 or q2. In quantization mode 2 where the inner
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sample has a quantized value in the range [448..511], the field value is
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(q0-384). Otherwise for quantization modes 0, 1 and 2: The outer sample
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is encoded as (q0-MAX(0,q1-64)). q3 is likewise coded based on q2.
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Each of these values must be in the range [0..127]. All these fields
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of 2, 9, 7, 7, 7 bits respectively are packed in little-endian order
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to give a 32-bit word with LE byte order.
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Quantization mode 3 has a "7.5-bit" escape, used when none of the above
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encodings will fit. Each pixel value is quantized to the nearest of 176
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levels, where the lowest 95 levels are multiples of FSD/256 and the
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remaining levels are multiples of FSD/128 (level 175 represents values
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very close to FSD and may require saturating arithmetic to decode).
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Each pair of quantized pixels (q0,q1) or (q2,q3) is jointly coded
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by a 15-bit field: 2816*(q0>>4) + 16*q1 + (q0&15).
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Three fields of 2, 15, 15 bits are packed in LE order {15,15,2}.
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An implementation of a software decoder of compressed formats is available
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in `Raspberry Pi camera applications code base
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<https://github.com/raspberrypi/rpicam-apps/blob/main/image/dng.cpp>`_.
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@ -1532,6 +1532,16 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
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case V4L2_PIX_FMT_MT2110T: descr = "Mediatek 10bit Tile Mode"; break;
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case V4L2_PIX_FMT_MT2110R: descr = "Mediatek 10bit Raster Mode"; break;
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case V4L2_PIX_FMT_HEXTILE: descr = "Hextile Compressed Format"; break;
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case V4L2_PIX_FMT_PISP_COMP1_RGGB: descr = "PiSP 8b RGRG/GBGB mode1 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP1_GRBG: descr = "PiSP 8b GRGR/BGBG mode1 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP1_GBRG: descr = "PiSP 8b GBGB/RGRG mode1 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP1_BGGR: descr = "PiSP 8b BGBG/GRGR mode1 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP1_MONO: descr = "PiSP 8b monochrome mode1 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP2_RGGB: descr = "PiSP 8b RGRG/GBGB mode2 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP2_GRBG: descr = "PiSP 8b GRGR/BGBG mode2 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP2_GBRG: descr = "PiSP 8b GBGB/RGRG mode2 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP2_BGGR: descr = "PiSP 8b BGBG/GRGR mode2 compr"; break;
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case V4L2_PIX_FMT_PISP_COMP2_MONO: descr = "PiSP 8b monochrome mode2 compr"; break;
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default:
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if (fmt->description[0])
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return;
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@ -816,6 +816,18 @@ struct v4l2_pix_format {
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#define V4L2_PIX_FMT_IPU3_SGRBG10 v4l2_fourcc('i', 'p', '3', 'G') /* IPU3 packed 10-bit GRBG bayer */
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#define V4L2_PIX_FMT_IPU3_SRGGB10 v4l2_fourcc('i', 'p', '3', 'r') /* IPU3 packed 10-bit RGGB bayer */
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/* Raspberry Pi PiSP compressed formats. */
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#define V4L2_PIX_FMT_PISP_COMP1_RGGB v4l2_fourcc('P', 'C', '1', 'R') /* PiSP 8-bit mode 1 compressed RGGB bayer */
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#define V4L2_PIX_FMT_PISP_COMP1_GRBG v4l2_fourcc('P', 'C', '1', 'G') /* PiSP 8-bit mode 1 compressed GRBG bayer */
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#define V4L2_PIX_FMT_PISP_COMP1_GBRG v4l2_fourcc('P', 'C', '1', 'g') /* PiSP 8-bit mode 1 compressed GBRG bayer */
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#define V4L2_PIX_FMT_PISP_COMP1_BGGR v4l2_fourcc('P', 'C', '1', 'B') /* PiSP 8-bit mode 1 compressed BGGR bayer */
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#define V4L2_PIX_FMT_PISP_COMP1_MONO v4l2_fourcc('P', 'C', '1', 'M') /* PiSP 8-bit mode 1 compressed monochrome */
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#define V4L2_PIX_FMT_PISP_COMP2_RGGB v4l2_fourcc('P', 'C', '2', 'R') /* PiSP 8-bit mode 2 compressed RGGB bayer */
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#define V4L2_PIX_FMT_PISP_COMP2_GRBG v4l2_fourcc('P', 'C', '2', 'G') /* PiSP 8-bit mode 2 compressed GRBG bayer */
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#define V4L2_PIX_FMT_PISP_COMP2_GBRG v4l2_fourcc('P', 'C', '2', 'g') /* PiSP 8-bit mode 2 compressed GBRG bayer */
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#define V4L2_PIX_FMT_PISP_COMP2_BGGR v4l2_fourcc('P', 'C', '2', 'B') /* PiSP 8-bit mode 2 compressed BGGR bayer */
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#define V4L2_PIX_FMT_PISP_COMP2_MONO v4l2_fourcc('P', 'C', '2', 'M') /* PiSP 8-bit mode 2 compressed monochrome */
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/* SDR formats - used only for Software Defined Radio devices */
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#define V4L2_SDR_FMT_CU8 v4l2_fourcc('C', 'U', '0', '8') /* IQ u8 */
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#define V4L2_SDR_FMT_CU16LE v4l2_fourcc('C', 'U', '1', '6') /* IQ u16le */
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