Re: [PATCH] to libv4lconvert, to do decompression for sn9c2028 cameras

[Hans de Goede <j.w.r.degoede@hhs.nl>]

Hi,

Thanks for the patch, but I see one big issue with this patch,
the decompression algorithm is GPL, where as libv4l is LGPL.

Any chance you could get this relicensed to LGPL ?

Regards,

Hans


On 05/24/2009 12:12 AM, Theodore Kilgore wrote:
>
> The purpose of the following patch is to do the decompression for the
> Sonix SN9C2028 cameras, which are already supported as still cameras in
> libgphoto2/camlibs/sonix. The decompression code is essentially
> identical to that which is used in the libgphoto2 driver, with minor
> changes to adapt it for libv4lconvert.
>
> The history and antecedents of this algorithm are described in
> libgphoto2/camlibs/sonix/README.sonix, which was Copyright (C) 2005
> Theodore Kilgore <kilgota@auburn.edu>, as follows:
>
> "The decompression algorithm originates, I understand, in the work of
> Bertrik Sikkens for the sn9c102 cameras. In the macam project for
> MacOS-X camera support (webcam-osx project on Sourceforge), the
> decompression algorithm for the sn9c2028 cameras was developed by
> Mattias Krauss and adapted for use with the Vivitar Vivicam 3350B in
> particular by Harald Ruda <hrx at users.sourceforge.net>. Harald brought
> to my attention the work already done in the macam project, pointed out
> that it is GPL code, and invited me to have a look. Thanks, Harald. The
> decompression algorithm used here is similar to what is used in the
> macam driver, but is considerably streamlined and improved."
>
> Signed-off-by Theodore Kilgore <kilgota@auburn.edu>
>
> -----------------------------------------------------------------------
> diff -r 276a90c8ac40 v4l2-apps/libv4l/libv4lconvert/Makefile
> --- a/v4l2-apps/libv4l/libv4lconvert/Makefile Wed May 20 07:23:00 2009
> +0200
> +++ b/v4l2-apps/libv4l/libv4lconvert/Makefile Wed May 20 13:10:53 2009
> -0500
> @@ -14,7 +14,7 @@
>
> CONVERT_OBJS = libv4lconvert.o tinyjpeg.o sn9c10x.o sn9c20x.o pac207.o \
> mr97310a.o flip.o crop.o jidctflt.o spca561-decompress.o \
> - rgbyuv.o spca501.o sq905c.o bayer.o hm12.o \
> + rgbyuv.o sn9c2028-decomp.o spca501.o sq905c.o bayer.o hm12.o \
> control/libv4lcontrol.o processing/libv4lprocessing.o \
> processing/rgbprocessing.o processing/bayerprocessing.o
> TARGETS = $(CONVERT_LIB) libv4lconvert.pc
> diff -r 276a90c8ac40 v4l2-apps/libv4l/libv4lconvert/libv4lconvert-priv.h
> --- a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert-priv.h Wed May 20
> 07:23:00 2009 +0200
> +++ b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert-priv.h Wed May 20
> 13:10:53 2009 -0500
> @@ -51,6 +51,10 @@
> #define V4L2_PIX_FMT_MR97310A v4l2_fourcc('M','3','1','0')
> #endif
>
> +#ifndef V4L2_PIX_FMT_SN9C2028
> +#define V4L2_PIX_FMT_SN9C2028 v4l2_fourcc('S', 'O', 'N', 'X')
> +#endif
> +
> #ifndef V4L2_PIX_FMT_SQ905C
> #define V4L2_PIX_FMT_SQ905C v4l2_fourcc('9', '0', '5', 'C')
> #endif
> @@ -193,6 +197,9 @@
> void v4lconvert_decode_mr97310a(const unsigned char *src, unsigned char
> *dst,
> int width, int height);
>
> +void v4lconvert_decode_sn9c2028(const unsigned char *src, unsigned char
> *dst,
> + int width, int height);
> +
> void v4lconvert_decode_sq905c(const unsigned char *src, unsigned char *dst,
> int width, int height);
>
> diff -r 276a90c8ac40 v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c
> --- a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c Wed May 20 07:23:00
> 2009 +0200
> +++ b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c Wed May 20 13:10:53
> 2009 -0500
> @@ -60,6 +60,7 @@
> { V4L2_PIX_FMT_JPEG, V4LCONVERT_COMPRESSED },
> { V4L2_PIX_FMT_SPCA561, V4LCONVERT_COMPRESSED },
> { V4L2_PIX_FMT_SN9C10X, V4LCONVERT_COMPRESSED },
> + { V4L2_PIX_FMT_SN9C2028, V4LCONVERT_COMPRESSED },
> { V4L2_PIX_FMT_PAC207, V4LCONVERT_COMPRESSED },
> { V4L2_PIX_FMT_MR97310A, V4LCONVERT_COMPRESSED },
> { V4L2_PIX_FMT_SQ905C, V4LCONVERT_COMPRESSED },
> @@ -460,6 +461,7 @@
> case V4L2_PIX_FMT_SN9C10X:
> case V4L2_PIX_FMT_PAC207:
> case V4L2_PIX_FMT_MR97310A:
> + case V4L2_PIX_FMT_SN9C2028:
> case V4L2_PIX_FMT_SQ905C:
> case V4L2_PIX_FMT_SBGGR8:
> case V4L2_PIX_FMT_SGBRG8:
> @@ -672,6 +674,7 @@
> case V4L2_PIX_FMT_SN9C10X:
> case V4L2_PIX_FMT_PAC207:
> case V4L2_PIX_FMT_MR97310A:
> + case V4L2_PIX_FMT_SN9C2028:
> case V4L2_PIX_FMT_SQ905C:
> {
> unsigned char *tmpbuf;
> @@ -699,6 +702,10 @@
> v4lconvert_decode_mr97310a(src, tmpbuf, width, height);
> tmpfmt.fmt.pix.pixelformat = V4L2_PIX_FMT_SBGGR8;
> break;
> + case V4L2_PIX_FMT_SN9C2028:
> + v4lconvert_decode_sn9c2028(src, tmpbuf, width, height);
> + src_pix_fmt = V4L2_PIX_FMT_SBGGR8;
> + break;
> case V4L2_PIX_FMT_SQ905C:
> v4lconvert_decode_sq905c(src, tmpbuf, width, height);
> tmpfmt.fmt.pix.pixelformat = V4L2_PIX_FMT_SRGGB8;
> diff -r 276a90c8ac40 v4l2-apps/libv4l/libv4lconvert/sn9c2028-decomp.c
> --- /dev/null Thu Jan 01 00:00:00 1970 +0000
> +++ b/v4l2-apps/libv4l/libv4lconvert/sn9c2028-decomp.c Wed May 20
> 13:10:53 2009 -0500
> @@ -0,0 +1,158 @@
> +/*
> + * sn9c2028-decomp.c
> + *
> + * Decompression function for the Sonix SN9C2028 dual-mode cameras.
> + *
> + * Code adapted from libgphoto2/camlibs/sonix, original version of
> which was
> + * Copyright (c) 2005 Theodore Kilgore <kilgota@auburn.edu>
> + *
> + * History:
> + *
> + * This decoding algorithm originates from the work of Bertrik Sikken
> for the
> + * SN9C102 cameras. This version is an adaptation of work done by Mattias
> + * Krauss for the webcam-osx (macam) project. There, it was further
> adapted
> + * for use with the Vivitar Vivicam 3350B (an SN9C2028 camera) by
> + * Harald Ruda <hrx@users.sourceforge.net>. Harald brought to my
> attention the
> + * work done in the macam project and suggested that I use it. The
> + * macam project is also licensed under the GPL. One improvement of my own
> + * was to notice that the even and odd columns of the image have been
> reversed
> + * by the decompression algorithm, and this needs to be corrected
> during the
> + * decompression.
> + *
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public
> + * License as published by the Free Software Foundation; either
> + * version 2 of the License, or (at your option) any later version.
> + *
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public
> + * License along with this program; if not, write to the
> + * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
> + * Boston, MA 02111-1307, USA.
> + */
> +
> +#include "libv4lconvert-priv.h"
> +
> +/* Four defines for bitstream operations, used in the decode function */
> +
> +#define PEEK_BITS(num,to) {\
> + if (bitBufCount < num) {\
> + do {\
> + bitBuf = (bitBuf << 8)|(*(src++));\
> + bitBufCount += 8; \
> + } \
> + while\
> + (bitBufCount < 24);\
> + } \
> + to = bitBuf >> (bitBufCount-num);\
> +}
> +
> +/*
> + * PEEK_BITS puts the next <num> bits into the low bits of <to>.
> + * when the buffer is empty, it is completely refilled.
> + * This strategy tries to reduce memory access. Note that the high bits
> + * are NOT set to zero!
> + */
> +
> +#define EAT_BITS(num) { bitBufCount -= num; bits_eaten += num; }
> +
> +/*
> + * EAT_BITS consumes <num> bits (PEEK_BITS does not consume anything,
> + * it just peeks)
> + */
> +
> +#define PARSE_PIXEL(val) {\
> + PEEK_BITS(10, bits);\
> + if ((bits&0x200) == 0) {\
> + EAT_BITS(1);\
> + } \
> + else if ((bits&0x380) == 0x280) {\
> + EAT_BITS(3);\
> + val += 3;\
> + if (val > 255)\
> + val = 255;\
> + } \
> + else if ((bits&0x380) == 0x300) {\
> + EAT_BITS(3);\
> + val -= 3;\
> + if (val < 0)\
> + val = 0;\
> + } \
> + else if ((bits&0x3c0) == 0x200) {\
> + EAT_BITS(4);\
> + val += 8;\
> + if (val > 255)\
> + val = 255;\
> + } \
> + else if ((bits&0x3c0) == 0x240) {\
> + EAT_BITS(4);\
> + val -= 8;\
> + if (val < 0)\
> + val = 0;\
> + } \
> + else if ((bits&0x3c0) == 0x3c0) {\
> + EAT_BITS(4);\
> + val -= 20;\
> + if (val < 0)\
> + val = 0;\
> + } \
> + else if ((bits&0x3e0) == 0x380) {\
> + EAT_BITS(5);\
> + val += 20;\
> + if (val > 255)\
> + val = 255;\
> + } \
> + else {\
> + EAT_BITS(10);\
> + val = 8*(bits&0x1f)+0;\
> + } \
> +}
> +
> +
> +#define PUT_PIXEL_PAIR {\
> + long pp;\
> + pp = (c1val<<8)+c2val;\
> + *((unsigned short *) (dst+dst_index)) = pp;\
> + dst_index += 2;\
> +}
> +
> +/* Now the decode function itself */
> +
> +void v4lconvert_decode_sn9c2028(const unsigned char *src, unsigned char
> *dst,
> + int width, int height)
> +{
> + long dst_index = 0;
> + int starting_row = 0;
> + unsigned short bits;
> + short c1val, c2val;
> + int x, y;
> + unsigned long bitBuf = 0;
> + unsigned long bitBufCount = 0;
> + unsigned long bits_eaten = 0;
> +
> + src += 12; /* Remove the header */
> +
> + for (y = starting_row; y < height; y++) {
> + PEEK_BITS(8, bits);
> + EAT_BITS(8);
> + c2val = (bits & 0xff);
> + PEEK_BITS(8, bits);
> + EAT_BITS(8);
> + c1val = (bits & 0xff);
> +
> + PUT_PIXEL_PAIR;
> +
> + for (x = 2; x < width ; x += 2) {
> + /* The compression reversed the even and odd columns.*/
> + PARSE_PIXEL(c2val);
> + PARSE_PIXEL(c1val);
> + PUT_PIXEL_PAIR;
> + }
> + }
> +}
>