spcadecoder.c

摄像头驱动

			/* code 10 */
			val = +5;
			len = 2;
		} else if ((i & 0xF0) == 0xC0) {
			/* code 1100 */
			val = -10;
			len = 4;
		} else if ((i & 0xF0) == 0xD0) {
			/* code 1101 */
			val = +10;
			len = 4;
		} else if ((i & 0xF8) == 0xE0) {
			/* code 11100 */
			val = -15;
			len = 5;
		} else if ((i & 0xF8) == 0xE8) {
			/* code 11101 */
			val = +15;
			len = 5;
		} else if ((i & 0xFC) == 0xF0) {
			/* code 111100 */
			val = -20;
			len = 6;
		} else if ((i & 0xFC) == 0xF4) {
			/* code 111101 */
			val = +20;
			len = 6;
		} else if ((i & 0xF8) == 0xF8) {
			/* code 11111xxxxxx */
			is_abs = 1;
			val = 0;
			len = 5;
		}
		table[i].is_abs = is_abs;
		table[i].val = val;
		table[i].len = len;
	}
}

static int
pac_decompress_row(struct code_table_t *table, unsigned char *inp,
		   unsigned char *outp, int width)
{
	int col;
	int val;
	int bitpos;
	unsigned char code;


	/* first two pixels are stored as raw 8-bit */
	*outp++ = inp[2];
	*outp++ = inp[3];
	bitpos = 32;

	/* main decoding loop */
	for (col = 2; col < width; col++) {
		/* get bitcode */

		code = getByte(inp, bitpos);
		bitpos += table[code].len;

		/* calculate pixel value */
		if (table[code].is_abs) {
			/* absolute value: get 6 more bits */
			code = getByte(inp, bitpos);
			bitpos += 6;
			*outp++ = code & 0xFC;
		} else {
			/* relative to left pixel */
			val = outp[-2] + table[code].val;
			*outp++ = CLIP(val);
		}
	}

	/* return line length, rounded up to next 16-bit word */
	return 2 * ((bitpos + 15) / 16);
}

static void tv8532_preprocess(struct spca50x_frame *myframe)
{
/* we should received a whole frame with header and EOL marker
in myframe->data and return a GBRG pattern in frame->tmpbuffer
 sequence 2bytes header the Alternate pixels bayer GB 4 bytes
 Alternate pixels bayer RG 4 bytes EOL */
	int width = myframe->hdrwidth;
	int height = myframe->hdrheight;
	int src = 0;
	unsigned char *dst = myframe->tmpbuffer;
	unsigned char *data = myframe->data;
	int i;
	int seq1, seq2;

	/* precompute where is the good bayer line */
	if ((((data[src + 3] + data[src + width + 7]) >> 1) +
	     (data[src + 4] >> 2) + (data[src + width + 6] >> 1)) >=
	    (((data[src + 2] + data[src + width + 6]) >> 1) +
	     (data[src + 3] >> 2) + (data[src + width + 5] >> 1))) {
		seq1 = 3;
		seq2 = 4;
	} else {
		seq1 = 2;
		seq2 = 5;
	}
	for (i = 0; i < height / 2; i++) {
		src += seq1;
		memcpy(dst, &myframe->data[src], width);
		src += (width + 3);
		dst += width;
		memcpy(dst, &myframe->data[src], width);
		src += (width + seq2);
		dst += width;
	}
}

static inline unsigned short getShort(unsigned char *pt)
{
	return ((pt[0] << 8) | pt[1]);
}

static int pixart_decompress(struct spca50x_frame *myframe)
{
/* we should received a whole frame with header and EOL marker
in myframe->data and return a GBRG pattern in frame->tmpbuffer
remove the header then copy line by line EOL is set with 0x0f 0xf0 marker
or 0x1e 0xe1 for compressed line*/
	int width = myframe->hdrwidth;
	int height = myframe->hdrheight;
	unsigned char *outp = myframe->tmpbuffer;
	unsigned char *inp = myframe->data;
	struct code_table_t *table = myframe->decoder->table;
	unsigned short word;
	int row;
	/* skip header */
	inp += 16;
	/* and ask to go at pixel +1 ?? */
	outp++;

	/* iterate over all rows */
	for (row = 0; row < height; row++) {
		word = getShort(inp);
		switch (word) {
		case 0x0FF0:
			memcpy(outp, inp + 2, width);
			inp += (2 + width);
			break;
		case 0x1EE1:
			inp += pac_decompress_row(table, inp, outp, width);
			break;

		default:

			return -1;
		}
		outp += width;
	}

	return 0;
}

/*
#	Decoder for compressed spca561 images			    		#
#	It was developed for "Labtec WebCam Elch 2(SPCA561A)" (046d:0929)	#
#	but it might work with other spca561 cameras				#
*/

static unsigned int bit_bucket;
static unsigned char *input_ptr;

static inline void refill(int *bitfill)
{
	if (*bitfill < 8) {
		bit_bucket = (bit_bucket << 8) | *(input_ptr++);
		*bitfill += 8;
	}
}

static inline int nbits(int *bitfill, int n)
{
	bit_bucket = (bit_bucket << 8) | *(input_ptr++);
	*bitfill -= n;
	return (bit_bucket >> (*bitfill & 0xff)) & ((1 << n) - 1);
}

static inline int _nbits(int *bitfill, int n)
{
	*bitfill -= n;
	return (bit_bucket >> (*bitfill & 0xff)) & ((1 << n) - 1);
}

static int fun_A(int *bitfill)
{
	int ret;
	static int tab[] =
	    { 12, 13, 14, 15, 16, 17, 18, 19, -12, -13, -14, -15, -16, -17,
     -18, -19, -19 };

	ret = tab[nbits(bitfill, 4)];

	refill(bitfill);
	return ret;
}
static int fun_B(int *bitfill)
{
	static int tab1[] =
	    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 31, 31,
    31, 31, 31, 31, 31, 31, 31, 31, 31, 31, 31, 31, 31, 31, 31, 16, 17, 18,
    19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 };
	static int tab[] =
	    { 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, -5,
     -6, -7, -8, -9, -10, -11, -12, -13, -14, -15, -16, -17, -18, -19 };
	unsigned int tmp;

	tmp = nbits(bitfill, 7) - 68;
	refill(bitfill);
	if (tmp > 47)
		return 0xff;
	return tab[tab1[tmp]];
}
static int fun_C(int *bitfill, int gkw)
{
	static int tab1[] =
	    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 23, 23, 23, 23, 23, 23,
    23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22 };
	static int tab[] =
	    { 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, -9, -10, -11,
     -12, -13, -14, -15, -16, -17, -18, -19 };
	unsigned int tmp;

	if (gkw == 0xfe) {

		if (nbits(bitfill, 1) == 0)
			return 7;
		else
			return -8;
	}

	if (gkw != 0xff)
		return 0xff;

	tmp = nbits(bitfill, 7) - 72;
	if (tmp > 43)
		return 0xff;

	refill(bitfill);
	return tab[tab1[tmp]];
}
static int fun_D(int *bitfill, int gkw)
{
	if (gkw == 0xfd) {
		if (nbits(bitfill, 1) == 0)
			return 12;
		else
			return -13;
	}

	if (gkw == 0xfc) {
		if (nbits(bitfill, 1) == 0)
			return 13;
		else
			return -14;
	}

	if (gkw == 0xfe) {
		switch (nbits(bitfill, 2)) {
		case 0:
			return 14;
		case 1:
			return -15;
		case 2:
			return 15;
		case 3:
			return -16;
		}

	}

	if (gkw == 0xff) {
		switch (nbits(bitfill, 3)) {
		case 4:
			return 16;
		case 5:
			return -17;
		case 6:
			return 17;
		case 7:
			return -18;
		case 2:
			return _nbits(bitfill, 1) ? 0xed : 0x12;
		case 3:
			*bitfill--;
			return 18;
		}

		return 0xff;
	}
	return gkw;
}

static int fun_E(int cur_byte, int *bitfill)
{
	static int tab0[] = { 0, -1, 1, -2, 2, -3, 3, -4 };
	static int tab1[] = { 4, -5, 5, -6, 6, -7, 7, -8 };
	static int tab2[] = { 8, -9, 9, -10, 10, -11, 11, -12 };
	static int tab3[] = { 12, -13, 13, -14, 14, -15, 15, -16 };
	static int tab4[] = { 16, -17, 17, -18, 18, -19, 19, -19 };

	if ((cur_byte & 0xf0) >= 0x80) {
		*bitfill -= 4;
		return tab0[(cur_byte >> 4) & 7];
	} else if ((cur_byte & 0xc0) == 0x40) {
		*bitfill -= 5;
		return tab1[(cur_byte >> 3) & 7];

	} else if ((cur_byte & 0xe0) == 0x20) {
		*bitfill -= 6;
		return tab2[(cur_byte >> 2) & 7];

	} else if ((cur_byte & 0xf0) == 0x10) {
		*bitfill -= 7;
		return tab3[(cur_byte >> 1) & 7];

	} else if ((cur_byte & 0xf8) == 8) {
		*bitfill -= 8;
		return tab4[cur_byte & 7];
	}

	return 0xff;
}

static int fun_F(int cur_byte, int *bitfill)
{
	*bitfill -= 5;
	switch (cur_byte & 0xf8) {
	case 0x80:
		return 0;
	case 0x88:
		return -1;
	case 0x90:
		return 1;
	case 0x98:
		return -2;
	case 0xa0:
		return 2;
	case 0xa8:
		return -3;
	case 0xb0:
		return 3;
	case 0xb8:
		return -4;
	case 0xc0:
		return 4;
	case 0xc8:
		return -5;
	case 0xd0:
		return 5;
	case 0xd8:
		return -6;
	case 0xe0:
		return 6;
	case 0xe8:
		return -7;
	case 0xf0:
		return 7;
	case 0xf8:
		return -8;
	}

	*bitfill -= 1;

	switch (cur_byte & 0xfc) {
	case 0x40:
		return 8;
	case 0x44:
		return -9;
	case 0x48:
		return 9;
	case 0x4c:
		return -10;
	case 0x50:
		return 10;
	case 0x54:
		return -11;
	case 0x58:
		return 11;
	case 0x5c:
		return -12;
	case 0x60:
		return 12;
	case 0x64:
		return -13;
	case 0x68:
		return 13;
	case 0x6c:
		return -14;
	case 0x70:
		return 14;
	case 0x74:
		return -15;
	case 0x78:
		return 15;
	case 0x7c:
		return -16;
	}

	*bitfill -= 1;

	switch (cur_byte & 0xfe) {
	case 0x20:
		return 16;
	case 0x22:
		return -17;
	case 0x24:
		return 17;
	case 0x26:
		return -18;
	case 0x28:
		return 18;
	case 0x2a:
		return -19;
	case 0x2c:
		return 19;
	}

	*bitfill += 7;
	return 0xff;
}
int internal_spca561_decode(int width, int height, unsigned char *inbuf, unsigned char *outbuf)	// {{{
{
	// buffers
	static int accum[8 * 8 * 8];
	static int i_hits[8 * 8 * 8];

	const static int nbits_A[] =
	    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
8, 8, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 0, 0, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, };
	const static int tab_A[] =
	    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,