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hadie/ssdv.c

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22 KiB
C
Czysty Bezpośredni odnośnik Wina Historia

/* SSDV - Slow Scan Digital Video */
/*=======================================================================*/
/* Copyright 2011-2012 Philip Heron <phil@sanslogic.co.uk */
/* */
/* 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 3 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 General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public License */
/* along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <stdint.h>
#include <string.h>
#include <avr/pgmspace.h>
#include "ssdv.h"
#include "rs8.h"
/* Recognised JPEG markers */
enum {
J_TEM = 0xFF01,
J_SOF0 = 0xFFC0, J_SOF1, J_SOF2, J_SOF3, J_DHT, J_SOF5, J_SOF6, J_SOF7,
J_JPG, J_SOF9, J_SOF10, J_SOF11, J_DAC, J_SOF13, J_SOF14, J_SOF15,
J_RST0, J_RST1, J_RST2, J_RST3, J_RST4, J_RST5, J_RST6, J_RST7,
J_SOI, J_EOI, J_SOS, J_DQT, J_DNL, J_DRI, J_DHP, J_EXP,
J_APP0, J_APP1, J_APP2, J_APP3, J_APP4, J_APP5, J_APP6, J_APP7,
J_APP8, J_APP9, J_APP10, J_APP11, J_APP12, J_APP13, J_APP14, J_APP15,
J_JPG0, J_JPG1, J_JPG2, J_JPG3, J_JPG4, J_JPG5, J_JPG6, J_SOF48,
J_LSE, J_JPG9, J_JPG10, J_JPG11, J_JPG12, J_JPG13, J_COM,
} jpeg_marker_t;
/* Quantisation tables */
PROGMEM static const uint8_t const std_dqt0[65] = {
0x00,0x10,0x0C,0x0C,0x0E,0x0C,0x0A,0x10,0x0E,0x0E,0x0E,0x12,0x12,0x10,0x14,0x18,
0x28,0x1A,0x18,0x16,0x16,0x18,0x32,0x24,0x26,0x1E,0x28,0x3A,0x34,0x3E,0x3C,0x3A,
0x34,0x38,0x38,0x40,0x48,0x5C,0x4E,0x40,0x44,0x58,0x46,0x38,0x38,0x50,0x6E,0x52,
0x58,0x60,0x62,0x68,0x68,0x68,0x3E,0x4E,0x72,0x7A,0x70,0x64,0x78,0x5C,0x66,0x68,
0x64,
};
PROGMEM static const uint8_t const std_dqt1[65] = {
0x01,0x12,0x12,0x12,0x16,0x16,0x16,0x30,0x1A,0x1A,0x30,0x64,0x42,0x38,0x42,0x64,
0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,
0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,
0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,0x64,
0x64,
};
/* Standard Huffman tables */
PROGMEM static const uint8_t const std_dht00[29] = {
0x00,0x00,0x01,0x05,0x01,0x01,0x01,0x01,0x01,0x01,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,
};
PROGMEM static const uint8_t const std_dht01[29] = {
0x01,0x00,0x03,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x00,0x00,0x00,0x00,
0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,
};
PROGMEM static const uint8_t const std_dht10[179] = {
0x10,0x00,0x02,0x01,0x03,0x03,0x02,0x04,0x03,0x05,0x05,0x04,0x04,0x00,0x00,0x01,
0x7D,0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,0x21,0x31,0x41,0x06,0x13,0x51,0x61,
0x07,0x22,0x71,0x14,0x32,0x81,0x91,0xA1,0x08,0x23,0x42,0xB1,0xC1,0x15,0x52,0xD1,
0xF0,0x24,0x33,0x62,0x72,0x82,0x09,0x0A,0x16,0x17,0x18,0x19,0x1A,0x25,0x26,0x27,
0x28,0x29,0x2A,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x43,0x44,0x45,0x46,0x47,0x48,
0x49,0x4A,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x63,0x64,0x65,0x66,0x67,0x68,
0x69,0x6A,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x83,0x84,0x85,0x86,0x87,0x88,
0x89,0x8A,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0xA2,0xA3,0xA4,0xA5,0xA6,
0xA7,0xA8,0xA9,0xAA,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xC2,0xC3,0xC4,
0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,0xE1,
0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,
0xF8,0xF9,0xFA,
};
PROGMEM static const uint8_t const std_dht11[179] = {
0x11,0x00,0x02,0x01,0x02,0x04,0x04,0x03,0x04,0x07,0x05,0x04,0x04,0x00,0x01,0x02,
0x77,0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,0x31,0x06,0x12,0x41,0x51,0x07,0x61,
0x71,0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,0xA1,0xB1,0xC1,0x09,0x23,0x33,0x52,
0xF0,0x15,0x62,0x72,0xD1,0x0A,0x16,0x24,0x34,0xE1,0x25,0xF1,0x17,0x18,0x19,0x1A,
0x26,0x27,0x28,0x29,0x2A,0x35,0x36,0x37,0x38,0x39,0x3A,0x43,0x44,0x45,0x46,0x47,
0x48,0x49,0x4A,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x63,0x64,0x65,0x66,0x67,
0x68,0x69,0x6A,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x82,0x83,0x84,0x85,0x86,
0x87,0x88,0x89,0x8A,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0xA2,0xA3,0xA4,
0xA5,0xA6,0xA7,0xA8,0xA9,0xAA,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xC2,
0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,
0xDA,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,
0xF8,0xF9,0xFA,
};
/* Helper for returning the current DHT table */
#define SDHT (s->sdht[s->acpart ? 1 : 0][s->component ? 1 : 0])
#define DDHT (s->ddht[s->acpart ? 1 : 0][s->component ? 1 : 0])
/* Helpers for looking up the current DQT value */
#define SDQT (s->sdqt[s->component ? 1 : 0][1 + s->acpart])
#define DDQT (s->ddqt[s->component ? 1 : 0][1 + s->acpart])
/* Helpers for converting between DQT tables */
#define AADJ(i) (SDQT == DDQT ? (i) : irdiv(i, DDQT))
#define UADJ(i) (SDQT == DDQT ? (i) : (i * SDQT))
#define BADJ(i) (SDQT == DDQT ? (i) : irdiv(i * SDQT, DDQT))
/* Integer-only division with rounding */
static int irdiv(int i, int div)
{
i = i * 2 / div;
if(i & 1) i += (i > 0 ? 1 : -1);
return(i / 2);
}
static void *dtblcpy(ssdv_t *s, const void *src, size_t n)
{
void *r;
if(s->dtbl_len + n > TBL_LEN) return(NULL);
r = memcpy_P(&s->dtbls[s->dtbl_len], src, n);
s->dtbl_len += n;
return(r);
}
static uint32_t crc32(void *data, size_t length)
{
uint32_t crc, x;
uint8_t i, *d;
for(d = data, crc = 0xFFFFFFFF; length; length--)
{
x = (crc ^ *(d++)) & 0xFF;
for(i = 8; i > 0; i--)
{
if(x & 1) x = (x >> 1) ^ 0xEDB88320;
else x >>= 1;
}
crc = (crc >> 8) ^ x;
}
return(crc ^ 0xFFFFFFFF);
}
static uint32_t encode_callsign(char *callsign)
{
uint32_t x;
char *c;
/* Point c at the end of the callsign */
for(c = callsign; *c; c++);
/* Encode it backwards */
x = 0;
for(c--; c >= callsign; c--)
{
x *= 40;
if(*c >= 'A' && *c <= 'Z') x += *c - 'A' + 14;
else if(*c >= 'a' && *c <= 'z') x += *c - 'a' + 14;
else if(*c >= '0' && *c <= '9') x += *c - '0' + 1;
}
return(x);
}
static inline char jpeg_dht_lookup(ssdv_t *s, uint8_t *symbol, uint8_t *width)
{
uint16_t code = 0;
uint8_t cw, n;
uint8_t *dht, *ss;
/* Select the appropriate huffman table */
dht = SDHT;
ss = &dht[17];
for(cw = 1; cw <= 16; cw++)
{
/* Got enough bits? */
if(cw > s->worklen) return(SSDV_FEED_ME);
/* Compare against each code 'cw' bits wide */
for(n = dht[cw]; n > 0; n--)
{
if(s->workbits >> (s->worklen - cw) == code)
{
/* Found a match */
*symbol = *ss;
*width = cw;
return(SSDV_OK);
}
ss++; code++;
}
code <<= 1;
}
/* No match found - error */
return(SSDV_ERROR);
}
static inline char jpeg_dht_lookup_symbol(ssdv_t *s, uint8_t symbol, uint16_t *bits, uint8_t *width)
{
uint16_t code = 0;
uint8_t cw, n;
uint8_t *dht, *ss;
dht = DDHT;
ss = &dht[17];
for(cw = 1; cw <= 16; cw++)
{
for(n = dht[cw]; n > 0; n--)
{
if(*ss == symbol)
{
/* Found a match */
*bits = code;
*width = cw;
return(SSDV_OK);
}
ss++; code++;
}
code <<= 1;
}
/* No match found - error */
return(SSDV_ERROR);
}
static inline int jpeg_int(int bits, int width)
{
int b = (1 << width) - 1;
if(bits <= b >> 1) bits = -(bits ^ b);
return(bits);
}
static inline void jpeg_encode_int(int value, int *bits, uint8_t *width)
{
*bits = value;
/* Calculate the number of bits */
if(value < 0) value = -value;
for(*width = 0; value; value >>= 1) (*width)++;
/* Fix negative values */
if(*bits < 0) *bits = -*bits ^ ((1 << *width) - 1);
}
/*****************************************************************************/
static char ssdv_outbits(ssdv_t *s, uint16_t bits, uint8_t length)
{
uint8_t b;
if(length)
{
s->outbits <<= length;
s->outbits |= bits & ((1 << length) - 1);
s->outlen += length;
}
while(s->outlen >= 8 && s->out_len > 0)
{
b = s->outbits >> (s->outlen - 8);
/* Put the byte into the output buffer */
*(s->outp++) = b;
s->outlen -= 8;
s->out_len--;
}
return(s->out_len ? SSDV_OK : SSDV_BUFFER_FULL);
}
static char ssdv_outbits_sync(ssdv_t *s)
{
uint8_t b = s->outlen % 8;
if(b) return(ssdv_outbits(s, 0xFF, 8 - b));
return(SSDV_OK);
}
static char ssdv_out_jpeg_int(ssdv_t *s, uint8_t rle, int value)
{
uint16_t huffbits = 0;
int intbits;
uint8_t hufflen = 0, intlen;
jpeg_encode_int(value, &intbits, &intlen);
jpeg_dht_lookup_symbol(s, (rle << 4) | (intlen & 0x0F), &huffbits, &hufflen);
ssdv_outbits(s, huffbits, hufflen);
if(intlen) ssdv_outbits(s, intbits, intlen);
return(SSDV_OK);
}
static char ssdv_process(ssdv_t *s)
{
if(s->state == S_HUFF)
{
uint8_t symbol, width;
int r;
/* Lookup the code, return if error or not enough bits yet */
if((r = jpeg_dht_lookup(s, &symbol, &width)) != SSDV_OK)
return(r);
if(s->acpart == 0) /* DC */
{
if(symbol == 0x00)
{
/* No change in DC from last block */
if(s->reset_mcu == s->mcu_id && (s->mcupart == 0 || s->mcupart >= s->ycparts))
{
ssdv_out_jpeg_int(s, 0, s->adc[s->component]);
}
else ssdv_out_jpeg_int(s, 0, 0);
/* skip to the next AC part immediately */
s->acpart++;
}
else
{
/* DC value follows, 'symbol' bits wide */
s->state = S_INT;
s->needbits = symbol;
}
}
else /* AC */
{
s->acrle = 0;
if(symbol == 0x00)
{
/* EOB -- all remaining AC parts are zero */
ssdv_out_jpeg_int(s, 0, 0);
s->acpart = 64;
}
else if(symbol == 0xF0)
{
/* The next 16 AC parts are zero */
ssdv_out_jpeg_int(s, 15, 0);
s->acpart += 16;
}
else
{
/* Next bits are an integer value */
s->state = S_INT;
s->acrle = symbol >> 4;
s->acpart += s->acrle;
s->needbits = symbol & 0x0F;
}
}
/* Clear processed bits */
s->worklen -= width;
s->workbits &= (1 << s->worklen) - 1;
}
else if(s->state == S_INT)
{
int i;
/* Not enough bits yet? */
if(s->worklen < s->needbits) return(SSDV_FEED_ME);
/* Decode the integer */
i = jpeg_int(s->workbits >> (s->worklen - s->needbits), s->needbits);
if(s->acpart == 0) /* DC */
{
if(s->reset_mcu == s->mcu_id && (s->mcupart == 0 || s->mcupart >= s->ycparts))
{
/* Output absolute DC value */
s->dc[s->component] += UADJ(i);
s->adc[s->component] = AADJ(s->dc[s->component]);
ssdv_out_jpeg_int(s, 0, s->adc[s->component]);
}
else
{
/* Output relative DC value */
s->dc[s->component] += UADJ(i);
/* Calculate closest adjusted DC value */
i = AADJ(s->dc[s->component]);
ssdv_out_jpeg_int(s, 0, i - s->adc[s->component]);
s->adc[s->component] = i;
}
}
else /* AC */
{
if((i = BADJ(i)))
{
s->accrle += s->acrle;
while(s->accrle >= 16)
{
ssdv_out_jpeg_int(s, 15, 0);
s->accrle -= 16;
}
ssdv_out_jpeg_int(s, s->accrle, i);
s->accrle = 0;
}
else
{
/* AC value got reduced to 0 in the DQT conversion */
if(s->acpart >= 63)
{
ssdv_out_jpeg_int(s, 0, 0);
s->accrle = 0;
}
else s->accrle += s->acrle + 1;
}
}
/* Next AC part to expect */
s->acpart++;
/* Next bits are a huffman code */
s->state = S_HUFF;
/* Clear processed bits */
s->worklen -= s->needbits;
s->workbits &= (1 << s->worklen) - 1;
}
if(s->acpart >= 64)
{
/* Reached the end of this MCU part */
if(++s->mcupart == s->ycparts + 2)
{
s->mcupart = 0;
s->mcu_id++;
/* Test for the end of image */
if(s->mcu_id >= s->mcu_count)
{
/* Flush any remaining bits */
ssdv_outbits_sync(s);
return(SSDV_EOI);
}
/* Set the packet MCU marker - encoder only */
if(s->packet_mcu_id == 0xFFFF)
{
/* The first MCU of each packet should be byte aligned */
ssdv_outbits_sync(s);
s->reset_mcu = s->mcu_id;
s->packet_mcu_id = s->mcu_id;
s->packet_mcu_offset = SSDV_PKT_SIZE_PAYLOAD - s->out_len;
}
/* Test for a reset marker */
if(s->dri > 0 && s->mcu_id > 0 && s->mcu_id % s->dri == 0)
{
s->state = S_MARKER;
return(SSDV_FEED_ME);
}
}
if(s->mcupart < s->ycparts) s->component = 0;
else s->component = s->mcupart - s->ycparts + 1;
s->acpart = 0;
s->accrle = 0;
}
if(s->out_len == 0) return(SSDV_BUFFER_FULL);
return(SSDV_OK);
}
/*****************************************************************************/
static void ssdv_memset_prng(uint8_t *s, size_t n)
{
/* A very simple PRNG for noise whitening */
uint8_t l = 0x00;
for(; n > 0; n--) *(s++) = (l = l * 245 + 45);
}
static char ssdv_have_marker(ssdv_t *s)
{
switch(s->marker)
{
case J_SOF0:
case J_SOS:
case J_DRI:
case J_DHT:
case J_DQT:
/* Copy the data before processing */
if(s->marker_len > TBL_LEN + HBUFF_LEN - s->stbl_len)
{
/* Not enough memory ... shouldn't happen! */
return(SSDV_ERROR);
}
s->marker_data = &s->stbls[s->stbl_len];
s->marker_data_len = 0;
s->state = S_MARKER_DATA;
break;
case J_SOF2:
/* Don't do progressive images! */
return(SSDV_ERROR);
case J_EOI:
s->state = S_EOI;
break;
case J_RST0:
case J_RST1:
case J_RST2:
case J_RST3:
case J_RST4:
case J_RST5:
case J_RST6:
case J_RST7:
s->dc[0] = s->dc[1] = s->dc[2] = 0;
s->mcupart = s->acpart = s->component = 0;
s->acrle = s->accrle = 0;
s->workbits = s->worklen = 0;
s->state = S_HUFF;
break;
default:
/* Ignore other marks, skipping any associated data */
s->in_skip = s->marker_len;
s->state = S_MARKER;
break;
}
return(SSDV_OK);
}
static char ssdv_have_marker_data(ssdv_t *s)
{
uint8_t *d = s->marker_data;
size_t l = s->marker_len;
int i;
switch(s->marker)
{
case J_SOF0:
s->width = (d[3] << 8) | d[4];
s->height = (d[1] << 8) | d[2];
/* The image must have a precision of 8 */
if(d[0] != 8) return(SSDV_ERROR);
/* The image must have 3 components (Y'Cb'Cr) */
if(d[5] != 3) return(SSDV_ERROR);
/* Maximum image is 4080x4080 */
if(s->width > 4080 || s->height > 4080) return(SSDV_ERROR);
/* The image dimensions must be a multiple of 16 */
if((s->width & 0x0F) || (s->height & 0x0F)) return(SSDV_ERROR);
/* TODO: Read in the quantisation table ID for each component */
// 01 22 00 02 11 01 03 11 01
for(i = 0; i < 3; i++)
{
uint8_t *dq = &d[i * 3 + 6];
if(dq[0] != i + 1) return(SSDV_ERROR);
/* The first (Y) component must have a factor of 2x2,2x1,1x2 or 1x1 */
if(dq[0] == 1)
{
switch(dq[1])
{
case 0x22: s->mcu_mode = 0; s->ycparts = 4; break;
case 0x12: s->mcu_mode = 1; s->ycparts = 2; break;
case 0x21: s->mcu_mode = 2; s->ycparts = 2; break;
case 0x11: s->mcu_mode = 3; s->ycparts = 1; break;
default: return(SSDV_ERROR);
}
}
else if(dq[0] != 1 && dq[1] != 0x11) return(SSDV_ERROR);
}
/* Calculate number of MCU blocks in this image */
switch(s->mcu_mode)
{
case 0: l = (s->width >> 4) * (s->height >> 4); break;
case 1: l = (s->width >> 4) * (s->height >> 3); break;
case 2: l = (s->width >> 3) * (s->height >> 4); break;
case 3: l = (s->width >> 3) * (s->height >> 3); break;
}
if(l > 0xFFFF) return(SSDV_ERROR);
s->mcu_count = l;
break;
case J_SOS:
/* The image must have 3 components (Y'Cb'Cr) */
if(d[0] != 3) return(SSDV_ERROR);
for(i = 0; i < 3; i++)
{
uint8_t *dh = &d[i * 2 + 1];
if(dh[0] != i + 1) return(SSDV_ERROR);
}
/* Do I need to look at the last three bytes of the SOS data? */
/* 00 3F 00 */
/* Verify all of the DQT and DHT tables where loaded */
if(!s->sdqt[0] || !s->sdqt[1]) return(SSDV_ERROR);
if(!s->sdht[0][0] || !s->sdht[0][1] ||
!s->sdht[1][0] || !s->sdht[1][1]) return(SSDV_ERROR);
/* The SOS data is followed by the image data */
s->state = S_HUFF;
return(SSDV_OK);
case J_DHT:
s->stbl_len += l;
while(l > 0)
{
int i, j;
switch(d[0])
{
case 0x00: s->sdht[0][0] = d; break;
case 0x01: s->sdht[0][1] = d; break;
case 0x10: s->sdht[1][0] = d; break;
case 0x11: s->sdht[1][1] = d; break;
}
/* Skip to the next DHT table */
for(j = 17, i = 1; i <= 16; i++)
j += d[i];
l -= j;
d += j;
}
break;
case J_DQT:
s->stbl_len += l;
while(l > 0)
{
switch(d[0])
{
case 0x00: s->sdqt[0] = d; break;
case 0x01: s->sdqt[1] = d; break;
}
/* Skip to the next one, if present */
l -= 65;
d += 65;
}
break;
case J_DRI:
s->dri = (d[0] << 8) + d[1];
break;
}
s->state = S_MARKER;
return(SSDV_OK);
}
char ssdv_enc_init(ssdv_t *s, char *callsign, uint8_t image_id)
{
memset(s, 0, sizeof(ssdv_t));
s->image_id = image_id;
s->callsign = encode_callsign(callsign);
/* Prepare the output JPEG tables */
s->ddqt[0] = dtblcpy(s, std_dqt0, sizeof(std_dqt0));
s->ddqt[1] = dtblcpy(s, std_dqt1, sizeof(std_dqt1));
s->ddht[0][0] = dtblcpy(s, std_dht00, sizeof(std_dht00));
s->ddht[0][1] = dtblcpy(s, std_dht01, sizeof(std_dht01));
s->ddht[1][0] = dtblcpy(s, std_dht10, sizeof(std_dht10));
s->ddht[1][1] = dtblcpy(s, std_dht11, sizeof(std_dht11));
return(SSDV_OK);
}
char ssdv_enc_set_buffer(ssdv_t *s, uint8_t *buffer)
{
s->out = buffer;
s->outp = buffer + SSDV_PKT_SIZE_HEADER;
s->out_len = SSDV_PKT_SIZE_PAYLOAD;
/* Zero the payload memory */
memset(s->out, 0, SSDV_PKT_SIZE);
/* Flush the output bits */
ssdv_outbits(s, 0, 0);
return(SSDV_OK);
}
char ssdv_enc_get_packet(ssdv_t *s)
{
int r;
uint8_t b;
/* Have we reached the end of the image? */
if(s->state == S_EOI) return(SSDV_EOI);
/* If the output buffer is empty, re-initialise */
if(s->out_len == 0) ssdv_enc_set_buffer(s, s->out);
while(s->in_len)
{
b = *(s->inp++);
s->in_len--;
/* Skip bytes if necessary */
if(s->in_skip) { s->in_skip--; continue; }
switch(s->state)
{
case S_MARKER:
s->marker = (s->marker << 8) | b;
if(s->marker == J_TEM ||
(s->marker >= J_RST0 && s->marker <= J_EOI))
{
/* Marker without data */
s->marker_len = 0;
r = ssdv_have_marker(s);
if(r != SSDV_OK) return(r);
}
else if(s->marker >= J_SOF0 && s->marker <= J_COM)
{
/* All other markers are followed by data */
s->marker_len = 0;
s->state = S_MARKER_LEN;
s->needbits = 16;
}
break;
case S_MARKER_LEN:
s->marker_len = (s->marker_len << 8) | b;
if((s->needbits -= 8) == 0)
{
s->marker_len -= 2;
r = ssdv_have_marker(s);
if(r != SSDV_OK) return(r);
}
break;
case S_MARKER_DATA:
s->marker_data[s->marker_data_len++] = b;
if(s->marker_data_len == s->marker_len)
{
r = ssdv_have_marker_data(s);
if(r != SSDV_OK) return(r);
}
break;
case S_HUFF:
case S_INT:
/* Is the next byte a stuffing byte? Skip it */
/* TODO: Test the next byte is actually 0x00 */
if(b == 0xFF) s->in_skip++;
/* Add the new byte to the work area */
s->workbits = (s->workbits << 8) | b;
s->worklen += 8;
/* Process the new data until more needed, or an error occurs */
while((r = ssdv_process(s)) == SSDV_OK);
if(r == SSDV_BUFFER_FULL || r == SSDV_EOI)
{
uint16_t mcu_id = s->packet_mcu_id;
uint8_t i, mcu_offset = s->packet_mcu_offset;
uint32_t x;
if(mcu_offset != 0xFF && mcu_offset >= SSDV_PKT_SIZE_PAYLOAD)
{
/* The first MCU begins in the next packet, not this one */
mcu_id = 0xFFFF;
mcu_offset = 0xFF;
s->packet_mcu_offset -= SSDV_PKT_SIZE_PAYLOAD;
}
else
{
/* Clear the MCU data for the next packet */
s->packet_mcu_id = 0xFFFF;
s->packet_mcu_offset = 0xFF;
}
/* A packet is ready, create the headers */
s->out[0] = 0x55; /* Sync */
s->out[1] = 0x66; /* Type */
s->out[2] = s->callsign >> 24;
s->out[3] = s->callsign >> 16;
s->out[4] = s->callsign >> 8;
s->out[5] = s->callsign;
s->out[6] = s->image_id; /* Image ID */
s->out[7] = s->packet_id >> 8; /* Packet ID MSB */
s->out[8] = s->packet_id & 0xFF; /* Packet ID LSB */
s->out[9] = s->width >> 4; /* Width / 16 */
s->out[10] = s->height >> 4; /* Height / 16 */
s->out[11] = s->mcu_mode & 0x03; /* MCU mode (2 bits) */
s->out[12] = mcu_offset; /* Next MCU offset */
s->out[13] = mcu_id >> 8; /* MCU ID MSB */
s->out[14] = mcu_id & 0xFF; /* MCU ID LSB */
/* Fill any remaining bytes with noise */
if(s->out_len > 0) ssdv_memset_prng(s->outp, s->out_len);
/* Calculate the CRC codes */
x = crc32(&s->out[1], SSDV_PKT_SIZE_CRCDATA);
i = 1 + SSDV_PKT_SIZE_CRCDATA;
s->out[i++] = (x >> 24) & 0xFF;
s->out[i++] = (x >> 16) & 0xFF;
s->out[i++] = (x >> 8) & 0xFF;
s->out[i++] = x & 0xFF;
/* Generate the RS codes */
encode_rs_8(&s->out[1], &s->out[i], 0);
s->packet_id++;
/* Have we reached the end of the image data? */
if(r == SSDV_EOI) s->state = S_EOI;
return(SSDV_OK);
}
else if(r != SSDV_FEED_ME) return(SSDV_ERROR);
break;
case S_EOI:
/* Shouldn't reach this point */
break;
}
}
/* Need more data */
return(SSDV_FEED_ME);
}
char ssdv_enc_feed(ssdv_t *s, uint8_t *buffer, size_t length)
{
s->inp = buffer;
s->in_len = length;
return(SSDV_OK);
}
/*****************************************************************************/
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