ssdv.h

/* 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>

#ifndef INC_SSDV_H
#define INC_SSDV_H
#ifdef __cplusplus
extern "C" {
#endif

#define SSDV_ERROR       (-1)
#define SSDV_OK          (0)
#define SSDV_FEED_ME     (1)
#define SSDV_HAVE_PACKET (2)
#define SSDV_BUFFER_FULL (3)
#define SSDV_EOI         (4)

/* Packet details */
#define SSDV_PKT_SIZE         (0x100)
#define SSDV_PKT_SIZE_HEADER  (0x0F)
#define SSDV_PKT_SIZE_CRC     (0x04)
#define SSDV_PKT_SIZE_RSCODES (0x20)
#define SSDV_PKT_SIZE_PAYLOAD (SSDV_PKT_SIZE - SSDV_PKT_SIZE_HEADER - SSDV_PKT_SIZE_CRC - SSDV_PKT_SIZE_RSCODES)
#define SSDV_PKT_SIZE_CRCDATA (SSDV_PKT_SIZE_HEADER + SSDV_PKT_SIZE_PAYLOAD - 1)

#define TBL_LEN (546) /* Maximum size of the DQT and DHT tables */
#define HBUFF_LEN (16) /* Extra space for reading marker data */
//#define COMPONENTS (3)

typedef struct
{
  /* Image information */
  uint16_t width;
  uint16_t height;
  uint32_t callsign;
  uint8_t  image_id;
  uint16_t packet_id;
  uint8_t  mcu_mode;  /* 0 = 2x2, 1 = 2x1, 2 = 1x2, 3 = 1x1           */
  uint16_t mcu_id;
  uint16_t mcu_count;
  uint16_t packet_mcu_id;
  uint8_t  packet_mcu_offset;

  /* Source buffer */
  uint8_t *inp;      /* Pointer to next input byte                    */
  size_t in_len;     /* Number of input bytes remaining               */
  size_t in_skip;    /* Number of input bytes to skip                 */

  /* Source bits */
  uint32_t workbits; /* Input bits currently being worked on          */
  uint8_t worklen;   /* Number of bits in the input bit buffer        */

  /* JPEG / Packet output buffer */
  uint8_t *out;      /* Pointer to the beginning of the output buffer */
  uint8_t *outp;     /* Pointer to the next output byte               */
  size_t out_len;    /* Number of output bytes remaining              */
  char out_stuff;    /* Flag to add stuffing bytes to output          */

  /* Output bits */
  uint32_t outbits;  /* Output bit buffer                             */
  uint8_t outlen;    /* Number of bits in the output bit buffer       */

  /* JPEG decoder state */
  enum {
    S_MARKER = 0,
    S_MARKER_LEN,
    S_MARKER_DATA,
    S_HUFF,
    S_INT,
    S_EOI,
  } state;
  uint16_t marker;    /* Current marker                               */
  uint16_t marker_len; /* Length of data following marker             */
  uint8_t *marker_data; /* Where to copy marker data too              */
  uint16_t marker_data_len; /* How much is there                      */
  uint8_t component;  /* 0 = Y, 1 = Cb, 2 = Cr                        */
  uint8_t ycparts;    /* Number of Y component parts per MCU          */
  uint8_t mcupart;    /* 0-3 = Y, 4 = Cb, 5 = Cr                      */
  uint8_t acpart;     /* 0 - 64; 0 = DC, 1 - 64 = AC                  */
  int dc[3];          /* DC value for each component                  */
  int adc[3];         /* DC adjusted value for each component         */
  uint8_t acrle;      /* RLE value for current AC value               */
  uint8_t accrle;     /* Accumulative RLE value                       */
  uint16_t dri;       /* Reset interval                               */
  enum {
    S_ENCODING = 0,
    S_DECODING,
  } mode;
  uint32_t reset_mcu; /* MCU block to do absolute encoding            */
  char needbits;      /* Number of bits needed to decode integer      */

  /* The input huffman and quantisation tables */
  uint8_t stbls[TBL_LEN + HBUFF_LEN];
  uint8_t *sdht[2][2], *sdqt[2];
  uint16_t stbl_len;

  /* The same for output */
  uint8_t dtbls[TBL_LEN];
  uint8_t *ddht[2][2], *ddqt[2];
  uint16_t dtbl_len;

} ssdv_t;

typedef struct {
  uint32_t callsign;
  uint8_t  image_id;
  uint16_t packet_id;
  uint16_t width;
  uint16_t height;
  uint16_t mcu_mode;
  uint8_t  mcu_offset;
  uint16_t mcu_id;
  uint16_t mcu_count;
} ssdv_packet_info_t;

/* Encoding */
extern char ssdv_enc_init(ssdv_t *s, const char *callsign, uint8_t image_id);
extern char ssdv_enc_set_buffer(ssdv_t *s, uint8_t *buffer);
extern char ssdv_enc_get_packet(ssdv_t *s);
extern char ssdv_enc_feed(ssdv_t *s, uint8_t *buffer, size_t length);

/* Decoding */
extern char ssdv_dec_init(ssdv_t *s);
extern char ssdv_dec_set_buffer(ssdv_t *s, uint8_t *buffer, size_t length);
extern char ssdv_dec_feed(ssdv_t *s, uint8_t *packet);
extern char ssdv_dec_get_jpeg(ssdv_t *s, uint8_t **jpeg, size_t *length);

extern char ssdv_dec_is_packet(uint8_t *packet, int *errors);
extern void ssdv_dec_header(ssdv_packet_info_t *info, uint8_t *packet);
extern char * ssdv_dec_callsign(char *callsign, uint32_t code);

#ifdef __cplusplus
}
#endif
#endif