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Only reset the MCU DC values for the first MCU on each packet

This commit is contained in:
Philip Heron 2012-01-29 18:56:17 +00:00
parent ca837206d5
commit fe7ff49074
3 changed files with 33 additions and 16 deletions
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2
.gitignore vendored
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@ -1,4 +1,4 @@
ssdv
*.o
*.jpeg
*.bin
*.bin*

37
ssdv.c
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@ -314,9 +314,9 @@ static char ssdv_process(ssdv_t *s)
if(symbol == 0x00)
{
/* No change in DC from last block */
if(s->mcupart == 0 || s->mcupart == 4 || s->mcupart == 5)
if(s->reset_mcu == s->mcu_id && (s->mcupart == 0 || s->mcupart == 4 || s->mcupart == 5))
{
if(s->dcmode == 0) ssdv_out_jpeg_int(s, 0, AADJ(s->dc[s->component]));
if(s->mode == S_ENCODING) ssdv_out_jpeg_int(s, 0, s->adc[s->component]);
else
{
ssdv_out_jpeg_int(s, 0, 0 - s->dc[s->component]);
@ -376,13 +376,14 @@ static char ssdv_process(ssdv_t *s)
if(s->acpart == 0) /* DC */
{
if(s->mcupart == 0 || s->mcupart == 4 || s->mcupart == 5)
if(s->reset_mcu == s->mcu_id && (s->mcupart == 0 || s->mcupart == 4 || s->mcupart == 5))
{
if(s->dcmode == 0)
if(s->mode == S_ENCODING)
{
/* Output absolute DC value */
s->dc[s->component] += UADJ(i);
ssdv_out_jpeg_int(s, 0, AADJ(s->dc[s->component]));
s->adc[s->component] = AADJ(s->dc[s->component]);
ssdv_out_jpeg_int(s, 0, s->adc[s->component]);
}
else
{
@ -393,9 +394,21 @@ static char ssdv_process(ssdv_t *s)
}
else
{
/* Output relative DC value */
s->dc[s->component] += UADJ(i);
ssdv_out_jpeg_int(s, 0, BADJ(i));
if(s->mode == S_DECODING)
{
s->dc[s->component] += UADJ(i);
ssdv_out_jpeg_int(s, 0, i);
}
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 */
@ -453,6 +466,7 @@ static char ssdv_process(ssdv_t *s)
/* Set the packet MCU marker - encoder only */
if(s->packet_mcu_id == 0xFFFF)
{
if(s->mode == S_ENCODING) s->reset_mcu = s->mcu_id;
s->packet_mcu_id = s->mcu_id;
s->packet_mcu_offset =
(SSDV_PKT_SIZE_PAYLOAD - s->out_len) * 8 + s->outlen;
@ -677,6 +691,7 @@ char ssdv_enc_init(ssdv_t *s, uint8_t image_id)
{
memset(s, 0, sizeof(ssdv_t));
s->image_id = image_id;
s->mode = S_ENCODING;
return(SSDV_OK);
}
@ -933,9 +948,7 @@ char ssdv_dec_init(ssdv_t *s)
/* The packet data should contain only scan data, no headers */
s->state = S_HUFF;
/* Converting absolute values to relative */
s->dcmode = 1;
s->mode = S_DECODING;
return(SSDV_OK);
}
@ -965,6 +978,8 @@ char ssdv_dec_feed(ssdv_t *s, uint8_t *packet)
s->packet_mcu_offset = (packet[7] << 8) | packet[8];
s->packet_mcu_id = (packet[9] << 8) | packet[10];
if(s->packet_mcu_id != 0xFFFF) s->reset_mcu = s->packet_mcu_id;
/* If this is the first packet, write the JPEG headers */
if(s->packet_id == 0)
{

10
ssdv.h
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@ -89,17 +89,19 @@ typedef struct
uint8_t mcupart; /* 0-3 = Y, 4 = Cb, 5 = Cr */
uint8_t acpart; /* 0 - 64; 0 = DC, 1 - 64 = AC */
int dc[COMPONENTS]; /* DC value for each component */
int adc[COMPONENTS];/* DC adjusted value for each component */
uint8_t acrle; /* RLE value for current AC value */
uint8_t accrle; /* Accumulative RLE value */
char dcmode; /* 0 = Absolute, 1 = Relative (parts 0, 4 & 5) */
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 */
/* Small buffer for reading SOF0 and SOS header data into */
uint8_t hbuff[HBUFF_LEN];
/* SSDV2 experiment */
int block[64];
} ssdv_t;
typedef struct {