Initial commit of stand-alone decoder

1 files changed, 220 insertions, 0 deletions

diff --git a/ipedec.c b/ipedec.c
new file mode 100644
index 0000000..48a1a7a
--- /dev/null
+++ b/ipedec.c
@@ -0,0 +1,220 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#define IPECAMERA_MAX_LINES 1088
+#define IPECAMERA_MAX_CHANNELS 16
+#define IPECAMERA_PIXELS_PER_CHANNEL 128
+#define IPECAMERA_WIDTH (IPECAMERA_MAX_CHANNELS * IPECAMERA_PIXELS_PER_CHANNEL)
+#define IPECAMERA_HEIGHT 1088
+
+int ipecamera_channel_order[IPECAMERA_MAX_CHANNELS] = { 15, 13, 14, 12, 10, 8, 11, 7, 9, 6, 5, 2, 4, 3, 0, 1 };
+
+#define CHECK_VALUE(value, expected) \
+    if (value != expected) { \
+        fprintf(stderr, "<%s:%i> 0x%x != 0x%x\n", __FILE__, __LINE__, value, expected); \
+        err = 1; \
+    }
+
+#define CHECK_FLAG(flag, check, ...) \
+    if (!(check)) { \
+        fprintf(stderr, "<%s:%i> Unexpected value 0x%x of " flag "\n", __FILE__, __LINE__,  __VA_ARGS__); \
+        err = 1; \
+    }
+
+
+static int ipecamera_get_payload(uint16_t *pixel_buffer, 
+        int line_req, size_t size, 
+        uint32_t *payload,
+        int *advance, int *increase_line)
+{
+    int ppw;
+    int err = 0;
+
+    uint32_t info = payload[0];
+    int channel = info & 0x0F;          // 4 bits
+    int line = (info >> 4) & 0x7FF;     // 11 bits
+    int bpp = (info >> 16) & 0x0F;      // 4 bits
+    int pixels = (info >> 20) & 0xFF;   // 8 bits
+    int header = (info >> 30) & 0x03;   // 2 bits
+
+    int bytes, pix, pix_offset = 0;
+    uint32_t data;
+
+    *increase_line = channel == 15 ? 1 : 0;
+    channel = ipecamera_channel_order[channel];
+
+    CHECK_FLAG("payload header magick", header == 2, header);
+    CHECK_FLAG("pixel size, only 10 bits are supported", bpp == 10, bpp);
+    CHECK_FLAG("row number, should be %i", line == line_req, line, line_req);
+    CHECK_FLAG("channel, limited by %i output channels", channel < IPECAMERA_MAX_CHANNELS, channel, IPECAMERA_MAX_CHANNELS);
+
+    if ((line < 2) && (pixels == (IPECAMERA_PIXELS_PER_CHANNEL - 1))) {
+        pix_offset = 1;
+        pixel_buffer[channel*IPECAMERA_PIXELS_PER_CHANNEL] = 0;
+    } 
+    else 
+        CHECK_FLAG("number of pixels, %i is expected", pixels == IPECAMERA_PIXELS_PER_CHANNEL, pixels, IPECAMERA_PIXELS_PER_CHANNEL);
+
+    bytes = pixels / 3;
+    ppw = pixels - bytes * 3;
+    if (ppw) 
+        ++bytes;
+
+    CHECK_FLAG("payload data bytes, at least %i are expected", bytes < size, (unsigned int) size, bytes);
+
+    if (err) 
+        return err;
+
+    pix = pix_offset;
+    for (int i = 1; i < bytes; i++) {
+        data = payload[i];
+        header = (data >> 30) & 0x03;   
+
+        CHECK_FLAG("payload data magick", header == 3, header);
+        if (err) 
+            return err;
+
+        pixel_buffer[channel*IPECAMERA_PIXELS_PER_CHANNEL + pix++] = (data >> 20) & 0x3FF;
+        pixel_buffer[channel*IPECAMERA_PIXELS_PER_CHANNEL + pix++] = (data >> 10) & 0x3FF;
+        pixel_buffer[channel*IPECAMERA_PIXELS_PER_CHANNEL + pix++] = data & 0x3FF;
+    }
+
+    data = payload[bytes];
+    header = (data >> 30) & 0x03;
+
+    CHECK_FLAG("payload data magick", header == 3, header);
+    CHECK_FLAG("payload footer magick", (data&0x3FF) == 0x55, (data&0x3FF));
+    if ((err) && ((data & 0x3FF) != 0x55)) {
+        err = 0; 
+        int counter = 0;
+        printf(" -> %x\n", data);
+        while ((data & 0x3FF) != 0x55) {
+            bytes++; 
+            data = payload[bytes];
+            counter++;
+        }
+        printf("skipped %i bytes: found %x\n", counter, data);
+    }
+    if (err) 
+        return err;
+
+    ppw = pixels % 3;
+    assert(ppw < 3);
+
+    for (int j = 0; j < ppw; j++, pix++)
+        pixel_buffer[channel*IPECAMERA_PIXELS_PER_CHANNEL + pix] = (data >> (10 * (ppw - j))) & 0x3FF;
+
+    *advance = bytes + 1;
+    return 0;
+}
+
+static int ipecamera_parse_image(int first_line, int num_lines, 
+        size_t size, uint32_t *linebuf, int *frames_decoded) 
+{
+    int err = 0, current_frame = 0;
+    int pos = 0, advance, increase_line;
+
+    if (size < 16) {
+        fprintf(stderr, "The payload is tool small, we should have at least 8 header dwords and 8 footer.");
+        return 1;
+    }
+
+    FILE *fp = fopen("image.dec.raw", "wb");
+    uint16_t *pixel_buffer = (uint16_t *) malloc(num_lines * IPECAMERA_WIDTH * sizeof(uint16_t));
+
+    printf("Decoding");
+    while (size > 0) {
+        printf(".");
+        int line = first_line;
+        CHECK_VALUE(linebuf[pos++], 0x51111111);
+        CHECK_VALUE(linebuf[pos++], 0x52222222);
+        CHECK_VALUE(linebuf[pos++], 0x53333333);
+        CHECK_VALUE(linebuf[pos++], 0x54444444);
+        CHECK_VALUE(linebuf[pos++], 0x55555555);
+        CHECK_VALUE(linebuf[pos++], 0x56666666);
+        CHECK_VALUE(linebuf[pos++], 0x57777777);
+        CHECK_VALUE(linebuf[pos++], 0x58888888);
+        if (err) 
+            return err;
+
+        size -= 16;
+
+        while ((size > 0) && (line < (first_line + num_lines))) {
+            err = ipecamera_get_payload(pixel_buffer + line * IPECAMERA_WIDTH,
+                    line - first_line, size, linebuf + pos, &advance, &increase_line);
+            if (err) 
+                return err;
+
+            pos += advance;
+            size -= advance;
+            line += increase_line;
+        }
+
+        CHECK_FLAG("lines read, we expect to read exactly %i lines", line == (first_line + num_lines), line - first_line, num_lines);
+
+        CHECK_VALUE(linebuf[pos++], 0x0AAAAAAA);
+        CHECK_VALUE(linebuf[pos++], 0x0BBBBBBB);
+        CHECK_VALUE(linebuf[pos++], 0x0CCCCCCC);
+        CHECK_VALUE(linebuf[pos++], 0x0DDDDDDD);
+        CHECK_VALUE(linebuf[pos++], 0x0EEEEEEE);
+        CHECK_VALUE(linebuf[pos++], 0x0FFFFFFF);
+        CHECK_VALUE(linebuf[pos++], 0x00000000);
+        CHECK_VALUE(linebuf[pos++], 0x01111111);
+
+        fwrite(pixel_buffer, IPECAMERA_WIDTH * num_lines, sizeof(uint16_t), fp);
+
+        if (linebuf[pos] == 0)
+            break;
+
+        current_frame++;
+    }
+    fclose(fp);
+    free(pixel_buffer);
+    printf("\n");
+    *frames_decoded = current_frame + 1;
+    return err;
+}
+
+int main(int argc, char const* argv[])
+{
+    if (argc < 3) {
+        fprintf(stderr, "Usage: ipedec <filename> <number of lines per frame>\n");
+        return 1;
+    }
+
+    FILE *fp = fopen(argv[1], "rb"); 
+    if (fp == NULL) {
+        fprintf(stderr, "Couldn't open file %s", argv[1]);
+        return 1;
+    }
+
+    const int lines_per_frame = atoi(argv[2]);
+
+    fseek(fp, 0, SEEK_END);
+    const size_t length = ftell(fp);
+    rewind(fp);
+
+    char *buffer = (char *) malloc(length);
+    if (buffer == NULL) {
+        fclose(fp);
+        return 1;
+    }
+
+    size_t buffer_length = fread(buffer, 1, length, fp);
+    fclose(fp);
+    if (buffer_length != length) {
+        free(buffer);
+        return 1;
+    }
+
+    int num_frames;
+    if (ipecamera_parse_image(0, lines_per_frame, length, (uint32_t *) buffer, &num_frames))
+        fprintf(stderr, "Couldn't parse image\n");
+
+    printf("Decoded %i frames.\n", num_frames);
+    free(buffer);
+    return 0;
+}
+