initial Interplay video decoder

Originally committed as revision 2275 to svn://svn.ffmpeg.org/ffmpeg/trunk

Changelog

@@ -3,7 +3,7 @@ Upcoming version 0.4.8:
 - Wing Commander III Movie (.mve) file playback subsystem (Mike Melanson
   and Mario Brito)
 - Xan DPCM audio decoder (Mario Brito)
-- Interplay MVE demuxer and DPCM audio decoder (Mike Melanson)
+- Interplay MVE playback subsystem (Mike Melanson)
 - Duck DK3 and DK4 ADPCM audio decoders (Mike Melanson)
 
 version 0.4.7:

doc/ffmpeg-doc.texi

@@ -681,6 +681,7 @@ following image formats are supported:
 @item Sony Playstation MDEC  @tab     @tab  X 
 @item Id RoQ                 @tab     @tab  X @tab used in Quake III, Jedi Knight 2, other computer games
 @item Xan/WC3                @tab     @tab  X @tab used in Wing Commander III .MVE files
+@item Interplay Video        @tab     @tab  X @tab used in Interplay .MVE files
 @end multitable
 
 @code{X} means that the encoding (resp. decoding) is supported.

libavcodec/interplayvideo.c

@@ -19,10 +19,18 @@
  */
 
 /**
- * @file roqvideo.c
- * Interplay MVE Video Decoder by Mike Melanson
+ * @file interplayvideo.c
+ * Interplay MVE Video Decoder by Mike Melanson (melanson@pcisys.net)
  * For more information about the Interplay MVE format, visit:
- *   http://www.pcisys.net/~melanson/codecs/
+ *   http://www.pcisys.net/~melanson/codecs/interplay-mve.txt
+ * This code is written in such a way that the identifiers match up
+ * with the encoding descriptions in the document.
+ *
+ * This decoder presently only supports a PAL8 output colorspace.
+ *
+ * An Interplay video frame consists of 2 parts: The decoding map and
+ * the video data. A demuxer must load these 2 parts together in a single
+ * buffer before sending it through the stream to this decoder.
  */
 
 #include <stdio.h>
@@ -34,6 +42,16 @@
 #include "avcodec.h"
 #include "dsputil.h"
 
+#define PALETTE_COUNT 256
+
+/* debugging support */
+#define DEBUG_INTERPLAY 0
+#if DEBUG_INTERPLAY
+#define debug_interplay printf
+#else
+static inline void debug_interplay(const char *format, ...) { }
+#endif
+
 typedef struct IpvideoContext {
 
     AVCodecContext *avctx;
@@ -41,30 +59,857 @@ typedef struct IpvideoContext {
     AVFrame last_frame;
     AVFrame current_frame;
     int first_frame;
-    int receiving_decoding_map;
     unsigned char *decoding_map;
     int decoding_map_size;
 
     unsigned char *buf;
     int size;
 
+    unsigned char palette[PALETTE_COUNT * 4];
+
 } IpvideoContext;
 
+#define CHECK_STREAM_PTR(n) \
+  if ((sg_stream_ptr + n) > sg_stream_end) { \
+    printf ("Interplay video warning: stream_ptr out of bounds (%p >= %p)\n", \
+      sg_stream_ptr + n, sg_stream_end); \
+    return -1; \
+  }
+
+static void ipvideo_new_palette(IpvideoContext *s, unsigned char *palette) {
+
+    int i;
+    unsigned char r, g, b;
+    unsigned int *palette32;
+
+    switch (s->avctx->pix_fmt) {
+
+    case PIX_FMT_PAL8:
+        palette32 = (unsigned int *)s->palette;
+        for (i = 0; i < PALETTE_COUNT; i++) {
+            r = *palette++;
+            g = *palette++;
+            b = *palette++;
+            palette32[i] = (r << 16) | (g << 8) | (b);
+        }
+        break;
+
+    default:
+        printf ("Interplay video: Unhandled video format\n");
+        break;
+    }
+}
+
+static unsigned char *sg_stream_ptr;
+static unsigned char *sg_stream_end;
+static unsigned char *sg_current_plane;
+static unsigned char *sg_output_plane;
+static unsigned char *sg_last_plane;
+static int sg_line_inc;
+static int sg_stride;
+static int sg_upper_motion_limit_offset;
+static DSPContext sg_dsp;
+
+static int ipvideo_decode_block_opcode_0x0_0x1(void)
+{
+    int x, y;
+    unsigned char *src_block;
+
+    /* skip block, which actually means to copy from previous frame */
+    src_block = sg_last_plane + (sg_output_plane - sg_current_plane);
+    for (y = 0; y < 8; y++) {
+        for (x = 0; x < 8; x++) {
+            *sg_output_plane++ = *src_block++;
+        }
+        sg_output_plane += sg_line_inc;
+        src_block += sg_line_inc;
+    }
+
+    /* report success */
+    return 0;
+}
+
+#define COPY_FROM_CURRENT() \
+    motion_offset = current_offset; \
+    motion_offset += y * sg_stride; \
+    motion_offset += x; \
+    if (motion_offset < 0) { \
+        printf (" Interplay video: motion offset < 0 (%d)\n", motion_offset); \
+        return -1; \
+    } else if (motion_offset > sg_upper_motion_limit_offset) { \
+        printf (" Interplay video: motion offset above limit (%d >= %d)\n", \
+            motion_offset, sg_upper_motion_limit_offset); \
+        return -1; \
+    } \
+    sg_dsp.put_pixels_tab[0][0](sg_output_plane, \
+        sg_current_plane + motion_offset, sg_stride, 8);
+
+#define COPY_FROM_PREVIOUS() \
+    motion_offset = current_offset; \
+    motion_offset += y * sg_stride; \
+    motion_offset += x; \
+    if (motion_offset < 0) { \
+        printf (" Interplay video: motion offset < 0 (%d)\n", motion_offset); \
+        return -1; \
+    } else if (motion_offset > sg_upper_motion_limit_offset) { \
+        printf (" Interplay video: motion offset above limit (%d >= %d)\n", \
+            motion_offset, sg_upper_motion_limit_offset); \
+        return -1; \
+    } \
+    sg_dsp.put_pixels_tab[0][0](sg_output_plane, \
+        sg_last_plane + motion_offset, sg_stride, 8);
+
+static int ipvideo_decode_block_opcode_0x2(void)
+{
+    unsigned char B;
+    int x, y;
+    int motion_offset;
+    int current_offset = sg_output_plane - sg_current_plane;
+
+    /* This is the opcode which claims to copy data from within the same
+     * frame at a coordinate which has not been rendered yet. Assume that
+     * it is supposed to be copied from the previous frame. */
+
+    /* need 1 more byte for motion */
+    CHECK_STREAM_PTR(1);
+    B = *sg_stream_ptr++;
+
+    if (B < 56) {
+        x = 8 + (B % 7);
+        y = B / 7;
+    } else {
+        x = -14 + ((B - 56) % 29);
+        y =   8 + ((B - 56) / 29);
+    }
+
+    debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
+    COPY_FROM_PREVIOUS();
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0x3(void)
+{
+    unsigned char B;
+    int x, y;
+    int motion_offset;
+    int current_offset = sg_output_plane - sg_current_plane;
+
+    /* copy 8x8 block from current frame from an up/left block */
+
+    /* need 1 more byte for motion */
+    CHECK_STREAM_PTR(1);
+    B = *sg_stream_ptr++;
+
+    if (B < 56) {
+        x = -(8 + (B % 7));
+        y = -(B / 7);
+    } else {
+        x = -(-14 + ((B - 56) % 29));
+        y = -(  8 + ((B - 56) / 29));
+    }
+
+    debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
+    COPY_FROM_CURRENT();
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0x4(void)
+{
+    int x, y;
+    unsigned char B, BL, BH;
+    int motion_offset;
+    int current_offset = sg_output_plane - sg_current_plane;
+
+    /* copy a block from the previous frame; need 1 more byte */
+    CHECK_STREAM_PTR(1);
+
+    B = *sg_stream_ptr++;
+    BL = B & 0x0F;
+    BH = (B >> 4) & 0x0F;
+    x = -8 + BL;
+    y = -8 + BH;
+
+    debug_interplay ("    motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
+    COPY_FROM_PREVIOUS();
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0x5(void)
+{
+    signed char x, y;
+    int motion_offset;
+    int current_offset = sg_output_plane - sg_current_plane;
+
+    /* copy a block from the previous frame using an expanded range;
+     * need 2 more bytes */
+    CHECK_STREAM_PTR(2);
+
+    x = *sg_stream_ptr++;
+    y = *sg_stream_ptr++;
+
+    debug_interplay ("    motion bytes = %d, %d\n", x, y);
+    COPY_FROM_PREVIOUS();
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0x6(void)
+{
+    /* mystery opcode? skip multiple blocks? */
+    printf ("  Interplay video: Help! Mystery opcode 0x6 seen\n");
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0x7(void)
+{
+    int x, y;
+    unsigned char P0, P1;
+    unsigned char B[8];
+    unsigned int flags;
+    int bitmask;
+
+    /* 2-color encoding */
+    CHECK_STREAM_PTR(2);
+
+    P0 = *sg_stream_ptr++;
+    P1 = *sg_stream_ptr++;
+
+    if (P0 <= P1) {
+
+        /* need 8 more bytes from the stream */
+        CHECK_STREAM_PTR(8);
+        for (y = 0; y < 8; y++)
+            B[y] = *sg_stream_ptr++;
+
+        for (y = 0; y < 8; y++) {
+            flags = B[y];
+            for (x = 0x80; x != 0; x >>= 1) {
+                if (flags & x)
+                    *sg_output_plane++ = P1;
+                else
+                    *sg_output_plane++ = P0;
+            }
+            sg_output_plane += sg_line_inc;
+        }
+
+    } else {
+
+        /* need 2 more bytes from the stream */
+        CHECK_STREAM_PTR(2);
+        B[0] = *sg_stream_ptr++;
+        B[1] = *sg_stream_ptr++;
+
+        flags = (B[0] << 8) | B[1];
+        bitmask = 0x8000;
+        for (y = 0; y < 8; y += 2) {
+            for (x = 0; x < 8; x += 2, bitmask >>= 1) {
+                if (flags & bitmask) {
+                    *(sg_output_plane + x) = P0;
+                    *(sg_output_plane + x + 1) = P0;
+                    *(sg_output_plane + sg_stride + x) = P0;
+                    *(sg_output_plane + sg_stride + x + 1) = P0;
+                } else {
+                    *(sg_output_plane + x) = P1;
+                    *(sg_output_plane + x + 1) = P1;
+                    *(sg_output_plane + sg_stride + x) = P1;
+                    *(sg_output_plane + sg_stride + x + 1) = P1;
+                }
+            }
+            sg_output_plane += sg_stride * 2;
+        }
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0x8(void)
+{
+    int x, y;
+    unsigned char P[8];
+    unsigned char B[8];
+    unsigned int flags = 0;
+    unsigned int bitmask = 0;
+    unsigned char P0 = 0, P1 = 0;
+    int lower_half = 0;
+
+    /* 2-color encoding for each 4x4 quadrant, or 2-color encoding on
+     * either top and bottom or left and right halves */
+    CHECK_STREAM_PTR(2);
+
+    P[0] = *sg_stream_ptr++;
+    P[1] = *sg_stream_ptr++;
+
+    if (P[0] <= P[1]) {
+
+        /* need 12 more bytes */
+        CHECK_STREAM_PTR(12);
+        B[0] = *sg_stream_ptr++;  B[1] = *sg_stream_ptr++;
+        P[2] = *sg_stream_ptr++;  P[3] = *sg_stream_ptr++;
+        B[2] = *sg_stream_ptr++;  B[3] = *sg_stream_ptr++;
+        P[4] = *sg_stream_ptr++;  P[5] = *sg_stream_ptr++;
+        B[4] = *sg_stream_ptr++;  B[5] = *sg_stream_ptr++;
+        P[6] = *sg_stream_ptr++;  P[7] = *sg_stream_ptr++;
+        B[6] = *sg_stream_ptr++;  B[7] = *sg_stream_ptr++;
+
+        for (y = 0; y < 8; y++) {
+
+            /* time to reload flags? */
+            if (y == 0) {
+                flags =
+                    ((B[0] & 0xF0) << 24) | ((B[4] & 0xF0) << 20) |
+                    ((B[0] & 0x0F) << 20) | ((B[4] & 0x0F) << 16) |
+                    ((B[1] & 0xF0) <<  8) | ((B[5] & 0xF0) <<  4) |
+                    ((B[1] & 0x0F) <<  4) | ((B[5] & 0x0F) <<  0);
+                bitmask = 0x80000000;
+                lower_half = 0;  /* still on top half */
+            } else if (y == 4) {
+                flags =
+                    ((B[2] & 0xF0) << 24) | ((B[6] & 0xF0) << 20) |
+                    ((B[2] & 0x0F) << 20) | ((B[6] & 0x0F) << 16) |
+                    ((B[3] & 0xF0) <<  8) | ((B[7] & 0xF0) <<  4) |
+                    ((B[3] & 0x0F) <<  4) | ((B[7] & 0x0F) <<  0);
+                bitmask = 0x80000000;
+                lower_half = 4;
+            }
+
+            for (x = 0; x < 8; x++, bitmask >>= 1) {
+                /* get the pixel values ready for this quadrant */
+                if (x == 0) {
+                    P0 = P[lower_half + 0];
+                    P1 = P[lower_half + 1];
+                } else if (x == 4) {
+                    P0 = P[lower_half + 2];
+                    P1 = P[lower_half + 3];
+                }
+
+                if (flags & bitmask)
+                    *sg_output_plane++ = P1;
+                else
+                    *sg_output_plane++ = P0;
+            }
+            sg_output_plane += sg_line_inc;
+        }
+
+    } else {
+
+        /* need 10 more bytes */
+        CHECK_STREAM_PTR(10);
+        B[0] = *sg_stream_ptr++;  B[1] = *sg_stream_ptr++;
+        B[2] = *sg_stream_ptr++;  B[3] = *sg_stream_ptr++;
+        P[2] = *sg_stream_ptr++;  P[3] = *sg_stream_ptr++;
+        B[4] = *sg_stream_ptr++;  B[5] = *sg_stream_ptr++;
+        B[6] = *sg_stream_ptr++;  B[7] = *sg_stream_ptr++;
+
+        if (P[2] <= P[3]) {
+
+            /* vertical split; left & right halves are 2-color encoded */
+
+            for (y = 0; y < 8; y++) {
+
+                /* time to reload flags? */
+                if (y == 0) {
+                    flags =
+                        ((B[0] & 0xF0) << 24) | ((B[4] & 0xF0) << 20) |
+                        ((B[0] & 0x0F) << 20) | ((B[4] & 0x0F) << 16) |
+                        ((B[1] & 0xF0) <<  8) | ((B[5] & 0xF0) <<  4) |
+                        ((B[1] & 0x0F) <<  4) | ((B[5] & 0x0F) <<  0);
+                    bitmask = 0x80000000;
+                } else if (y == 4) {
+                    flags =
+                        ((B[2] & 0xF0) << 24) | ((B[6] & 0xF0) << 20) |
+                        ((B[2] & 0x0F) << 20) | ((B[6] & 0x0F) << 16) |
+                        ((B[3] & 0xF0) <<  8) | ((B[7] & 0xF0) <<  4) |
+                        ((B[3] & 0x0F) <<  4) | ((B[7] & 0x0F) <<  0);
+                    bitmask = 0x80000000;
+                }
+
+                for (x = 0; x < 8; x++, bitmask >>= 1) {
+                    /* get the pixel values ready for this half */
+                    if (x == 0) {
+                        P0 = P[0];
+                        P1 = P[1];
+                    } else if (x == 4) {
+                        P0 = P[2];
+                        P1 = P[3];
+                    }
+
+                    if (flags & bitmask)
+                        *sg_output_plane++ = P0;
+                    else
+                        *sg_output_plane++ = P1;
+                }
+                sg_output_plane += sg_line_inc;
+            }
+
+        } else {
+
+            /* horizontal split; top & bottom halves are 2-color encoded */
+
+            for (y = 0; y < 8; y++) {
+
+                flags = B[y];
+                if (y == 0) {
+                    P0 = P[0];
+                    P1 = P[1];
+                } else if (y == 4) {
+                    P0 = P[2];
+                    P1 = P[3];
+                }
+
+                for (bitmask = 0x80; bitmask != 0; bitmask >>= 1) {
+
+                    if (flags & bitmask)
+                        *sg_output_plane++ = P0;
+                    else
+                        *sg_output_plane++ = P1;
+                }
+                sg_output_plane += sg_line_inc;
+            }
+        }
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0x9(void)
+{
+    int x, y;
+    unsigned char P[4];
+    unsigned int flags = 0;
+    int shifter = 0;
+    unsigned char pix;
+
+    /* 4-color encoding */
+    CHECK_STREAM_PTR(4);
+
+    for (y = 0; y < 4; y++)
+        P[y] = *sg_stream_ptr++;
+
+    if ((P[0] <= P[1]) && (P[2] <= P[3])) {
+
+        /* 1 of 4 colors for each pixel, need 16 more bytes */
+        CHECK_STREAM_PTR(16);
+
+        for (y = 0; y < 8; y++) {
+            /* get the next set of 8 2-bit flags */
+            flags = (sg_stream_ptr[0] << 8) | sg_stream_ptr[1];
+            sg_stream_ptr += 2;
+            for (x = 0, shifter = 14; x < 8; x++, shifter -= 2) {
+                *sg_output_plane++ = P[(flags >> shifter) & 0x03];
+            }
+            sg_output_plane += sg_line_inc;
+        }
+
+    } else if ((P[0] <= P[1]) && (P[2] > P[3])) {
+
+        /* 1 of 4 colors for each 2x2 block, need 4 more bytes */
+        CHECK_STREAM_PTR(4);
+
+        flags = 0;
+        flags = (flags << 8) | *sg_stream_ptr++;
+        flags = (flags << 8) | *sg_stream_ptr++;
+        flags = (flags << 8) | *sg_stream_ptr++;
+        flags = (flags << 8) | *sg_stream_ptr++;
+        shifter = 30;
+
+        for (y = 0; y < 8; y += 2) {
+            for (x = 0; x < 8; x += 2, shifter -= 2) {
+                pix = P[(flags >> shifter) & 0x03];
+                *(sg_output_plane + x) = pix;
+                *(sg_output_plane + x + 1) = pix;
+                *(sg_output_plane + sg_stride + x) = pix;
+                *(sg_output_plane + sg_stride + x + 1) = pix;
+            }
+            sg_output_plane += sg_stride * 2;
+        }
+
+    } else if ((P[0] > P[1]) && (P[2] <= P[3])) {
+
+        /* 1 of 4 colors for each 2x1 block, need 8 more bytes */
+        CHECK_STREAM_PTR(8);
+
+        for (y = 0; y < 8; y++) {
+            /* time to reload flags? */
+            if ((y == 0) || (y == 4)) {
+                flags = 0;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                shifter = 30;
+            }
+            for (x = 0; x < 8; x += 2, shifter -= 2) {
+                pix = P[(flags >> shifter) & 0x03];
+                *(sg_output_plane + x) = pix;
+                *(sg_output_plane + x + 1) = pix;
+            }
+            sg_output_plane += sg_stride;
+        }
+
+    } else {
+
+        /* 1 of 4 colors for each 1x2 block, need 8 more bytes */
+        CHECK_STREAM_PTR(8);
+
+        for (y = 0; y < 8; y += 2) {
+            /* time to reload flags? */
+            if ((y == 0) || (y == 4)) {
+                flags = 0;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                flags = (flags << 8) | *sg_stream_ptr++;
+                shifter = 30;
+            }
+            for (x = 0; x < 8; x++, shifter -= 2) {
+                pix = P[(flags >> shifter) & 0x03];
+                *(sg_output_plane + x) = pix;
+                *(sg_output_plane + sg_stride + x) = pix;
+            }
+            sg_output_plane += sg_stride * 2;
+        }
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0xA(void)
+{
+    int x, y;
+    unsigned char P[16];
+    unsigned char B[16];
+    int flags = 0;
+    int shifter = 0;
+    int index;
+    int split;
+    int lower_half;
+
+    /* 4-color encoding for each 4x4 quadrant, or 4-color encoding on
+     * either top and bottom or left and right halves */
+    CHECK_STREAM_PTR(4);
+
+    for (y = 0; y < 4; y++)
+        P[y] = *sg_stream_ptr++;
+
+    if (P[0] <= P[1]) {
+
+        /* 4-color encoding for each quadrant; need 28 more bytes */
+        CHECK_STREAM_PTR(28);
+
+        for (y = 0; y < 4; y++)
+            B[y] = *sg_stream_ptr++;
+        for (y = 4; y < 16; y += 4) {
+            for (x = y; x < y + 4; x++)
+                P[x] = *sg_stream_ptr++;
+            for (x = y; x < y + 4; x++)
+                B[x] = *sg_stream_ptr++;
+        }
+
+        for (y = 0; y < 8; y++) {
+
+            lower_half = (y >= 4) ? 4 : 0;
+            flags = (B[y] << 8) | B[y + 8];
+
+            for (x = 0, shifter = 14; x < 8; x++, shifter -= 2) {
+                split = (x >= 4) ? 8 : 0;
+                index = split + lower_half + ((flags >> shifter) & 0x03);
+                *sg_output_plane++ = P[index];
+            }
+
+            sg_output_plane += sg_line_inc;
+        }
+
+    } else {
+
+        /* 4-color encoding for either left and right or top and bottom
+         * halves; need 20 more bytes */
+        CHECK_STREAM_PTR(20);
+
+        for (y = 0; y < 8; y++)
+            B[y] = *sg_stream_ptr++;
+        for (y = 4; y < 8; y++)
+            P[y] = *sg_stream_ptr++;
+        for (y = 8; y < 16; y++)
+            B[y] = *sg_stream_ptr++;
+
+        if (P[4] <= P[5]) {
+
+            /* block is divided into left and right halves */
+            for (y = 0; y < 8; y++) {
+
+                flags = (B[y] << 8) | B[y + 8];
+                split = 0;
+
+                for (x = 0, shifter = 14; x < 8; x++, shifter -= 2) {
+                    if (x == 4)
+                        split = 4;
+                    *sg_output_plane++ = P[split + ((flags >> shifter) & 0x03)];
+                }
+
+                sg_output_plane += sg_line_inc;
+            }
+
+        } else {
+
+            /* block is divided into top and bottom halves */
+            split = 0;
+            for (y = 0; y < 8; y++) {
+
+                flags = (B[y * 2] << 8) | B[y * 2 + 1];
+                if (y == 4)
+                    split = 4;
+
+                for (x = 0, shifter = 14; x < 8; x++, shifter -= 2)
+                    *sg_output_plane++ = P[split + ((flags >> shifter) & 0x03)];
+
+                sg_output_plane += sg_line_inc;
+            }
+        }
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0xB(void)
+{
+    int x, y;
+
+    /* 64-color encoding (each pixel in block is a different color) */
+    CHECK_STREAM_PTR(64);
+
+    for (y = 0; y < 8; y++) {
+        for (x = 0; x < 8; x++) {
+            *sg_output_plane++ = *sg_stream_ptr++;
+        }
+        sg_output_plane += sg_line_inc;
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0xC(void)
+{
+    int x, y;
+    unsigned char pix;
+
+    /* 16-color block encoding: each 2x2 block is a different color */
+    CHECK_STREAM_PTR(16);
+
+    for (y = 0; y < 8; y += 2) {
+        for (x = 0; x < 8; x += 2) {
+            pix = *sg_stream_ptr++;
+            *(sg_output_plane + x) = pix;
+            *(sg_output_plane + x + 1) = pix;
+            *(sg_output_plane + sg_stride + x) = pix;
+            *(sg_output_plane + sg_stride + x + 1) = pix;
+        }
+        sg_output_plane += sg_stride * 2;
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0xD(void)
+{
+    int x, y;
+    unsigned char P[4];
+    unsigned char index = 0;
+
+    /* 4-color block encoding: each 4x4 block is a different color */
+    CHECK_STREAM_PTR(4);
+
+    for (y = 0; y < 4; y++)
+        P[y] = *sg_stream_ptr++;
+
+    for (y = 0; y < 8; y++) {
+        if (y < 4)
+            index = 0;
+        else
+            index = 2;
+
+        for (x = 0; x < 8; x++) {
+            if (x == 4)
+                index++;
+            *sg_output_plane++ = P[index];
+        }
+        sg_output_plane += sg_line_inc;
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0xE(void)
+{
+    int x, y;
+    unsigned char pix;
+
+    /* 1-color encoding: the whole block is 1 solid color */
+    CHECK_STREAM_PTR(1);
+    pix = *sg_stream_ptr++;
+
+    for (y = 0; y < 8; y++) {
+        for (x = 0; x < 8; x++) {
+            *sg_output_plane++ = pix;
+        }
+        sg_output_plane += sg_line_inc;
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int ipvideo_decode_block_opcode_0xF(void)
+{
+    int x, y;
+    unsigned char sample0, sample1;
+
+    /* dithered encoding */
+    CHECK_STREAM_PTR(2);
+    sample0 = *sg_stream_ptr++;
+    sample1 = *sg_stream_ptr++;
+
+    for (y = 0; y < 8; y++) {
+        for (x = 0; x < 8; x += 2) {
+            if (y & 1) {
+                *sg_output_plane++ = sample1;
+                *sg_output_plane++ = sample0;
+            } else {
+                *sg_output_plane++ = sample0;
+                *sg_output_plane++ = sample1;
+            }
+        }
+        sg_output_plane += sg_line_inc;
+    }
+
+    /* report success */
+    return 0;
+}
+
+static int (*ipvideo_decode_block[16])(void);
+
+static void ipvideo_decode_opcodes(IpvideoContext *s)
+{
+    int x, y;
+    int index = 0;
+    unsigned char opcode;
+    int ret;
+    int code_counts[16];
+    static int frame = 0;
+
+    debug_interplay("------------------ frame %d\n", frame);
+    frame++;
+
+    for (x = 0; x < 16; x++)
+        code_counts[x] = 0;
+
+    /* this is PAL8, so make the palette available */
+    if (s->avctx->pix_fmt == PIX_FMT_PAL8)
+        memcpy(s->current_frame.data[1], s->palette, PALETTE_COUNT * 4);
+
+    switch (s->avctx->pix_fmt) {
+
+    case PIX_FMT_PAL8:
+        sg_stride = s->current_frame.linesize[0];
+        sg_stream_ptr = s->buf + 14;  /* data starts 14 bytes in */
+        sg_stream_end = s->buf + s->size;
+        sg_line_inc = sg_stride - 8;
+        sg_current_plane = s->current_frame.data[0];
+        sg_last_plane = s->last_frame.data[0];
+        sg_upper_motion_limit_offset = (s->avctx->height - 8) * sg_stride
+            + s->avctx->width - 8;
+        sg_dsp = s->dsp;
+
+        for (y = 0; y < (sg_stride * s->avctx->height); y += sg_stride * 8) {
+            for (x = y; x < y + s->avctx->width; x += 8) {
+                /* bottom nibble first, then top nibble (which makes it
+                 * hard to use a GetBitcontext) */
+                if (index & 1)
+                    opcode = s->decoding_map[index >> 1] >> 4;
+                else
+                    opcode = s->decoding_map[index >> 1] & 0xF;
+                index++;
+
+                debug_interplay("  block @ (%3d, %3d): encoding 0x%X, data ptr @ %p\n",
+                    x - y, y / sg_stride, opcode, sg_stream_ptr);
+                code_counts[opcode]++;
+
+                sg_output_plane = sg_current_plane + x;
+                ret = ipvideo_decode_block[opcode]();
+                if (ret != 0) {
+                    printf(" Interplay video: decode problem on frame %d, @ block (%d, %d)\n",
+                        frame, x - y, y / sg_stride);
+                    return;
+                }
+            }
+        }
+        if ((sg_stream_ptr != sg_stream_end) &&
+            (sg_stream_ptr + 1 != sg_stream_end)) {
+            printf (" Interplay video: decode finished with %d bytes left over\n",
+                sg_stream_end - sg_stream_ptr);
+        }
+        break;
+
+    default:
+        printf ("Interplay video: Unhandled video format\n");
+        break;
+    }
+
+}
+
 static int ipvideo_decode_init(AVCodecContext *avctx)
 {
     IpvideoContext *s = avctx->priv_data;
 
     s->avctx = avctx;
-    avctx->pix_fmt = PIX_FMT_YUV444P;
+
+    if (s->avctx->extradata_size != sizeof(AVPaletteControl)) {
+        printf (" Interplay video: expected extradata_size of %d\n",
+            sizeof(AVPaletteControl));
+        return -1;
+    }
+
+    avctx->pix_fmt = PIX_FMT_PAL8;
     avctx->has_b_frames = 0;
     dsputil_init(&s->dsp, avctx);
 
     s->first_frame = 1;
-    s->receiving_decoding_map = 1;  /* decoding map will be received first */
 
     /* decoding map contains 4 bits of information per 8x8 block */
     s->decoding_map_size = avctx->width * avctx->height / (8 * 8 * 2);
-    s->decoding_map = av_malloc(s->decoding_map_size);
+
+    /* assign block decode functions */
+    ipvideo_decode_block[0x0] = ipvideo_decode_block_opcode_0x0_0x1;
+    ipvideo_decode_block[0x1] = ipvideo_decode_block_opcode_0x0_0x1;
+    ipvideo_decode_block[0x2] = ipvideo_decode_block_opcode_0x2;
+    ipvideo_decode_block[0x3] = ipvideo_decode_block_opcode_0x3;
+    ipvideo_decode_block[0x4] = ipvideo_decode_block_opcode_0x4;
+    ipvideo_decode_block[0x5] = ipvideo_decode_block_opcode_0x5;
+    ipvideo_decode_block[0x6] = ipvideo_decode_block_opcode_0x6;
+    ipvideo_decode_block[0x7] = ipvideo_decode_block_opcode_0x7;
+    ipvideo_decode_block[0x8] = ipvideo_decode_block_opcode_0x8;
+    ipvideo_decode_block[0x9] = ipvideo_decode_block_opcode_0x9;
+    ipvideo_decode_block[0xA] = ipvideo_decode_block_opcode_0xA;
+    ipvideo_decode_block[0xB] = ipvideo_decode_block_opcode_0xB;
+    ipvideo_decode_block[0xC] = ipvideo_decode_block_opcode_0xC;
+    ipvideo_decode_block[0xD] = ipvideo_decode_block_opcode_0xD;
+    ipvideo_decode_block[0xE] = ipvideo_decode_block_opcode_0xE;
+    ipvideo_decode_block[0xF] = ipvideo_decode_block_opcode_0xF;
 
     return 0;
 }
@@ -74,49 +919,38 @@ static int ipvideo_decode_frame(AVCodecContext *avctx,
                                 uint8_t *buf, int buf_size)
 {
     IpvideoContext *s = avctx->priv_data;
+    AVPaletteControl *palette_control = (AVPaletteControl *)avctx->extradata;
 
-    if (s->receiving_decoding_map) {
-        /* receiving the decoding map on this iteration */
-        s->receiving_decoding_map = 0;
-
-        if (buf_size != s->decoding_map_size)
-            printf (" Interplay video: buf_size != decoding_map_size (%d != %d)\n",
-                buf_size, s->decoding_map_size);
-        else
-            memcpy(s->decoding_map, buf, buf_size);
+    if (palette_control->palette_changed) {
+        /* load the new palette and reset the palette control */
+        ipvideo_new_palette(s, palette_control->palette);
+        palette_control->palette_changed = 0;
+    }
 
-        *data_size = 0;
-        *(AVFrame*)data = s->last_frame;
-    } else {
-        /* receiving the compressed video data on this iteration */
-        s->receiving_decoding_map = 1;
-        s->buf = buf;
-        s->size = buf_size;
+    s->decoding_map = buf;
+    s->buf = buf + s->decoding_map_size;
+    s->size = buf_size - s->decoding_map_size;
 
-        if (avctx->get_buffer(avctx, &s->current_frame)) {
-            printf ("  Interplay Video: get_buffer() failed\n");
-            return -1;
-        }
+    if (avctx->get_buffer(avctx, &s->current_frame)) {
+        printf ("  Interplay Video: get_buffer() failed\n");
+        return -1;
+    }
 
-//        ipvideo_decode_frame(s);
-memset(s->current_frame.data[0], 0x80, s->current_frame.linesize[0] * avctx->height);
-memset(s->current_frame.data[1], 0x80, s->current_frame.linesize[1] * avctx->height / 4);
-memset(s->current_frame.data[2], 0x80, s->current_frame.linesize[2] * avctx->height / 4);
+    ipvideo_decode_opcodes(s);
 
-        /* release the last frame if it is allocated */
-        if (s->first_frame)
-            s->first_frame = 0;
-        else
-            avctx->release_buffer(avctx, &s->last_frame);
+    /* release the last frame if it is allocated */
+    if (s->first_frame)
+        s->first_frame = 0;
+    else
+        avctx->release_buffer(avctx, &s->last_frame);
 
-        /* shuffle frames */
-        s->last_frame = s->current_frame;
+    /* shuffle frames */
+    s->last_frame = s->current_frame;
 
-        *data_size = sizeof(AVFrame);
-        *(AVFrame*)data = s->current_frame;
-    }
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*)data = s->current_frame;
 
-    /* always report that the buffer was completely consumed */
+    /* report that the buffer was completely consumed */
     return buf_size;
 }
 
@@ -127,8 +961,6 @@ static int ipvideo_decode_end(AVCodecContext *avctx)
     /* release the last frame */
     avctx->release_buffer(avctx, &s->last_frame);
 
-    av_free(s->decoding_map);
-
     return 0;
 }