New fringe codecs: WC3/Xan video, Xan DPCM, DK3 & DK4 ADPCM

Originally committed as revision 2217 to svn://svn.ffmpeg.org/ffmpeg/trunk

6 files changed, 795 insertions, 12 deletions

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 33e8857183..98f66ac1e3 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -18,7 +18,7 @@ OBJS= common.o utils.o mem.o allcodecs.o \
       ratecontrol.o adpcm.o eval.o dv.o error_resilience.o \
       fft.o mdct.o mace.o huffyuv.o cyuv.o opts.o raw.o h264.o golomb.o \
       vp3.o asv1.o 4xm.o cabac.o ffv1.o ra144.o ra288.o vcr1.o cljr.o \
-      roqvideo.o dpcm.o interplayvideo.o
+      roqvideo.o dpcm.o interplayvideo.o xan.o
 
 ifeq ($(AMR_NB),yes)
 ifeq ($(AMR_NB_FIXED),yes)
diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index 45c9dd1959..a9b3195d27 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -1,6 +1,6 @@
 /*
  * ADPCM codecs
- * Copyright (c) 2001 Fabrice Bellard.
+ * Copyright (c) 2001-2003 The ffmpeg Project
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -22,11 +22,13 @@
  * @file adpcm.c
  * ADPCM codecs.
  * First version by Francois Revol revol@free.fr
+ * Fringe ADPCM codecs (e.g., DK3 and DK4) 
+ *   by Mike Melanson (melanson@pcisys.net)
  *
  * Features and limitations:
  *
  * Reference documents:
- * http://www.pcisys.net/~melanson/codecs/adpcm.txt
+ * http://www.pcisys.net/~melanson/codecs/simpleaudio.html
  * http://www.geocities.com/SiliconValley/8682/aud3.txt
  * http://openquicktime.sourceforge.net/plugins.htm
  * XAnim sources (xa_codec.c) http://www.rasnaimaging.com/people/lapus/download.html
@@ -293,14 +295,10 @@ static inline short adpcm_ima_expand_nibble(ADPCMChannelStatus *c, char nibble)
 
     sign = nibble & 8;
     delta = nibble & 7;
-#if 0
-    diff = step >> 3;
-    if (delta & 4) diff += step;
-    if (delta & 2) diff += step >> 1;
-    if (delta & 1) diff += step >> 2;
-#else
-    diff = ((2 * delta + 1) * step) >> 3; // no jumps
-#endif
+    /* perform direct multiplication instead of series of jumps proposed by
+     * the reference ADPCM implementation since modern CPUs can do the mults
+     * quickly enough */
+    diff = ((2 * delta + 1) * step) >> 3;
     predictor = c->predictor;
     if (sign) predictor -= diff;
     else predictor += diff;
@@ -355,6 +353,21 @@ static inline short adpcm_ms_expand_nibble(ADPCMChannelStatus *c, char nibble)
     return (short)predictor;
 }
 
+/* DK3 ADPCM support macro */
+#define DK3_GET_NEXT_NIBBLE() \
+    if (decode_top_nibble_next) \
+    { \
+        nibble = (last_byte >> 4) & 0x0F; \
+        decode_top_nibble_next = 0; \
+    } \
+    else \
+    { \
+        last_byte = *src++; \
+        if (src >= buf + buf_size) break; \
+        nibble = last_byte & 0x0F; \
+        decode_top_nibble_next = 1; \
+    }
+
 static int adpcm_decode_frame(AVCodecContext *avctx,
 			    void *data, int *data_size,
 			    uint8_t *buf, int buf_size)
@@ -367,6 +380,12 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
     uint8_t *src;
     int st; /* stereo */
 
+    /* DK3 ADPCM accounting variables */
+    unsigned char last_byte = 0;
+    unsigned char nibble;
+    int decode_top_nibble_next = 0;
+    int diff_channel;
+
     samples = data;
     src = buf;
 
@@ -551,6 +570,94 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
             src ++;
         }
         break;
+    case CODEC_ID_ADPCM_IMA_DK4:
+        if (buf_size > BLKSIZE) {
+            if (avctx->block_align != 0)
+                buf_size = avctx->block_align;
+            else
+                buf_size = BLKSIZE;
+        }
+        c->status[0].predictor = (src[0] | (src[1] << 8));
+        c->status[0].step_index = src[2];
+        src += 4;
+        if(c->status[0].predictor & 0x8000)
+            c->status[0].predictor -= 0x10000;
+        *samples++ = c->status[0].predictor;
+        if (st) {
+            c->status[1].predictor = (src[0] | (src[1] << 8));
+            c->status[1].step_index = src[2];
+            src += 4;
+            if(c->status[1].predictor & 0x8000)
+                c->status[1].predictor -= 0x10000;
+            *samples++ = c->status[1].predictor;
+        }
+        while (src < buf + buf_size) {
+
+            /* take care of the top nibble (always left or mono channel) */
+            *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
+                (src[0] >> 4) & 0x0F);
+
+            /* take care of the bottom nibble, which is right sample for
+             * stereo, or another mono sample */
+            if (st)
+                *samples++ = adpcm_ima_expand_nibble(&c->status[1], 
+                    src[0] & 0x0F);
+            else
+                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
+                    src[0] & 0x0F);
+
+            src++;
+        }
+        break;
+    case CODEC_ID_ADPCM_IMA_DK3:
+        if (buf_size > BLKSIZE) {
+            if (avctx->block_align != 0)
+                buf_size = avctx->block_align;
+            else
+                buf_size = BLKSIZE;
+        }
+        c->status[0].predictor = (src[10] | (src[11] << 8));
+        c->status[1].predictor = (src[12] | (src[13] << 8));
+        c->status[0].step_index = src[14];
+        c->status[1].step_index = src[15];
+        /* sign extend the predictors */
+        if(c->status[0].predictor & 0x8000)
+            c->status[0].predictor -= 0x10000;
+        if(c->status[1].predictor & 0x8000)
+            c->status[1].predictor -= 0x10000;
+        src += 16;
+        diff_channel = c->status[1].predictor;
+
+        /* the DK3_GET_NEXT_NIBBLE macro issues the break statement when
+         * the buffer is consumed */
+        while (1) {
+
+            /* for this algorithm, c->status[0] is the sum channel and
+             * c->status[1] is the diff channel */
+
+            /* process the first predictor of the sum channel */
+            DK3_GET_NEXT_NIBBLE();
+            adpcm_ima_expand_nibble(&c->status[0], nibble);
+
+            /* process the diff channel predictor */
+            DK3_GET_NEXT_NIBBLE();
+            adpcm_ima_expand_nibble(&c->status[1], nibble);
+
+            /* process the first pair of stereo PCM samples */
+            diff_channel = (diff_channel + c->status[1].predictor) / 2;
+            *samples++ = c->status[0].predictor + c->status[1].predictor;
+            *samples++ = c->status[0].predictor - c->status[1].predictor;
+
+            /* process the second predictor of the sum channel */
+            DK3_GET_NEXT_NIBBLE();
+            adpcm_ima_expand_nibble(&c->status[0], nibble);
+
+            /* process the second pair of stereo PCM samples */
+            diff_channel = (diff_channel + c->status[1].predictor) / 2;
+            *samples++ = c->status[0].predictor + c->status[1].predictor;
+            *samples++ = c->status[0].predictor - c->status[1].predictor;
+        }
+        break;
     default:
         *data_size = 0;
         return -1;
@@ -583,8 +690,9 @@ AVCodec name ## _decoder = {                    \
 
 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
+ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3);
+ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4);
 ADPCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
 ADPCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
 
 #undef ADPCM_CODEC
-
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index c687ecf5e2..4e792ba081 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -123,6 +123,7 @@ void avcodec_register_all(void)
     register_avcodec(&mdec_decoder);
     register_avcodec(&roq_decoder);
     register_avcodec(&interplay_video_decoder);
+    register_avcodec(&xan_wc3_decoder);
 #ifdef CONFIG_AC3
     register_avcodec(&ac3_decoder);
 #endif
@@ -130,6 +131,7 @@ void avcodec_register_all(void)
     register_avcodec(&ra_288_decoder);
     register_avcodec(&roq_dpcm_decoder);
     register_avcodec(&interplay_dpcm_decoder);
+    register_avcodec(&xan_dpcm_decoder);
 #endif /* CONFIG_DECODERS */
 
 #ifdef AMR_NB
@@ -154,6 +156,8 @@ PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
     /* adpcm codecs */
 PCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
 PCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
+PCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3);
+PCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4);
 PCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
 PCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
 
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index f877b36958..78f60ab959 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -68,6 +68,8 @@ enum CodecID {
     CODEC_ID_MDEC,
     CODEC_ID_ROQ,
     CODEC_ID_INTERPLAY_VIDEO,
+    CODEC_ID_XAN_WC3,
+    CODEC_ID_XAN_WC4,
 
     /* various pcm "codecs" */
     CODEC_ID_PCM_S16LE,
@@ -82,6 +84,8 @@ enum CodecID {
     /* various adpcm codecs */
     CODEC_ID_ADPCM_IMA_QT,
     CODEC_ID_ADPCM_IMA_WAV,
+    CODEC_ID_ADPCM_IMA_DK3,
+    CODEC_ID_ADPCM_IMA_DK4,
     CODEC_ID_ADPCM_MS,
     CODEC_ID_ADPCM_4XM,
 
@@ -94,6 +98,7 @@ enum CodecID {
     /* various DPCM codecs */
     CODEC_ID_ROQ_DPCM,
     CODEC_ID_INTERPLAY_DPCM,
+    CODEC_ID_XAN_DPCM,
 };
 #define CODEC_ID_MPEGVIDEO CODEC_ID_MPEG1VIDEO
 
@@ -1356,10 +1361,12 @@ extern AVCodec fourxm_decoder;
 extern AVCodec mdec_decoder;
 extern AVCodec roq_decoder;
 extern AVCodec interplay_video_decoder;
+extern AVCodec xan_wc3_decoder;
 extern AVCodec ra_144_decoder;
 extern AVCodec ra_288_decoder;
 extern AVCodec roq_dpcm_decoder;
 extern AVCodec interplay_dpcm_decoder;
+extern AVCodec xan_dpcm_decoder;
 
 /* pcm codecs */
 #define PCM_CODEC(id, name) \
@@ -1379,6 +1386,8 @@ PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
 
 PCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
 PCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
+PCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3);
+PCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4);
 PCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
 PCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
 
diff --git a/libavcodec/dpcm.c b/libavcodec/dpcm.c
index bd3ad7fd0f..958e46467d 100644
--- a/libavcodec/dpcm.c
+++ b/libavcodec/dpcm.c
@@ -21,8 +21,17 @@
  * @file: dpcm.c
  * Assorted DPCM (differential pulse code modulation) audio codecs
  * by Mike Melanson (melanson@pcisys.net)
+ * Xan DPCM decoder by Mario Brito (mbrito@student.dei.uc.pt)
  * for more information on the specific data formats, visit:
  *   http://www.pcisys.net/~melanson/codecs/simpleaudio.html
+ *
+ * Note about using the Xan DPCM decoder: Xan DPCM is used in AVI files
+ * found in the Wing Commander IV computer game. These AVI files contain
+ * WAVEFORMAT headers which report the audio format as 0x01: raw PCM.
+ * Clearly incorrect. To detect Xan DPCM, you will probably have to
+ * special-case your AVI demuxer to use Xan DPCM if the file uses 'Xxan'
+ * (Xan video) for its video codec. Alternately, such AVI files also contain
+ * the fourcc 'Axan' in the 'auds' chunk of the AVI header.
  */
 
 #include "avcodec.h"
@@ -115,6 +124,9 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
     int channel_number = 0;
     short *output_samples = data;
     int sequence_number;
+    int shift[2];
+    unsigned char byte;
+    short diff;
 
     switch(avctx->codec->id) {
 
@@ -171,6 +183,40 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
             s->last_delta[i] = predictor[i];
 
         break;
+
+    case CODEC_ID_XAN_DPCM:
+        in = 0;
+        shift[0] = shift[1] = 4;
+        predictor[0] = LE_16(&buf[in]);
+        in += 2;
+        SE_16BIT(predictor[0]);
+        if (s->channels == 2) {
+            predictor[1] = LE_16(&buf[in]);
+            in += 2;
+            SE_16BIT(predictor[1]);
+        }
+
+        while (in < buf_size) {
+            byte = buf[in++];
+            diff = (byte & 0xFC) << 8;
+            if ((byte & 0x03) == 3)
+                shift[channel_number]++;
+            else
+                shift[channel_number] -= (2 * (byte & 3));
+            /* saturate the shifter to a lower limit of 0 */
+            if (shift[channel_number] < 0)
+                shift[channel_number] = 0;
+
+            diff >>= shift[channel_number];
+            predictor[channel_number] += diff;
+
+            SATURATE_S16(predictor[channel_number]);
+            output_samples[out++] = predictor[channel_number];
+
+            /* toggle channel */
+            channel_number ^= s->channels - 1;
+        }
+        break;
     }
 
     *data_size = out * sizeof(short);
@@ -198,3 +244,14 @@ AVCodec interplay_dpcm_decoder = {
     NULL,
     dpcm_decode_frame,
 };
+
+AVCodec xan_dpcm_decoder = {
+    "xan_dpcm",
+    CODEC_TYPE_AUDIO,
+    CODEC_ID_XAN_DPCM,
+    sizeof(DPCMContext),
+    dpcm_decode_init,
+    NULL,
+    NULL,
+    dpcm_decode_frame,
+};
diff --git a/libavcodec/xan.c b/libavcodec/xan.c
new file mode 100644
index 0000000000..72d4e5f14f
--- /dev/null
+++ b/libavcodec/xan.c
@@ -0,0 +1,605 @@
+/*
+ * Wing Commander/Xan Video Decoder
+ * Copyright (C) 2003 the ffmpeg project
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+/**
+ * @file xan.c
+ * Xan video decoder for Wing Commander III & IV computer games
+ * by Mario Brito (mbrito@student.dei.uc.pt)
+ * and Mike Melanson (melanson@pcisys.net)
+ * For more information about the Xan format, visit:
+ *   http://www.pcisys.net/~melanson/codecs/
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "common.h"
+#include "avcodec.h"
+#include "dsputil.h"
+
+#define PALETTE_COUNT 256
+#define PALETTE_CONTROL_SIZE ((256 * 3) + 1)
+
+typedef struct XanContext {
+
+    AVCodecContext *avctx;
+    DSPContext dsp;
+    AVFrame last_frame;
+    AVFrame current_frame;
+
+    unsigned char *buf;
+    int size;
+
+    unsigned char palette[PALETTE_COUNT * 4];
+
+    /* scratch space */
+    unsigned char *buffer1;
+    unsigned char *buffer2;
+
+} XanContext;
+
+#define BE_16(x)  ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])
+#define LE_16(x)  ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
+#define LE_32(x)  ((((uint8_t*)(x))[3] << 24) | \
+                   (((uint8_t*)(x))[2] << 16) | \
+                   (((uint8_t*)(x))[1] << 8) | \
+                    ((uint8_t*)(x))[0])
+
+/* RGB -> YUV conversion stuff */
+#define SCALEFACTOR 65536
+#define CENTERSAMPLE 128
+
+#define COMPUTE_Y(r, g, b) \
+  (unsigned char) \
+  ((y_r_table[r] + y_g_table[g] + y_b_table[b]) / SCALEFACTOR)
+#define COMPUTE_U(r, g, b) \
+  (unsigned char) \
+  ((u_r_table[r] + u_g_table[g] + u_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
+#define COMPUTE_V(r, g, b) \
+  (unsigned char) \
+  ((v_r_table[r] + v_g_table[g] + v_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
+
+#define Y_R (SCALEFACTOR *  0.29900)
+#define Y_G (SCALEFACTOR *  0.58700)
+#define Y_B (SCALEFACTOR *  0.11400)
+
+#define U_R (SCALEFACTOR * -0.16874)
+#define U_G (SCALEFACTOR * -0.33126)
+#define U_B (SCALEFACTOR *  0.50000)
+
+#define V_R (SCALEFACTOR *  0.50000)
+#define V_G (SCALEFACTOR * -0.41869)
+#define V_B (SCALEFACTOR * -0.08131)
+
+/*
+ * Precalculate all of the YUV tables since it requires fewer than
+ * 10 kilobytes to store them.
+ */
+static int y_r_table[256];
+static int y_g_table[256];
+static int y_b_table[256];
+
+static int u_r_table[256];
+static int u_g_table[256];
+static int u_b_table[256];
+
+static int v_r_table[256];
+static int v_g_table[256];
+static int v_b_table[256];
+
+static int xan_decode_init(AVCodecContext *avctx)
+{
+    XanContext *s = avctx->priv_data;
+    int i;
+
+    s->avctx = avctx;
+
+    if ((avctx->codec->id == CODEC_ID_XAN_WC3) && 
+        (s->avctx->extradata_size != PALETTE_CONTROL_SIZE)) {
+        printf (" WC3 Xan video: expected extradata_size of %d\n",
+            PALETTE_CONTROL_SIZE);
+        return -1;
+    }
+
+    avctx->pix_fmt = PIX_FMT_YUV444P;
+    avctx->has_b_frames = 0;
+    dsputil_init(&s->dsp, avctx);
+
+    /* initialize the RGB -> YUV tables */
+    for (i = 0; i < 256; i++) {
+        y_r_table[i] = Y_R * i;
+        y_g_table[i] = Y_G * i;
+        y_b_table[i] = Y_B * i;
+
+        u_r_table[i] = U_R * i;
+        u_g_table[i] = U_G * i;
+        u_b_table[i] = U_B * i;
+
+        v_r_table[i] = V_R * i;
+        v_g_table[i] = V_G * i;
+        v_b_table[i] = V_B * i;
+    }
+
+    s->buffer1 = av_malloc(avctx->width * avctx->height * 4);
+    s->buffer2 = av_malloc(avctx->width * avctx->height * 4);
+    if (!s->buffer1 || !s->buffer2)
+        return -1;
+
+    return 0;
+}
+
+/* This function is used in lieu of memcpy(). This decoder can not use 
+ * memcpy because the memory locations often overlap and
+ * memcpy doesn't like that; it's not uncommon, for example, for
+ * dest = src+1, to turn byte A into  pattern AAAAAAAA.
+ * This was originally repz movsb in Intel x86 ASM. */
+static inline void bytecopy(unsigned char *dest, unsigned char *src, int count)
+{
+    int i;
+
+    for (i = 0; i < count; i++)
+        dest[i] = src[i];
+}
+
+static int xan_decode_method_1(unsigned char *dest, unsigned char *src)
+{
+    unsigned char byte = *src++;
+    unsigned char ival = byte + 0x16;
+    unsigned char * ptr = src + byte*2;
+    unsigned char val = ival;
+    int counter = 0;
+
+    unsigned char bits = *ptr++;
+
+    while ( val != 0x16 ) {
+        if ( (1 << counter) & bits )
+            val = src[byte + val - 0x17];
+        else
+            val = src[val - 0x17];
+
+        if ( val < 0x16 ) {
+            *dest++ = val;
+            val = ival;
+        }
+
+        if (counter++ == 7) {
+            counter = 0;
+            bits = *ptr++;
+        }
+    }
+
+    return 0;
+}
+
+static int xan_decode_method_2(unsigned char *dest, unsigned char *src)
+{
+    unsigned char opcode;
+    int size;
+    int offset;
+    int byte1, byte2, byte3;
+
+    for (;;) {
+        opcode = *src++;
+
+        if ( (opcode & 0x80) == 0 ) {
+
+            offset = *src++;
+
+            size = opcode & 3;
+            bytecopy(dest, src, size);  dest += size;  src += size;
+
+            size = ((opcode & 0x1c) >> 2) + 3;
+            bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);
+            dest += size;
+
+        } else if ( (opcode & 0x40) == 0 ) {
+
+            byte1 = *src++;
+            byte2 = *src++;
+
+            size = byte1 >> 6;
+            bytecopy (dest, src, size);  dest += size;  src += size;
+
+            size = (opcode & 0x3f) + 4;
+            bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);
+            dest += size;
+
+        } else if ( (opcode & 0x20) == 0 ) {
+
+            byte1 = *src++;
+            byte2 = *src++;
+            byte3 = *src++;
+
+            size = opcode & 3;
+            bytecopy (dest, src, size);  dest += size;  src += size;
+
+            size = byte3 + 5 + ((opcode & 0xc) << 6);
+            bytecopy (dest,
+                dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),
+                size);
+            dest += size;
+        } else {
+            size = ((opcode & 0x1f) << 2) + 4;
+
+            if (size > 0x70)
+                break;
+
+            bytecopy (dest, src, size);  dest += size;  src += size;
+        }
+    }
+
+    size = opcode & 3;
+    bytecopy(dest, src, size);  dest += size;  src += size;
+
+    return 0;
+}
+
+static void inline xan_wc3_build_palette(XanContext *s, 
+    unsigned char *palette_data)
+{
+    int i;
+    unsigned char r, g, b;
+
+    /* transform the palette passed through the palette control structure
+     * into the necessary internal format depending on colorspace */
+
+    switch (s->avctx->pix_fmt) {
+
+    case PIX_FMT_YUV444P:
+        for (i = 0; i < PALETTE_COUNT; i++) {
+            r = *palette_data++;
+            g = *palette_data++;
+            b = *palette_data++;
+            s->palette[i * 4 + 0] = COMPUTE_Y(r, g, b);
+            s->palette[i * 4 + 1] = COMPUTE_U(r, g, b);
+            s->palette[i * 4 + 2] = COMPUTE_V(r, g, b);
+        }
+        break;
+
+    default:
+        printf (" Xan WC3: Unhandled colorspace\n");
+        break;
+    }
+}
+
+static void inline xan_wc3_output_pixel_run(XanContext *s, 
+    unsigned char *pixel_buffer, int x, int y, int pixel_count)
+{
+    int stride;
+    int line_inc;
+    int index;
+    int current_x;
+    int width = s->avctx->width;
+    unsigned char pixel;
+    unsigned char *y_plane;
+    unsigned char *u_plane;
+    unsigned char *v_plane;
+
+    switch (s->avctx->pix_fmt) {
+
+    case PIX_FMT_YUV444P:
+        y_plane = s->current_frame.data[0];
+        u_plane = s->current_frame.data[1];
+        v_plane = s->current_frame.data[2];
+        stride = s->current_frame.linesize[0];
+        line_inc = stride - width;
+        index = y * stride + x;
+        current_x = x;
+        while(pixel_count--) {
+            pixel = *pixel_buffer++;
+
+            y_plane[index] = s->palette[pixel * 4 + 0];
+            u_plane[index] = s->palette[pixel * 4 + 1];
+            v_plane[index] = s->palette[pixel * 4 + 2];
+
+            index++;
+            current_x++;
+            if (current_x >= width) {
+                /* reset accounting variables */
+                index += line_inc;
+                current_x = 0;
+            }
+        }
+        break;
+
+    default:
+        printf (" Xan WC3: Unhandled colorspace\n");
+        break;
+    }
+}
+
+static void inline xan_wc3_copy_pixel_run(XanContext *s, 
+    int x, int y, int pixel_count, int motion_x, int motion_y)
+{
+    int stride;
+    int line_inc;
+    int curframe_index, prevframe_index;
+    int curframe_x, prevframe_x;
+    int width = s->avctx->width;
+    unsigned char *y_plane, *u_plane, *v_plane;
+    unsigned char *prev_y_plane, *prev_u_plane, *prev_v_plane;
+
+    switch (s->avctx->pix_fmt) {
+
+    case PIX_FMT_YUV444P:
+        y_plane = s->current_frame.data[0];
+        u_plane = s->current_frame.data[1];
+        v_plane = s->current_frame.data[2];
+        prev_y_plane = s->last_frame.data[0];
+        prev_u_plane = s->last_frame.data[1];
+        prev_v_plane = s->last_frame.data[2];
+        stride = s->current_frame.linesize[0];
+        line_inc = stride - width;
+        curframe_index = y * stride + x;
+        curframe_x = x;
+        prevframe_index = (y + motion_x) * stride + x + motion_x;
+        prevframe_x = x + motion_x;
+        while(pixel_count--) {
+
+            y_plane[curframe_index] = prev_y_plane[prevframe_index];
+            u_plane[curframe_index] = prev_u_plane[prevframe_index];
+            v_plane[curframe_index] = prev_v_plane[prevframe_index];
+
+            curframe_index++;
+            curframe_x++;
+            if (curframe_x >= width) {
+                /* reset accounting variables */
+                curframe_index += line_inc;
+                curframe_x = 0;
+            }
+
+            prevframe_index++;
+            prevframe_x++;
+            if (prevframe_x >= width) {
+                /* reset accounting variables */
+                prevframe_index += line_inc;
+                prevframe_x = 0;
+            }
+        }
+        break;
+
+    default:
+        printf (" Xan WC3: Unhandled colorspace\n");
+        break;
+    }
+}
+
+static void xan_wc3_decode_frame(XanContext *s) {
+
+    int width = s->avctx->width;
+    int height = s->avctx->height;
+    int total_pixels = width * height;
+    unsigned char opcode;
+    unsigned char flag = 0;
+    int size = 0;
+    int motion_x, motion_y;
+    int x, y;
+
+    unsigned char *method1_buffer = s->buffer1;
+    unsigned char *method2_buffer = s->buffer2;
+
+    /* pointers to segments inside the compressed chunk */
+    unsigned char *method1_segment;
+    unsigned char *size_segment;
+    unsigned char *vector_segment;
+    unsigned char *method2_segment;
+
+    method1_segment = s->buf + LE_16(&s->buf[0]);
+    size_segment =    s->buf + LE_16(&s->buf[2]);
+    vector_segment =  s->buf + LE_16(&s->buf[4]);
+    method2_segment = s->buf + LE_16(&s->buf[6]);
+
+    xan_decode_method_1(method1_buffer, method1_segment);
+    if (method2_segment[0] == 2)
+        xan_decode_method_2(method2_buffer, method2_segment + 1);
+    else
+        method2_buffer = method2_segment + 1;
+
+    /* use the decoded data segments to build the frame */
+    x = y = 0;
+    while (total_pixels) {
+
+        opcode = *method1_buffer++;
+        size = 0;
+
+        switch (opcode) {
+
+        case 0:
+            flag ^= 1;
+            continue;
+
+        case 1:
+        case 2:
+        case 3:
+        case 4:
+        case 5:
+        case 6:
+        case 7:
+        case 8:
+            size = opcode;
+            break;
+
+        case 12:
+        case 13:
+        case 14:
+        case 15:
+        case 16:
+        case 17:
+        case 18:
+            size += (opcode - 10);
+            break;
+
+        case 9:
+        case 19:
+            size = *size_segment++;
+            break;
+
+        case 10:
+        case 20:
+            size = BE_16(&size_segment[0]);
+            size_segment += 2;
+            break;
+
+        case 11:
+        case 21:
+            size = (size_segment[0] << 16) | (size_segment[1] << 8) |
+                size_segment[2];
+            size_segment += 3;
+            break;
+        }
+
+        if (opcode < 12) {
+            flag ^= 1;
+            if (flag) {
+                /* run of (size) pixels is unchanged from last frame */
+                xan_wc3_copy_pixel_run(s, x, y, size, 0, 0);
+            } else {
+                /* output a run of pixels from method2_buffer */
+                xan_wc3_output_pixel_run(s, method2_buffer, x, y, size);
+                method2_buffer += size;
+            }
+        } else {
+            /* run-based motion compensation from last frame */
+            motion_x = (*vector_segment >> 4) & 0xF;
+            motion_y = *vector_segment & 0xF;
+            vector_segment++;
+
+            /* sign extension */
+            if (motion_x & 0x8)
+                motion_x |= 0xFFFFFFF0;
+            if (motion_y & 0x8)
+                motion_y |= 0xFFFFFFF0;
+
+            /* copy a run of pixels from the previous frame */
+            xan_wc3_copy_pixel_run(s, x, y, size, motion_x, motion_y);
+
+            flag = 0;
+        }
+
+        /* coordinate accounting */
+        total_pixels -= size;
+        while (size) {
+            if (x + size >= width) {
+                y++;
+                size -= (width - x);
+                x = 0;
+            } else {
+                x += size;
+                size = 0;
+            }
+        }
+    }
+}
+
+static void xan_wc4_decode_frame(XanContext *s) {
+}
+
+static int xan_decode_frame(AVCodecContext *avctx,
+                            void *data, int *data_size,
+                            uint8_t *buf, int buf_size)
+{
+    XanContext *s = avctx->priv_data;
+    unsigned char *palette_control = avctx->extradata;
+    int keyframe = 0;
+
+    if (palette_control[0]) {
+        /* load the new palette and reset the palette control */
+        xan_wc3_build_palette(s, &palette_control[1]);
+        palette_control[0] = 0;
+        keyframe = 1;
+    }
+
+    if (avctx->get_buffer(avctx, &s->current_frame)) {
+        printf ("  Interplay Video: get_buffer() failed\n");
+        return -1;
+    }
+
+    s->buf = buf;
+    s->size = buf_size;
+
+    if (avctx->codec->id == CODEC_ID_XAN_WC3) {
+//        if (keyframe)
+        if (1)
+            xan_wc3_decode_frame(s);
+        else {
+            memcpy(s->current_frame.data[0], s->last_frame.data[0],
+                s->current_frame.linesize[0] * avctx->height);
+            memcpy(s->current_frame.data[1], s->last_frame.data[1],
+                s->current_frame.linesize[1] * avctx->height);
+            memcpy(s->current_frame.data[2], s->last_frame.data[2],
+                s->current_frame.linesize[2] * avctx->height);
+        }
+    } else if (avctx->codec->id == CODEC_ID_XAN_WC4)
+        xan_wc4_decode_frame(s);
+    
+    /* release the last frame if it is allocated */
+    if (s->last_frame.data[0])
+        avctx->release_buffer(avctx, &s->last_frame);
+
+    /* shuffle frames */
+    s->last_frame = s->current_frame;
+
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*)data = s->current_frame;
+
+    /* always report that the buffer was completely consumed */
+    return buf_size;
+}
+
+static int xan_decode_end(AVCodecContext *avctx)
+{
+    XanContext *s = avctx->priv_data;
+
+    /* release the last frame */
+    avctx->release_buffer(avctx, &s->last_frame);
+
+    av_free(s->buffer1);
+    av_free(s->buffer2);
+
+    return 0;
+}
+
+AVCodec xan_wc3_decoder = {
+    "xan_wc3",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_XAN_WC3,
+    sizeof(XanContext),
+    xan_decode_init,
+    NULL,
+    xan_decode_end,
+    xan_decode_frame,
+    CODEC_CAP_DR1,
+};
+
+/*
+AVCodec xan_wc4_decoder = {
+    "xan_wc4",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_XAN_WC4,
+    sizeof(XanContext),
+    xan_decode_init,
+    NULL,
+    xan_decode_end,
+    xan_decode_frame,
+    CODEC_CAP_DR1,
+};
+*/