Xan4 decoder

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
(cherry picked from commit 44ddfd47d671d2587903d94c8b565f68f45bd4bc)

6 files changed, 435 insertions, 2 deletions

diff --git a/Changelog b/Changelog
index 8b7efb6105..a85a9d3221 100644
--- a/Changelog
+++ b/Changelog
@@ -74,6 +74,7 @@ version <next>:
 - Lagarith decoder
 - ffmpeg -copytb option added
 - IVF muxer added
+- Wing Commander IV movies decoder added
 
 
 version 0.6:
diff --git a/doc/general.texi b/doc/general.texi
index 950159f1b3..ad34c70ef7 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -511,6 +511,8 @@ following image formats are supported:
     @tab not completely working
 @item Wing Commander III / Xan  @tab     @tab  X
     @tab Used in Wing Commander III .MVE files.
+@item Wing Commander IV / Xan  @tab     @tab  X
+    @tab Used in Wing Commander IV.
 @item Winnov WNV1            @tab     @tab  X
 @item WMV7                   @tab  X  @tab  X
 @item YAMAHA SMAF            @tab  X  @tab  X
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 6a0a05b870..fa6c0bb9cd 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -415,7 +415,7 @@ OBJS-$(CONFIG_WNV1_DECODER)            += wnv1.o
 OBJS-$(CONFIG_WS_SND1_DECODER)         += ws-snd1.o
 OBJS-$(CONFIG_XAN_DPCM_DECODER)        += dpcm.o
 OBJS-$(CONFIG_XAN_WC3_DECODER)         += xan.o
-OBJS-$(CONFIG_XAN_WC4_DECODER)         += xan.o
+OBJS-$(CONFIG_XAN_WC4_DECODER)         += xxan.o
 OBJS-$(CONFIG_XL_DECODER)              += xl.o
 OBJS-$(CONFIG_XSUB_DECODER)            += xsubdec.o
 OBJS-$(CONFIG_XSUB_ENCODER)            += xsubenc.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 04c5c6aad4..108a3ab7c8 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -214,6 +214,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER (WMV3_VDPAU, wmv3_vdpau);
     REGISTER_DECODER (WNV1, wnv1);
     REGISTER_DECODER (XAN_WC3, xan_wc3);
+    REGISTER_DECODER (XAN_WC4, xan_wc4);
     REGISTER_DECODER (XL, xl);
     REGISTER_DECODER (YOP, yop);
     REGISTER_ENCDEC  (ZLIB, zlib);
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index aa5fa0a9ef..3904245181 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -32,7 +32,7 @@
 #include "libavutil/cpu.h"
 
 #define LIBAVCODEC_VERSION_MAJOR 52
-#define LIBAVCODEC_VERSION_MINOR 109
+#define LIBAVCODEC_VERSION_MINOR 110
 #define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
diff --git a/libavcodec/xxan.c b/libavcodec/xxan.c
new file mode 100644
index 0000000000..10ec53f467
--- /dev/null
+++ b/libavcodec/xxan.c
@@ -0,0 +1,429 @@
+/*
+ * Wing Commander/Xan Video Decoder
+ * Copyright (C) 2011 Konstantin Shishkov
+ * based on work by Mike Melanson
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+#include "libavutil/intreadwrite.h"
+#include "bytestream.h"
+#define ALT_BITSTREAM_READER_LE
+#include "get_bits.h"
+// for av_memcpy_backptr
+#include "libavutil/lzo.h"
+
+typedef struct XanContext {
+    AVCodecContext *avctx;
+    AVFrame pic;
+
+    uint8_t *y_buffer;
+    uint8_t *scratch_buffer;
+    int     buffer_size;
+} XanContext;
+
+static av_cold int xan_decode_init(AVCodecContext *avctx)
+{
+    XanContext *s = avctx->priv_data;
+
+    s->avctx = avctx;
+
+    avctx->pix_fmt = PIX_FMT_YUV420P;
+
+    s->buffer_size = avctx->width * avctx->height;
+    s->y_buffer = av_malloc(s->buffer_size);
+    if (!s->y_buffer)
+        return AVERROR(ENOMEM);
+    s->scratch_buffer = av_malloc(s->buffer_size + 130);
+    if (!s->scratch_buffer) {
+        av_freep(&s->y_buffer);
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+static int xan_unpack_luma(const uint8_t *src, const int src_size,
+                           uint8_t *dst, const int dst_size)
+{
+   int tree_size, eof;
+   const uint8_t *tree;
+   int bits, mask;
+   int tree_root, node;
+   const uint8_t *dst_end = dst + dst_size;
+   const uint8_t *src_end = src + src_size;
+
+   tree_size = *src++;
+   eof       = *src++;
+   tree      = src - eof * 2 - 2;
+   tree_root = eof + tree_size;
+   src += tree_size * 2;
+
+   node = tree_root;
+   bits = *src++;
+   mask = 0x80;
+   for (;;) {
+       int bit = !!(bits & mask);
+       mask >>= 1;
+       node = tree[node*2 + bit];
+       if (node == eof)
+           break;
+       if (node < eof) {
+           *dst++ = node;
+           if (dst > dst_end)
+               break;
+           node = tree_root;
+       }
+       if (!mask) {
+           bits = *src++;
+           if (src > src_end)
+               break;
+           mask = 0x80;
+       }
+   }
+   return dst != dst_end;
+}
+
+/* almost the same as in xan_wc3 decoder */
+static int xan_unpack(uint8_t *dest, const int dest_len,
+                      const uint8_t *src, const int src_len)
+{
+    uint8_t opcode;
+    int size;
+    uint8_t *orig_dest = dest;
+    const uint8_t *src_end = src + src_len;
+    const uint8_t *dest_end = dest + dest_len;
+
+    while (dest < dest_end) {
+        opcode = *src++;
+
+        if (opcode < 0xe0) {
+            int size2, back;
+            if ((opcode & 0x80) == 0) {
+                size  = opcode & 3;
+                back  = ((opcode & 0x60) << 3) + *src++ + 1;
+                size2 = ((opcode & 0x1c) >> 2) + 3;
+            } else if ((opcode & 0x40) == 0) {
+                size  = *src >> 6;
+                back  = (bytestream_get_be16(&src) & 0x3fff) + 1;
+                size2 = (opcode & 0x3f) + 4;
+            } else {
+                size  = opcode & 3;
+                back  = ((opcode & 0x10) << 12) + bytestream_get_be16(&src) + 1;
+                size2 = ((opcode & 0x0c) <<  6) + *src++ + 5;
+                if (size + size2 > dest_end - dest)
+                    break;
+            }
+            if (src + size > src_end || dest + size + size2 > dest_end)
+                return -1;
+            bytestream_get_buffer(&src, dest, size);
+            dest += size;
+            av_memcpy_backptr(dest, back, size2);
+            dest += size2;
+        } else {
+            int finish = opcode >= 0xfc;
+
+            size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
+            if (src + size > src_end || dest + size > dest_end)
+                return -1;
+            bytestream_get_buffer(&src, dest, size);
+            dest += size;
+            if (finish)
+                break;
+        }
+    }
+    return dest - orig_dest;
+}
+
+static int xan_decode_chroma(AVCodecContext *avctx, AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    XanContext *s = avctx->priv_data;
+    uint8_t *U, *V;
+    unsigned chroma_off;
+    int val, uval, vval;
+    int i, j;
+    const uint8_t *src, *src_end;
+    const uint8_t *table;
+    int mode, offset, dec_size;
+
+    chroma_off = AV_RL32(buf + 4);
+    if (!chroma_off)
+        return 0;
+    if (chroma_off + 10 >= avpkt->size) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
+        return -1;
+    }
+    src    = avpkt->data + 4 + chroma_off;
+    table  = src + 2;
+    mode   = bytestream_get_le16(&src);
+    offset = bytestream_get_le16(&src) * 2;
+
+    if (src - avpkt->data >= avpkt->size - offset) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
+        return -1;
+    }
+
+    memset(s->scratch_buffer, 0, s->buffer_size);
+    dec_size = xan_unpack(s->scratch_buffer, s->buffer_size, src + offset,
+                          avpkt->size - offset - (src - avpkt->data));
+    if (dec_size < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
+        return -1;
+    }
+
+    U = s->pic.data[1];
+    V = s->pic.data[2];
+    src     = s->scratch_buffer;
+    src_end = src + dec_size;
+    if (mode) {
+        for (j = 0; j < avctx->height >> 1; j++) {
+            for (i = 0; i < avctx->width >> 1; i++) {
+                val = *src++;
+                if (val) {
+                    val  = AV_RL16(table + (val << 1));
+                    uval = (val >> 3) & 0xF8;
+                    vval = (val >> 8) & 0xF8;
+                    U[i] = uval | (uval >> 5);
+                    V[i] = vval | (vval >> 5);
+                }
+                if (src == src_end)
+                    return 0;
+            }
+            U += s->pic.linesize[1];
+            V += s->pic.linesize[2];
+        }
+    } else {
+        uint8_t *U2 = U + s->pic.linesize[1];
+        uint8_t *V2 = V + s->pic.linesize[2];
+
+        for (j = 0; j < avctx->height >> 2; j++) {
+            for (i = 0; i < avctx->width >> 1; i += 2) {
+                val = *src++;
+                if (val) {
+                    val  = AV_RL16(table + (val << 1));
+                    uval = (val >> 3) & 0xF8;
+                    vval = (val >> 8) & 0xF8;
+                    U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
+                    V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
+                }
+            }
+            U  += s->pic.linesize[1] * 2;
+            V  += s->pic.linesize[2] * 2;
+            U2 += s->pic.linesize[1] * 2;
+            V2 += s->pic.linesize[2] * 2;
+        }
+    }
+
+    return 0;
+}
+
+static int xan_decode_frame_type0(AVCodecContext *avctx, AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    XanContext *s = avctx->priv_data;
+    uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
+    unsigned  chroma_off, corr_off;
+    int cur, last, size;
+    int i, j;
+    int ret;
+
+    corr_off   = AV_RL32(buf + 8);
+    chroma_off = AV_RL32(buf + 4);
+
+    if ((ret = xan_decode_chroma(avctx, avpkt)) != 0)
+        return ret;
+
+    size = avpkt->size - 4;
+    if (corr_off >= avpkt->size) {
+        av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
+        corr_off = 0;
+    }
+    if (corr_off)
+        size = corr_off;
+    if (chroma_off)
+        size = FFMIN(size, chroma_off);
+    ret = xan_unpack_luma(buf + 12, size, src, s->buffer_size >> 1);
+    if (ret) {
+        av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
+        return ret;
+    }
+
+    ybuf = s->y_buffer;
+    last = *src++;
+    ybuf[0] = last << 1;
+    for (j = 1; j < avctx->width - 1; j += 2) {
+        cur = (last + *src++) & 0x1F;
+        ybuf[j]   = last + cur;
+        ybuf[j+1] = cur << 1;
+        last = cur;
+    }
+    ybuf[j]  = last << 1;
+    prev_buf = ybuf;
+    ybuf += avctx->width;
+
+    for (i = 1; i < avctx->height; i++) {
+        last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
+        ybuf[0] = last << 1;
+        for (j = 1; j < avctx->width - 1; j += 2) {
+            cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
+            ybuf[j]   = last + cur;
+            ybuf[j+1] = cur << 1;
+            last = cur;
+        }
+        ybuf[j] = last << 1;
+        prev_buf = ybuf;
+        ybuf += avctx->width;
+    }
+
+    if (corr_off) {
+        int corr_end, dec_size;
+
+        corr_end = avpkt->size;
+        if (chroma_off > corr_off)
+            corr_end = chroma_off;
+        dec_size = xan_unpack(s->scratch_buffer, s->buffer_size,
+                              avpkt->data + 8 + corr_off,
+                              corr_end - corr_off);
+        if (dec_size < 0)
+            dec_size = 0;
+        for (i = 0; i < dec_size; i++)
+            s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
+    }
+
+    src  = s->y_buffer;
+    ybuf = s->pic.data[0];
+    for (j = 0; j < avctx->height; j++) {
+        for (i = 0; i < avctx->width; i++)
+            ybuf[i] = (src[i] << 2) | (src[i] >> 3);
+        src  += avctx->width;
+        ybuf += s->pic.linesize[0];
+    }
+
+    return 0;
+}
+
+static int xan_decode_frame_type1(AVCodecContext *avctx, AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    XanContext *s = avctx->priv_data;
+    uint8_t *ybuf, *src = s->scratch_buffer;
+    int cur, last;
+    int i, j;
+    int ret;
+
+    if ((ret = xan_decode_chroma(avctx, avpkt)) != 0)
+        return ret;
+
+    ret = xan_unpack_luma(buf + 16, avpkt->size - 16, src,
+                          s->buffer_size >> 1);
+    if (ret) {
+        av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
+        return ret;
+    }
+
+    ybuf = s->y_buffer;
+    for (i = 0; i < avctx->height; i++) {
+        last = (ybuf[0] + (*src++ << 1)) & 0x3F;
+        ybuf[0] = last;
+        for (j = 1; j < avctx->width - 1; j += 2) {
+            cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
+            ybuf[j]   = (last + cur) >> 1;
+            ybuf[j+1] = cur;
+            last = cur;
+        }
+        ybuf[j] = last;
+        ybuf += avctx->width;
+    }
+
+    src = s->y_buffer;
+    ybuf = s->pic.data[0];
+    for (j = 0; j < avctx->height; j++) {
+        for (i = 0; i < avctx->width; i++)
+            ybuf[i] = (src[i] << 2) | (src[i] >> 3);
+        src  += avctx->width;
+        ybuf += s->pic.linesize[0];
+    }
+
+    return 0;
+}
+
+static int xan_decode_frame(AVCodecContext *avctx,
+                            void *data, int *data_size,
+                            AVPacket *avpkt)
+{
+    XanContext *s = avctx->priv_data;
+    int ftype;
+    int ret;
+
+    s->pic.reference = 1;
+    s->pic.buffer_hints = FF_BUFFER_HINTS_VALID |
+                          FF_BUFFER_HINTS_PRESERVE |
+                          FF_BUFFER_HINTS_REUSABLE;
+    if ((ret = avctx->reget_buffer(avctx, &s->pic))) {
+        av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
+        return ret;
+    }
+
+    ftype = AV_RL32(avpkt->data);
+    switch (ftype) {
+    case 0:
+        ret = xan_decode_frame_type0(avctx, avpkt);
+        break;
+    case 1:
+        ret = xan_decode_frame_type1(avctx, avpkt);
+        break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
+        return -1;
+    }
+    if (ret)
+        return ret;
+
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*)data = s->pic;
+
+    return avpkt->size;
+}
+
+static av_cold int xan_decode_end(AVCodecContext *avctx)
+{
+    XanContext *s = avctx->priv_data;
+
+    if (s->pic.data[0])
+        avctx->release_buffer(avctx, &s->pic);
+
+    av_freep(&s->y_buffer);
+    av_freep(&s->scratch_buffer);
+
+    return 0;
+}
+
+AVCodec ff_xan_wc4_decoder = {
+    "xan_wc4",
+    AVMEDIA_TYPE_VIDEO,
+    CODEC_ID_XAN_WC4,
+    sizeof(XanContext),
+    xan_decode_init,
+    NULL,
+    xan_decode_end,
+    xan_decode_frame,
+    CODEC_CAP_DR1,
+    .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
+};
+