complete AVS playback system (from Creature Shock computer game),

courtesy of Aurelien Jacobs <aurel at gnuage dot org>

Originally committed as revision 5028 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 158 insertions, 0 deletions

diff --git a/libavcodec/avs.c b/libavcodec/avs.c
new file mode 100644
index 0000000000..557e9becb3
--- /dev/null
+++ b/libavcodec/avs.c
@@ -0,0 +1,158 @@
+/*
+ * AVS video decoder.
+ * Copyright (c) 2006  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "avcodec.h"
+#include "bitstream.h"
+
+
+typedef struct {
+    AVFrame picture;
+} avs_context_t;
+
+typedef enum {
+    AVS_VIDEO     = 0x01,
+    AVS_AUDIO     = 0x02,
+    AVS_PALETTE   = 0x03,
+    AVS_GAME_DATA = 0x04,
+} avs_block_type_t;
+
+typedef enum {
+    AVS_I_FRAME     = 0x00,
+    AVS_P_FRAME_3X3 = 0x01,
+    AVS_P_FRAME_2X2 = 0x02,
+    AVS_P_FRAME_2X3 = 0x03,
+} avs_video_sub_type_t;
+
+
+static int
+avs_decode_frame(AVCodecContext * avctx,
+                 void *data, int *data_size, uint8_t * buf, int buf_size)
+{
+    avs_context_t *const avs = avctx->priv_data;
+    AVFrame *picture = data;
+    AVFrame *const p = (AVFrame *) & avs->picture;
+    uint8_t *table, *vect, *out;
+    int i, j, x, y, stride, vect_w = 3, vect_h = 3;
+    int sub_type;
+    avs_block_type_t type;
+    GetBitContext change_map;
+
+    if (avctx->reget_buffer(avctx, p)) {
+        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
+        return -1;
+    }
+    p->reference = 1;
+    p->pict_type = FF_P_TYPE;
+    p->key_frame = 0;
+
+    out = avs->picture.data[0];
+    stride = avs->picture.linesize[0];
+
+    sub_type = buf[0];
+    type = buf[1];
+    buf += 4;
+
+    if (type == AVS_PALETTE) {
+        int first, last;
+        uint32_t *pal = (uint32_t *) avs->picture.data[1];
+
+        first = LE_16(buf);
+        last = first + LE_16(buf + 2);
+        buf += 4;
+        for (i=first; i<last; i++, buf+=3)
+            pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
+
+        sub_type = buf[0];
+        type = buf[1];
+        buf += 4;
+    }
+
+    if (type != AVS_VIDEO)
+        return -1;
+
+    switch (sub_type) {
+    case AVS_I_FRAME:
+        p->pict_type = FF_I_TYPE;
+        p->key_frame = 1;
+    case AVS_P_FRAME_3X3:
+        vect_w = 3;
+        vect_h = 3;
+        break;
+
+    case AVS_P_FRAME_2X2:
+        vect_w = 2;
+        vect_h = 2;
+        break;
+
+    case AVS_P_FRAME_2X3:
+        vect_w = 2;
+        vect_h = 3;
+        break;
+
+    default:
+      return -1;
+    }
+
+    table = buf + (256 * vect_w * vect_h);
+    if (sub_type != AVS_I_FRAME) {
+        int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
+        init_get_bits(&change_map, table, map_size);
+        table += map_size;
+    }
+
+    for (y=0; y<198; y+=vect_h) {
+        for (x=0; x<318; x+=vect_w) {
+            if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
+                vect = &buf[*table++ * (vect_w * vect_h)];
+                for (j=0; j<vect_w; j++) {
+                    out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
+                    out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
+                    if (vect_h == 3)
+                        out[(y + 2) * stride + x + j] =
+                            vect[(2 * vect_w) + j];
+                }
+            }
+        }
+        if (sub_type != AVS_I_FRAME)
+            align_get_bits(&change_map);
+    }
+
+    *picture = *(AVFrame *) & avs->picture;
+    *data_size = sizeof(AVPicture);
+
+    return buf_size;
+}
+
+static int avs_decode_init(AVCodecContext * avctx)
+{
+    avctx->pix_fmt = PIX_FMT_PAL8;
+    return 0;
+}
+
+AVCodec avs_decoder = {
+    "avs",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_AVS,
+    sizeof(avs_context_t),
+    avs_decode_init,
+    NULL,
+    NULL,
+    avs_decode_frame,
+    CODEC_CAP_DR1,
+};