complete American Laser Games MM playback system, courtesy of Peter Ross

(suxen_drol at hotmail dot com)

Originally committed as revision 4999 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 204 insertions, 0 deletions

diff --git a/libavcodec/mmvideo.c b/libavcodec/mmvideo.c
new file mode 100644
index 0000000000..b2e146839d
--- /dev/null
+++ b/libavcodec/mmvideo.c
@@ -0,0 +1,204 @@
+/*
+ * American Laser Games MM Video Decoder
+ * Copyright (c) 2006 Peter Ross
+ *
+ * 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 mm.c
+ * American Laser Games MM Video Decoder
+ * by Peter Ross (suxen_drol at hotmail dot com)
+ *
+ * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
+ * including Mad Dog McCree and Crime Patrol.
+ *
+ * Technical details here:
+ *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
+ */
+
+#include "avcodec.h"
+
+#define MM_PREAMBLE_SIZE    6
+
+#define MM_TYPE_INTER       0x5
+#define MM_TYPE_INTRA       0x8
+#define MM_TYPE_INTRA_HH    0xc
+#define MM_TYPE_INTER_HH    0xd
+#define MM_TYPE_INTRA_HHV   0xe
+#define MM_TYPE_INTER_HHV   0xf
+
+typedef struct MmContext {
+    AVCodecContext *avctx;
+    AVFrame frame;
+} MmContext;
+
+static int mm_decode_init(AVCodecContext *avctx)
+{
+    MmContext *s = avctx->priv_data;
+
+    s->avctx = avctx;
+
+    if (s->avctx->palctrl == NULL) {
+        av_log(avctx, AV_LOG_ERROR, "mmvideo: palette expected.\n");
+        return -1;
+    }
+
+    avctx->pix_fmt = PIX_FMT_PAL8;
+    avctx->has_b_frames = 0;
+
+    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height))
+        return -1;
+
+    s->frame.reference = 1;
+    if (avctx->get_buffer(avctx, &s->frame)) {
+        av_log(s->avctx, AV_LOG_ERROR, "mmvideo: get_buffer() failed\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
+{
+    int i, x, y;
+    i=0; x=0; y=0;
+
+    while(i<buf_size) {
+        int run_length, color;
+
+        if (buf[i] & 0x80) {
+            run_length = 1;
+            color = buf[i];
+            i++;
+        }else{
+            run_length = (buf[i] & 0x7f) + 2;
+            color = buf[i+1];
+            i+=2;
+        }
+
+        if (half_horiz)
+            run_length *=2;
+
+        if (color) {
+            memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
+            if (half_vert)
+                memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
+        }
+        x+= run_length;
+
+        if (x >= s->avctx->width) {
+            x=0;
+            y += half_vert ? 2 : 1;
+        }
+    }
+}
+
+static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
+{
+    const int data_ptr = 2 + LE_16(&buf[0]);
+    int d, r, y;
+    d = data_ptr; r = 2; y = 0;
+
+    while(r < data_ptr) {
+        int i, j;
+        int length = buf[r] & 0x7f;
+        int x = buf[r+1] + ((buf[r] & 0x80) << 1);
+        r += 2;
+
+        if (length==0) {
+            y += x;
+            continue;
+        }
+
+        for(i=0; i<length; i++) {
+            for(j=0; j<8; j++) {
+                int replace = (buf[r+i] >> (7-j)) & 1;
+                if (replace) {
+                    int color = buf[d];
+                    s->frame.data[0][y*s->frame.linesize[0] + x] = color;
+                    if (half_horiz)
+                        s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
+                    if (half_vert) {
+                        s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
+                        if (half_horiz)
+                            s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
+                    }
+                    d++;
+                }
+                x += half_horiz ? 2 : 1;
+            }
+        }
+
+        r += length;
+        y += half_vert ? 2 : 1;
+    }
+}
+
+static int mm_decode_frame(AVCodecContext *avctx,
+                            void *data, int *data_size,
+                            uint8_t *buf, int buf_size)
+{
+    MmContext *s = avctx->priv_data;
+    AVPaletteControl *palette_control = avctx->palctrl;
+    int type;
+
+    if (palette_control->palette_changed) {
+        memcpy(s->frame.data[1], palette_control->palette, AVPALETTE_SIZE);
+        palette_control->palette_changed = 0;
+    }
+
+    type = LE_16(&buf[0]);
+    buf += MM_PREAMBLE_SIZE;
+    buf_size -= MM_PREAMBLE_SIZE;
+
+    switch(type) {
+    case MM_TYPE_INTRA     : mm_decode_intra(s, 0, 0, buf, buf_size); break;
+    case MM_TYPE_INTRA_HH  : mm_decode_intra(s, 1, 0, buf, buf_size); break;
+    case MM_TYPE_INTRA_HHV : mm_decode_intra(s, 1, 1, buf, buf_size); break;
+    case MM_TYPE_INTER     : mm_decode_inter(s, 0, 0, buf, buf_size); break;
+    case MM_TYPE_INTER_HH  : mm_decode_inter(s, 1, 0, buf, buf_size); break;
+    case MM_TYPE_INTER_HHV : mm_decode_inter(s, 1, 1, buf, buf_size); break;
+    default :
+        return -1;
+    }
+
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*)data = s->frame;
+
+    return buf_size;
+}
+
+static int mm_decode_end(AVCodecContext *avctx)
+{
+    MmContext *s = avctx->priv_data;
+
+    if(s->frame.data[0])
+        avctx->release_buffer(avctx, &s->frame);
+
+    return 0;
+}
+
+AVCodec mmvideo_decoder = {
+    "mmvideo",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_MMVIDEO,
+    sizeof(MmContext),
+    mm_decode_init,
+    NULL,
+    mm_decode_end,
+    mm_decode_frame,
+    CODEC_CAP_DR1,
+};