Bethsoft VID demuxer and video decoder

patch by Nicholas Tung, ntung ntung com

Originally committed as revision 8649 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 139 insertions, 0 deletions

diff --git a/libavcodec/bethsoftvideo.c b/libavcodec/bethsoftvideo.c
new file mode 100644
index 0000000000..a59743789a
--- /dev/null
+++ b/libavcodec/bethsoftvideo.c
@@ -0,0 +1,139 @@
+/*
+ * Bethesda VID video decoder
+ * Copyright (C) 2007 Nicholas Tung
+ *
+ * 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
+ */
+
+/**
+ * @file bethsoftvideo.c
+ * @brief Bethesda Softworks VID Video Decoder
+ * @author Nicholas Tung [ntung (at. ntung com] (2007-03)
+ * @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
+ * @sa http://www.svatopluk.com/andux/docs/dfvid.html
+ */
+
+#include "common.h"
+#include "dsputil.h"
+#include "bethsoftvideo.h"
+#include "bytestream.h"
+
+typedef struct BethsoftvidContext {
+    AVFrame frame;
+} BethsoftvidContext;
+
+static int bethsoftvid_decode_init(AVCodecContext *avctx)
+{
+    BethsoftvidContext *vid = avctx->priv_data;
+    vid->frame.reference = 1;
+    vid->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
+        FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
+    avctx->pix_fmt = PIX_FMT_PAL8;    // palette in vid->frame.data[1]
+    av_log(avctx, AV_LOG_DEBUG, "[bethsoftvid video decoder] init\n");
+    return 0;
+}
+
+static void set_palette(AVFrame * frame, uint8_t * palette_buffer)
+{
+    uint32_t * palette = (uint32_t *)frame->data[1];
+    int a;
+    for(a = 0; a < VID_PALETTE_NUMCOLORS; a++)
+    {
+        palette[a] = AV_RB24(&palette_buffer[a * 3]) * 4;    // multiply all colors by 4
+    }
+    frame->palette_has_changed = 1;
+}
+
+static int bethsoftvid_decode_frame(AVCodecContext *avctx,
+                              void *data, int *data_size,
+                              uint8_t *buf, int buf_size)
+{
+    BethsoftvidContext * vid = avctx->priv_data;
+    char block_type;
+    uint8_t * destination;
+    uint8_t * frame_end;
+    int line_remaining = avctx->width;          // number of bytes remaining on a line
+    const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
+    uint8_t rle_num_bytes;
+    int yoffset;
+
+    av_log(avctx, AV_LOG_DEBUG, "[bethsoftvid video decoder] decoding frame\n");
+
+    // reget buffer will copy old data, good for simple difference frames
+    if (avctx->reget_buffer(avctx, &vid->frame)) {
+        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
+        return -1;
+    }
+    destination = vid->frame.data[0];
+    frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
+
+    switch(block_type = *buf++)
+    {
+        case PALETTE_BLOCK: set_palette(&vid->frame, buf); return 0;
+        case VIDEO_YOFFSET_DIFFERENCE_FRAME_BLOCK:
+            yoffset = bytestream_get_le16(&buf);
+            if(yoffset >= avctx->height) { return -1; }
+            destination += vid->frame.linesize[0] * yoffset;
+    }
+
+    // main code
+    while((rle_num_bytes = *buf++))
+    {
+        int length = rle_num_bytes & 0x7f;
+
+        // copy any bytes starting at the current position, and ending at the frame width
+        while(length > line_remaining)
+        {
+            if(rle_num_bytes < 0x80) { bytestream_get_buffer(&buf, destination, line_remaining); }
+            else if(block_type == VIDEO_FULL_FRAME_BLOCK) { memset(destination, buf[0], line_remaining); }
+            length -= line_remaining;      // decrement the number of bytes to be copied
+            destination += line_remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
+            line_remaining = avctx->width;
+            if(destination == frame_end) { goto end; }
+        }
+
+        // copy any remaining bytes after / if line overflows
+        if(rle_num_bytes < 0x80) { bytestream_get_buffer(&buf, destination, length); }
+        else if(block_type == VIDEO_FULL_FRAME_BLOCK) { memset(destination, *buf++, length); }
+        line_remaining -= length;
+        destination += length;
+    }
+    end:
+
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*)data = vid->frame;
+
+    return buf_size;
+}
+
+static int bethsoftvid_decode_end(AVCodecContext *avctx)
+{
+    BethsoftvidContext * vid = avctx->priv_data;
+    av_log(avctx, AV_LOG_DEBUG, "[bethsoftvid video decoder] closing\n");
+    if(vid->frame.data[0]) { avctx->release_buffer(avctx, &vid->frame); }
+    return 0;
+}
+
+AVCodec bethsoftvid_decoder = {
+    .name = "bethsoftvid",
+    .type = CODEC_TYPE_VIDEO,
+    .id = CODEC_ID_BETHSOFTVID,
+    .priv_data_size = sizeof(BethsoftvidContext),
+    .init = bethsoftvid_decode_init,
+    .close = bethsoftvid_decode_end,
+    .decode = bethsoftvid_decode_frame,
+};