BFI video decoder.

Patch by Sisir Koppaka sisir koppaka gmail
Original thread: [FFmpeg-devel] BFI video decoder
Date: 04/17/2008 04:25 PM

Originally committed as revision 12890 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 181 insertions, 0 deletions

diff --git a/libavcodec/bfi.c b/libavcodec/bfi.c
new file mode 100644
index 0000000000..ffb13f7209
--- /dev/null
+++ b/libavcodec/bfi.c
@@ -0,0 +1,181 @@
+/*
+ * Brute Force & Ignorance (BFI) video decoder
+ * Copyright (c) 2008 Sisir Koppaka
+ *
+ * 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 bfi.c
+ * @brief Brute Force & Ignorance (.bfi) video decoder
+ * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
+ * @sa http://wiki.multimedia.cx/index.php?title=BFI
+ */
+
+#include "avcodec.h"
+#include "common.h"
+#include "bytestream.h"
+
+typedef struct BFIContext {
+    AVCodecContext *avctx;
+    AVFrame frame;
+    uint8_t *dst;
+} BFIContext;
+
+static int bfi_decode_init(AVCodecContext * avctx)
+{
+    BFIContext *bfi = avctx->priv_data;
+    avctx->pix_fmt = PIX_FMT_PAL8;
+    bfi->dst = av_mallocz(avctx->width * avctx->height);
+    return 0;
+}
+
+static int bfi_decode_frame(AVCodecContext * avctx, void *data,
+                            int *data_size, const uint8_t * buf,
+                            int buf_size)
+{
+    BFIContext *bfi = avctx->priv_data;
+    uint8_t *dst = bfi->dst;
+    uint8_t *src, *dst_offset, colour1, colour2;
+    uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
+    uint32_t *pal;
+    int i, j, height = avctx->height;
+
+    if (bfi->frame.data[0])
+        avctx->release_buffer(avctx, &bfi->frame);
+
+    bfi->frame.reference = 1;
+
+    if (avctx->get_buffer(avctx, &bfi->frame) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+        return -1;
+    }
+
+    /* Set frame parameters and palette, if necessary */
+    if (!avctx->frame_number) {
+        bfi->frame.pict_type = FF_I_TYPE;
+        bfi->frame.key_frame = 1;
+        /* Setting the palette */
+        if(avctx->extradata_size>768) {
+            av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");
+            return -1;
+        }
+        pal = (uint32_t *) bfi->frame.data[1];
+        for (i = 0; i < avctx->extradata_size / 3; i++) {
+            int shift = 16;
+            *pal = 0;
+            for (j = 0; j < 3; j++, shift -= 8)
+                *pal +=
+                    ((avctx->extradata[i * 3 + j] << 2) |
+                    (avctx->extradata[i * 3 + j] >> 4)) << shift;
+            pal++;
+        }
+        bfi->frame.palette_has_changed = 1;
+    } else {
+        bfi->frame.pict_type = FF_P_TYPE;
+        bfi->frame.key_frame = 0;
+    }
+
+    buf += 4; //Unpacked size, not required.
+
+    while (dst != frame_end) {
+        static const uint8_t lentab[4]={0,2,0,1};
+        unsigned int byte = *buf++, offset;
+        unsigned int code = byte >> 6;
+        unsigned int length = byte & ~0xC0;
+
+        /* Get length and offset(if required) */
+        if (length == 0) {
+            if (code == 1) {
+                length = bytestream_get_byte(&buf);
+                offset = bytestream_get_le16(&buf);
+            } else {
+                length = bytestream_get_le16(&buf);
+                if (code == 2 && length == 0)
+                    break;
+            }
+        } else {
+            if (code == 1)
+                offset = bytestream_get_byte(&buf);
+        }
+
+        /* Do boundary check */
+        if (dst + (length<<lentab[code]) > frame_end)
+            break;
+
+        switch (code) {
+
+        case 0:                //Normal Chain
+            bytestream_get_buffer(&buf, dst, length);
+            dst += length;
+            break;
+
+        case 1:                //Back Chain
+            dst_offset = dst - offset;
+            length *= 4;        //Convert dwords to bytes.
+            if (dst_offset < bfi->dst)
+                break;
+            while (length--)
+                *dst++ = *dst_offset++;
+            break;
+
+        case 2:                //Skip Chain
+            dst += length;
+            break;
+
+        case 3:                //Fill Chain
+            colour1 = bytestream_get_byte(&buf);
+            colour2 = bytestream_get_byte(&buf);
+            while (length--) {
+                *dst++ = colour1;
+                *dst++ = colour2;
+            }
+            break;
+
+        }
+    }
+
+    src = bfi->dst;
+    dst = bfi->frame.data[0];
+    while (height--) {
+        memcpy(dst, src, avctx->width);
+        src += avctx->width;
+        dst += bfi->frame.linesize[0];
+    }
+    *data_size = sizeof(AVFrame);
+    *(AVFrame *) data = bfi->frame;
+    return buf_size;
+}
+
+static int bfi_decode_close(AVCodecContext * avctx)
+{
+    BFIContext *bfi = avctx->priv_data;
+    if (bfi->frame.data[0])
+        avctx->release_buffer(avctx, &bfi->frame);
+    av_free(bfi->dst);
+    return 0;
+}
+
+AVCodec bfi_decoder = {
+    .name = "bfi",
+    .type = CODEC_TYPE_VIDEO,
+    .id = CODEC_ID_BFI,
+    .priv_data_size = sizeof(BFIContext),
+    .init = bfi_decode_init,
+    .close = bfi_decode_close,
+    .decode = bfi_decode_frame,
+};