Flash Screen Video decoder (fourcc:FSV1)

Originally committed as revision 5436 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 274 insertions, 0 deletions

diff --git a/libavcodec/flashsv.c b/libavcodec/flashsv.c
new file mode 100644
index 0000000000..3214d18605
--- /dev/null
+++ b/libavcodec/flashsv.c
@@ -0,0 +1,274 @@
+/*
+ * Flash Screen Video decoder
+ * Copyright (C) 2004 Alex Beregszaszi
+ * Copyright (C) 2006 Benjamin Larsson
+ *
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file flashsv.c
+ * Flash Screen Video decoder
+ * @author Alex Beregszaszi
+ * @author Benjamin Larsson
+ */
+
+/* Bitstream description
+ * The picture is divided into blocks that are zlib compressed.
+ *
+ * The decoder is fed complete frames, the frameheader contains:
+ * 4bits of block width
+ * 12bits of frame width
+ * 4bits of block height
+ * 12bits of frame height
+ *
+ * Directly after the header are the compressed blocks. The blocks
+ * have their compressed size represented with 16bits in the beginnig.
+ * If the size = 0 then the block is unchanged from the previous frame.
+ * All blocks are decompressed until the buffer is consumed.
+ *
+ * Encoding ideas, a basic encoder would just use a fixed block size.
+ * Block sizes can be multipels of 16, from 16 to 256. The blocks don't
+ * have to be quadratic. A brute force search with a set of diffrent
+ * block sizes should give a better result then to just use a fixed size.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "common.h"
+#include "avcodec.h"
+#include "bitstream.h"
+
+#ifdef CONFIG_ZLIB
+#include <zlib.h>
+#endif
+
+typedef struct FlashSVContext {
+    AVCodecContext *avctx;
+    AVFrame frame;
+    int image_width, image_height;
+    int block_width, block_height;
+    uint8_t* tmpblock;
+    int block_size;
+#ifdef CONFIG_ZLIB
+    z_stream zstream;
+#endif
+} FlashSVContext;
+
+
+static void copy_region(uint8_t *sptr, uint8_t *dptr,
+        int dx, int dy, int h, int w, int stride)
+{
+    int i;
+
+    for (i = dx+h; i > dx; i--)
+    {
+        memcpy(dptr+(i*stride)+dy*3, sptr, w*3);
+        sptr += w*3;
+    }
+}
+
+
+static int flashsv_decode_init(AVCodecContext *avctx)
+{
+    FlashSVContext *s = (FlashSVContext *)avctx->priv_data;
+    int zret; // Zlib return code
+
+    s->avctx = avctx;
+#ifdef CONFIG_ZLIB
+    s->zstream.zalloc = Z_NULL;
+    s->zstream.zfree = Z_NULL;
+    s->zstream.opaque = Z_NULL;
+    zret = inflateInit(&(s->zstream));
+    if (zret != Z_OK) {
+        av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
+        return 1;
+    }
+#else
+    av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled. Needed for the decoder.\n");
+    return 1;
+#endif
+    avctx->pix_fmt = PIX_FMT_BGR24;
+    avctx->has_b_frames = 0;
+    s->frame.data[0] = NULL;
+
+    return 0;
+}
+
+
+static int flashsv_decode_frame(AVCodecContext *avctx,
+                                    void *data, int *data_size,
+                                    uint8_t *buf, int buf_size)
+{
+    FlashSVContext *s = (FlashSVContext *)avctx->priv_data;
+    int h_blocks, v_blocks, h_part, v_part, i, j;
+    GetBitContext gb;
+
+    /* no supplementary picture */
+    if (buf_size == 0)
+        return 0;
+
+    if(s->frame.data[0])
+            avctx->release_buffer(avctx, &s->frame);
+
+    init_get_bits(&gb, buf, buf_size * 8);
+
+    /* start to parse the bitstream */
+    s->block_width = 16* (get_bits(&gb, 4)+1);
+    s->image_width =     get_bits(&gb,12);
+    s->block_height= 16* (get_bits(&gb, 4)+1);
+    s->image_height=     get_bits(&gb,12);
+
+    /* calculate amount of blocks and the size of the border blocks */
+    h_blocks = s->image_width / s->block_width;
+    h_part = s->image_width % s->block_width;
+    v_blocks = s->image_height / s->block_height;
+    v_part = s->image_height % s->block_height;
+
+    /* the block size could change between frames, make sure the buffer
+     * is large enough, if not, get a larger one */
+    if(s->block_size < s->block_width*s->block_height) {
+        if (s->tmpblock != NULL)
+            av_free(s->tmpblock);
+        s->block_size = s->block_width*s->block_height;
+        if ((s->tmpblock = av_malloc(3*s->block_size)) == NULL) {
+            av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
+            return -1;
+        }
+    }
+
+    /* init the image size once */
+    if((avctx->width==0) && (avctx->height==0)){
+        avctx->width = s->image_width;
+        avctx->height = s->image_height;
+    }
+
+    /* check for changes of image width and image height */
+    if ((avctx->width != s->image_width) || (avctx->height != s->image_height)) {
+        av_log(avctx, AV_LOG_ERROR, "Frame width or height differs from first frames!\n");
+        av_log(avctx, AV_LOG_ERROR, "fh = %d, fv %d  vs  ch = %d, cv = %d\n",avctx->height,
+        avctx->width,s->image_height,s->image_width);
+        return -1;
+    }
+
+    av_log(avctx, AV_LOG_DEBUG, "image: %dx%d block: %dx%d num: %dx%d part: %dx%d\n",
+        s->image_width, s->image_height, s->block_width, s->block_height,
+        h_blocks, v_blocks, h_part, v_part);
+
+    s->frame.reference = 1;
+    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
+    if (avctx->get_buffer(avctx, &s->frame) < 0) {
+        av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+        return -1;
+    }
+
+    /* loop over all block columns */
+    for (j = 0; j < v_blocks + (v_part?1:0); j++)
+    {
+
+        int hp = j*s->block_height; // horiz position in frame
+        int hs = (j<v_blocks)?s->block_height:v_part; // size of block
+
+
+        /* loop over all block rows */
+        for (i = 0; i < h_blocks + (h_part?1:0); i++)
+        {
+            int wp = i*s->block_width; // vert position in frame
+            int ws = (i<h_blocks)?s->block_width:h_part; // size of block
+
+            /* get the size of the compressed zlib chunk */
+            int size = get_bits(&gb, 16);
+
+            if (size == 0) {
+                /* no change, don't do anything */
+            } else {
+                /* decompress block */
+#ifdef CONFIG_ZLIB
+                int ret = inflateReset(&(s->zstream));
+                if (ret != Z_OK)
+                {
+                    av_log(avctx, AV_LOG_ERROR, "error in decompression (reset) of block %dx%d\n", i, j);
+                    /* return -1; */
+                }
+                s->zstream.next_in = buf+(get_bits_count(&gb)/8);
+                s->zstream.avail_in = size;
+                s->zstream.next_out = s->tmpblock;
+                s->zstream.avail_out = s->block_size*3;
+                ret = inflate(&(s->zstream), Z_FINISH);
+                if (ret == Z_DATA_ERROR)
+                {
+                    av_log(avctx, AV_LOG_ERROR, "Zlib resync occured\n");
+                    inflateSync(&(s->zstream));
+                    ret = inflate(&(s->zstream), Z_FINISH);
+                }
+
+                if ((ret != Z_OK) && (ret != Z_STREAM_END))
+                {
+                    av_log(avctx, AV_LOG_ERROR, "error in decompression of block %dx%d: %d\n", i, j, ret);
+                    /* return -1; */
+                }
+#else
+                av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled in.\n");
+                return -1;
+#endif
+                copy_region(s->tmpblock, s->frame.data[0], s->image_height-(hp+hs+1), wp, hs, ws, s->frame.linesize[0]);
+                skip_bits(&gb, 8*size);   /* skip the consumed bits */
+            }
+        }
+    }
+
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*)data = s->frame;
+
+    if ((get_bits_count(&gb)/8) != buf_size)
+        av_log(avctx, AV_LOG_ERROR, "buffer not fully consumed (%d != %d)\n",
+            buf_size, (get_bits_count(&gb)/8));
+
+    /* report that the buffer was completely consumed */
+    return buf_size;
+}
+
+
+static int flashsv_decode_end(AVCodecContext *avctx)
+{
+    FlashSVContext *s = (FlashSVContext *)avctx->priv_data;
+#ifdef CONFIG_ZLIB
+    inflateEnd(&(s->zstream));
+#endif
+    /* release the frame if needed */
+    if (s->frame.data[0])
+        avctx->release_buffer(avctx, &s->frame);
+
+    /* free the tmpblock */
+    if (s->tmpblock != NULL)
+        av_free(s->tmpblock);
+
+    return 0;
+}
+
+
+AVCodec flashsv_decoder = {
+    "flashsv",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_FLASHSV,
+    sizeof(FlashSVContext),
+    flashsv_decode_init,
+    NULL,
+    flashsv_decode_end,
+    flashsv_decode_frame,
+    CODEC_CAP_DR1,
+    .pix_fmts = (enum PixelFormat[]){PIX_FMT_BGR24, -1},
+};