* Copyright (C) 2004 Alex Beregszaszi
* Copyright (C) 2006 Benjamin Larsson
*
- * This file is part of Libav.
+ * This file is part of FFmpeg.
*
- * Libav is free software; you can redistribute it and/or
+ * 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.
*
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
* Flash Screen Video encoder
* @author Alex Beregszaszi
* @author Benjamin Larsson
+ *
+ * A description of the bitstream format for Flash Screen Video version 1/2
+ * is part of the SWF File Format Specification (version 10), which can be
+ * downloaded from http://www.adobe.com/devnet/swf.html.
*/
-/* Bitstream description
- * The picture is divided into blocks that are zlib-compressed.
- *
- * The decoder is fed complete frames, the frameheader contains:
- * 4 bits of block width
- * 12 bits of frame width
- * 4 bits of block height
- * 12 bits of frame height
- *
- * Directly after the header are the compressed blocks. The blocks
- * have their compressed size represented with 16 bits in the beginning.
- * 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 multiples of 16, from 16 to 256. The blocks don't
* have to be quadratic. A brute force search with a set of different
/* loop over all block columns */
for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) {
- int hp = j * block_height; // horizontal position in frame
- int hs = (j < v_blocks) ? block_height : v_part; // size of block
+ int y_pos = j * block_height; // vertical position in frame
+ int cur_blk_height = (j < v_blocks) ? block_height : v_part;
/* loop over all block rows */
for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) {
- int wp = i * block_width; // vertical position in frame
- int ws = (i < h_blocks) ? block_width : h_part; // size of block
+ int x_pos = i * block_width; // horizontal position in frame
+ int cur_blk_width = (i < h_blocks) ? block_width : h_part;
int ret = Z_OK;
- uint8_t *ptr;
-
- ptr = buf + buf_pos;
+ uint8_t *ptr = buf + buf_pos;
/* copy the block to the temp buffer before compression
* (if it differs from the previous frame's block) */
res = copy_region_enc(p->data[0], s->tmpblock,
- s->image_height - (hp + hs + 1),
- wp, hs, ws, p->linesize[0], previous_frame);
+ s->image_height - (y_pos + cur_blk_height + 1),
+ x_pos, cur_blk_height, cur_blk_width,
+ p->linesize[0], previous_frame);
if (res || *I_frame) {
- unsigned long zsize;
- zsize = 3 * block_width * block_height;
- ret = compress2(ptr + 2, &zsize, s->tmpblock, 3 * ws * hs, 9);
-
+ unsigned long zsize = 3 * block_width * block_height;
+ ret = compress2(ptr + 2, &zsize, s->tmpblock,
+ 3 * cur_blk_width * cur_blk_height, 9);
//ret = deflateReset(&s->zstream);
if (ret != Z_OK)
av_log(s->avctx, AV_LOG_ERROR,
"error while compressing block %dx%d\n", i, j);
- bytestream_put_be16(&ptr, (unsigned int) zsize);
+ bytestream_put_be16(&ptr, zsize);
buf_pos += zsize + 2;
- av_dlog(avctx, "buf_pos = %d\n", buf_pos);
+ av_dlog(s->avctx, "buf_pos = %d\n", buf_pos);
} else {
pred_blocks++;
bytestream_put_be16(&ptr, 0);
uint8_t *pfptr;
int res;
int I_frame = 0;
- int opt_w, opt_h;
+ int opt_w = 4, opt_h = 4;
*p = *pict;
pfptr = s->previous_frame;
/* Check the placement of keyframes */
- if (avctx->gop_size > 0) {
- if (avctx->frame_number >= s->last_key_frame + avctx->gop_size) {
- I_frame = 1;
- }
+ if (avctx->gop_size > 0 &&
+ avctx->frame_number >= s->last_key_frame + avctx->gop_size) {
+ I_frame = 1;
}
- opt_w = 4;
- opt_h = 4;
-
if (buf_size < s->image_width * s->image_height * 3) {
//Conservative upper bound check for compressed data
av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n",