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/*
* Flash Screen Video decoder
* Copyright (C) 2004 Alex Beregszaszi
* Copyright (C) 2006 Benjamin Larsson
*
* This file is part of Libav.
*
* Libav 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,
* 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
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Flash Screen Video decoder
* @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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <zlib.h>
#include "avcodec.h"
#include "get_bits.h"
typedef struct FlashSVContext {
AVCodecContext *avctx;
AVFrame frame;
int image_width, image_height;
int block_width, block_height;
uint8_t *tmpblock;
int block_size;
z_stream zstream;
} FlashSVContext;
static av_cold int flashsv_decode_init(AVCodecContext *avctx)
{
FlashSVContext *s = avctx->priv_data;
int zret; // Zlib return code
s->avctx = avctx;
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;
}
avctx->pix_fmt = PIX_FMT_BGR24;
s->frame.data[0] = NULL;
return 0;
}
static int flashsv_decode_frame(AVCodecContext *avctx, void *data,
int *data_size, AVPacket *avpkt)
{
int buf_size = avpkt->size;
FlashSVContext *s = 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 (buf_size < 4)
return -1;
init_get_bits(&gb, avpkt->data, 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 number of blocks and size of border (partial) 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) {
av_free(s->tmpblock);
if ((s->tmpblock = av_malloc(3 * s->block_width * s->block_height)) == NULL) {
av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
return AVERROR(ENOMEM);
}
}
s->block_size = s->block_width * s->block_height;
/* initialize 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 AVERROR_INVALIDDATA;
}
av_dlog(avctx, "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 = 3;
s->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
FF_BUFFER_HINTS_PRESERVE |
FF_BUFFER_HINTS_REUSABLE;
if (avctx->reget_buffer(avctx, &s->frame) < 0) {
av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
return -1;
}
/* loop over all block columns */
for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) {
int y_pos = j * s->block_height; // vertical position in frame
int cur_blk_height = (j < v_blocks) ? s->block_height : v_part;
/* loop over all block rows */
for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) {
int x_pos = i * s->block_width; // horizontal position in frame
int cur_blk_width = (i < h_blocks) ? s->block_width : h_part;
/* get the size of the compressed zlib chunk */
int size = get_bits(&gb, 16);
if (8 * size > get_bits_left(&gb)) {
avctx->release_buffer(avctx, &s->frame);
s->frame.data[0] = NULL;
return AVERROR_INVALIDDATA;
}
/* skip unchanged blocks, which have size 0 */
if (size) {
/* decompress block */
uint8_t *line = s->tmpblock;
int k;
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 = avpkt->data + 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 occurred\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; */
}
/* Flash Screen Video stores the image upside down, so copy
* lines to destination in reverse order. */
for (k = 1; k <= cur_blk_height; k++) {
memcpy(s->frame.data[0] + x_pos * 3 +
(s->image_height - y_pos - k) * s->frame.linesize[0],
line, cur_blk_width * 3);
/* advance source pointer to next line */
line += cur_blk_width * 3;
}
skip_bits_long(&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 av_cold int flashsv_decode_end(AVCodecContext *avctx)
{
FlashSVContext *s = avctx->priv_data;
inflateEnd(&s->zstream);
/* release the frame if needed */
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
/* free the tmpblock */
av_free(s->tmpblock);
return 0;
}
AVCodec ff_flashsv_decoder = {
.name = "flashsv",
.type = AVMEDIA_TYPE_VIDEO,
.id = CODEC_ID_FLASHSV,
.priv_data_size = sizeof(FlashSVContext),
.init = flashsv_decode_init,
.close = flashsv_decode_end,
.decode = flashsv_decode_frame,
.capabilities = CODEC_CAP_DR1,
.pix_fmts = (const enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video v1"),
};
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