mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-26 19:01:44 +02:00
259 lines
8.1 KiB
C
259 lines
8.1 KiB
C
/*
|
|
* Flash Screen Video decoder
|
|
* Copyright (C) 2004 Alex Beregszaszi
|
|
* Copyright (C) 2006 Benjamin Larsson
|
|
*
|
|
* 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 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 "avcodec.h"
|
|
#include "bitstream.h"
|
|
|
|
#include <zlib.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 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 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,
|
|
const uint8_t *buf, int buf_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(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);
|
|
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 -1;
|
|
}
|
|
}
|
|
s->block_size = s->block_width*s->block_height;
|
|
|
|
/* 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 */
|
|
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 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; */
|
|
}
|
|
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 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 */
|
|
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},
|
|
};
|