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/*
* MatchWare Screen Capture Codec decoder
*
* Copyright (c) 2018 Paul B Mahol
*
* 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
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#include <zlib.h>
typedef struct MWSCContext {
unsigned int decomp_size;
uint8_t *decomp_buf;
z_stream zstream;
AVFrame *prev_frame;
} MWSCContext;
static int rle_uncompress(GetByteContext *gb, PutByteContext *pb, GetByteContext *gbp,
int width, int height, int stride, int pb_linesize, int gbp_linesize)
{
int intra = 1, w = 0;
bytestream2_seek_p(pb, (height - 1) * pb_linesize, SEEK_SET);
while (bytestream2_get_bytes_left(gb) > 0) {
uint32_t fill = bytestream2_get_le24(gb);
unsigned run = bytestream2_get_byte(gb);
if (run == 0) {
run = bytestream2_get_le32(gb);
for (int j = 0; j < run; j++, w++) {
if (w == width) {
w = 0;
bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
}
bytestream2_put_le24(pb, fill);
}
} else if (run == 255) {
int pos = bytestream2_tell_p(pb);
bytestream2_seek(gbp, pos, SEEK_SET);
for (int j = 0; j < fill; j++, w++) {
if (w == width) {
w = 0;
bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
bytestream2_seek(gbp, -(gbp_linesize + stride), SEEK_CUR);
}
bytestream2_put_le24(pb, bytestream2_get_le24(gbp));
}
intra = 0;
} else {
for (int j = 0; j < run; j++, w++) {
if (w == width) {
w = 0;
bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
}
bytestream2_put_le24(pb, fill);
}
}
}
return intra;
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
MWSCContext *s = avctx->priv_data;
AVFrame *frame = data;
uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
GetByteContext gb;
GetByteContext gbp;
PutByteContext pb;
int ret;
ret = inflateReset(&s->zstream);
if (ret != Z_OK) {
av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret);
return AVERROR_EXTERNAL;
}
s->zstream.next_in = buf;
s->zstream.avail_in = buf_size;
s->zstream.next_out = s->decomp_buf;
s->zstream.avail_out = s->decomp_size;
ret = inflate(&s->zstream, Z_FINISH);
if (ret != Z_STREAM_END) {
av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", ret);
return AVERROR_EXTERNAL;
}
if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
return ret;
bytestream2_init(&gb, s->decomp_buf, s->zstream.total_out);
bytestream2_init(&gbp, s->prev_frame->data[0], avctx->height * s->prev_frame->linesize[0]);
bytestream2_init_writer(&pb, frame->data[0], avctx->height * frame->linesize[0]);
frame->key_frame = rle_uncompress(&gb, &pb, &gbp, avctx->width, avctx->height, avctx->width * 3,
frame->linesize[0], s->prev_frame->linesize[0]);
frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
av_frame_unref(s->prev_frame);
if ((ret = av_frame_ref(s->prev_frame, frame)) < 0)
return ret;
*got_frame = 1;
return avpkt->size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
MWSCContext *s = avctx->priv_data;
int64_t size;
int zret;
avctx->pix_fmt = AV_PIX_FMT_BGR24;
size = 32LL * avctx->height * avctx->width;
if (size >= INT32_MAX)
return AVERROR_INVALIDDATA;
s->decomp_size = size;
if (!(s->decomp_buf = av_malloc(s->decomp_size)))
return AVERROR(ENOMEM);
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 AVERROR_EXTERNAL;
}
s->prev_frame = av_frame_alloc();
if (!s->prev_frame)
return AVERROR(ENOMEM);
return 0;
}
static av_cold int decode_close(AVCodecContext *avctx)
{
MWSCContext *s = avctx->priv_data;
av_frame_free(&s->prev_frame);
av_freep(&s->decomp_buf);
s->decomp_size = 0;
inflateEnd(&s->zstream);
return 0;
}
AVCodec ff_mwsc_decoder = {
.name = "mwsc",
.long_name = NULL_IF_CONFIG_SMALL("MatchWare Screen Capture Codec"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_MWSC,
.priv_data_size = sizeof(MWSCContext),
.init = decode_init,
.close = decode_close,
.decode = decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP,
};
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