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ffmpeg/libavcodec/sga.c

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/*
* Copyright (c) 2021 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 "libavutil/common.h"
#include "libavutil/mem.h"
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "decode.h"
#define PALDATA_FOLLOWS_TILEDATA 4
#define HAVE_COMPRESSED_TILEMAP 32
#define HAVE_TILEMAP 128
typedef struct SGAVideoContext {
GetByteContext gb;
int metadata_size;
int tiledata_size;
int tiledata_offset;
int tilemapdata_size;
int tilemapdata_offset;
int paldata_size;
int paldata_offset;
int palmapdata_offset;
int palmapdata_size;
int flags;
int nb_pal;
int nb_tiles;
int tiles_w, tiles_h;
int shift;
int plus;
int swap;
uint32_t pal[256];
uint8_t *tileindex_data;
unsigned tileindex_size;
uint8_t *palmapindex_data;
unsigned palmapindex_size;
uint8_t uncompressed[65536];
} SGAVideoContext;
static av_cold int sga_decode_init(AVCodecContext *avctx)
{
avctx->pix_fmt = AV_PIX_FMT_PAL8;
return 0;
}
static int decode_palette(GetByteContext *gb, uint32_t *pal)
{
GetBitContext gbit;
if (bytestream2_get_bytes_left(gb) < 18)
return AVERROR_INVALIDDATA;
memset(pal, 0, 16 * sizeof(*pal));
(void)init_get_bits8(&gbit, gb->buffer, 18);
for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
for (int index = 0; index < 16; index++) {
unsigned color = get_bits1(&gbit) << RGBIndex;
pal[15 - index] |= color << (5 + 16);
}
}
for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
for (int index = 0; index < 16; index++) {
unsigned color = get_bits1(&gbit) << RGBIndex;
pal[15 - index] |= color << (5 + 8);
}
}
for (int RGBIndex = 0; RGBIndex < 3; RGBIndex++) {
for (int index = 0; index < 16; index++) {
unsigned color = get_bits1(&gbit) << RGBIndex;
pal[15 - index] |= color << (5 + 0);
}
}
for (int index = 0; index < 16; index++)
pal[index] = (0xFFU << 24) | pal[index] | (pal[index] >> 3);
bytestream2_skip(gb, 18);
return 0;
}
static int decode_index_palmap(SGAVideoContext *s, AVFrame *frame)
{
const uint8_t *tt = s->tileindex_data;
for (int y = 0; y < s->tiles_h; y++) {
for (int x = 0; x < s->tiles_w; x++) {
int pal_idx = s->palmapindex_data[y * s->tiles_w + x] * 16;
uint8_t *dst = frame->data[0] + y * 8 * frame->linesize[0] + x * 8;
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[xx] = pal_idx + tt[xx];
tt += 8;
dst += frame->linesize[0];
}
}
}
return 0;
}
static int decode_index_tilemap(SGAVideoContext *s, AVFrame *frame)
{
GetByteContext *gb = &s->gb, gb2;
bytestream2_seek(gb, s->tilemapdata_offset, SEEK_SET);
if (bytestream2_get_bytes_left(gb) < s->tilemapdata_size)
return AVERROR_INVALIDDATA;
gb2 = *gb;
for (int y = 0; y < s->tiles_h; y++) {
for (int x = 0; x < s->tiles_w; x++) {
uint8_t tile[64];
int tilemap = bytestream2_get_be16u(&gb2);
int flip_x = (tilemap >> 11) & 1;
int flip_y = (tilemap >> 12) & 1;
int tindex = av_clip((tilemap & 511) - 1, 0, s->nb_tiles - 1);
const uint8_t *tt = s->tileindex_data + tindex * 64;
int pal_idx = ((tilemap >> 13) & 3) * 16;
uint8_t *dst = frame->data[0] + y * 8 * frame->linesize[0] + x * 8;
if (!flip_x && !flip_y) {
memcpy(tile, tt, 64);
} else if (flip_x && flip_y) {
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++)
tile[i * 8 + j] = tt[(7 - i) * 8 + 7 - j];
}
} else if (flip_x) {
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++)
tile[i * 8 + j] = tt[i * 8 + 7 - j];
}
} else {
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++)
tile[i * 8 + j] = tt[(7 - i) * 8 + j];
}
}
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[xx] = pal_idx + tile[xx + yy * 8];
dst += frame->linesize[0];
}
}
}
return 0;
}
static int decode_index(SGAVideoContext *s, AVFrame *frame)
{
const uint8_t *src = s->tileindex_data;
uint8_t *dst = frame->data[0];
for (int y = 0; y < frame->height; y += 8) {
for (int x = 0; x < frame->width; x += 8) {
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[x + xx + yy * frame->linesize[0]] = src[xx];
src += 8;
}
}
dst += 8 * frame->linesize[0];
}
return 0;
}
static int lzss_decompress(AVCodecContext *avctx,
GetByteContext *gb, uint8_t *dst,
int dst_size, int shift, int plus)
{
int oi = 0;
while (bytestream2_get_bytes_left(gb) > 0 && oi < dst_size) {
uint16_t displace, header = bytestream2_get_be16(gb);
int count, offset;
for (int i = 0; i < 16; i++) {
switch (header >> 15) {
case 0:
if (oi + 2 < dst_size) {
dst[oi++] = bytestream2_get_byte(gb);
dst[oi++] = bytestream2_get_byte(gb);
}
break;
case 1:
displace = bytestream2_get_be16(gb);
count = displace >> shift;
offset = displace & ((1 << shift) - 1);
if (displace == 0) {
while (bytestream2_get_bytes_left(gb) > 0 &&
oi < dst_size)
dst[oi++] = bytestream2_get_byte(gb);
return oi;
}
count += plus;
if (offset <= 0)
offset = 1;
if (oi < offset || oi + count * 2 > dst_size)
return AVERROR_INVALIDDATA;
for (int j = 0; j < count * 2; j++) {
dst[oi] = dst[oi - offset];
oi++;
}
break;
}
header <<= 1;
}
}
return AVERROR_INVALIDDATA;
}
static int decode_palmapdata(AVCodecContext *avctx)
{
SGAVideoContext *s = avctx->priv_data;
const int bits = (s->nb_pal + 1) / 2;
GetByteContext *gb = &s->gb;
GetBitContext pm;
int ret;
bytestream2_seek(gb, s->palmapdata_offset, SEEK_SET);
if (bytestream2_get_bytes_left(gb) < s->palmapdata_size)
return AVERROR_INVALIDDATA;
ret = init_get_bits8(&pm, gb->buffer, s->palmapdata_size);
av_assert1(ret >= 0);
for (int y = 0; y < s->tiles_h; y++) {
uint8_t *dst = s->palmapindex_data + y * s->tiles_w;
for (int x = 0; x < s->tiles_w; x++)
dst[x] = get_bits(&pm, bits);
dst += s->tiles_w;
}
return 0;
}
static int decode_tiledata(AVCodecContext *avctx)
{
SGAVideoContext *s = avctx->priv_data;
GetByteContext *gb = &s->gb;
GetBitContext tm;
int ret;
bytestream2_seek(gb, s->tiledata_offset, SEEK_SET);
if (bytestream2_get_bytes_left(gb) < s->tiledata_size)
return AVERROR_INVALIDDATA;
ret = init_get_bits8(&tm, gb->buffer, s->tiledata_size);
av_assert1(ret >= 0);
for (int n = 0; n < s->nb_tiles; n++) {
uint8_t *dst = s->tileindex_data + n * 64;
for (int yy = 0; yy < 8; yy++) {
for (int xx = 0; xx < 8; xx++)
dst[xx] = get_bits(&tm, 4);
dst += 8;
}
}
for (int i = 0; i < s->nb_tiles && s->swap; i++) {
uint8_t *dst = s->tileindex_data + i * 64;
for (int j = 8; j < 64; j += 16) {
for (int k = 0; k < 8; k += 2)
FFSWAP(uint8_t, dst[j + k], dst[j+k+1]);
}
}
return 0;
}
static int sga_decode_frame(AVCodecContext *avctx, AVFrame *frame,
int *got_frame, AVPacket *avpkt)
{
SGAVideoContext *s = avctx->priv_data;
GetByteContext *gb = &s->gb;
int ret, type;
if (avpkt->size <= 14)
return AVERROR_INVALIDDATA;
s->flags = avpkt->data[8];
s->nb_pal = avpkt->data[9];
s->tiles_w = avpkt->data[10];
s->tiles_h = avpkt->data[11];
if (s->nb_pal > 4)
return AVERROR_INVALIDDATA;
if ((ret = ff_set_dimensions(avctx,
s->tiles_w * 8,
s->tiles_h * 8)) < 0)
return ret;
av_fast_padded_malloc(&s->tileindex_data, &s->tileindex_size,
avctx->width * avctx->height);
if (!s->tileindex_data)
return AVERROR(ENOMEM);
av_fast_padded_malloc(&s->palmapindex_data, &s->palmapindex_size,
s->tiles_w * s->tiles_h);
if (!s->palmapindex_data)
return AVERROR(ENOMEM);
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
bytestream2_init(gb, avpkt->data, avpkt->size);
type = bytestream2_get_byte(gb);
s->metadata_size = 12 + ((!!(s->flags & HAVE_TILEMAP)) * 2);
s->nb_tiles = s->flags & HAVE_TILEMAP ? AV_RB16(avpkt->data + 12) : s->tiles_w * s->tiles_h;
if (s->nb_tiles > s->tiles_w * s->tiles_h)
return AVERROR_INVALIDDATA;
av_log(avctx, AV_LOG_DEBUG, "type: %X flags: %X nb_tiles: %d\n", type, s->flags, s->nb_tiles);
switch (type) {
case 0xE7:
case 0xCB:
case 0xCD:
s->swap = 1;
s->shift = 12;
s->plus = 1;
break;
case 0xC9:
s->swap = 1;
s->shift = 13;
s->plus = 1;
break;
case 0xC8:
s->swap = 1;
s->shift = 13;
s->plus = 0;
break;
case 0xC7:
s->swap = 0;
s->shift = 13;
s->plus = 1;
break;
case 0xC6:
s->swap = 0;
s->shift = 13;
s->plus = 0;
break;
}
if (type == 0xE7) {
int offset = s->metadata_size, left;
int sizes[3];
bytestream2_seek(gb, s->metadata_size, SEEK_SET);
for (int i = 0; i < 3; i++)
sizes[i] = bytestream2_get_be16(gb);
for (int i = 0; i < 3; i++) {
int size = sizes[i];
int raw = size >> 15;
size &= (1 << 15) - 1;
if (raw) {
if (bytestream2_get_bytes_left(gb) < size)
return AVERROR_INVALIDDATA;
if (sizeof(s->uncompressed) - offset < size)
return AVERROR_INVALIDDATA;
memcpy(s->uncompressed + offset, gb->buffer, size);
bytestream2_skip(gb, size);
} else {
GetByteContext gb2;
if (bytestream2_get_bytes_left(gb) < size)
return AVERROR_INVALIDDATA;
bytestream2_init(&gb2, gb->buffer, size);
ret = lzss_decompress(avctx, &gb2, s->uncompressed + offset,
sizeof(s->uncompressed) - offset, s->shift, s->plus);
if (ret < 0)
return ret;
bytestream2_skip(gb, size);
size = ret;
}
offset += size;
}
left = bytestream2_get_bytes_left(gb);
if (sizeof(s->uncompressed) - offset < left)
return AVERROR_INVALIDDATA;
bytestream2_get_buffer(gb, s->uncompressed + offset, left);
offset += left;
bytestream2_init(gb, s->uncompressed, offset);
}
switch (type) {
case 0xCD:
case 0xCB:
case 0xC9:
case 0xC8:
case 0xC7:
case 0xC6:
bytestream2_seek(gb, s->metadata_size, SEEK_SET);
ret = lzss_decompress(avctx, gb, s->uncompressed + s->metadata_size,
sizeof(s->uncompressed) - s->metadata_size, s->shift, s->plus);
if (ret < 0)
return ret;
bytestream2_init(gb, s->uncompressed, ret + s->metadata_size);
case 0xE7:
case 0xC1:
s->tiledata_size = s->nb_tiles * 32;
s->paldata_size = s->nb_pal * 18;
s->tiledata_offset = s->flags & PALDATA_FOLLOWS_TILEDATA ? s->metadata_size : s->metadata_size + s->paldata_size;
s->paldata_offset = s->flags & PALDATA_FOLLOWS_TILEDATA ? s->metadata_size + s->tiledata_size : s->metadata_size;
s->palmapdata_offset = (s->flags & HAVE_TILEMAP) ? -1 : s->paldata_offset + s->paldata_size;
s->palmapdata_size = (s->flags & HAVE_TILEMAP) || s->nb_pal < 2 ? 0 : (s->tiles_w * s->tiles_h * ((s->nb_pal + 1) / 2) + 7) / 8;
s->tilemapdata_size = (s->flags & HAVE_TILEMAP) ? s->tiles_w * s->tiles_h * 2 : 0;
s->tilemapdata_offset = (s->flags & HAVE_TILEMAP) ? s->paldata_offset + s->paldata_size: -1;
bytestream2_seek(gb, s->paldata_offset, SEEK_SET);
for (int n = 0; n < s->nb_pal; n++) {
ret = decode_palette(gb, s->pal + 16 * n);
if (ret < 0)
return ret;
}
if (s->tiledata_size > 0) {
ret = decode_tiledata(avctx);
if (ret < 0)
return ret;
}
if (s->palmapdata_size > 0) {
ret = decode_palmapdata(avctx);
if (ret < 0)
return ret;
}
if (s->palmapdata_size > 0 && s->tiledata_size > 0) {
ret = decode_index_palmap(s, frame);
if (ret < 0)
return ret;
} else if (s->tilemapdata_size > 0 && s->tiledata_size > 0) {
ret = decode_index_tilemap(s, frame);
if (ret < 0)
return ret;
} else if (s->tiledata_size > 0) {
ret = decode_index(s, frame);
if (ret < 0)
return ret;
}
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown type: %X\n", type);
return AVERROR_INVALIDDATA;
}
memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
#if FF_API_PALETTE_HAS_CHANGED
FF_DISABLE_DEPRECATION_WARNINGS
frame->palette_has_changed = 1;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
frame->pict_type = AV_PICTURE_TYPE_I;
frame->flags |= AV_FRAME_FLAG_KEY;
*got_frame = 1;
return avpkt->size;
}
static av_cold int sga_decode_end(AVCodecContext *avctx)
{
SGAVideoContext *s = avctx->priv_data;
av_freep(&s->tileindex_data);
s->tileindex_size = 0;
av_freep(&s->palmapindex_data);
s->palmapindex_size = 0;
return 0;
}
const FFCodec ff_sga_decoder = {
.p.name = "sga",
CODEC_LONG_NAME("Digital Pictures SGA Video"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_SGA_VIDEO,
.priv_data_size = sizeof(SGAVideoContext),
.init = sga_decode_init,
FF_CODEC_DECODE_CB(sga_decode_frame),
.close = sga_decode_end,
.p.capabilities = AV_CODEC_CAP_DR1,
};
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