/*
* American Laser Games MM Video Decoder
* Copyright (c) 2006,2008 Peter Ross
*
* 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
* American Laser Games MM Video Decoder
* by Peter Ross (pross@xvid.org)
*
* The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
* including Mad Dog McCree and Crime Patrol.
*
* Technical details here:
* http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
*/
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#define MM_PREAMBLE_SIZE 6
#define MM_TYPE_INTER 0x5
#define MM_TYPE_INTRA 0x8
#define MM_TYPE_INTRA_HH 0xc
#define MM_TYPE_INTER_HH 0xd
#define MM_TYPE_INTRA_HHV 0xe
#define MM_TYPE_INTER_HHV 0xf
#define MM_TYPE_PALETTE 0x31
typedef struct MmContext {
AVCodecContext *avctx;
AVFrame frame;
int palette[AVPALETTE_COUNT];
GetByteContext gb;
} MmContext;
static av_cold int mm_decode_init(AVCodecContext *avctx)
{
MmContext *s = avctx->priv_data;
s->avctx = avctx;
avctx->pix_fmt = AV_PIX_FMT_PAL8;
avcodec_get_frame_defaults(&s->frame);
return 0;
}
static int mm_decode_pal(MmContext *s)
{
int i;
bytestream2_skip(&s->gb, 4);
for (i = 0; i < 128; i++) {
s->palette[i] = 0xFFU << 24 | bytestream2_get_be24(&s->gb);
s->palette[i+128] = s->palette[i]<<2;
}
return 0;
}
/**
* @param half_horiz Half horizontal resolution (0 or 1)
* @param half_vert Half vertical resolution (0 or 1)
*/
static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
{
int x = 0, y = 0;
while (bytestream2_get_bytes_left(&s->gb) > 0) {
int run_length, color;
if (y >= s->avctx->height)
return 0;
color = bytestream2_get_byte(&s->gb);
if (color & 0x80) {
run_length = 1;
}else{
run_length = (color & 0x7f) + 2;
color = bytestream2_get_byte(&s->gb);
}
if (half_horiz)
run_length *=2;
if (run_length > s->avctx->width - x)
return AVERROR_INVALIDDATA;
if (color) {
memset(s
->frame.
data[0] + y
*s
->frame.
linesize[0] + x
, color
, run_length
); if (half_vert)
memset(s
->frame.
data[0] + (y
+1)*s
->frame.
linesize[0] + x
, color
, run_length
); }
x+= run_length;
if (x >= s->avctx->width) {
x=0;
y += 1 + half_vert;
}
}
return 0;
}
/**
* @param half_horiz Half horizontal resolution (0 or 1)
* @param half_vert Half vertical resolution (0 or 1)
*/
static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
{
int data_off = bytestream2_get_le16(&s->gb), y = 0;
GetByteContext data_ptr;
if (bytestream2_get_bytes_left(&s->gb) < data_off)
return AVERROR_INVALIDDATA;
bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
while (s->gb.buffer < data_ptr.buffer_start) {
int i, j;
int length = bytestream2_get_byte(&s->gb);
int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
length &= 0x7F;
if (length==0) {
y += x;
continue;
}
if (y + half_vert >= s->avctx->height)
return 0;
for(i=0; i<length; i++) {
int replace_array = bytestream2_get_byte(&s->gb);
for(j=0; j<8; j++) {
int replace = (replace_array >> (7-j)) & 1;
if (x + half_horiz >= s->avctx->width)
return AVERROR_INVALIDDATA;
if (replace) {
int color = bytestream2_get_byte(&data_ptr);
s->frame.data[0][y*s->frame.linesize[0] + x] = color;
if (half_horiz)
s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
if (half_vert) {
s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
if (half_horiz)
s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
}
}
x += 1 + half_horiz;
}
}
y += 1 + half_vert;
}
return 0;
}
static int mm_decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
MmContext *s = avctx->priv_data;
int type, res;
if (buf_size < MM_PREAMBLE_SIZE)
return AVERROR_INVALIDDATA;
type = AV_RL16(&buf[0]);
buf += MM_PREAMBLE_SIZE;
buf_size -= MM_PREAMBLE_SIZE;
bytestream2_init(&s->gb, buf, buf_size);
if ((res = ff_reget_buffer(avctx, &s->frame)) < 0)
return res;
switch(type) {
case MM_TYPE_PALETTE : res = mm_decode_pal(s); return avpkt->size;
case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
default:
res = AVERROR_INVALIDDATA;
break;
}
if (res < 0)
return res;
memcpy(s
->frame.
data[1], s
->palette
, AVPALETTE_SIZE
);
if ((res = av_frame_ref(data, &s->frame)) < 0)
return res;
*got_frame = 1;
return avpkt->size;
}
static av_cold int mm_decode_end(AVCodecContext *avctx)
{
MmContext *s = avctx->priv_data;
av_frame_unref(&s->frame);
return 0;
}
AVCodec ff_mmvideo_decoder = {
.name = "mmvideo",
.long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_MMVIDEO,
.priv_data_size = sizeof(MmContext),
.init = mm_decode_init,
.close = mm_decode_end,
.decode = mm_decode_frame,
.capabilities = CODEC_CAP_DR1,
};