/*
* Wing Commander/Xan Video Decoder
* Copyright (C) 2011 Konstantin Shishkov
* based on work by Mike Melanson
*
* 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 "avcodec.h"
#include "libavutil/intreadwrite.h"
#include "bytestream.h"
#define ALT_BITSTREAM_READER_LE
#include "get_bits.h"
// for av_memcpy_backptr
#include "libavutil/lzo.h"
typedef struct XanContext {
AVCodecContext *avctx;
AVFrame pic;
uint8_t *y_buffer;
uint8_t *scratch_buffer;
int buffer_size;
} XanContext;
static av_cold int xan_decode_init(AVCodecContext *avctx)
{
XanContext *s = avctx->priv_data;
s->avctx = avctx;
avctx->pix_fmt = PIX_FMT_YUV420P;
s->buffer_size = avctx->width * avctx->height;
s->y_buffer = av_malloc(s->buffer_size);
if (!s->y_buffer)
return AVERROR(ENOMEM);
s->scratch_buffer = av_malloc(s->buffer_size + 130);
if (!s->scratch_buffer) {
av_freep(&s->y_buffer);
return AVERROR(ENOMEM);
}
return 0;
}
static int xan_unpack_luma(const uint8_t *src, const int src_size,
uint8_t *dst, const int dst_size)
{
int tree_size, eof;
const uint8_t *tree;
int bits, mask;
int tree_root, node;
const uint8_t *dst_end = dst + dst_size;
const uint8_t *src_end = src + src_size;
tree_size = *src++;
eof = *src++;
tree = src - eof * 2 - 2;
tree_root = eof + tree_size;
src += tree_size * 2;
node = tree_root;
bits = *src++;
mask = 0x80;
for (;;) {
int bit = !!(bits & mask);
mask >>= 1;
node = tree[node*2 + bit];
if (node == eof)
break;
if (node < eof) {
*dst++ = node;
if (dst > dst_end)
break;
node = tree_root;
}
if (!mask) {
bits = *src++;
if (src > src_end)
break;
mask = 0x80;
}
}
return dst != dst_end;
}
/* almost the same as in xan_wc3 decoder */
static int xan_unpack(uint8_t *dest, const int dest_len,
const uint8_t *src, const int src_len)
{
uint8_t opcode;
int size;
uint8_t *orig_dest = dest;
const uint8_t *src_end = src + src_len;
const uint8_t *dest_end = dest + dest_len;
while (dest < dest_end) {
opcode = *src++;
if (opcode < 0xe0) {
int size2, back;
if ((opcode & 0x80) == 0) {
size = opcode & 3;
back = ((opcode & 0x60) << 3) + *src++ + 1;
size2 = ((opcode & 0x1c) >> 2) + 3;
} else if ((opcode & 0x40) == 0) {
size = *src >> 6;
back = (bytestream_get_be16(&src) & 0x3fff) + 1;
size2 = (opcode & 0x3f) + 4;
} else {
size = opcode & 3;
back = ((opcode & 0x10) << 12) + bytestream_get_be16(&src) + 1;
size2 = ((opcode & 0x0c) << 6) + *src++ + 5;
if (size + size2 > dest_end - dest)
break;
}
if (src + size > src_end ||
dest + size + size2 > dest_end ||
dest + size - orig_dest < back )
return -1;
bytestream_get_buffer(&src, dest, size);
dest += size;
av_memcpy_backptr(dest, back, size2);
dest += size2;
} else {
int finish = opcode >= 0xfc;
size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
if (src + size > src_end || dest + size > dest_end)
return -1;
bytestream_get_buffer(&src, dest, size);
dest += size;
if (finish)
break;
}
}
return dest - orig_dest;
}
static int xan_decode_chroma(AVCodecContext *avctx, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
XanContext *s = avctx->priv_data;
uint8_t *U, *V;
unsigned chroma_off;
int val, uval, vval;
int i, j;
const uint8_t *src, *src_end;
const uint8_t *table;
int mode, offset, dec_size;
chroma_off = AV_RL32(buf + 4);
if (!chroma_off)
return 0;
if (chroma_off + 10 >= avpkt->size) {
av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
return -1;
}
src = avpkt->data + 4 + chroma_off;
table = src + 2;
mode = bytestream_get_le16(&src);
offset = bytestream_get_le16(&src) * 2;
if (src - avpkt->data >= avpkt->size - offset) {
av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
return -1;
}
memset(s->scratch_buffer, 0, s->buffer_size);
dec_size = xan_unpack(s->scratch_buffer, s->buffer_size, src + offset,
avpkt->size - offset - (src - avpkt->data));
if (dec_size < 0) {
av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
return -1;
}
U = s->pic.data[1];
V = s->pic.data[2];
src = s->scratch_buffer;
src_end = src + dec_size;
if (mode) {
for (j = 0; j < avctx->height >> 1; j++) {
for (i = 0; i < avctx->width >> 1; i++) {
if (src_end - src < 1)
return 0;
val = *src++;
if (val) {
val = AV_RL16(table + (val << 1));
uval = (val >> 3) & 0xF8;
vval = (val >> 8) & 0xF8;
U[i] = uval | (uval >> 5);
V[i] = vval | (vval >> 5);
}
}
U += s->pic.linesize[1];
V += s->pic.linesize[2];
}
} else {
uint8_t *U2 = U + s->pic.linesize[1];
uint8_t *V2 = V + s->pic.linesize[2];
for (j = 0; j < avctx->height >> 2; j++) {
for (i = 0; i < avctx->width >> 1; i += 2) {
if (src_end - src < 1)
return 0;
val = *src++;
if (val) {
val = AV_RL16(table + (val << 1));
uval = (val >> 3) & 0xF8;
vval = (val >> 8) & 0xF8;
U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
}
}
U += s->pic.linesize[1] * 2;
V += s->pic.linesize[2] * 2;
U2 += s->pic.linesize[1] * 2;
V2 += s->pic.linesize[2] * 2;
}
}
return 0;
}
static int xan_decode_frame_type0(AVCodecContext *avctx, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
XanContext *s = avctx->priv_data;
uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
unsigned chroma_off, corr_off;
int cur, last, size;
int i, j;
int ret;
corr_off = AV_RL32(buf + 8);
chroma_off = AV_RL32(buf + 4);
if ((ret = xan_decode_chroma(avctx, avpkt)) != 0)
return ret;
size = avpkt->size - 4;
if (corr_off >= avpkt->size) {
av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
corr_off = 0;
}
if (corr_off)
size = corr_off;
if (chroma_off)
size = FFMIN(size, chroma_off);
ret = xan_unpack_luma(buf + 12, size, src, s->buffer_size >> 1);
if (ret) {
av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
return ret;
}
ybuf = s->y_buffer;
last = *src++;
ybuf[0] = last << 1;
for (j = 1; j < avctx->width - 1; j += 2) {
cur = (last + *src++) & 0x1F;
ybuf[j] = last + cur;
ybuf[j+1] = cur << 1;
last = cur;
}
ybuf[j] = last << 1;
prev_buf = ybuf;
ybuf += avctx->width;
for (i = 1; i < avctx->height; i++) {
last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
ybuf[0] = last << 1;
for (j = 1; j < avctx->width - 1; j += 2) {
cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
ybuf[j] = last + cur;
ybuf[j+1] = cur << 1;
last = cur;
}
ybuf[j] = last << 1;
prev_buf = ybuf;
ybuf += avctx->width;
}
if (corr_off) {
int corr_end, dec_size;
corr_end = avpkt->size;
if (chroma_off > corr_off)
corr_end = chroma_off;
dec_size = xan_unpack(s->scratch_buffer, s->buffer_size,
avpkt->data + 8 + corr_off,
corr_end - corr_off);
if (dec_size < 0)
dec_size = 0;
else
dec_size = FFMIN(dec_size, s->buffer_size/2 - 1);
for (i = 0; i < dec_size; i++)
s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
}
src = s->y_buffer;
ybuf = s->pic.data[0];
for (j = 0; j < avctx->height; j++) {
for (i = 0; i < avctx->width; i++)
ybuf[i] = (src[i] << 2) | (src[i] >> 3);
src += avctx->width;
ybuf += s->pic.linesize[0];
}
return 0;
}
static int xan_decode_frame_type1(AVCodecContext *avctx, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
XanContext *s = avctx->priv_data;
uint8_t *ybuf, *src = s->scratch_buffer;
int cur, last;
int i, j;
int ret;
if ((ret = xan_decode_chroma(avctx, avpkt)) != 0)
return ret;
ret = xan_unpack_luma(buf + 16, avpkt->size - 16, src,
s->buffer_size >> 1);
if (ret) {
av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
return ret;
}
ybuf = s->y_buffer;
for (i = 0; i < avctx->height; i++) {
last = (ybuf[0] + (*src++ << 1)) & 0x3F;
ybuf[0] = last;
for (j = 1; j < avctx->width - 1; j += 2) {
cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
ybuf[j] = (last + cur) >> 1;
ybuf[j+1] = cur;
last = cur;
}
ybuf[j] = last;
ybuf += avctx->width;
}
src = s->y_buffer;
ybuf = s->pic.data[0];
for (j = 0; j < avctx->height; j++) {
for (i = 0; i < avctx->width; i++)
ybuf[i] = (src[i] << 2) | (src[i] >> 3);
src += avctx->width;
ybuf += s->pic.linesize[0];
}
return 0;
}
static int xan_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
XanContext *s = avctx->priv_data;
int ftype;
int ret;
s->pic.reference = 3;
s->pic.buffer_hints = FF_BUFFER_HINTS_VALID |
FF_BUFFER_HINTS_PRESERVE |
FF_BUFFER_HINTS_REUSABLE;
if ((ret = avctx->reget_buffer(avctx, &s->pic))) {
av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
return ret;
}
ftype = AV_RL32(avpkt->data);
switch (ftype) {
case 0:
ret = xan_decode_frame_type0(avctx, avpkt);
break;
case 1:
ret = xan_decode_frame_type1(avctx, avpkt);
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
return -1;
}
if (ret)
return ret;
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->pic;
return avpkt->size;
}
static av_cold int xan_decode_end(AVCodecContext *avctx)
{
XanContext *s = avctx->priv_data;
if (s->pic.data[0])
avctx->release_buffer(avctx, &s->pic);
av_freep(&s->y_buffer);
av_freep(&s->scratch_buffer);
return 0;
}
AVCodec ff_xan_wc4_decoder = {
.name = "xan_wc4",
.type = AVMEDIA_TYPE_VIDEO,
.id = CODEC_ID_XAN_WC4,
.priv_data_size = sizeof(XanContext),
.init = xan_decode_init,
.close = xan_decode_end,
.decode = xan_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
};