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FFmpeg/libavcodec/xxan.c
Andreas Rheinhardt 20f9727018 avcodec/codec_internal: Add FFCodec, hide internal part of AVCodec 
Up until now, codec.h contains both public and private parts
of AVCodec. This exposes the internals of AVCodec to users
and leads them into the temptation of actually using them
and forces us to forward-declare structures and types that
users can't use at all.

This commit changes this by adding a new structure FFCodec to
codec_internal.h that extends AVCodec, i.e. contains the public
AVCodec as first member; the private fields of AVCodec are moved
to this structure, leaving codec.h clean.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-03-21 01:33:09 +01:00

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/*
* 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 "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "internal.h"
typedef struct XanContext {
AVCodecContext *avctx;
AVFrame *pic;
uint8_t *y_buffer;
uint8_t *scratch_buffer;
int buffer_size;
GetByteContext gb;
} XanContext;
static av_cold int xan_decode_end(AVCodecContext *avctx)
{
XanContext *s = avctx->priv_data;
av_frame_free(&s->pic);
av_freep(&s->y_buffer);
av_freep(&s->scratch_buffer);
return 0;
}
static av_cold int xan_decode_init(AVCodecContext *avctx)
{
XanContext *s = avctx->priv_data;
s->avctx = avctx;
avctx->pix_fmt = AV_PIX_FMT_YUV420P;
if (avctx->height < 8) {
av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);
return AVERROR(EINVAL);
}
if (avctx->width & 1) {
av_log(avctx, AV_LOG_ERROR, "Invalid frame width: %d.\n", avctx->width);
return AVERROR(EINVAL);
}
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)
return AVERROR(ENOMEM);
s->pic = av_frame_alloc();
if (!s->pic)
return AVERROR(ENOMEM);
return 0;
}
static int xan_unpack_luma(XanContext *s,
uint8_t *dst, const int dst_size)
{
int tree_size, eof;
int bits, mask;
int tree_root, node;
const uint8_t *dst_end = dst + dst_size;
GetByteContext tree = s->gb;
int start_off = bytestream2_tell(&tree);
tree_size = bytestream2_get_byte(&s->gb);
eof = bytestream2_get_byte(&s->gb);
tree_root = eof + tree_size;
bytestream2_skip(&s->gb, tree_size * 2);
node = tree_root;
bits = bytestream2_get_byte(&s->gb);
mask = 0x80;
for (;;) {
int bit = !!(bits & mask);
mask >>= 1;
bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
node = bytestream2_get_byte(&tree);
if (node == eof)
break;
if (node < eof) {
*dst++ = node;
if (dst > dst_end)
break;
node = tree_root;
}
if (!mask) {
if (bytestream2_get_bytes_left(&s->gb) <= 0)
break;
bits = bytestream2_get_byteu(&s->gb);
mask = 0x80;
}
}
return dst != dst_end ? AVERROR_INVALIDDATA : 0;
}
/* almost the same as in xan_wc3 decoder */
static int xan_unpack(XanContext *s,
uint8_t *dest, const int dest_len)
{
uint8_t opcode;
int size;
uint8_t *orig_dest = dest;
const uint8_t *dest_end = dest + dest_len;
while (dest < dest_end) {
if (bytestream2_get_bytes_left(&s->gb) <= 0)
return AVERROR_INVALIDDATA;
opcode = bytestream2_get_byteu(&s->gb);
if (opcode < 0xe0) {
int size2, back;
if ((opcode & 0x80) == 0) {
size = opcode & 3;
back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
size2 = ((opcode & 0x1c) >> 2) + 3;
} else if ((opcode & 0x40) == 0) {
size = bytestream2_peek_byte(&s->gb) >> 6;
back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
size2 = (opcode & 0x3f) + 4;
} else {
size = opcode & 3;
back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
if (size + size2 > dest_end - dest)
break;
}
if (dest + size + size2 > dest_end ||
dest - orig_dest + size < back)
return AVERROR_INVALIDDATA;
bytestream2_get_buffer(&s->gb, 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 (dest_end - dest < size)
return AVERROR_INVALIDDATA;
bytestream2_get_buffer(&s->gb, dest, size);
dest += size;
if (finish)
break;
}
}
return dest - orig_dest;
}
static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
{
XanContext *s = avctx->priv_data;
uint8_t *U, *V;
int val, uval, vval;
int i, j;
const uint8_t *src, *src_end;
const uint8_t *table;
int mode, offset, dec_size, table_size;
if (!chroma_off)
return 0;
if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
return AVERROR_INVALIDDATA;
}
bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
mode = bytestream2_get_le16(&s->gb);
table = s->gb.buffer;
table_size = bytestream2_get_le16(&s->gb);
offset = table_size * 2;
table_size += 1;
if (offset >= bytestream2_get_bytes_left(&s->gb)) {
av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
return AVERROR_INVALIDDATA;
}
bytestream2_skip(&s->gb, offset);
memset(s->scratch_buffer, 0, s->buffer_size);
dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
if (dec_size < 0) {
av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
return dec_size;
}
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) {
if (val >= table_size)
return AVERROR_INVALIDDATA;
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];
}
if (avctx->height & 1) {
memcpy(U, U - s->pic->linesize[1], avctx->width >> 1);
memcpy(V, V - s->pic->linesize[2], avctx->width >> 1);
}
} 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) {
if (val >= table_size)
return AVERROR_INVALIDDATA;
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;
}
if (avctx->height & 3) {
int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;
memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]);
memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]);
}
}
return 0;
}
static int xan_decode_frame_type0(AVCodecContext *avctx)
{
XanContext *s = avctx->priv_data;
uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
unsigned chroma_off, corr_off;
int cur, last;
int i, j;
int ret;
chroma_off = bytestream2_get_le32(&s->gb);
corr_off = bytestream2_get_le32(&s->gb);
if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
return ret;
if (corr_off >= bytestream2_size(&s->gb)) {
av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
corr_off = 0;
}
bytestream2_seek(&s->gb, 12, SEEK_SET);
ret = xan_unpack_luma(s, 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 dec_size;
bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
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)
{
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, bytestream2_get_le32(&s->gb))) != 0)
return ret;
bytestream2_seek(&s->gb, 16, SEEK_SET);
ret = xan_unpack_luma(s, 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 *got_frame,
AVPacket *avpkt)
{
XanContext *s = avctx->priv_data;
int ftype;
int ret;
if ((ret = ff_reget_buffer(avctx, s->pic, 0)) < 0)
return ret;
bytestream2_init(&s->gb, avpkt->data, avpkt->size);
ftype = bytestream2_get_le32(&s->gb);
switch (ftype) {
case 0:
ret = xan_decode_frame_type0(avctx);
break;
case 1:
ret = xan_decode_frame_type1(avctx);
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
return AVERROR_INVALIDDATA;
}
if (ret)
return ret;
if ((ret = av_frame_ref(data, s->pic)) < 0)
return ret;
*got_frame = 1;
return avpkt->size;
}
const FFCodec ff_xan_wc4_decoder = {
.p.name = "xan_wc4",
.p.long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_XAN_WC4,
.priv_data_size = sizeof(XanContext),
.init = xan_decode_init,
.close = xan_decode_end,
.decode = xan_decode_frame,
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
};
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