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-rw-r--r--ffmpeg/libavcodec/xxan.c444
1 files changed, 444 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/xxan.c b/ffmpeg/libavcodec/xxan.c
new file mode 100644
index 0000000..e2b1b8c
--- /dev/null
+++ b/ffmpeg/libavcodec/xxan.c
@@ -0,0 +1,444 @@
+/*
+ * 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 "libavutil/mem.h"
+#include "bytestream.h"
+#define BITSTREAM_READER_LE
+#include "get_bits.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_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);
+ }
+
+ 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(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;
+ }
+ if(j < avctx->width)
+ 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;
+ }
+ if(j < avctx->width)
+ 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;
+ }
+ if(j < avctx->width)
+ 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)
+ 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;
+}
+
+static av_cold int xan_decode_end(AVCodecContext *avctx)
+{
+ XanContext *s = avctx->priv_data;
+
+ av_frame_unref(&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 = AV_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"),
+};
generated by cgit v1.2.3 (git 2.39.1) at 2025-12-06 19:04:25 +0000