2 * Wing Commander/Xan Video Decoder
3 * Copyright (C) 2011 Konstantin Shishkov
4 * based on work by Mike Melanson
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "libavutil/intreadwrite.h"
25 #include "bytestream.h"
26 #define BITSTREAM_READER_LE
28 // for av_memcpy_backptr
29 #include "libavutil/lzo.h"
31 typedef struct XanContext {
32 AVCodecContext *avctx;
36 uint8_t *scratch_buffer;
41 static av_cold int xan_decode_init(AVCodecContext *avctx)
43 XanContext *s = avctx->priv_data;
47 avctx->pix_fmt = PIX_FMT_YUV420P;
49 s->buffer_size = avctx->width * avctx->height;
50 s->y_buffer = av_malloc(s->buffer_size);
52 return AVERROR(ENOMEM);
53 s->scratch_buffer = av_malloc(s->buffer_size + 130);
54 if (!s->scratch_buffer) {
55 av_freep(&s->y_buffer);
56 return AVERROR(ENOMEM);
62 static int xan_unpack_luma(XanContext *s,
63 uint8_t *dst, const int dst_size)
68 const uint8_t *dst_end = dst + dst_size;
69 GetByteContext tree = s->gb;
70 int start_off = bytestream2_tell(&tree);
72 tree_size = bytestream2_get_byte(&s->gb);
73 eof = bytestream2_get_byte(&s->gb);
74 tree_root = eof + tree_size;
75 bytestream2_skip(&s->gb, tree_size * 2);
78 bits = bytestream2_get_byte(&s->gb);
81 int bit = !!(bits & mask);
83 bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
84 node = bytestream2_get_byte(&tree);
94 if (bytestream2_get_bytes_left(&s->gb) <= 0)
96 bits = bytestream2_get_byteu(&s->gb);
100 return dst != dst_end ? AVERROR_INVALIDDATA : 0;
103 /* almost the same as in xan_wc3 decoder */
104 static int xan_unpack(XanContext *s,
105 uint8_t *dest, const int dest_len)
109 uint8_t *orig_dest = dest;
110 const uint8_t *dest_end = dest + dest_len;
112 while (dest < dest_end) {
113 if (bytestream2_get_bytes_left(&s->gb) <= 0)
114 return AVERROR_INVALIDDATA;
116 opcode = bytestream2_get_byteu(&s->gb);
120 if ((opcode & 0x80) == 0) {
122 back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
123 size2 = ((opcode & 0x1c) >> 2) + 3;
124 } else if ((opcode & 0x40) == 0) {
125 size = bytestream2_peek_byte(&s->gb) >> 6;
126 back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
127 size2 = (opcode & 0x3f) + 4;
130 back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
131 size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
132 if (size + size2 > dest_end - dest)
135 if (dest + size + size2 > dest_end ||
136 dest - orig_dest + size < back)
138 bytestream2_get_buffer(&s->gb, dest, size);
140 av_memcpy_backptr(dest, back, size2);
143 int finish = opcode >= 0xfc;
145 size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
146 if (dest_end - dest < size)
148 bytestream2_get_buffer(&s->gb, dest, size);
154 return dest - orig_dest;
157 static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
159 XanContext *s = avctx->priv_data;
163 const uint8_t *src, *src_end;
164 const uint8_t *table;
165 int mode, offset, dec_size, table_size;
169 if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
170 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
173 bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
174 mode = bytestream2_get_le16(&s->gb);
175 table = s->gb.buffer;
176 table_size = bytestream2_get_le16(&s->gb);
177 offset = table_size * 2;
180 if (offset >= bytestream2_get_bytes_left(&s->gb)) {
181 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
185 bytestream2_skip(&s->gb, offset);
186 memset(s->scratch_buffer, 0, s->buffer_size);
187 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
189 av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
195 src = s->scratch_buffer;
196 src_end = src + dec_size;
198 for (j = 0; j < avctx->height >> 1; j++) {
199 for (i = 0; i < avctx->width >> 1; i++) {
200 if (src_end - src < 1)
204 if (val >= table_size)
205 return AVERROR_INVALIDDATA;
206 val = AV_RL16(table + (val << 1));
207 uval = (val >> 3) & 0xF8;
208 vval = (val >> 8) & 0xF8;
209 U[i] = uval | (uval >> 5);
210 V[i] = vval | (vval >> 5);
213 U += s->pic.linesize[1];
214 V += s->pic.linesize[2];
217 uint8_t *U2 = U + s->pic.linesize[1];
218 uint8_t *V2 = V + s->pic.linesize[2];
220 for (j = 0; j < avctx->height >> 2; j++) {
221 for (i = 0; i < avctx->width >> 1; i += 2) {
222 if (src_end - src < 1)
226 if (val >= table_size)
227 return AVERROR_INVALIDDATA;
228 val = AV_RL16(table + (val << 1));
229 uval = (val >> 3) & 0xF8;
230 vval = (val >> 8) & 0xF8;
231 U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
232 V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
235 U += s->pic.linesize[1] * 2;
236 V += s->pic.linesize[2] * 2;
237 U2 += s->pic.linesize[1] * 2;
238 V2 += s->pic.linesize[2] * 2;
245 static int xan_decode_frame_type0(AVCodecContext *avctx)
247 XanContext *s = avctx->priv_data;
248 uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
249 unsigned chroma_off, corr_off;
254 chroma_off = bytestream2_get_le32(&s->gb);
255 corr_off = bytestream2_get_le32(&s->gb);
257 if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
260 if (corr_off >= bytestream2_size(&s->gb)) {
261 av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
264 bytestream2_seek(&s->gb, 12, SEEK_SET);
265 ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
267 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
274 for (j = 1; j < avctx->width - 1; j += 2) {
275 cur = (last + *src++) & 0x1F;
276 ybuf[j] = last + cur;
277 ybuf[j+1] = cur << 1;
282 ybuf += avctx->width;
284 for (i = 1; i < avctx->height; i++) {
285 last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
287 for (j = 1; j < avctx->width - 1; j += 2) {
288 cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
289 ybuf[j] = last + cur;
290 ybuf[j+1] = cur << 1;
295 ybuf += avctx->width;
301 bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
302 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
306 dec_size = FFMIN(dec_size, s->buffer_size/2 - 1);
308 for (i = 0; i < dec_size; i++)
309 s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
313 ybuf = s->pic.data[0];
314 for (j = 0; j < avctx->height; j++) {
315 for (i = 0; i < avctx->width; i++)
316 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
318 ybuf += s->pic.linesize[0];
324 static int xan_decode_frame_type1(AVCodecContext *avctx)
326 XanContext *s = avctx->priv_data;
327 uint8_t *ybuf, *src = s->scratch_buffer;
332 if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
335 bytestream2_seek(&s->gb, 16, SEEK_SET);
336 ret = xan_unpack_luma(s, src,
337 s->buffer_size >> 1);
339 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
344 for (i = 0; i < avctx->height; i++) {
345 last = (ybuf[0] + (*src++ << 1)) & 0x3F;
347 for (j = 1; j < avctx->width - 1; j += 2) {
348 cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
349 ybuf[j] = (last + cur) >> 1;
354 ybuf += avctx->width;
358 ybuf = s->pic.data[0];
359 for (j = 0; j < avctx->height; j++) {
360 for (i = 0; i < avctx->width; i++)
361 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
363 ybuf += s->pic.linesize[0];
369 static int xan_decode_frame(AVCodecContext *avctx,
370 void *data, int *data_size,
373 XanContext *s = avctx->priv_data;
377 s->pic.reference = 3;
378 s->pic.buffer_hints = FF_BUFFER_HINTS_VALID |
379 FF_BUFFER_HINTS_PRESERVE |
380 FF_BUFFER_HINTS_REUSABLE;
381 if ((ret = avctx->reget_buffer(avctx, &s->pic))) {
382 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
386 bytestream2_init(&s->gb, avpkt->data, avpkt->size);
387 ftype = bytestream2_get_le32(&s->gb);
390 ret = xan_decode_frame_type0(avctx);
393 ret = xan_decode_frame_type1(avctx);
396 av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
402 *data_size = sizeof(AVFrame);
403 *(AVFrame*)data = s->pic;
408 static av_cold int xan_decode_end(AVCodecContext *avctx)
410 XanContext *s = avctx->priv_data;
413 avctx->release_buffer(avctx, &s->pic);
415 av_freep(&s->y_buffer);
416 av_freep(&s->scratch_buffer);
421 AVCodec ff_xan_wc4_decoder = {
423 .type = AVMEDIA_TYPE_VIDEO,
424 .id = CODEC_ID_XAN_WC4,
425 .priv_data_size = sizeof(XanContext),
426 .init = xan_decode_init,
427 .close = xan_decode_end,
428 .decode = xan_decode_frame,
429 .capabilities = CODEC_CAP_DR1,
430 .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),