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 Libav.
8 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include "libavutil/intreadwrite.h"
24 #include "libavutil/mem.h"
27 #include "bytestream.h"
30 typedef struct XanContext {
31 AVCodecContext *avctx;
35 uint8_t *scratch_buffer;
40 static av_cold int xan_decode_end(AVCodecContext *avctx)
42 XanContext *s = avctx->priv_data;
44 av_frame_free(&s->pic);
46 av_freep(&s->y_buffer);
47 av_freep(&s->scratch_buffer);
52 static av_cold int xan_decode_init(AVCodecContext *avctx)
54 XanContext *s = avctx->priv_data;
58 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
60 if (avctx->height < 8) {
61 av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);
62 return AVERROR(EINVAL);
64 if (avctx->width & 1) {
65 av_log(avctx, AV_LOG_ERROR, "Invalid frame width: %d.\n", avctx->width);
66 return AVERROR(EINVAL);
69 s->buffer_size = avctx->width * avctx->height;
70 s->y_buffer = av_malloc(s->buffer_size);
72 return AVERROR(ENOMEM);
73 s->scratch_buffer = av_malloc(s->buffer_size + 130);
74 if (!s->scratch_buffer) {
75 av_freep(&s->y_buffer);
76 return AVERROR(ENOMEM);
79 s->pic = av_frame_alloc();
81 xan_decode_end(avctx);
82 return AVERROR(ENOMEM);
88 static int xan_unpack_luma(XanContext *s,
89 uint8_t *dst, const int dst_size)
94 const uint8_t *dst_end = dst + dst_size;
95 GetByteContext tree = s->gb;
96 int start_off = bytestream2_tell(&tree);
98 tree_size = bytestream2_get_byte(&s->gb);
99 eof = bytestream2_get_byte(&s->gb);
100 tree_root = eof + tree_size;
101 bytestream2_skip(&s->gb, tree_size * 2);
104 bits = bytestream2_get_byte(&s->gb);
107 int bit = !!(bits & mask);
109 bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
110 node = bytestream2_get_byte(&tree);
120 if (bytestream2_get_bytes_left(&s->gb) <= 0)
122 bits = bytestream2_get_byteu(&s->gb);
126 return dst != dst_end ? AVERROR_INVALIDDATA : 0;
129 /* almost the same as in xan_wc3 decoder */
130 static int xan_unpack(XanContext *s,
131 uint8_t *dest, const int dest_len)
135 uint8_t *orig_dest = dest;
136 const uint8_t *dest_end = dest + dest_len;
138 while (dest < dest_end) {
139 if (bytestream2_get_bytes_left(&s->gb) <= 0)
140 return AVERROR_INVALIDDATA;
142 opcode = bytestream2_get_byteu(&s->gb);
146 if ((opcode & 0x80) == 0) {
148 back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
149 size2 = ((opcode & 0x1c) >> 2) + 3;
150 } else if ((opcode & 0x40) == 0) {
151 size = bytestream2_peek_byte(&s->gb) >> 6;
152 back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
153 size2 = (opcode & 0x3f) + 4;
156 back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
157 size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
158 if (size + size2 > dest_end - dest)
161 if (dest + size + size2 > dest_end ||
162 dest - orig_dest + size < back)
163 return AVERROR_INVALIDDATA;
164 bytestream2_get_buffer(&s->gb, dest, size);
166 av_memcpy_backptr(dest, back, size2);
169 int finish = opcode >= 0xfc;
171 size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
172 if (dest_end - dest < size)
173 return AVERROR_INVALIDDATA;
174 bytestream2_get_buffer(&s->gb, dest, size);
180 return dest - orig_dest;
183 static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
185 XanContext *s = avctx->priv_data;
189 const uint8_t *src, *src_end;
190 const uint8_t *table;
191 int mode, offset, dec_size, table_size;
195 if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
196 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
197 return AVERROR_INVALIDDATA;
199 bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
200 mode = bytestream2_get_le16(&s->gb);
201 table = s->gb.buffer;
202 table_size = bytestream2_get_le16(&s->gb);
203 offset = table_size * 2;
206 if (offset >= bytestream2_get_bytes_left(&s->gb)) {
207 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
208 return AVERROR_INVALIDDATA;
211 bytestream2_skip(&s->gb, offset);
212 memset(s->scratch_buffer, 0, s->buffer_size);
213 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
215 av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
221 src = s->scratch_buffer;
222 src_end = src + dec_size;
224 for (j = 0; j < avctx->height >> 1; j++) {
225 for (i = 0; i < avctx->width >> 1; i++) {
227 if (val && val < table_size) {
228 val = AV_RL16(table + (val << 1));
229 uval = (val >> 3) & 0xF8;
230 vval = (val >> 8) & 0xF8;
231 U[i] = uval | (uval >> 5);
232 V[i] = vval | (vval >> 5);
237 U += s->pic->linesize[1];
238 V += s->pic->linesize[2];
240 if (avctx->height & 1) {
241 memcpy(U, U - s->pic->linesize[1], avctx->width >> 1);
242 memcpy(V, V - s->pic->linesize[2], avctx->width >> 1);
245 uint8_t *U2 = U + s->pic->linesize[1];
246 uint8_t *V2 = V + s->pic->linesize[2];
248 for (j = 0; j < avctx->height >> 2; j++) {
249 for (i = 0; i < avctx->width >> 1; i += 2) {
251 if (val && val < table_size) {
252 val = AV_RL16(table + (val << 1));
253 uval = (val >> 3) & 0xF8;
254 vval = (val >> 8) & 0xF8;
255 U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
256 V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
259 U += s->pic->linesize[1] * 2;
260 V += s->pic->linesize[2] * 2;
261 U2 += s->pic->linesize[1] * 2;
262 V2 += s->pic->linesize[2] * 2;
264 if (avctx->height & 3) {
265 int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;
267 memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]);
268 memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]);
275 static int xan_decode_frame_type0(AVCodecContext *avctx)
277 XanContext *s = avctx->priv_data;
278 uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
279 unsigned chroma_off, corr_off;
284 chroma_off = bytestream2_get_le32(&s->gb);
285 corr_off = bytestream2_get_le32(&s->gb);
287 if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
290 if (corr_off >= (s->gb.buffer_end - s->gb.buffer_start)) {
291 av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
294 bytestream2_seek(&s->gb, 12, SEEK_SET);
295 ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
297 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
304 for (j = 1; j < avctx->width - 1; j += 2) {
305 cur = (last + *src++) & 0x1F;
306 ybuf[j] = last + cur;
307 ybuf[j+1] = cur << 1;
312 ybuf += avctx->width;
314 for (i = 1; i < avctx->height; i++) {
315 last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
317 for (j = 1; j < avctx->width - 1; j += 2) {
318 cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
319 ybuf[j] = last + cur;
320 ybuf[j+1] = cur << 1;
325 ybuf += avctx->width;
331 bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
332 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
335 for (i = 0; i < dec_size; i++)
336 s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
340 ybuf = s->pic->data[0];
341 for (j = 0; j < avctx->height; j++) {
342 for (i = 0; i < avctx->width; i++)
343 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
345 ybuf += s->pic->linesize[0];
351 static int xan_decode_frame_type1(AVCodecContext *avctx)
353 XanContext *s = avctx->priv_data;
354 uint8_t *ybuf, *src = s->scratch_buffer;
359 if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
362 bytestream2_seek(&s->gb, 16, SEEK_SET);
363 ret = xan_unpack_luma(s, src,
364 s->buffer_size >> 1);
366 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
371 for (i = 0; i < avctx->height; i++) {
372 last = (ybuf[0] + (*src++ << 1)) & 0x3F;
374 for (j = 1; j < avctx->width - 1; j += 2) {
375 cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
376 ybuf[j] = (last + cur) >> 1;
381 ybuf += avctx->width;
385 ybuf = s->pic->data[0];
386 for (j = 0; j < avctx->height; j++) {
387 for (i = 0; i < avctx->width; i++)
388 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
390 ybuf += s->pic->linesize[0];
396 static int xan_decode_frame(AVCodecContext *avctx,
397 void *data, int *got_frame,
400 XanContext *s = avctx->priv_data;
404 if ((ret = ff_reget_buffer(avctx, s->pic))) {
405 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
409 bytestream2_init(&s->gb, avpkt->data, avpkt->size);
410 ftype = bytestream2_get_le32(&s->gb);
413 ret = xan_decode_frame_type0(avctx);
416 ret = xan_decode_frame_type1(avctx);
419 av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
420 return AVERROR_INVALIDDATA;
425 if ((ret = av_frame_ref(data, s->pic)) < 0)
433 AVCodec ff_xan_wc4_decoder = {
435 .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
436 .type = AVMEDIA_TYPE_VIDEO,
437 .id = AV_CODEC_ID_XAN_WC4,
438 .priv_data_size = sizeof(XanContext),
439 .init = xan_decode_init,
440 .close = xan_decode_end,
441 .decode = xan_decode_frame,
442 .capabilities = AV_CODEC_CAP_DR1,