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
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/mem.h"
26 #include "bytestream.h"
27 #define BITSTREAM_READER_LE
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 = AV_PIX_FMT_YUV420P;
49 if (avctx->height < 8) {
50 av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);
51 return AVERROR(EINVAL);
53 if (avctx->width & 1) {
54 av_log(avctx, AV_LOG_ERROR, "Invalid frame width: %d.\n", avctx->width);
55 return AVERROR(EINVAL);
58 s->buffer_size = avctx->width * avctx->height;
59 s->y_buffer = av_malloc(s->buffer_size);
61 return AVERROR(ENOMEM);
62 s->scratch_buffer = av_malloc(s->buffer_size + 130);
63 if (!s->scratch_buffer) {
64 av_freep(&s->y_buffer);
65 return AVERROR(ENOMEM);
71 static int xan_unpack_luma(XanContext *s,
72 uint8_t *dst, const int dst_size)
77 const uint8_t *dst_end = dst + dst_size;
78 GetByteContext tree = s->gb;
79 int start_off = bytestream2_tell(&tree);
81 tree_size = bytestream2_get_byte(&s->gb);
82 eof = bytestream2_get_byte(&s->gb);
83 tree_root = eof + tree_size;
84 bytestream2_skip(&s->gb, tree_size * 2);
87 bits = bytestream2_get_byte(&s->gb);
90 int bit = !!(bits & mask);
92 bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
93 node = bytestream2_get_byte(&tree);
103 if (bytestream2_get_bytes_left(&s->gb) <= 0)
105 bits = bytestream2_get_byteu(&s->gb);
109 return dst != dst_end ? AVERROR_INVALIDDATA : 0;
112 /* almost the same as in xan_wc3 decoder */
113 static int xan_unpack(XanContext *s,
114 uint8_t *dest, const int dest_len)
118 uint8_t *orig_dest = dest;
119 const uint8_t *dest_end = dest + dest_len;
121 while (dest < dest_end) {
122 if (bytestream2_get_bytes_left(&s->gb) <= 0)
123 return AVERROR_INVALIDDATA;
125 opcode = bytestream2_get_byteu(&s->gb);
129 if ((opcode & 0x80) == 0) {
131 back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
132 size2 = ((opcode & 0x1c) >> 2) + 3;
133 } else if ((opcode & 0x40) == 0) {
134 size = bytestream2_peek_byte(&s->gb) >> 6;
135 back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
136 size2 = (opcode & 0x3f) + 4;
139 back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
140 size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
141 if (size + size2 > dest_end - dest)
144 if (dest + size + size2 > dest_end ||
145 dest - orig_dest + size < back)
146 return AVERROR_INVALIDDATA;
147 bytestream2_get_buffer(&s->gb, dest, size);
149 av_memcpy_backptr(dest, back, size2);
152 int finish = opcode >= 0xfc;
154 size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
155 if (dest_end - dest < size)
156 return AVERROR_INVALIDDATA;
157 bytestream2_get_buffer(&s->gb, dest, size);
163 return dest - orig_dest;
166 static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
168 XanContext *s = avctx->priv_data;
172 const uint8_t *src, *src_end;
173 const uint8_t *table;
174 int mode, offset, dec_size, table_size;
178 if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
179 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
180 return AVERROR_INVALIDDATA;
182 bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
183 mode = bytestream2_get_le16(&s->gb);
184 table = s->gb.buffer;
185 table_size = bytestream2_get_le16(&s->gb);
186 offset = table_size * 2;
189 if (offset >= bytestream2_get_bytes_left(&s->gb)) {
190 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
191 return AVERROR_INVALIDDATA;
194 bytestream2_skip(&s->gb, offset);
195 memset(s->scratch_buffer, 0, s->buffer_size);
196 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
198 av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
204 src = s->scratch_buffer;
205 src_end = src + dec_size;
207 for (j = 0; j < avctx->height >> 1; j++) {
208 for (i = 0; i < avctx->width >> 1; i++) {
210 if (val && val < table_size) {
211 val = AV_RL16(table + (val << 1));
212 uval = (val >> 3) & 0xF8;
213 vval = (val >> 8) & 0xF8;
214 U[i] = uval | (uval >> 5);
215 V[i] = vval | (vval >> 5);
220 U += s->pic.linesize[1];
221 V += s->pic.linesize[2];
223 if (avctx->height & 1) {
224 memcpy(U, U - s->pic.linesize[1], avctx->width >> 1);
225 memcpy(V, V - s->pic.linesize[2], avctx->width >> 1);
228 uint8_t *U2 = U + s->pic.linesize[1];
229 uint8_t *V2 = V + s->pic.linesize[2];
231 for (j = 0; j < avctx->height >> 2; j++) {
232 for (i = 0; i < avctx->width >> 1; i += 2) {
234 if (val && val < table_size) {
235 val = AV_RL16(table + (val << 1));
236 uval = (val >> 3) & 0xF8;
237 vval = (val >> 8) & 0xF8;
238 U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
239 V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
242 U += s->pic.linesize[1] * 2;
243 V += s->pic.linesize[2] * 2;
244 U2 += s->pic.linesize[1] * 2;
245 V2 += s->pic.linesize[2] * 2;
247 if (avctx->height & 3) {
248 int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;
250 memcpy(U, U - lines * s->pic.linesize[1], lines * s->pic.linesize[1]);
251 memcpy(V, V - lines * s->pic.linesize[2], lines * s->pic.linesize[2]);
258 static int xan_decode_frame_type0(AVCodecContext *avctx)
260 XanContext *s = avctx->priv_data;
261 uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
262 unsigned chroma_off, corr_off;
267 chroma_off = bytestream2_get_le32(&s->gb);
268 corr_off = bytestream2_get_le32(&s->gb);
270 if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
273 if (corr_off >= (s->gb.buffer_end - s->gb.buffer_start)) {
274 av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
277 bytestream2_seek(&s->gb, 12, SEEK_SET);
278 ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
280 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
287 for (j = 1; j < avctx->width - 1; j += 2) {
288 cur = (last + *src++) & 0x1F;
289 ybuf[j] = last + cur;
290 ybuf[j+1] = cur << 1;
295 ybuf += avctx->width;
297 for (i = 1; i < avctx->height; i++) {
298 last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
300 for (j = 1; j < avctx->width - 1; j += 2) {
301 cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
302 ybuf[j] = last + cur;
303 ybuf[j+1] = cur << 1;
308 ybuf += avctx->width;
314 bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
315 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
318 for (i = 0; i < dec_size; i++)
319 s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
323 ybuf = s->pic.data[0];
324 for (j = 0; j < avctx->height; j++) {
325 for (i = 0; i < avctx->width; i++)
326 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
328 ybuf += s->pic.linesize[0];
334 static int xan_decode_frame_type1(AVCodecContext *avctx)
336 XanContext *s = avctx->priv_data;
337 uint8_t *ybuf, *src = s->scratch_buffer;
342 if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
345 bytestream2_seek(&s->gb, 16, SEEK_SET);
346 ret = xan_unpack_luma(s, src,
347 s->buffer_size >> 1);
349 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
354 for (i = 0; i < avctx->height; i++) {
355 last = (ybuf[0] + (*src++ << 1)) & 0x3F;
357 for (j = 1; j < avctx->width - 1; j += 2) {
358 cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
359 ybuf[j] = (last + cur) >> 1;
364 ybuf += avctx->width;
368 ybuf = s->pic.data[0];
369 for (j = 0; j < avctx->height; j++) {
370 for (i = 0; i < avctx->width; i++)
371 ybuf[i] = (src[i] << 2) | (src[i] >> 3);
373 ybuf += s->pic.linesize[0];
379 static int xan_decode_frame(AVCodecContext *avctx,
380 void *data, int *got_frame,
383 XanContext *s = avctx->priv_data;
387 if ((ret = ff_reget_buffer(avctx, &s->pic))) {
388 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
392 bytestream2_init(&s->gb, avpkt->data, avpkt->size);
393 ftype = bytestream2_get_le32(&s->gb);
396 ret = xan_decode_frame_type0(avctx);
399 ret = xan_decode_frame_type1(avctx);
402 av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
403 return AVERROR_INVALIDDATA;
408 if ((ret = av_frame_ref(data, &s->pic)) < 0)
416 static av_cold int xan_decode_end(AVCodecContext *avctx)
418 XanContext *s = avctx->priv_data;
420 av_frame_unref(&s->pic);
422 av_freep(&s->y_buffer);
423 av_freep(&s->scratch_buffer);
428 AVCodec ff_xan_wc4_decoder = {
430 .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
431 .type = AVMEDIA_TYPE_VIDEO,
432 .id = AV_CODEC_ID_XAN_WC4,
433 .priv_data_size = sizeof(XanContext),
434 .init = xan_decode_init,
435 .close = xan_decode_end,
436 .decode = xan_decode_frame,
437 .capabilities = CODEC_CAP_DR1,