2 * Gremlin Digital Video (GDV) decoder
3 * Copyright (c) 2017 Konstantin Shishkov
4 * Copyright (c) 2017 Paul B Mahol
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
23 #include "libavutil/common.h"
25 #include "bytestream.h"
28 typedef struct GDVContext {
29 AVCodecContext *avctx;
38 unsigned scale_h, scale_v;
41 typedef struct Bits8 {
46 typedef struct Bits32 {
51 #define PREAMBLE_SIZE 4096
53 static av_cold int gdv_decode_init(AVCodecContext *avctx)
55 GDVContext *gdv = avctx->priv_data;
58 avctx->pix_fmt = AV_PIX_FMT_PAL8;
59 gdv->frame_size = avctx->width * avctx->height + PREAMBLE_SIZE;
60 gdv->frame = av_calloc(gdv->frame_size, 1);
62 return AVERROR(ENOMEM);
64 for (i = 0; i < 2; i++) {
65 for (j = 0; j < 256; j++) {
66 for (k = 0; k < 8; k++) {
67 gdv->frame[i * 2048 + j * 8 + k] = j;
75 static void scaleup(uint8_t *dst, const uint8_t *src, int w)
78 for (x = 0; x < w - 7; x+=8) {
80 dst[x + 1] = src[(x>>1) + 0];
82 dst[x + 3] = src[(x>>1) + 1];
84 dst[x + 5] = src[(x>>1) + 2];
86 dst[x + 7] = src[(x>>1) + 3];
93 static void scaleup_rev(uint8_t *dst, const uint8_t *src, int w)
97 for (x = w - 1; (x+1) & 7; x--) {
100 for (x -= 7; x >= 0; x -= 8) {
102 dst[x + 7] = src[(x>>1) + 3];
104 dst[x + 5] = src[(x>>1) + 2];
106 dst[x + 3] = src[(x>>1) + 1];
108 dst[x + 1] = src[(x>>1) + 0];
112 static void scaledown(uint8_t *dst, const uint8_t *src, int w)
115 for (x = 0; x < w - 7; x+=8) {
116 dst[x + 0] = src[2*x + 0];
117 dst[x + 1] = src[2*x + 2];
118 dst[x + 2] = src[2*x + 4];
119 dst[x + 3] = src[2*x + 6];
120 dst[x + 4] = src[2*x + 8];
121 dst[x + 5] = src[2*x +10];
122 dst[x + 6] = src[2*x +12];
123 dst[x + 7] = src[2*x +14];
130 static void rescale(GDVContext *gdv, uint8_t *dst, int w, int h, int scale_v, int scale_h)
134 if ((gdv->scale_v == scale_v) && (gdv->scale_h == scale_h)) {
139 for (j = 0; j < h; j++) {
141 uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
142 uint8_t *src1 = dst + PREAMBLE_SIZE + (y>>!!gdv->scale_h) * (w>>1);
144 scaleup_rev(dst1, src1, w);
146 } else if (gdv->scale_h) {
147 for (j = 0; j < h; j++) {
149 uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
150 uint8_t *src1 = dst + PREAMBLE_SIZE + (y>>1) * w;
151 memcpy(dst1, src1, w);
155 if (scale_h && scale_v) {
156 for (y = 0; y < (h>>1); y++) {
157 uint8_t *dst1 = dst + PREAMBLE_SIZE + y * (w>>1);
158 uint8_t *src1 = dst + PREAMBLE_SIZE + y*2 * w;
159 scaledown(dst1, src1, w>>1);
161 } else if (scale_h) {
162 for (y = 0; y < (h>>1); y++) {
163 uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
164 uint8_t *src1 = dst + PREAMBLE_SIZE + y*2 * w;
165 memcpy(dst1, src1, w);
167 } else if (scale_v) {
168 for (y = 0; y < h; y++) {
169 uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
170 scaledown(dst1, dst1, w>>1);
174 gdv->scale_v = scale_v;
175 gdv->scale_h = scale_h;
178 static int read_bits2(Bits8 *bits, GetByteContext *gb)
182 if (bits->fill == 0) {
183 bits->queue |= bytestream2_get_byte(gb);
186 res = bits->queue >> 6;
193 static void fill_bits32(Bits32 *bits, GetByteContext *gb)
195 bits->queue = bytestream2_get_le32(gb);
199 static int read_bits32(Bits32 *bits, GetByteContext *gb, int nbits)
201 int res = bits->queue & ((1 << nbits) - 1);
203 bits->queue >>= nbits;
205 if (bits->fill <= 16) {
206 bits->queue |= bytestream2_get_le16(gb) << bits->fill;
213 static void lz_copy(PutByteContext *pb, GetByteContext *g2, int offset, unsigned len)
220 bytestream2_seek(g2, bytestream2_tell_p(pb) - 1, SEEK_SET);
221 c = bytestream2_get_byte(g2);
222 for (i = 0; i < len; i++) {
223 bytestream2_put_byte(pb, c);
225 } else if (offset < 0) {
226 int start = bytestream2_tell_p(pb) - (-offset);
228 bytestream2_seek(g2, start, SEEK_SET);
229 for (i = 0; i < len; i++) {
230 bytestream2_put_byte(pb, bytestream2_get_byte(g2));
233 int start = bytestream2_tell_p(pb) + offset;
235 bytestream2_seek(g2, start, SEEK_SET);
236 for (i = 0; i < len; i++) {
237 bytestream2_put_byte(pb, bytestream2_get_byte(g2));
242 static int decompress_2(AVCodecContext *avctx)
244 GDVContext *gdv = avctx->priv_data;
245 GetByteContext *gb = &gdv->gb;
246 GetByteContext *g2 = &gdv->g2;
247 PutByteContext *pb = &gdv->pb;
251 bytestream2_init(g2, gdv->frame, gdv->frame_size);
252 bytestream2_skip_p(pb, PREAMBLE_SIZE);
254 for (c = 0; c < 256; c++) {
255 for (i = 0; i < 16; i++) {
256 gdv->frame[c * 16 + i] = c;
260 while (bytestream2_get_bytes_left_p(pb) > 0 && bytestream2_get_bytes_left(gb) > 0) {
261 int tag = read_bits2(&bits, gb);
263 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
264 } else if (tag == 1) {
265 int b = bytestream2_get_byte(gb);
266 int len = (b & 0xF) + 3;
267 int top = (b >> 4) & 0xF;
268 int off = (bytestream2_get_byte(gb) << 4) + top - 4096;
269 lz_copy(pb, g2, off, len);
270 } else if (tag == 2) {
271 int len = (bytestream2_get_byte(gb)) + 2;
272 bytestream2_skip_p(pb, len);
278 if (bytestream2_get_bytes_left_p(pb) > 0)
279 return AVERROR_INVALIDDATA;
284 static int decompress_5(AVCodecContext *avctx, unsigned skip)
286 GDVContext *gdv = avctx->priv_data;
287 GetByteContext *gb = &gdv->gb;
288 GetByteContext *g2 = &gdv->g2;
289 PutByteContext *pb = &gdv->pb;
292 bytestream2_init(g2, gdv->frame, gdv->frame_size);
293 bytestream2_skip_p(pb, skip + PREAMBLE_SIZE);
295 while (bytestream2_get_bytes_left_p(pb) > 0 && bytestream2_get_bytes_left(gb) > 0) {
296 int tag = read_bits2(&bits, gb);
298 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
299 } else if (tag == 1) {
300 int b = bytestream2_get_byte(gb);
301 int len = (b & 0xF) + 3;
303 int off = (bytestream2_get_byte(gb) << 4) + top - 4096;
304 lz_copy(pb, g2, off, len);
305 } else if (tag == 2) {
307 int b = bytestream2_get_byte(gb);
314 len = bytestream2_get_le16(gb);
316 bytestream2_skip_p(pb, len + 1);
318 int b = bytestream2_get_byte(gb);
319 int len = (b & 0x3) + 2;
320 int off = -(b >> 2) - 1;
321 lz_copy(pb, g2, off, len);
327 static int decompress_68(AVCodecContext *avctx, unsigned skip, unsigned use8)
329 GDVContext *gdv = avctx->priv_data;
330 GetByteContext *gb = &gdv->gb;
331 GetByteContext *g2 = &gdv->g2;
332 PutByteContext *pb = &gdv->pb;
335 bytestream2_init(g2, gdv->frame, gdv->frame_size);
336 bytestream2_skip_p(pb, skip + PREAMBLE_SIZE);
337 fill_bits32(&bits, gb);
339 while (bytestream2_get_bytes_left_p(pb) > 0 && bytestream2_get_bytes_left(gb) > 0) {
340 int tag = read_bits32(&bits, gb, 2);
342 int b = read_bits32(&bits, gb, 1);
344 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
352 val = read_bits32(&bits, gb, lbits);
354 if (val != ((1 << lbits) - 1)) {
359 for (i = 0; i < len; i++) {
360 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
363 } else if (tag == 1) {
364 int b = read_bits32(&bits, gb, 1);
368 len = (read_bits32(&bits, gb, 4)) + 2;
370 int bb = bytestream2_get_byte(gb);
371 if ((bb & 0x80) == 0) {
374 int top = (bb & 0x7F) << 8;
375 len = top + bytestream2_get_byte(gb) + 146;
378 bytestream2_skip_p(pb, len);
379 } else if (tag == 2) {
380 int i, subtag = read_bits32(&bits, gb, 2);
383 int top = (read_bits32(&bits, gb, 4)) << 8;
384 int offs = top + bytestream2_get_byte(gb);
385 if ((subtag != 0) || (offs <= 0xF80)) {
386 int len = (subtag) + 3;
387 lz_copy(pb, g2, (offs) - 4096, len);
389 int real_off, len, c1, c2;
395 real_off = ((offs >> 4) & 0x7) + 1;
396 len = ((offs & 0xF) + 2) * 2;
397 c1 = gdv->frame[bytestream2_tell_p(pb) - real_off];
398 c2 = gdv->frame[bytestream2_tell_p(pb) - real_off + 1];
399 for (i = 0; i < len/2; i++) {
400 bytestream2_put_byte(pb, c1);
401 bytestream2_put_byte(pb, c2);
405 int b = bytestream2_get_byte(gb);
406 int off = ((b & 0x7F)) + 1;
407 int len = ((b & 0x80) == 0) ? 2 : 3;
409 lz_copy(pb, g2, -off, len);
415 int q, b = bytestream2_get_byte(gb);
416 if ((b & 0xC0) == 0xC0) {
417 len = ((b & 0x3F)) + 8;
418 q = read_bits32(&bits, gb, 4);
419 off = (q << 8) + (bytestream2_get_byte(gb)) + 1;
422 if ((b & 0x80) == 0) {
423 len = ((b >> 4)) + 6;
426 len = ((b & 0x3F)) + 14;
427 ofs1 = read_bits32(&bits, gb, 4);
429 off = (ofs1 << 8) + (bytestream2_get_byte(gb)) - 4096;
432 int ofs1, b = bytestream2_get_byte(gb);
434 if ((b >> 4) == 0xF) {
435 len = bytestream2_get_byte(gb) + 21;
440 off = (ofs1 << 8) + bytestream2_get_byte(gb) - 4096;
442 lz_copy(pb, g2, off, len);
449 static int gdv_decode_frame(AVCodecContext *avctx, void *data,
450 int *got_frame, AVPacket *avpkt)
452 GDVContext *gdv = avctx->priv_data;
453 GetByteContext *gb = &gdv->gb;
454 PutByteContext *pb = &gdv->pb;
455 AVFrame *frame = data;
456 int ret, i, pal_size;
457 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, &pal_size);
462 bytestream2_init(gb, avpkt->data, avpkt->size);
463 bytestream2_init_writer(pb, gdv->frame, gdv->frame_size);
465 flags = bytestream2_get_le32(gb);
466 compression = flags & 0xF;
468 if (compression == 4 || compression == 7 || compression > 8)
469 return AVERROR_INVALIDDATA;
471 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
473 if (pal && pal_size == AVPALETTE_SIZE)
474 memcpy(gdv->pal, pal, AVPALETTE_SIZE);
476 rescale(gdv, gdv->frame, avctx->width, avctx->height,
477 !!(flags & 0x10), !!(flags & 0x20));
479 switch (compression) {
481 memset(gdv->frame + PREAMBLE_SIZE, 0, gdv->frame_size - PREAMBLE_SIZE);
483 if (bytestream2_get_bytes_left(gb) < 256*3)
484 return AVERROR_INVALIDDATA;
485 for (i = 0; i < 256; i++) {
486 unsigned r = bytestream2_get_byte(gb);
487 unsigned g = bytestream2_get_byte(gb);
488 unsigned b = bytestream2_get_byte(gb);
489 gdv->pal[i] = 0xFFU << 24 | r << 18 | g << 10 | b << 2;
493 ret = decompress_2(avctx);
498 ret = decompress_5(avctx, flags >> 8);
501 ret = decompress_68(avctx, flags >> 8, 0);
504 ret = decompress_68(avctx, flags >> 8, 1);
512 memcpy(frame->data[1], gdv->pal, AVPALETTE_SIZE);
513 dst = frame->data[0];
515 if (!gdv->scale_v && !gdv->scale_h) {
516 int sidx = PREAMBLE_SIZE, didx = 0;
519 for (y = 0; y < avctx->height; y++) {
520 memcpy(dst + didx, gdv->frame + sidx, avctx->width);
521 sidx += avctx->width;
522 didx += frame->linesize[0];
525 int sidx = PREAMBLE_SIZE, didx = 0;
528 for (y = 0; y < avctx->height; y++) {
530 memcpy(dst + didx, gdv->frame + sidx, avctx->width);
532 uint8_t *dst2 = dst + didx;
533 uint8_t *src2 = gdv->frame + sidx;
535 scaleup(dst2, src2, avctx->width);
537 if (!gdv->scale_h || ((y & 1) == 1)) {
538 sidx += !gdv->scale_v ? avctx->width : avctx->width/2;
540 didx += frame->linesize[0];
546 return ret < 0 ? ret : avpkt->size;
549 static av_cold int gdv_decode_close(AVCodecContext *avctx)
551 GDVContext *gdv = avctx->priv_data;
552 av_freep(&gdv->frame);
556 AVCodec ff_gdv_decoder = {
558 .long_name = NULL_IF_CONFIG_SMALL("Gremlin Digital Video"),
559 .type = AVMEDIA_TYPE_VIDEO,
560 .id = AV_CODEC_ID_GDV,
561 .priv_data_size = sizeof(GDVContext),
562 .init = gdv_decode_init,
563 .close = gdv_decode_close,
564 .decode = gdv_decode_frame,
565 .capabilities = AV_CODEC_CAP_DR1,
566 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,