2 * Interplay MVE Video Decoder
3 * Copyright (C) 2003 the ffmpeg project
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * @file libavcodec/interplayvideo.c
24 * Interplay MVE Video Decoder by Mike Melanson (melanson@pcisys.net)
25 * For more information about the Interplay MVE format, visit:
26 * http://www.pcisys.net/~melanson/codecs/interplay-mve.txt
27 * This code is written in such a way that the identifiers match up
28 * with the encoding descriptions in the document.
30 * This decoder presently only supports a PAL8 output colorspace.
32 * An Interplay video frame consists of 2 parts: The decoding map and
33 * the video data. A demuxer must load these 2 parts together in a single
34 * buffer before sending it through the stream to this decoder.
43 #include "bytestream.h"
46 #define PALETTE_COUNT 256
48 /* debugging support */
49 #define DEBUG_INTERPLAY 0
51 #define debug_interplay(x,...) av_log(NULL, AV_LOG_DEBUG, x, __VA_ARGS__)
53 static inline void debug_interplay(const char *format, ...) { }
56 typedef struct IpvideoContext {
58 AVCodecContext *avctx;
60 AVFrame second_last_frame;
62 AVFrame current_frame;
63 const unsigned char *decoding_map;
64 int decoding_map_size;
66 const unsigned char *buf;
69 const unsigned char *stream_ptr;
70 const unsigned char *stream_end;
71 unsigned char *pixel_ptr;
74 int upper_motion_limit_offset;
78 #define CHECK_STREAM_PTR(n) \
79 if (s->stream_end - s->stream_ptr < n) { \
80 av_log(s->avctx, AV_LOG_ERROR, "Interplay video warning: stream_ptr out of bounds (%p >= %p)\n", \
81 s->stream_ptr + n, s->stream_end); \
85 static int copy_from(IpvideoContext *s, AVFrame *src, int delta_x, int delta_y)
87 int current_offset = s->pixel_ptr - s->current_frame.data[0];
88 int motion_offset = current_offset + delta_y * s->stride + delta_x;
89 if (motion_offset < 0) {
90 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset < 0 (%d)\n", motion_offset);
92 } else if (motion_offset > s->upper_motion_limit_offset) {
93 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: motion offset above limit (%d >= %d)\n",
94 motion_offset, s->upper_motion_limit_offset);
97 s->dsp.put_pixels_tab[1][0](s->pixel_ptr, src->data[0] + motion_offset, s->stride, 8);
101 static int ipvideo_decode_block_opcode_0x0(IpvideoContext *s)
103 return copy_from(s, &s->last_frame, 0, 0);
106 static int ipvideo_decode_block_opcode_0x1(IpvideoContext *s)
108 return copy_from(s, &s->second_last_frame, 0, 0);
111 static int ipvideo_decode_block_opcode_0x2(IpvideoContext *s)
116 /* copy block from 2 frames ago using a motion vector; need 1 more byte */
118 B = *s->stream_ptr++;
124 x = -14 + ((B - 56) % 29);
125 y = 8 + ((B - 56) / 29);
128 debug_interplay (" motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
129 return copy_from(s, &s->second_last_frame, x, y);
132 static int ipvideo_decode_block_opcode_0x3(IpvideoContext *s)
137 /* copy 8x8 block from current frame from an up/left block */
139 /* need 1 more byte for motion */
141 B = *s->stream_ptr++;
147 x = -(-14 + ((B - 56) % 29));
148 y = -( 8 + ((B - 56) / 29));
151 debug_interplay (" motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
152 return copy_from(s, &s->current_frame, x, y);
155 static int ipvideo_decode_block_opcode_0x4(IpvideoContext *s)
158 unsigned char B, BL, BH;
160 /* copy a block from the previous frame; need 1 more byte */
163 B = *s->stream_ptr++;
165 BH = (B >> 4) & 0x0F;
169 debug_interplay (" motion byte = %d, (x, y) = (%d, %d)\n", B, x, y);
170 return copy_from(s, &s->last_frame, x, y);
173 static int ipvideo_decode_block_opcode_0x5(IpvideoContext *s)
177 /* copy a block from the previous frame using an expanded range;
178 * need 2 more bytes */
181 x = *s->stream_ptr++;
182 y = *s->stream_ptr++;
184 debug_interplay (" motion bytes = %d, %d\n", x, y);
185 return copy_from(s, &s->last_frame, x, y);
188 static int ipvideo_decode_block_opcode_0x6(IpvideoContext *s)
190 /* mystery opcode? skip multiple blocks? */
191 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: Help! Mystery opcode 0x6 seen\n");
197 static int ipvideo_decode_block_opcode_0x7(IpvideoContext *s)
203 /* 2-color encoding */
206 P[0] = *s->stream_ptr++;
207 P[1] = *s->stream_ptr++;
211 /* need 8 more bytes from the stream */
214 for (y = 0; y < 8; y++) {
215 flags = *s->stream_ptr++ | 0x100;
216 for (; flags != 1; flags >>= 1) {
217 *s->pixel_ptr++ = P[flags & 1];
219 s->pixel_ptr += s->line_inc;
224 /* need 2 more bytes from the stream */
227 flags = bytestream_get_le16(&s->stream_ptr);
228 for (y = 0; y < 8; y += 2) {
229 for (x = 0; x < 8; x += 2, flags >>= 1) {
231 s->pixel_ptr[x + 1 ] =
232 s->pixel_ptr[x + s->stride] =
233 s->pixel_ptr[x + 1 + s->stride] = P[flags & 1];
235 s->pixel_ptr += s->stride * 2;
243 static int ipvideo_decode_block_opcode_0x8(IpvideoContext *s)
247 unsigned int flags = 0;
249 /* 2-color encoding for each 4x4 quadrant, or 2-color encoding on
250 * either top and bottom or left and right halves */
253 P[0] = *s->stream_ptr++;
254 P[1] = *s->stream_ptr++;
258 CHECK_STREAM_PTR(14);
261 for (y = 0; y < 16; y++) {
262 // new values for each 4x4 block
264 P[0] = *s->stream_ptr++; P[1] = *s->stream_ptr++;
265 flags = bytestream_get_le16(&s->stream_ptr);
268 for (x = 0; x < 4; x++, flags >>= 1) {
269 *s->pixel_ptr++ = P[flags & 1];
271 s->pixel_ptr += s->stride - 4;
272 // switch to right half
273 if (y == 7) s->pixel_ptr -= 8 * s->stride - 4;
278 /* need 10 more bytes */
279 CHECK_STREAM_PTR(10);
281 if (s->stream_ptr[4] <= s->stream_ptr[5]) {
283 flags = bytestream_get_le32(&s->stream_ptr);
285 /* vertical split; left & right halves are 2-color encoded */
287 for (y = 0; y < 16; y++) {
288 for (x = 0; x < 4; x++, flags >>= 1) {
289 *s->pixel_ptr++ = P[flags & 1];
291 s->pixel_ptr += s->stride - 4;
292 // switch to right half
294 s->pixel_ptr -= 8 * s->stride - 4;
295 P[0] = *s->stream_ptr++; P[1] = *s->stream_ptr++;
296 flags = bytestream_get_le32(&s->stream_ptr);
302 /* horizontal split; top & bottom halves are 2-color encoded */
304 for (y = 0; y < 8; y++) {
306 P[0] = *s->stream_ptr++;
307 P[1] = *s->stream_ptr++;
309 flags = *s->stream_ptr++ | 0x100;
311 for (; flags != 1; flags >>= 1) {
313 *s->pixel_ptr++ = P[flags & 1];
315 s->pixel_ptr += s->line_inc;
324 static int ipvideo_decode_block_opcode_0x9(IpvideoContext *s)
329 /* 4-color encoding */
332 memcpy(P, s->stream_ptr, 4);
338 /* 1 of 4 colors for each pixel, need 16 more bytes */
339 CHECK_STREAM_PTR(16);
341 for (y = 0; y < 8; y++) {
342 /* get the next set of 8 2-bit flags */
343 int flags = bytestream_get_le16(&s->stream_ptr);
344 for (x = 0; x < 8; x++, flags >>= 2) {
345 *s->pixel_ptr++ = P[flags & 0x03];
347 s->pixel_ptr += s->line_inc;
353 /* 1 of 4 colors for each 2x2 block, need 4 more bytes */
356 flags = bytestream_get_le32(&s->stream_ptr);
358 for (y = 0; y < 8; y += 2) {
359 for (x = 0; x < 8; x += 2, flags >>= 2) {
361 s->pixel_ptr[x + 1 ] =
362 s->pixel_ptr[x + s->stride] =
363 s->pixel_ptr[x + 1 + s->stride] = P[flags & 0x03];
365 s->pixel_ptr += s->stride * 2;
372 /* 1 of 4 colors for each 2x1 or 1x2 block, need 8 more bytes */
375 flags = bytestream_get_le64(&s->stream_ptr);
377 for (y = 0; y < 8; y++) {
378 for (x = 0; x < 8; x += 2, flags >>= 2) {
380 s->pixel_ptr[x + 1] = P[flags & 0x03];
382 s->pixel_ptr += s->stride;
385 for (y = 0; y < 8; y += 2) {
386 for (x = 0; x < 8; x++, flags >>= 2) {
388 s->pixel_ptr[x + s->stride] = P[flags & 0x03];
390 s->pixel_ptr += s->stride * 2;
399 static int ipvideo_decode_block_opcode_0xA(IpvideoContext *s)
405 /* 4-color encoding for each 4x4 quadrant, or 4-color encoding on
406 * either top and bottom or left and right halves */
407 CHECK_STREAM_PTR(24);
409 if (s->stream_ptr[0] <= s->stream_ptr[1]) {
411 /* 4-color encoding for each quadrant; need 32 bytes */
412 CHECK_STREAM_PTR(32);
414 for (y = 0; y < 16; y++) {
415 // new values for each 4x4 block
417 memcpy(P, s->stream_ptr, 4);
419 flags = bytestream_get_le32(&s->stream_ptr);
422 for (x = 0; x < 4; x++, flags >>= 2) {
423 *s->pixel_ptr++ = P[flags & 0x03];
426 s->pixel_ptr += s->stride - 4;
427 // switch to right half
428 if (y == 7) s->pixel_ptr -= 8 * s->stride - 4;
433 int vert = s->stream_ptr[12] <= s->stream_ptr[13];
436 /* 4-color encoding for either left and right or top and bottom
439 for (y = 0; y < 16; y++) {
440 // load values for each half
442 memcpy(P, s->stream_ptr, 4);
444 flags = bytestream_get_le64(&s->stream_ptr);
447 for (x = 0; x < 4; x++, flags >>= 2)
448 *s->pixel_ptr++ = P[flags & 0x03];
451 s->pixel_ptr += s->stride - 4;
452 // switch to right half
453 if (y == 7) s->pixel_ptr -= 8 * s->stride - 4;
454 } else if (y & 1) s->pixel_ptr += s->line_inc;
462 static int ipvideo_decode_block_opcode_0xB(IpvideoContext *s)
466 /* 64-color encoding (each pixel in block is a different color) */
467 CHECK_STREAM_PTR(64);
469 for (y = 0; y < 8; y++) {
470 memcpy(s->pixel_ptr, s->stream_ptr, 8);
472 s->pixel_ptr += s->stride;
479 static int ipvideo_decode_block_opcode_0xC(IpvideoContext *s)
483 /* 16-color block encoding: each 2x2 block is a different color */
484 CHECK_STREAM_PTR(16);
486 for (y = 0; y < 8; y += 2) {
487 for (x = 0; x < 8; x += 2) {
489 s->pixel_ptr[x + 1 ] =
490 s->pixel_ptr[x + s->stride] =
491 s->pixel_ptr[x + 1 + s->stride] = *s->stream_ptr++;
493 s->pixel_ptr += s->stride * 2;
500 static int ipvideo_decode_block_opcode_0xD(IpvideoContext *s)
505 /* 4-color block encoding: each 4x4 block is a different color */
508 for (y = 0; y < 16; y++) {
509 if (!(y & 3)) // start of block
510 P = *s->stream_ptr++;
511 memset(s->pixel_ptr, P, 4);
512 s->pixel_ptr += s->stride;
513 // switch to right half
514 if (y == 7) s->pixel_ptr -= 8 * s->stride - 4;
521 static int ipvideo_decode_block_opcode_0xE(IpvideoContext *s)
526 /* 1-color encoding: the whole block is 1 solid color */
528 pix = *s->stream_ptr++;
530 for (y = 0; y < 8; y++) {
531 memset(s->pixel_ptr, pix, 8);
532 s->pixel_ptr += s->stride;
539 static int ipvideo_decode_block_opcode_0xF(IpvideoContext *s)
542 unsigned char sample[2];
544 /* dithered encoding */
546 sample[0] = *s->stream_ptr++;
547 sample[1] = *s->stream_ptr++;
549 for (y = 0; y < 8; y++) {
550 for (x = 0; x < 8; x += 2) {
551 *s->pixel_ptr++ = sample[ y & 1 ];
552 *s->pixel_ptr++ = sample[!(y & 1)];
554 s->pixel_ptr += s->line_inc;
561 static int (* const ipvideo_decode_block[])(IpvideoContext *s) = {
562 ipvideo_decode_block_opcode_0x0, ipvideo_decode_block_opcode_0x1,
563 ipvideo_decode_block_opcode_0x2, ipvideo_decode_block_opcode_0x3,
564 ipvideo_decode_block_opcode_0x4, ipvideo_decode_block_opcode_0x5,
565 ipvideo_decode_block_opcode_0x6, ipvideo_decode_block_opcode_0x7,
566 ipvideo_decode_block_opcode_0x8, ipvideo_decode_block_opcode_0x9,
567 ipvideo_decode_block_opcode_0xA, ipvideo_decode_block_opcode_0xB,
568 ipvideo_decode_block_opcode_0xC, ipvideo_decode_block_opcode_0xD,
569 ipvideo_decode_block_opcode_0xE, ipvideo_decode_block_opcode_0xF,
572 static void ipvideo_decode_opcodes(IpvideoContext *s)
576 unsigned char opcode;
578 int code_counts[16] = {0};
579 static int frame = 0;
581 debug_interplay("------------------ frame %d\n", frame);
584 /* this is PAL8, so make the palette available */
585 memcpy(s->current_frame.data[1], s->avctx->palctrl->palette, PALETTE_COUNT * 4);
587 s->stride = s->current_frame.linesize[0];
588 s->stream_ptr = s->buf + 14; /* data starts 14 bytes in */
589 s->stream_end = s->buf + s->size;
590 s->line_inc = s->stride - 8;
591 s->upper_motion_limit_offset = (s->avctx->height - 8) * s->stride
592 + s->avctx->width - 8;
594 for (y = 0; y < (s->stride * s->avctx->height); y += s->stride * 8) {
595 for (x = y; x < y + s->avctx->width; x += 8) {
596 /* bottom nibble first, then top nibble (which makes it
597 * hard to use a GetBitcontext) */
599 opcode = s->decoding_map[index >> 1] >> 4;
601 opcode = s->decoding_map[index >> 1] & 0xF;
604 debug_interplay(" block @ (%3d, %3d): encoding 0x%X, data ptr @ %p\n",
605 x - y, y / s->stride, opcode, s->stream_ptr);
606 code_counts[opcode]++;
608 s->pixel_ptr = s->current_frame.data[0] + x;
609 ret = ipvideo_decode_block[opcode](s);
611 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode problem on frame %d, @ block (%d, %d)\n",
612 frame, x - y, y / s->stride);
617 if (s->stream_end - s->stream_ptr > 1) {
618 av_log(s->avctx, AV_LOG_ERROR, " Interplay video: decode finished with %td bytes left over\n",
619 s->stream_end - s->stream_ptr);
623 static av_cold int ipvideo_decode_init(AVCodecContext *avctx)
625 IpvideoContext *s = avctx->priv_data;
629 if (s->avctx->palctrl == NULL) {
630 av_log(avctx, AV_LOG_ERROR, " Interplay video: palette expected.\n");
634 avctx->pix_fmt = PIX_FMT_PAL8;
635 dsputil_init(&s->dsp, avctx);
637 /* decoding map contains 4 bits of information per 8x8 block */
638 s->decoding_map_size = avctx->width * avctx->height / (8 * 8 * 2);
640 s->current_frame.data[0] = s->last_frame.data[0] =
641 s->second_last_frame.data[0] = NULL;
646 static int ipvideo_decode_frame(AVCodecContext *avctx,
647 void *data, int *data_size,
648 const uint8_t *buf, int buf_size)
650 IpvideoContext *s = avctx->priv_data;
651 AVPaletteControl *palette_control = avctx->palctrl;
653 /* compressed buffer needs to be large enough to at least hold an entire
655 if (buf_size < s->decoding_map_size)
658 s->decoding_map = buf;
659 s->buf = buf + s->decoding_map_size;
660 s->size = buf_size - s->decoding_map_size;
662 s->current_frame.reference = 3;
663 if (avctx->get_buffer(avctx, &s->current_frame)) {
664 av_log(avctx, AV_LOG_ERROR, " Interplay Video: get_buffer() failed\n");
668 ipvideo_decode_opcodes(s);
670 if (palette_control->palette_changed) {
671 palette_control->palette_changed = 0;
672 s->current_frame.palette_has_changed = 1;
675 *data_size = sizeof(AVFrame);
676 *(AVFrame*)data = s->current_frame;
679 if (s->second_last_frame.data[0])
680 avctx->release_buffer(avctx, &s->second_last_frame);
681 s->second_last_frame = s->last_frame;
682 s->last_frame = s->current_frame;
683 s->current_frame.data[0] = NULL; /* catch any access attempts */
685 /* report that the buffer was completely consumed */
689 static av_cold int ipvideo_decode_end(AVCodecContext *avctx)
691 IpvideoContext *s = avctx->priv_data;
693 /* release the last frame */
694 if (s->last_frame.data[0])
695 avctx->release_buffer(avctx, &s->last_frame);
696 if (s->second_last_frame.data[0])
697 avctx->release_buffer(avctx, &s->second_last_frame);
702 AVCodec interplay_video_decoder = {
705 CODEC_ID_INTERPLAY_VIDEO,
706 sizeof(IpvideoContext),
710 ipvideo_decode_frame,
712 .long_name = NULL_IF_CONFIG_SMALL("Interplay MVE video"),