2 * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder
26 #include "libavutil/avassert.h"
27 #include "error_resilience.h"
37 typedef struct MSS2Context {
47 static void arith2_normalise(ArithCoder *c)
49 while ((c->high >> 15) - (c->low >> 15) < 2) {
50 if ((c->low ^ c->high) & 0x10000) {
55 c->high = (uint16_t)c->high << 8 | 0xFF;
56 c->value = (uint16_t)c->value << 8 | bytestream2_get_byte(c->gbc.gB);
57 c->low = (uint16_t)c->low << 8;
63 /* L. Stuiver and A. Moffat: "Piecewise Integer Mapping for Arithmetic Coding."
64 * In Proc. 8th Data Compression Conference (DCC '98), pp. 3-12, Mar. 1998 */
66 static int arith2_get_scaled_value(int value, int n, int range)
68 int split = (n << 1) - range;
71 return split + (value - split >> 1);
76 static void arith2_rescale_interval(ArithCoder *c, int range,
77 int low, int high, int n)
79 int split = (n << 1) - range;
82 c->high = split + (high - split << 1);
86 c->high += c->low - 1;
89 c->low += split + (low - split << 1);
94 static int arith2_get_number(ArithCoder *c, int n)
96 int range = c->high - c->low + 1;
97 int scale = av_log2(range) - av_log2(n);
100 if (n << scale > range)
105 val = arith2_get_scaled_value(c->value - c->low, n, range) >> scale;
107 arith2_rescale_interval(c, range, val << scale, (val + 1) << scale, n);
114 static int arith2_get_prob(ArithCoder *c, int16_t *probs)
116 int range = c->high - c->low + 1, n = *probs;
117 int scale = av_log2(range) - av_log2(n);
120 if (n << scale > range)
125 val = arith2_get_scaled_value(c->value - c->low, n, range) >> scale;
126 while (probs[++i] > val) ;
128 arith2_rescale_interval(c, range,
129 probs[i] << scale, probs[i - 1] << scale, n);
134 ARITH_GET_MODEL_SYM(arith2)
136 static int arith2_get_consumed_bytes(ArithCoder *c)
138 int diff = (c->high >> 16) - (c->low >> 16);
139 int bp = bytestream2_tell(c->gbc.gB) - 3 << 3;
142 while (!(diff & 0x80)) {
147 return (bits + bp + 7 >> 3) + ((c->low >> 16) + 1 == c->high >> 16);
150 static void arith2_init(ArithCoder *c, GetByteContext *gB)
154 c->value = bytestream2_get_be24(gB);
157 c->get_model_sym = arith2_get_model_sym;
158 c->get_number = arith2_get_number;
161 static int decode_pal_v2(MSS12Context *ctx, const uint8_t *buf, int buf_size)
164 uint32_t *pal = ctx->pal + 256 - ctx->free_colours;
166 if (!ctx->free_colours)
170 if (ncol > ctx->free_colours || buf_size < 2 + ncol * 3)
171 return AVERROR_INVALIDDATA;
172 for (i = 0; i < ncol; i++)
173 *pal++ = AV_RB24(buf + 3 * i);
178 static int decode_555(AVCodecContext *avctx, GetByteContext *gB, uint16_t *dst, ptrdiff_t stride,
179 int keyframe, int w, int h)
181 int last_symbol = 0, repeat = 0, prev_avail = 0;
184 int x, y, endx, endy, t;
186 #define READ_PAIR(a, b) \
187 a = bytestream2_get_byte(gB) << 4; \
188 t = bytestream2_get_byte(gB); \
190 b = (t & 0xF) << 8; \
191 b |= bytestream2_get_byte(gB); \
196 if (endx >= w || endy >= h || x > endx || y > endy)
197 return AVERROR_INVALIDDATA;
198 dst += x + stride * y;
209 int b = bytestream2_get_byte(gB);
211 last_symbol = b << 8 | bytestream2_get_byte(gB);
215 if (repeat >= (INT_MAX >> 8) - 1) {
216 av_log(avctx, AV_LOG_ERROR, "repeat overflow\n");
217 return AVERROR_INVALIDDATA;
219 repeat = (repeat << 8) + bytestream2_get_byte(gB) + 1;
221 if (last_symbol == -2) {
222 int skip = FFMIN((unsigned)repeat, dst + w - p);
227 last_symbol = 127 - b;
229 if (last_symbol >= 0)
231 else if (last_symbol == -1 && prev_avail)
233 } while (++p < dst + w);
241 static int decode_rle(GetBitContext *gb, uint8_t *pal_dst, ptrdiff_t pal_stride,
242 uint8_t *rgb_dst, ptrdiff_t rgb_stride, uint32_t *pal,
243 int keyframe, int kf_slipt, int slice, int w, int h)
245 uint8_t bits[270] = { 0 };
249 int current_length = 0, read_codes = 0, next_code = 0, current_codes = 0;
250 int remaining_codes, surplus_codes, i;
252 const int alphabet_size = 270 - keyframe;
254 int last_symbol = 0, repeat = 0, prev_avail = 0;
257 int x, y, clipw, cliph;
259 x = get_bits(gb, 12);
260 y = get_bits(gb, 12);
261 clipw = get_bits(gb, 12) + 1;
262 cliph = get_bits(gb, 12) + 1;
264 if (x + clipw > w || y + cliph > h)
265 return AVERROR_INVALIDDATA;
266 pal_dst += pal_stride * y + x;
267 rgb_dst += rgb_stride * y + x * 3;
274 pal_dst += pal_stride * kf_slipt;
275 rgb_dst += rgb_stride * kf_slipt;
282 /* read explicit codes */
284 while (current_codes--) {
285 int symbol = get_bits(gb, 8);
286 if (symbol >= 204 - keyframe)
287 symbol += 14 - keyframe;
288 else if (symbol > 189)
289 symbol = get_bits1(gb) + (symbol << 1) - 190;
291 return AVERROR_INVALIDDATA;
292 bits[symbol] = current_length;
293 codes[symbol] = next_code++;
298 remaining_codes = (1 << current_length) - next_code;
299 current_codes = get_bits(gb, av_ceil_log2(remaining_codes + 1));
300 if (current_length > 22 || current_codes > remaining_codes)
301 return AVERROR_INVALIDDATA;
302 } while (current_codes != remaining_codes);
304 remaining_codes = alphabet_size - read_codes;
306 /* determine the minimum length to fit the rest of the alphabet */
307 while ((surplus_codes = (2 << current_length) -
308 (next_code << 1) - remaining_codes) < 0) {
313 /* add the rest of the symbols lexicographically */
314 for (i = 0; i < alphabet_size; i++)
316 if (surplus_codes-- == 0) {
320 bits[i] = current_length;
321 codes[i] = next_code++;
324 if (next_code != 1 << current_length)
325 return AVERROR_INVALIDDATA;
327 if ((i = init_vlc(&vlc, 9, alphabet_size, bits, 1, 1, codes, 4, 4, 0)) < 0)
332 uint8_t *pp = pal_dst;
333 uint8_t *rp = rgb_dst;
336 int b = get_vlc2(gb, vlc.table, 9, 3);
342 b = get_bits(gb, 4) + 10;
347 repeat = get_bits(gb, b);
349 repeat += (1 << b) - 1;
351 if (last_symbol == -2) {
352 int skip = FFMIN(repeat, pal_dst + w - pp);
358 last_symbol = 267 - b;
360 if (last_symbol >= 0) {
362 AV_WB24(rp, pal[last_symbol]);
363 } else if (last_symbol == -1 && prev_avail) {
364 *pp = *(pp - pal_stride);
365 memcpy(rp, rp - rgb_stride, 3);
368 } while (++pp < pal_dst + w);
369 pal_dst += pal_stride;
370 rgb_dst += rgb_stride;
378 static int decode_wmv9(AVCodecContext *avctx, const uint8_t *buf, int buf_size,
379 int x, int y, int w, int h, int wmv9_mask)
381 MSS2Context *ctx = avctx->priv_data;
382 MSS12Context *c = &ctx->c;
383 VC1Context *v = avctx->priv_data;
384 MpegEncContext *s = &v->s;
388 ff_mpeg_flush(avctx);
390 if ((ret = init_get_bits8(&s->gb, buf, buf_size)) < 0)
393 s->loop_filter = avctx->skip_loop_filter < AVDISCARD_ALL;
395 if (ff_vc1_parse_frame_header(v, &s->gb) < 0) {
396 av_log(v->s.avctx, AV_LOG_ERROR, "header error\n");
397 return AVERROR_INVALIDDATA;
400 if (s->pict_type != AV_PICTURE_TYPE_I) {
401 av_log(v->s.avctx, AV_LOG_ERROR, "expected I-frame\n");
402 return AVERROR_INVALIDDATA;
405 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
407 if ((ret = ff_mpv_frame_start(s, avctx)) < 0) {
408 av_log(v->s.avctx, AV_LOG_ERROR, "ff_mpv_frame_start error\n");
409 avctx->pix_fmt = AV_PIX_FMT_RGB24;
413 ff_mpeg_er_frame_start(s);
415 v->bits = buf_size * 8;
417 v->end_mb_x = (w + 15) >> 4;
418 s->end_mb_y = (h + 15) >> 4;
420 v->end_mb_x = v->end_mb_x + 1 >> 1;
422 s->end_mb_y = s->end_mb_y + 1 >> 1;
424 ff_vc1_decode_blocks(v);
426 if (v->end_mb_x == s->mb_width && s->end_mb_y == s->mb_height) {
427 ff_er_frame_end(&s->er);
429 av_log(v->s.avctx, AV_LOG_WARNING,
430 "disabling error correction due to block count mismatch %dx%d != %dx%d\n",
431 v->end_mb_x, s->end_mb_y, s->mb_width, s->mb_height);
436 f = s->current_picture.f;
438 if (v->respic == 3) {
439 ctx->dsp.upsample_plane(f->data[0], f->linesize[0], w, h);
440 ctx->dsp.upsample_plane(f->data[1], f->linesize[1], w+1 >> 1, h+1 >> 1);
441 ctx->dsp.upsample_plane(f->data[2], f->linesize[2], w+1 >> 1, h+1 >> 1);
442 } else if (v->respic)
443 avpriv_request_sample(v->s.avctx,
444 "Asymmetric WMV9 rectangle subsampling");
446 av_assert0(f->linesize[1] == f->linesize[2]);
449 ctx->dsp.mss2_blit_wmv9_masked(c->rgb_pic + y * c->rgb_stride + x * 3,
450 c->rgb_stride, wmv9_mask,
451 c->pal_pic + y * c->pal_stride + x,
453 f->data[0], f->linesize[0],
454 f->data[1], f->data[2], f->linesize[1],
457 ctx->dsp.mss2_blit_wmv9(c->rgb_pic + y * c->rgb_stride + x * 3,
459 f->data[0], f->linesize[0],
460 f->data[1], f->data[2], f->linesize[1],
463 avctx->pix_fmt = AV_PIX_FMT_RGB24;
469 int coded, x, y, w, h;
472 #define MAX_WMV9_RECTANGLES 20
473 #define ARITH2_PADDING 2
475 static int mss2_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
478 const uint8_t *buf = avpkt->data;
479 int buf_size = avpkt->size;
480 MSS2Context *ctx = avctx->priv_data;
481 MSS12Context *c = &ctx->c;
482 AVFrame *frame = data;
487 int keyframe, has_wmv9, has_mv, is_rle, is_555, ret;
489 struct Rectangle wmv9rects[MAX_WMV9_RECTANGLES], *r;
490 int used_rects = 0, i, implicit_rect = 0, av_uninit(wmv9_mask);
492 if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
495 if (keyframe = get_bits1(&gb))
497 has_wmv9 = get_bits1(&gb);
498 has_mv = keyframe ? 0 : get_bits1(&gb);
499 is_rle = get_bits1(&gb);
500 is_555 = is_rle && get_bits1(&gb);
501 if (c->slice_split > 0)
502 ctx->split_position = c->slice_split;
503 else if (c->slice_split < 0) {
504 if (get_bits1(&gb)) {
505 if (get_bits1(&gb)) {
507 ctx->split_position = get_bits(&gb, 16);
509 ctx->split_position = get_bits(&gb, 12);
511 ctx->split_position = get_bits(&gb, 8) << 4;
514 ctx->split_position = avctx->height / 2;
517 ctx->split_position = avctx->height;
519 if (c->slice_split && (ctx->split_position < 1 - is_555 ||
520 ctx->split_position > avctx->height - 1))
521 return AVERROR_INVALIDDATA;
524 buf += get_bits_count(&gb) >> 3;
525 buf_size -= get_bits_count(&gb) >> 3;
528 return AVERROR_INVALIDDATA;
530 if (is_555 && (has_wmv9 || has_mv || c->slice_split && ctx->split_position))
531 return AVERROR_INVALIDDATA;
533 avctx->pix_fmt = is_555 ? AV_PIX_FMT_RGB555 : AV_PIX_FMT_RGB24;
534 if (ctx->last_pic->format != avctx->pix_fmt)
535 av_frame_unref(ctx->last_pic);
538 bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
539 arith2_init(&acoder, &gB);
541 implicit_rect = !arith2_get_bit(&acoder);
543 while (arith2_get_bit(&acoder)) {
544 if (used_rects == MAX_WMV9_RECTANGLES)
545 return AVERROR_INVALIDDATA;
546 r = &wmv9rects[used_rects];
548 r->x = arith2_get_number(&acoder, avctx->width);
550 r->x = arith2_get_number(&acoder, avctx->width -
551 wmv9rects[used_rects - 1].x) +
552 wmv9rects[used_rects - 1].x;
553 r->y = arith2_get_number(&acoder, avctx->height);
554 r->w = arith2_get_number(&acoder, avctx->width - r->x) + 1;
555 r->h = arith2_get_number(&acoder, avctx->height - r->y) + 1;
559 if (implicit_rect && used_rects) {
560 av_log(avctx, AV_LOG_ERROR, "implicit_rect && used_rects > 0\n");
561 return AVERROR_INVALIDDATA;
567 wmv9rects[0].w = avctx->width;
568 wmv9rects[0].h = avctx->height;
572 for (i = 0; i < used_rects; i++) {
573 if (!implicit_rect && arith2_get_bit(&acoder)) {
574 av_log(avctx, AV_LOG_ERROR, "Unexpected grandchildren\n");
575 return AVERROR_INVALIDDATA;
578 wmv9_mask = arith2_get_bit(&acoder) - 1;
580 wmv9_mask = arith2_get_number(&acoder, 256);
582 wmv9rects[i].coded = arith2_get_number(&acoder, 2);
585 buf += arith2_get_consumed_bytes(&acoder);
586 buf_size -= arith2_get_consumed_bytes(&acoder);
588 return AVERROR_INVALIDDATA;
592 if (keyframe && !is_555) {
593 if ((i = decode_pal_v2(c, buf, buf_size)) < 0)
594 return AVERROR_INVALIDDATA;
601 return AVERROR_INVALIDDATA;
602 c->mvX = AV_RB16(buf - 4) - avctx->width;
603 c->mvY = AV_RB16(buf - 2) - avctx->height;
606 if (c->mvX < 0 || c->mvY < 0) {
607 FFSWAP(uint8_t *, c->pal_pic, c->last_pal_pic);
609 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
612 if (ctx->last_pic->data[0]) {
613 av_assert0(frame->linesize[0] == ctx->last_pic->linesize[0]);
614 c->last_rgb_pic = ctx->last_pic->data[0] +
615 ctx->last_pic->linesize[0] * (avctx->height - 1);
617 av_log(avctx, AV_LOG_ERROR, "Missing keyframe\n");
618 return AVERROR_INVALIDDATA;
621 if ((ret = ff_reget_buffer(avctx, ctx->last_pic, 0)) < 0)
623 if ((ret = av_frame_ref(frame, ctx->last_pic)) < 0)
626 c->last_rgb_pic = NULL;
628 c->rgb_pic = frame->data[0] +
629 frame->linesize[0] * (avctx->height - 1);
630 c->rgb_stride = -frame->linesize[0];
632 frame->key_frame = keyframe;
633 frame->pict_type = keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
636 bytestream2_init(&gB, buf, buf_size);
638 if (decode_555(avctx, &gB, (uint16_t *)c->rgb_pic, c->rgb_stride >> 1,
639 keyframe, avctx->width, avctx->height))
640 return AVERROR_INVALIDDATA;
642 buf_size -= bytestream2_tell(&gB);
646 ff_mss12_slicecontext_reset(&ctx->sc[0]);
648 ff_mss12_slicecontext_reset(&ctx->sc[1]);
651 if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
653 if (ret = decode_rle(&gb, c->pal_pic, c->pal_stride,
654 c->rgb_pic, c->rgb_stride, c->pal, keyframe,
655 ctx->split_position, 0,
656 avctx->width, avctx->height))
661 if (ret = decode_rle(&gb, c->pal_pic, c->pal_stride,
662 c->rgb_pic, c->rgb_stride, c->pal, keyframe,
663 ctx->split_position, 1,
664 avctx->width, avctx->height))
668 buf += get_bits_count(&gb) >> 3;
669 buf_size -= get_bits_count(&gb) >> 3;
670 } else if (!implicit_rect || wmv9_mask != -1) {
672 return AVERROR_INVALIDDATA;
673 bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
674 arith2_init(&acoder, &gB);
675 c->keyframe = keyframe;
676 if (c->corrupted = ff_mss12_decode_rect(&ctx->sc[0], &acoder, 0, 0,
678 ctx->split_position))
679 return AVERROR_INVALIDDATA;
681 buf += arith2_get_consumed_bytes(&acoder);
682 buf_size -= arith2_get_consumed_bytes(&acoder);
683 if (c->slice_split) {
685 return AVERROR_INVALIDDATA;
686 bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
687 arith2_init(&acoder, &gB);
688 if (c->corrupted = ff_mss12_decode_rect(&ctx->sc[1], &acoder, 0,
691 avctx->height - ctx->split_position))
692 return AVERROR_INVALIDDATA;
694 buf += arith2_get_consumed_bytes(&acoder);
695 buf_size -= arith2_get_consumed_bytes(&acoder);
698 memset(c->pal_pic, 0, c->pal_stride * avctx->height);
702 for (i = 0; i < used_rects; i++) {
703 int x = wmv9rects[i].x;
704 int y = wmv9rects[i].y;
705 int w = wmv9rects[i].w;
706 int h = wmv9rects[i].h;
707 if (wmv9rects[i].coded) {
708 int WMV9codedFrameSize;
709 if (buf_size < 4 || !(WMV9codedFrameSize = AV_RL24(buf)))
710 return AVERROR_INVALIDDATA;
711 if (ret = decode_wmv9(avctx, buf + 3, buf_size - 3,
712 x, y, w, h, wmv9_mask))
714 buf += WMV9codedFrameSize + 3;
715 buf_size -= WMV9codedFrameSize + 3;
717 uint8_t *dst = c->rgb_pic + y * c->rgb_stride + x * 3;
718 if (wmv9_mask != -1) {
719 ctx->dsp.mss2_gray_fill_masked(dst, c->rgb_stride,
721 c->pal_pic + y * c->pal_stride + x,
726 memset(dst, 0x80, w * 3);
727 dst += c->rgb_stride;
735 av_log(avctx, AV_LOG_WARNING, "buffer not fully consumed\n");
737 if (c->mvX < 0 || c->mvY < 0) {
738 av_frame_unref(ctx->last_pic);
739 ret = av_frame_ref(ctx->last_pic, frame);
749 static av_cold int wmv9_init(AVCodecContext *avctx)
751 VC1Context *v = avctx->priv_data;
756 if ((ret = ff_vc1_init_common(v)) < 0)
758 ff_vc1dsp_init(&v->vc1dsp);
760 v->profile = PROFILE_MAIN;
762 v->zz_8x4 = ff_wmv2_scantableA;
763 v->zz_4x8 = ff_wmv2_scantableB;
767 v->frmrtq_postproc = 7;
768 v->bitrtq_postproc = 31;
785 v->resync_marker = 0;
788 v->s.max_b_frames = avctx->max_b_frames = 0;
789 v->quantizer_mode = 0;
795 ff_vc1_init_transposed_scantables(v);
797 if ((ret = ff_msmpeg4_decode_init(avctx)) < 0 ||
798 (ret = ff_vc1_decode_init_alloc_tables(v)) < 0)
801 /* error concealment */
802 v->s.me.qpel_put = v->s.qdsp.put_qpel_pixels_tab;
803 v->s.me.qpel_avg = v->s.qdsp.avg_qpel_pixels_tab;
808 static av_cold int mss2_decode_end(AVCodecContext *avctx)
810 MSS2Context *const ctx = avctx->priv_data;
812 av_frame_free(&ctx->last_pic);
814 ff_mss12_decode_end(&ctx->c);
815 av_freep(&ctx->c.pal_pic);
816 av_freep(&ctx->c.last_pal_pic);
817 ff_vc1_decode_end(avctx);
822 static av_cold int mss2_decode_init(AVCodecContext *avctx)
824 MSS2Context * const ctx = avctx->priv_data;
825 MSS12Context *c = &ctx->c;
828 if (ret = ff_mss12_decode_init(c, 1, &ctx->sc[0], &ctx->sc[1]))
830 ctx->last_pic = av_frame_alloc();
831 c->pal_stride = c->mask_stride;
832 c->pal_pic = av_mallocz(c->pal_stride * avctx->height);
833 c->last_pal_pic = av_mallocz(c->pal_stride * avctx->height);
834 if (!c->pal_pic || !c->last_pal_pic || !ctx->last_pic) {
835 mss2_decode_end(avctx);
836 return AVERROR(ENOMEM);
838 if (ret = wmv9_init(avctx)) {
839 mss2_decode_end(avctx);
842 ff_mss2dsp_init(&ctx->dsp);
843 ff_qpeldsp_init(&ctx->qdsp);
845 avctx->pix_fmt = c->free_colours == 127 ? AV_PIX_FMT_RGB555
852 AVCodec ff_mss2_decoder = {
854 .long_name = NULL_IF_CONFIG_SMALL("MS Windows Media Video V9 Screen"),
855 .type = AVMEDIA_TYPE_VIDEO,
856 .id = AV_CODEC_ID_MSS2,
857 .priv_data_size = sizeof(MSS2Context),
858 .init = mss2_decode_init,
859 .close = mss2_decode_end,
860 .decode = mss2_decode_frame,
861 .capabilities = AV_CODEC_CAP_DR1,