/* * ScreenPressor decoder * * Copyright (c) 2017 Paul B Mahol * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "avcodec.h" #include "bytestream.h" #include "internal.h" #define TOP 0x01000000 #define BOT 0x010000 typedef struct RangeCoder { unsigned code; unsigned range; unsigned code1; } RangeCoder; typedef struct PixelModel { unsigned freq[256]; unsigned lookup[16]; unsigned total_freq; } PixelModel; typedef struct SCPRContext { AVFrame *last_frame; AVFrame *current_frame; GetByteContext gb; RangeCoder rc; PixelModel pixel_model[3][4096]; unsigned op_model[6][7]; unsigned run_model[6][257]; unsigned range_model[257]; unsigned count_model[257]; unsigned fill_model[6]; unsigned sxy_model[4][17]; unsigned mv_model[2][513]; unsigned nbx, nby; unsigned nbcount; unsigned *blocks; unsigned cbits; int cxshift; int (*get_freq)(RangeCoder *rc, unsigned total_freq, unsigned *freq); int (*decode)(GetByteContext *gb, RangeCoder *rc, unsigned cumFreq, unsigned freq, unsigned total_freq); } SCPRContext; static void init_rangecoder(RangeCoder *rc, GetByteContext *gb) { rc->code1 = 0; rc->range = 0xFFFFFFFFU; rc->code = bytestream2_get_be32(gb); } static void reinit_tables(SCPRContext *s) { int comp, i, j; for (comp = 0; comp < 3; comp++) { for (j = 0; j < 4096; j++) { if (s->pixel_model[comp][j].total_freq != 256) { for (i = 0; i < 256; i++) s->pixel_model[comp][j].freq[i] = 1; for (i = 0; i < 16; i++) s->pixel_model[comp][j].lookup[i] = 16; s->pixel_model[comp][j].total_freq = 256; } } } for (j = 0; j < 6; j++) { unsigned *p = s->run_model[j]; for (i = 0; i < 256; i++) p[i] = 1; p[256] = 256; } for (j = 0; j < 6; j++) { unsigned *op = s->op_model[j]; for (i = 0; i < 6; i++) op[i] = 1; op[6] = 6; } for (i = 0; i < 256; i++) { s->range_model[i] = 1; s->count_model[i] = 1; } s->range_model[256] = 256; s->count_model[256] = 256; for (i = 0; i < 5; i++) { s->fill_model[i] = 1; } s->fill_model[5] = 5; for (j = 0; j < 4; j++) { for (i = 0; i < 16; i++) { s->sxy_model[j][i] = 1; } s->sxy_model[j][16] = 16; } for (i = 0; i < 512; i++) { s->mv_model[0][i] = 1; s->mv_model[1][i] = 1; } s->mv_model[0][512] = 512; s->mv_model[1][512] = 512; } static int decode(GetByteContext *gb, RangeCoder *rc, unsigned cumFreq, unsigned freq, unsigned total_freq) { rc->code -= cumFreq * rc->range; rc->range *= freq; while (rc->range < TOP && bytestream2_get_bytes_left(gb) > 0) { unsigned byte = bytestream2_get_byte(gb); rc->code = (rc->code << 8) | byte; rc->range <<= 8; } return 0; } static int get_freq(RangeCoder *rc, unsigned total_freq, unsigned *freq) { if (total_freq == 0) return AVERROR_INVALIDDATA; rc->range = rc->range / total_freq; if (rc->range == 0) return AVERROR_INVALIDDATA; *freq = rc->code / rc->range; return 0; } static int decode0(GetByteContext *gb, RangeCoder *rc, unsigned cumFreq, unsigned freq, unsigned total_freq) { unsigned t; if (total_freq == 0) return AVERROR_INVALIDDATA; t = rc->range * (uint64_t)cumFreq / total_freq; rc->code1 += t + 1; rc->range = rc->range * (uint64_t)(freq + cumFreq) / total_freq - (t + 1); while (rc->range < TOP && bytestream2_get_bytes_left(gb) > 0) { unsigned byte = bytestream2_get_byte(gb); rc->code = (rc->code << 8) | byte; rc->code1 <<= 8; rc->range <<= 8; } return 0; } static int get_freq0(RangeCoder *rc, unsigned total_freq, unsigned *freq) { if (rc->range == 0) return AVERROR_INVALIDDATA; *freq = total_freq * (uint64_t)(rc->code - rc->code1) / rc->range; return 0; } static int decode_value(SCPRContext *s, unsigned *cnt, unsigned maxc, unsigned step, unsigned *rval) { GetByteContext *gb = &s->gb; RangeCoder *rc = &s->rc; unsigned totfr = cnt[maxc]; unsigned value; unsigned c = 0, cumfr = 0, cnt_c = 0; int i, ret; if ((ret = s->get_freq(rc, totfr, &value)) < 0) return ret; while (c < maxc) { cnt_c = cnt[c]; if (value >= cumfr + cnt_c) cumfr += cnt_c; else break; c++; } if ((ret = s->decode(gb, rc, cumfr, cnt_c, totfr)) < 0) return ret; cnt[c] = cnt_c + step; totfr += step; if (totfr > BOT) { totfr = 0; for (i = 0; i < maxc; i++) { unsigned nc = (cnt[i] >> 1) + 1; cnt[i] = nc; totfr += nc; } } cnt[maxc] = totfr; *rval = c; return 0; } static int decode_unit(SCPRContext *s, PixelModel *pixel, unsigned step, unsigned *rval) { GetByteContext *gb = &s->gb; RangeCoder *rc = &s->rc; unsigned totfr = pixel->total_freq; unsigned value, x = 0, cumfr = 0, cnt_x = 0; int i, j, ret, c, cnt_c; if ((ret = s->get_freq(rc, totfr, &value)) < 0) return ret; while (x < 16) { cnt_x = pixel->lookup[x]; if (value >= cumfr + cnt_x) cumfr += cnt_x; else break; x++; } c = x * 16; cnt_c = 0; while (c < 256) { cnt_c = pixel->freq[c]; if (value >= cumfr + cnt_c) cumfr += cnt_c; else break; c++; } if (x >= 16 || c >= 256) { return AVERROR_INVALIDDATA; } if ((ret = s->decode(gb, rc, cumfr, cnt_c, totfr)) < 0) return ret; pixel->freq[c] = cnt_c + step; pixel->lookup[x] = cnt_x + step; totfr += step; if (totfr > BOT) { totfr = 0; for (i = 0; i < 256; i++) { unsigned nc = (pixel->freq[i] >> 1) + 1; pixel->freq[i] = nc; totfr += nc; } for (i = 0; i < 16; i++) { unsigned sum = 0; unsigned i16_17 = i << 4; for (j = 0; j < 16; j++) sum += pixel->freq[i16_17 + j]; pixel->lookup[i] = sum; } } pixel->total_freq = totfr; *rval = c & s->cbits; return 0; } static int decompress_i(AVCodecContext *avctx, uint32_t *dst, int linesize) { SCPRContext *s = avctx->priv_data; GetByteContext *gb = &s->gb; int cx = 0, cx1 = 0, k = 0, clr = 0; int run, r, g, b, off, y = 0, x = 0, z, ret; unsigned backstep = linesize - avctx->width; const int cxshift = s->cxshift; unsigned lx, ly, ptype; reinit_tables(s); bytestream2_skip(gb, 2); init_rangecoder(&s->rc, gb); while (k < avctx->width + 1) { ret = decode_unit(s, &s->pixel_model[0][cx + cx1], 400, &r); if (ret < 0) return ret; cx1 = (cx << 6) & 0xFC0; cx = r >> cxshift; ret = decode_unit(s, &s->pixel_model[1][cx + cx1], 400, &g); if (ret < 0) return ret; cx1 = (cx << 6) & 0xFC0; cx = g >> cxshift; ret = decode_unit(s, &s->pixel_model[2][cx + cx1], 400, &b); if (ret < 0) return ret; cx1 = (cx << 6) & 0xFC0; cx = b >> cxshift; ret = decode_value(s, s->run_model[0], 256, 400, &run); if (ret < 0) return ret; clr = (b << 16) + (g << 8) + r; k += run; while (run-- > 0) { if (y >= avctx->height) return AVERROR_INVALIDDATA; dst[y * linesize + x] = clr; lx = x; ly = y; x++; if (x >= avctx->width) { x = 0; y++; } } } off = -linesize - 1; ptype = 0; while (x < avctx->width && y < avctx->height) { ret = decode_value(s, s->op_model[ptype], 6, 1000, &ptype); if (ret < 0) return ret; if (ptype == 0) { ret = decode_unit(s, &s->pixel_model[0][cx + cx1], 400, &r); if (ret < 0) return ret; cx1 = (cx << 6) & 0xFC0; cx = r >> cxshift; ret = decode_unit(s, &s->pixel_model[1][cx + cx1], 400, &g); if (ret < 0) return ret; cx1 = (cx << 6) & 0xFC0; cx = g >> cxshift; ret = decode_unit(s, &s->pixel_model[2][cx + cx1], 400, &b); if (ret < 0) return ret; clr = (b << 16) + (g << 8) + r; } if (ptype > 5) return AVERROR_INVALIDDATA; ret = decode_value(s, s->run_model[ptype], 256, 400, &run); if (ret < 0) return ret; switch (ptype) { case 0: while (run-- > 0) { if (y >= avctx->height) return AVERROR_INVALIDDATA; dst[y * linesize + x] = clr; lx = x; ly = y; x++; if (x >= avctx->width) { x = 0; y++; } } break; case 1: while (run-- > 0) { if (y >= avctx->height) return AVERROR_INVALIDDATA; dst[y * linesize + x] = dst[ly * linesize + lx]; lx = x; ly = y; x++; if (x >= avctx->width) { x = 0; y++; } } clr = dst[ly * linesize + lx]; break; case 2: while (run-- > 0) { if (y < 1 || y >= avctx->height) return AVERROR_INVALIDDATA; clr = dst[y * linesize + x + off + 1]; dst[y * linesize + x] = clr; lx = x; ly = y; x++; if (x >= avctx->width) { x = 0; y++; } } break; case 4: while (run-- > 0) { uint8_t *odst = (uint8_t *)dst; if (y < 1 || y >= avctx->height || (y == 1 && x == 0)) return AVERROR_INVALIDDATA; if (x == 0) { z = backstep; } else { z = 0; } r = odst[(ly * linesize + lx) * 4] + odst[((y * linesize + x) + off - z) * 4 + 4] - odst[((y * linesize + x) + off - z) * 4]; g = odst[(ly * linesize + lx) * 4 + 1] + odst[((y * linesize + x) + off - z) * 4 + 5] - odst[((y * linesize + x) + off - z) * 4 + 1]; b = odst[(ly * linesize + lx) * 4 + 2] + odst[((y * linesize + x) + off - z) * 4 + 6] - odst[((y * linesize + x) + off - z) * 4 + 2]; clr = ((b & 0xFF) << 16) + ((g & 0xFF) << 8) + (r & 0xFF); dst[y * linesize + x] = clr; lx = x; ly = y; x++; if (x >= avctx->width) { x = 0; y++; } } break; case 5: while (run-- > 0) { if (y < 1 || y >= avctx->height || (y == 1 && x == 0)) return AVERROR_INVALIDDATA; if (x == 0) { z = backstep; } else { z = 0; } clr = dst[y * linesize + x + off - z]; dst[y * linesize + x] = clr; lx = x; ly = y; x++; if (x >= avctx->width) { x = 0; y++; } } break; } if (avctx->bits_per_coded_sample == 16) { cx1 = (clr & 0x3F00) >> 2; cx = (clr & 0x3FFFFF) >> 16; } else { cx1 = (clr & 0xFC00) >> 4; cx = (clr & 0xFFFFFF) >> 18; } } return 0; } static int decompress_p(AVCodecContext *avctx, uint32_t *dst, int linesize, uint32_t *prev, int plinesize) { SCPRContext *s = avctx->priv_data; GetByteContext *gb = &s->gb; int ret, temp, min, max, x, y, cx = 0, cx1 = 0; int backstep = linesize - avctx->width; const int cxshift = s->cxshift; if (bytestream2_get_byte(gb) == 0) return 0; bytestream2_skip(gb, 1); init_rangecoder(&s->rc, gb); ret = decode_value(s, s->range_model, 256, 1, &min); ret |= decode_value(s, s->range_model, 256, 1, &temp); min += temp << 8; ret |= decode_value(s, s->range_model, 256, 1, &max); ret |= decode_value(s, s->range_model, 256, 1, &temp); if (ret < 0) return ret; max += temp << 8; memset(s->blocks, 0, sizeof(*s->blocks) * s->nbcount); while (min <= max) { int fill, count; ret = decode_value(s, s->fill_model, 5, 10, &fill); ret |= decode_value(s, s->count_model, 256, 20, &count); if (ret < 0) return ret; while (min < s->nbcount && count-- > 0) { s->blocks[min++] = fill; } } for (y = 0; y < s->nby; y++) { for (x = 0; x < s->nbx; x++) { int sy1 = 0, sy2 = 16, sx1 = 0, sx2 = 16; if (s->blocks[y * s->nbx + x] == 0) continue; if (((s->blocks[y * s->nbx + x] - 1) & 1) > 0) { ret = decode_value(s, s->sxy_model[0], 16, 100, &sx1); ret |= decode_value(s, s->sxy_model[1], 16, 100, &sy1); ret |= decode_value(s, s->sxy_model[2], 16, 100, &sx2); ret |= decode_value(s, s->sxy_model[3], 16, 100, &sy2); if (ret < 0) return ret; sx2++; sy2++; } if (((s->blocks[y * s->nbx + x] - 1) & 2) > 0) { int i, j, by = y * 16, bx = x * 16; int mvx, mvy; ret = decode_value(s, s->mv_model[0], 512, 100, &mvx); ret |= decode_value(s, s->mv_model[1], 512, 100, &mvy); if (ret < 0) return ret; mvx -= 256; mvy -= 256; if (by + mvy + sy1 < 0 || bx + mvx + sx1 < 0 || by + mvy + sy1 >= avctx->height || bx + mvx + sx1 >= avctx->width) return AVERROR_INVALIDDATA; for (i = 0; i < sy2 - sy1 && (by + sy1 + i) < avctx->height && (by + mvy + sy1 + i) < avctx->height; i++) { for (j = 0; j < sx2 - sx1 && (bx + sx1 + j) < avctx->width && (bx + mvx + sx1 + j) < avctx->width; j++) { dst[(by + i + sy1) * linesize + bx + sx1 + j] = prev[(by + mvy + sy1 + i) * plinesize + bx + sx1 + mvx + j]; } } } else { int run, r, g, b, z, bx = x * 16 + sx1, by = y * 16 + sy1; unsigned clr, ptype = 0; for (; by < y * 16 + sy2 && by < avctx->height;) { ret = decode_value(s, s->op_model[ptype], 6, 1000, &ptype); if (ret < 0) return ret; if (ptype == 0) { ret = decode_unit(s, &s->pixel_model[0][cx + cx1], 400, &r); if (ret < 0) return ret; cx1 = (cx << 6) & 0xFC0; cx = r >> cxshift; ret = decode_unit(s, &s->pixel_model[1][cx + cx1], 400, &g); if (ret < 0) return ret; cx1 = (cx << 6) & 0xFC0; cx = g >> cxshift; ret = decode_unit(s, &s->pixel_model[2][cx + cx1], 400, &b); if (ret < 0) return ret; clr = (b << 16) + (g << 8) + r; } if (ptype > 5) return AVERROR_INVALIDDATA; ret = decode_value(s, s->run_model[ptype], 256, 400, &run); if (ret < 0) return ret; switch (ptype) { case 0: while (run-- > 0) { if (by >= avctx->height) return AVERROR_INVALIDDATA; dst[by * linesize + bx] = clr; bx++; if (bx >= x * 16 + sx2 || bx >= avctx->width) { bx = x * 16 + sx1; by++; } } break; case 1: while (run-- > 0) { if (bx == 0) { if (by < 1) return AVERROR_INVALIDDATA; z = backstep; } else { z = 0; } if (by >= avctx->height) return AVERROR_INVALIDDATA; clr = dst[by * linesize + bx - 1 - z]; dst[by * linesize + bx] = clr; bx++; if (bx >= x * 16 + sx2 || bx >= avctx->width) { bx = x * 16 + sx1; by++; } } break; case 2: while (run-- > 0) { if (by < 1 || by >= avctx->height) return AVERROR_INVALIDDATA; clr = dst[(by - 1) * linesize + bx]; dst[by * linesize + bx] = clr; bx++; if (bx >= x * 16 + sx2 || bx >= avctx->width) { bx = x * 16 + sx1; by++; } } break; case 3: while (run-- > 0) { if (by >= avctx->height) return AVERROR_INVALIDDATA; clr = prev[by * plinesize + bx]; dst[by * linesize + bx] = clr; bx++; if (bx >= x * 16 + sx2 || bx >= avctx->width) { bx = x * 16 + sx1; by++; } } break; case 4: while (run-- > 0) { uint8_t *odst = (uint8_t *)dst; if (by < 1 || by >= avctx->height) return AVERROR_INVALIDDATA; if (bx == 0) { z = backstep; } else { z = 0; } r = odst[((by - 1) * linesize + bx) * 4] + odst[(by * linesize + bx - 1 - z) * 4] - odst[((by - 1) * linesize + bx - 1 - z) * 4]; g = odst[((by - 1) * linesize + bx) * 4 + 1] + odst[(by * linesize + bx - 1 - z) * 4 + 1] - odst[((by - 1) * linesize + bx - 1 - z) * 4 + 1]; b = odst[((by - 1) * linesize + bx) * 4 + 2] + odst[(by * linesize + bx - 1 - z) * 4 + 2] - odst[((by - 1) * linesize + bx - 1 - z) * 4 + 2]; clr = ((b & 0xFF) << 16) + ((g & 0xFF) << 8) + (r & 0xFF); dst[by * linesize + bx] = clr; bx++; if (bx >= x * 16 + sx2 || bx >= avctx->width) { bx = x * 16 + sx1; by++; } } break; case 5: while (run-- > 0) { if (by < 1 || by >= avctx->height) return AVERROR_INVALIDDATA; if (bx == 0) { z = backstep; } else { z = 0; } clr = dst[(by - 1) * linesize + bx - 1 - z]; dst[by * linesize + bx] = clr; bx++; if (bx >= x * 16 + sx2 || bx >= avctx->width) { bx = x * 16 + sx1; by++; } } break; } if (avctx->bits_per_coded_sample == 16) { cx1 = (clr & 0x3F00) >> 2; cx = (clr & 0x3FFFFF) >> 16; } else { cx1 = (clr & 0xFC00) >> 4; cx = (clr & 0xFFFFFF) >> 18; } } } } } return 0; } static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { SCPRContext *s = avctx->priv_data; GetByteContext *gb = &s->gb; AVFrame *frame = data; int ret, type; if (avctx->bits_per_coded_sample == 16) { if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) return ret; } if ((ret = ff_reget_buffer(avctx, s->current_frame)) < 0) return ret; bytestream2_init(gb, avpkt->data, avpkt->size); type = bytestream2_peek_byte(gb); if (type == 2) { s->get_freq = get_freq0; s->decode = decode0; frame->key_frame = 1; ret = decompress_i(avctx, (uint32_t *)s->current_frame->data[0], s->current_frame->linesize[0] / 4); } else if (type == 18) { s->get_freq = get_freq; s->decode = decode; frame->key_frame = 1; ret = decompress_i(avctx, (uint32_t *)s->current_frame->data[0], s->current_frame->linesize[0] / 4); } else if (type == 17) { uint32_t clr, *dst = (uint32_t *)s->current_frame->data[0]; int x, y; frame->key_frame = 1; bytestream2_skip(gb, 1); if (avctx->bits_per_coded_sample == 16) { uint16_t value = bytestream2_get_le16(gb); int r, g, b; r = (value ) & 31; g = (value >> 5) & 31; b = (value >> 10) & 31; clr = (r << 16) + (g << 8) + b; } else { clr = bytestream2_get_le24(gb); } for (y = 0; y < avctx->height; y++) { for (x = 0; x < avctx->width; x++) { dst[x] = clr; } dst += s->current_frame->linesize[0] / 4; } } else if (type == 0 || type == 1) { frame->key_frame = 0; ret = av_frame_copy(s->current_frame, s->last_frame); if (ret < 0) return ret; ret = decompress_p(avctx, (uint32_t *)s->current_frame->data[0], s->current_frame->linesize[0] / 4, (uint32_t *)s->last_frame->data[0], s->last_frame->linesize[0] / 4); } else { return AVERROR_PATCHWELCOME; } if (ret < 0) return ret; if (avctx->bits_per_coded_sample != 16) { ret = av_frame_ref(data, s->current_frame); if (ret < 0) return ret; } else { uint8_t *dst = frame->data[0]; int x, y; ret = av_frame_copy(frame, s->current_frame); if (ret < 0) return ret; // scale up each sample by 8 for (y = 0; y < avctx->height; y++) { // If the image is sufficiently aligned, compute 8 samples at once if (!(((uintptr_t)dst) & 7)) { uint64_t *dst64 = (uint64_t *)dst; int w = avctx->width>>1; for (x = 0; x < w; x++) { dst64[x] = (dst64[x] << 3) & 0xFCFCFCFCFCFCFCFCULL; } x *= 8; } else x = 0; for (; x < avctx->width * 4; x++) { dst[x] = dst[x] << 3; } dst += frame->linesize[0]; } } frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P; FFSWAP(AVFrame *, s->current_frame, s->last_frame); frame->data[0] += frame->linesize[0] * (avctx->height - 1); frame->linesize[0] *= -1; *got_frame = 1; return avpkt->size; } static av_cold int decode_init(AVCodecContext *avctx) { SCPRContext *s = avctx->priv_data; switch (avctx->bits_per_coded_sample) { case 16: avctx->pix_fmt = AV_PIX_FMT_RGB0; break; case 24: case 32: avctx->pix_fmt = AV_PIX_FMT_BGR0; break; default: av_log(avctx, AV_LOG_ERROR, "Unsupported bitdepth %i\n", avctx->bits_per_coded_sample); return AVERROR_INVALIDDATA; } s->get_freq = get_freq0; s->decode = decode0; s->cxshift = avctx->bits_per_coded_sample == 16 ? 0 : 2; s->cbits = avctx->bits_per_coded_sample == 16 ? 0x1F : 0xFF; s->nbx = (avctx->width + 15) / 16; s->nby = (avctx->height + 15) / 16; s->nbcount = s->nbx * s->nby; s->blocks = av_malloc_array(s->nbcount, sizeof(*s->blocks)); if (!s->blocks) return AVERROR(ENOMEM); s->last_frame = av_frame_alloc(); s->current_frame = av_frame_alloc(); if (!s->last_frame || !s->current_frame) return AVERROR(ENOMEM); return 0; } static av_cold int decode_close(AVCodecContext *avctx) { SCPRContext *s = avctx->priv_data; av_freep(&s->blocks); av_frame_free(&s->last_frame); av_frame_free(&s->current_frame); return 0; } AVCodec ff_scpr_decoder = { .name = "scpr", .long_name = NULL_IF_CONFIG_SMALL("ScreenPressor"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_SCPR, .priv_data_size = sizeof(SCPRContext), .init = decode_init, .close = decode_close, .decode = decode_frame, .capabilities = AV_CODEC_CAP_DR1, .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP, };