388 lines
12 KiB
C
388 lines
12 KiB
C
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/*
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* CD Graphics Video Decoder
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* Copyright (c) 2009 Michael Tison
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "bytestream.h"
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#include "internal.h"
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/**
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* @file
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* @brief CD Graphics Video Decoder
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* @author Michael Tison
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* @see http://wiki.multimedia.cx/index.php?title=CD_Graphics
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* @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
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*/
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/// default screen sizes
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#define CDG_FULL_WIDTH 300
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#define CDG_FULL_HEIGHT 216
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#define CDG_DISPLAY_WIDTH 294
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#define CDG_DISPLAY_HEIGHT 204
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#define CDG_BORDER_WIDTH 6
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#define CDG_BORDER_HEIGHT 12
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/// masks
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#define CDG_COMMAND 0x09
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#define CDG_MASK 0x3F
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/// instruction codes
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#define CDG_INST_MEMORY_PRESET 1
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#define CDG_INST_BORDER_PRESET 2
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#define CDG_INST_TILE_BLOCK 6
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#define CDG_INST_SCROLL_PRESET 20
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#define CDG_INST_SCROLL_COPY 24
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#define CDG_INST_TRANSPARENT_COL 28
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#define CDG_INST_LOAD_PAL_LO 30
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#define CDG_INST_LOAD_PAL_HIGH 31
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#define CDG_INST_TILE_BLOCK_XOR 38
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/// data sizes
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#define CDG_PACKET_SIZE 24
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#define CDG_DATA_SIZE 16
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#define CDG_TILE_HEIGHT 12
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#define CDG_TILE_WIDTH 6
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#define CDG_MINIMUM_PKT_SIZE 6
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#define CDG_MINIMUM_SCROLL_SIZE 3
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#define CDG_HEADER_SIZE 8
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#define CDG_PALETTE_SIZE 16
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typedef struct CDGraphicsContext {
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AVFrame *frame;
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int hscroll;
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int vscroll;
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int transparency;
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int cleared;
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} CDGraphicsContext;
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static av_cold int cdg_decode_init(AVCodecContext *avctx)
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{
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CDGraphicsContext *cc = avctx->priv_data;
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cc->frame = av_frame_alloc();
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if (!cc->frame)
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return AVERROR(ENOMEM);
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cc->transparency = -1;
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avctx->pix_fmt = AV_PIX_FMT_PAL8;
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return ff_set_dimensions(avctx, CDG_FULL_WIDTH, CDG_FULL_HEIGHT);
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}
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static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
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{
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int y;
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int lsize = cc->frame->linesize[0];
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uint8_t *buf = cc->frame->data[0];
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int color = data[0] & 0x0F;
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if (!(data[1] & 0x0F)) {
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/// fill the top and bottom borders
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memset(buf, color, CDG_BORDER_HEIGHT * lsize);
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memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
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color, CDG_BORDER_HEIGHT * lsize);
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/// fill the side borders
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for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
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memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
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memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
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color, CDG_BORDER_WIDTH);
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}
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}
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}
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static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
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{
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uint8_t r, g, b;
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uint16_t color;
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int i;
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int array_offset = low ? 0 : 8;
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uint32_t *palette = (uint32_t *) cc->frame->data[1];
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for (i = 0; i < 8; i++) {
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color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
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r = ((color >> 8) & 0x000F) * 17;
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g = ((color >> 4) & 0x000F) * 17;
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b = ((color ) & 0x000F) * 17;
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palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b;
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if (cc->transparency >= 0)
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palette[cc->transparency] &= 0xFFFFFF;
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}
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cc->frame->palette_has_changed = 1;
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}
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static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
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{
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unsigned ci, ri;
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int color;
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int x, y;
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int ai;
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int stride = cc->frame->linesize[0];
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uint8_t *buf = cc->frame->data[0];
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ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
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ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll;
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if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
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return AVERROR(EINVAL);
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if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
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return AVERROR(EINVAL);
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for (y = 0; y < CDG_TILE_HEIGHT; y++) {
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for (x = 0; x < CDG_TILE_WIDTH; x++) {
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if (!((data[4 + y] >> (5 - x)) & 0x01))
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color = data[0] & 0x0F;
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else
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color = data[1] & 0x0F;
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ai = ci + x + (stride * (ri + y));
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if (b)
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color ^= buf[ai];
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buf[ai] = color;
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}
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}
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return 0;
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}
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#define UP 2
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#define DOWN 1
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#define LEFT 2
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#define RIGHT 1
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static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
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int in_tl_x, int in_tl_y, uint8_t *in,
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int w, int h, int stride)
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{
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int y;
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in += in_tl_x + in_tl_y * stride;
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out += out_tl_x + out_tl_y * stride;
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for (y = 0; y < h; y++)
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memcpy(out + y * stride, in + y * stride, w);
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}
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static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
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int color, int w, int h, int stride)
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{
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int y;
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for (y = tl_y; y < tl_y + h; y++)
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memset(out + tl_x + y * stride, color, w);
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}
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static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
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int in_tl_x, int in_tl_y, uint8_t *in,
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int color, int w, int h, int stride, int roll)
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{
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if (roll) {
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cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
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in, w, h, stride);
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} else {
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cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
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}
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}
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static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
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AVFrame *new_frame, int roll_over)
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{
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int color;
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int hscmd, h_off, hinc, vscmd, v_off, vinc;
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int y;
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int stride = cc->frame->linesize[0];
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uint8_t *in = cc->frame->data[0];
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uint8_t *out = new_frame->data[0];
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color = data[0] & 0x0F;
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hscmd = (data[1] & 0x30) >> 4;
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vscmd = (data[2] & 0x30) >> 4;
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h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1);
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v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
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/// find the difference and save the offset for cdg_tile_block usage
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hinc = h_off - cc->hscroll;
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vinc = v_off - cc->vscroll;
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cc->hscroll = h_off;
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cc->vscroll = v_off;
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if (vscmd == UP)
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vinc -= 12;
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if (vscmd == DOWN)
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vinc += 12;
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if (hscmd == LEFT)
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hinc -= 6;
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if (hscmd == RIGHT)
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hinc += 6;
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if (!hinc && !vinc)
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return;
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memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4);
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for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
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memcpy(out + FFMAX(0, hinc) + stride * y,
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in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
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FFMIN(stride + hinc, stride));
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if (vinc > 0)
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cdg_fill_wrapper(0, 0, out,
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0, CDG_FULL_HEIGHT - vinc, in, color,
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stride, vinc, stride, roll_over);
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else if (vinc < 0)
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cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
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0, 0, in, color,
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stride, -1 * vinc, stride, roll_over);
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if (hinc > 0)
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cdg_fill_wrapper(0, 0, out,
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CDG_FULL_WIDTH - hinc, 0, in, color,
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hinc, CDG_FULL_HEIGHT, stride, roll_over);
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else if (hinc < 0)
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cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
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0, 0, in, color,
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-1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
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}
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static int cdg_decode_frame(AVCodecContext *avctx,
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void *data, int *got_frame, AVPacket *avpkt)
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{
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GetByteContext gb;
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int buf_size = avpkt->size;
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int ret;
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uint8_t command, inst;
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uint8_t cdg_data[CDG_DATA_SIZE] = {0};
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AVFrame *frame = data;
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CDGraphicsContext *cc = avctx->priv_data;
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if (buf_size < CDG_MINIMUM_PKT_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
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return AVERROR(EINVAL);
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}
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if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n");
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return AVERROR(EINVAL);
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}
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bytestream2_init(&gb, avpkt->data, avpkt->size);
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if ((ret = ff_reget_buffer(avctx, cc->frame, 0)) < 0)
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return ret;
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if (!cc->cleared) {
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memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height);
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memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
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cc->cleared = 1;
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}
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command = bytestream2_get_byte(&gb);
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inst = bytestream2_get_byte(&gb);
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inst &= CDG_MASK;
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bytestream2_skip(&gb, 2);
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bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data));
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if ((command & CDG_MASK) == CDG_COMMAND) {
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switch (inst) {
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case CDG_INST_MEMORY_PRESET:
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if (!(cdg_data[1] & 0x0F))
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memset(cc->frame->data[0], cdg_data[0] & 0x0F,
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cc->frame->linesize[0] * CDG_FULL_HEIGHT);
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break;
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case CDG_INST_LOAD_PAL_LO:
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case CDG_INST_LOAD_PAL_HIGH:
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if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
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return AVERROR(EINVAL);
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}
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cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
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break;
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case CDG_INST_BORDER_PRESET:
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cdg_border_preset(cc, cdg_data);
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break;
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case CDG_INST_TILE_BLOCK_XOR:
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case CDG_INST_TILE_BLOCK:
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if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
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return AVERROR(EINVAL);
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}
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ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
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if (ret) {
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av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
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return ret;
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}
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break;
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case CDG_INST_SCROLL_PRESET:
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case CDG_INST_SCROLL_COPY:
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if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
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return AVERROR(EINVAL);
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}
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if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
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return ret;
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cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY);
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av_frame_unref(cc->frame);
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ret = av_frame_ref(cc->frame, frame);
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||
|
|
if (ret < 0)
|
||
|
|
return ret;
|
||
|
|
break;
|
||
|
|
case CDG_INST_TRANSPARENT_COL:
|
||
|
|
cc->transparency = cdg_data[0] & 0xF;
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!frame->data[0]) {
|
||
|
|
ret = av_frame_ref(frame, cc->frame);
|
||
|
|
if (ret < 0)
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
*got_frame = 1;
|
||
|
|
} else {
|
||
|
|
*got_frame = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
return avpkt->size;
|
||
|
|
}
|
||
|
|
|
||
|
|
static av_cold int cdg_decode_end(AVCodecContext *avctx)
|
||
|
|
{
|
||
|
|
CDGraphicsContext *cc = avctx->priv_data;
|
||
|
|
|
||
|
|
av_frame_free(&cc->frame);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
AVCodec ff_cdgraphics_decoder = {
|
||
|
|
.name = "cdgraphics",
|
||
|
|
.long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"),
|
||
|
|
.type = AVMEDIA_TYPE_VIDEO,
|
||
|
|
.id = AV_CODEC_ID_CDGRAPHICS,
|
||
|
|
.priv_data_size = sizeof(CDGraphicsContext),
|
||
|
|
.init = cdg_decode_init,
|
||
|
|
.close = cdg_decode_end,
|
||
|
|
.decode = cdg_decode_frame,
|
||
|
|
.capabilities = AV_CODEC_CAP_DR1,
|
||
|
|
};
|