| /* |
| * CD Graphics Video Decoder |
| * Copyright (c) 2009 Michael Tison |
| * |
| * 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 "avcodec.h" |
| #include "bytestream.h" |
| #include "internal.h" |
| |
| /** |
| * @file |
| * @brief CD Graphics Video Decoder |
| * @author Michael Tison |
| * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics |
| * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg |
| */ |
| |
| /// default screen sizes |
| #define CDG_FULL_WIDTH 300 |
| #define CDG_FULL_HEIGHT 216 |
| #define CDG_DISPLAY_WIDTH 294 |
| #define CDG_DISPLAY_HEIGHT 204 |
| #define CDG_BORDER_WIDTH 6 |
| #define CDG_BORDER_HEIGHT 12 |
| |
| /// masks |
| #define CDG_COMMAND 0x09 |
| #define CDG_MASK 0x3F |
| |
| /// instruction codes |
| #define CDG_INST_MEMORY_PRESET 1 |
| #define CDG_INST_BORDER_PRESET 2 |
| #define CDG_INST_TILE_BLOCK 6 |
| #define CDG_INST_SCROLL_PRESET 20 |
| #define CDG_INST_SCROLL_COPY 24 |
| #define CDG_INST_TRANSPARENT_COL 28 |
| #define CDG_INST_LOAD_PAL_LO 30 |
| #define CDG_INST_LOAD_PAL_HIGH 31 |
| #define CDG_INST_TILE_BLOCK_XOR 38 |
| |
| /// data sizes |
| #define CDG_PACKET_SIZE 24 |
| #define CDG_DATA_SIZE 16 |
| #define CDG_TILE_HEIGHT 12 |
| #define CDG_TILE_WIDTH 6 |
| #define CDG_MINIMUM_PKT_SIZE 6 |
| #define CDG_MINIMUM_SCROLL_SIZE 3 |
| #define CDG_HEADER_SIZE 8 |
| #define CDG_PALETTE_SIZE 16 |
| |
| typedef struct CDGraphicsContext { |
| AVFrame *frame; |
| int hscroll; |
| int vscroll; |
| int transparency; |
| } CDGraphicsContext; |
| |
| static av_cold int cdg_decode_init(AVCodecContext *avctx) |
| { |
| CDGraphicsContext *cc = avctx->priv_data; |
| |
| cc->frame = av_frame_alloc(); |
| if (!cc->frame) |
| return AVERROR(ENOMEM); |
| cc->transparency = -1; |
| |
| avctx->width = CDG_FULL_WIDTH; |
| avctx->height = CDG_FULL_HEIGHT; |
| avctx->pix_fmt = AV_PIX_FMT_PAL8; |
| |
| return 0; |
| } |
| |
| static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data) |
| { |
| int y; |
| int lsize = cc->frame->linesize[0]; |
| uint8_t *buf = cc->frame->data[0]; |
| int color = data[0] & 0x0F; |
| |
| if (!(data[1] & 0x0F)) { |
| /// fill the top and bottom borders |
| memset(buf, color, CDG_BORDER_HEIGHT * lsize); |
| memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize, |
| color, CDG_BORDER_HEIGHT * lsize); |
| |
| /// fill the side borders |
| for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) { |
| memset(buf + y * lsize, color, CDG_BORDER_WIDTH); |
| memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize, |
| color, CDG_BORDER_WIDTH); |
| } |
| } |
| } |
| |
| static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low) |
| { |
| uint8_t r, g, b; |
| uint16_t color; |
| int i; |
| int array_offset = low ? 0 : 8; |
| uint32_t *palette = (uint32_t *) cc->frame->data[1]; |
| |
| for (i = 0; i < 8; i++) { |
| color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F); |
| r = ((color >> 8) & 0x000F) * 17; |
| g = ((color >> 4) & 0x000F) * 17; |
| b = ((color ) & 0x000F) * 17; |
| palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b; |
| if (cc->transparency >= 0) |
| palette[cc->transparency] &= 0xFFFFFF; |
| } |
| cc->frame->palette_has_changed = 1; |
| } |
| |
| static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b) |
| { |
| unsigned ci, ri; |
| int color; |
| int x, y; |
| int ai; |
| int stride = cc->frame->linesize[0]; |
| uint8_t *buf = cc->frame->data[0]; |
| |
| ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll; |
| ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll; |
| |
| if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT)) |
| return AVERROR(EINVAL); |
| if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH)) |
| return AVERROR(EINVAL); |
| |
| for (y = 0; y < CDG_TILE_HEIGHT; y++) { |
| for (x = 0; x < CDG_TILE_WIDTH; x++) { |
| if (!((data[4 + y] >> (5 - x)) & 0x01)) |
| color = data[0] & 0x0F; |
| else |
| color = data[1] & 0x0F; |
| |
| ai = ci + x + (stride * (ri + y)); |
| if (b) |
| color ^= buf[ai]; |
| buf[ai] = color; |
| } |
| } |
| |
| return 0; |
| } |
| |
| #define UP 2 |
| #define DOWN 1 |
| #define LEFT 2 |
| #define RIGHT 1 |
| |
| static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out, |
| int in_tl_x, int in_tl_y, uint8_t *in, |
| int w, int h, int stride) |
| { |
| int y; |
| |
| in += in_tl_x + in_tl_y * stride; |
| out += out_tl_x + out_tl_y * stride; |
| for (y = 0; y < h; y++) |
| memcpy(out + y * stride, in + y * stride, w); |
| } |
| |
| static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out, |
| int color, int w, int h, int stride) |
| { |
| int y; |
| |
| for (y = tl_y; y < tl_y + h; y++) |
| memset(out + tl_x + y * stride, color, w); |
| } |
| |
| static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out, |
| int in_tl_x, int in_tl_y, uint8_t *in, |
| int color, int w, int h, int stride, int roll) |
| { |
| if (roll) { |
| cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y, |
| in, w, h, stride); |
| } else { |
| cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride); |
| } |
| } |
| |
| static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data, |
| AVFrame *new_frame, int roll_over) |
| { |
| int color; |
| int hscmd, h_off, hinc, vscmd, v_off, vinc; |
| int y; |
| int stride = cc->frame->linesize[0]; |
| uint8_t *in = cc->frame->data[0]; |
| uint8_t *out = new_frame->data[0]; |
| |
| color = data[0] & 0x0F; |
| hscmd = (data[1] & 0x30) >> 4; |
| vscmd = (data[2] & 0x30) >> 4; |
| |
| h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1); |
| v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1); |
| |
| /// find the difference and save the offset for cdg_tile_block usage |
| hinc = h_off - cc->hscroll; |
| vinc = v_off - cc->vscroll; |
| cc->hscroll = h_off; |
| cc->vscroll = v_off; |
| |
| if (vscmd == UP) |
| vinc -= 12; |
| if (vscmd == DOWN) |
| vinc += 12; |
| if (hscmd == LEFT) |
| hinc -= 6; |
| if (hscmd == RIGHT) |
| hinc += 6; |
| |
| if (!hinc && !vinc) |
| return; |
| |
| memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4); |
| |
| for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++) |
| memcpy(out + FFMAX(0, hinc) + stride * y, |
| in + FFMAX(0, hinc) - hinc + (y - vinc) * stride, |
| FFMIN(stride + hinc, stride)); |
| |
| if (vinc > 0) |
| cdg_fill_wrapper(0, 0, out, |
| 0, CDG_FULL_HEIGHT - vinc, in, color, |
| stride, vinc, stride, roll_over); |
| else if (vinc < 0) |
| cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out, |
| 0, 0, in, color, |
| stride, -1 * vinc, stride, roll_over); |
| |
| if (hinc > 0) |
| cdg_fill_wrapper(0, 0, out, |
| CDG_FULL_WIDTH - hinc, 0, in, color, |
| hinc, CDG_FULL_HEIGHT, stride, roll_over); |
| else if (hinc < 0) |
| cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out, |
| 0, 0, in, color, |
| -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over); |
| |
| } |
| |
| static int cdg_decode_frame(AVCodecContext *avctx, |
| void *data, int *got_frame, AVPacket *avpkt) |
| { |
| GetByteContext gb; |
| int buf_size = avpkt->size; |
| int ret; |
| uint8_t command, inst; |
| uint8_t cdg_data[CDG_DATA_SIZE] = {0}; |
| AVFrame *frame = data; |
| CDGraphicsContext *cc = avctx->priv_data; |
| |
| if (buf_size < CDG_MINIMUM_PKT_SIZE) { |
| av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n"); |
| return AVERROR(EINVAL); |
| } |
| if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) { |
| av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| bytestream2_init(&gb, avpkt->data, avpkt->size); |
| |
| if ((ret = ff_reget_buffer(avctx, cc->frame)) < 0) |
| return ret; |
| if (!avctx->frame_number) { |
| memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height); |
| memset(cc->frame->data[1], 0, AVPALETTE_SIZE); |
| } |
| |
| command = bytestream2_get_byte(&gb); |
| inst = bytestream2_get_byte(&gb); |
| inst &= CDG_MASK; |
| bytestream2_skip(&gb, 2); |
| bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data)); |
| |
| if ((command & CDG_MASK) == CDG_COMMAND) { |
| switch (inst) { |
| case CDG_INST_MEMORY_PRESET: |
| if (!(cdg_data[1] & 0x0F)) |
| memset(cc->frame->data[0], cdg_data[0] & 0x0F, |
| cc->frame->linesize[0] * CDG_FULL_HEIGHT); |
| break; |
| case CDG_INST_LOAD_PAL_LO: |
| case CDG_INST_LOAD_PAL_HIGH: |
| if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) { |
| av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO); |
| break; |
| case CDG_INST_BORDER_PRESET: |
| cdg_border_preset(cc, cdg_data); |
| break; |
| case CDG_INST_TILE_BLOCK_XOR: |
| case CDG_INST_TILE_BLOCK: |
| if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) { |
| av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR); |
| if (ret) { |
| av_log(avctx, AV_LOG_ERROR, "tile is out of range\n"); |
| return ret; |
| } |
| break; |
| case CDG_INST_SCROLL_PRESET: |
| case CDG_INST_SCROLL_COPY: |
| if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) { |
| av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n"); |
| return AVERROR(EINVAL); |
| } |
| |
| if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) |
| return ret; |
| |
| cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY); |
| av_frame_unref(cc->frame); |
| ret = av_frame_ref(cc->frame, frame); |
| 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, |
| }; |
