yading@10: /*
yading@10:  * CD Graphics Video Decoder
yading@10:  * Copyright (c) 2009 Michael Tison
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "bytestream.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * @brief CD Graphics Video Decoder
yading@10:  * @author Michael Tison
yading@10:  * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics
yading@10:  * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
yading@10:  */
yading@10: 
yading@10: /// default screen sizes
yading@10: #define CDG_FULL_WIDTH           300
yading@10: #define CDG_FULL_HEIGHT          216
yading@10: #define CDG_DISPLAY_WIDTH        294
yading@10: #define CDG_DISPLAY_HEIGHT       204
yading@10: #define CDG_BORDER_WIDTH           6
yading@10: #define CDG_BORDER_HEIGHT         12
yading@10: 
yading@10: /// masks
yading@10: #define CDG_COMMAND             0x09
yading@10: #define CDG_MASK                0x3F
yading@10: 
yading@10: /// instruction codes
yading@10: #define CDG_INST_MEMORY_PRESET     1
yading@10: #define CDG_INST_BORDER_PRESET     2
yading@10: #define CDG_INST_TILE_BLOCK        6
yading@10: #define CDG_INST_SCROLL_PRESET    20
yading@10: #define CDG_INST_SCROLL_COPY      24
yading@10: #define CDG_INST_LOAD_PAL_LO      30
yading@10: #define CDG_INST_LOAD_PAL_HIGH    31
yading@10: #define CDG_INST_TILE_BLOCK_XOR   38
yading@10: 
yading@10: /// data sizes
yading@10: #define CDG_PACKET_SIZE           24
yading@10: #define CDG_DATA_SIZE             16
yading@10: #define CDG_TILE_HEIGHT           12
yading@10: #define CDG_TILE_WIDTH             6
yading@10: #define CDG_MINIMUM_PKT_SIZE       6
yading@10: #define CDG_MINIMUM_SCROLL_SIZE    3
yading@10: #define CDG_HEADER_SIZE            8
yading@10: #define CDG_PALETTE_SIZE          16
yading@10: 
yading@10: typedef struct CDGraphicsContext {
yading@10:     AVFrame *frame;
yading@10:     int hscroll;
yading@10:     int vscroll;
yading@10: } CDGraphicsContext;
yading@10: 
yading@10: static av_cold int cdg_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     CDGraphicsContext *cc = avctx->priv_data;
yading@10: 
yading@10:     cc->frame = av_frame_alloc();
yading@10:     if (!cc->frame)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     avctx->width   = CDG_FULL_WIDTH;
yading@10:     avctx->height  = CDG_FULL_HEIGHT;
yading@10:     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
yading@10: {
yading@10:     int y;
yading@10:     int lsize    = cc->frame->linesize[0];
yading@10:     uint8_t *buf = cc->frame->data[0];
yading@10:     int color    = data[0] & 0x0F;
yading@10: 
yading@10:     if (!(data[1] & 0x0F)) {
yading@10:         /// fill the top and bottom borders
yading@10:         memset(buf, color, CDG_BORDER_HEIGHT * lsize);
yading@10:         memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
yading@10:                color, CDG_BORDER_HEIGHT * lsize);
yading@10: 
yading@10:         /// fill the side borders
yading@10:         for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
yading@10:             memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
yading@10:             memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
yading@10:                    color, CDG_BORDER_WIDTH);
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
yading@10: {
yading@10:     uint8_t r, g, b;
yading@10:     uint16_t color;
yading@10:     int i;
yading@10:     int array_offset  = low ? 0 : 8;
yading@10:     uint32_t *palette = (uint32_t *) cc->frame->data[1];
yading@10: 
yading@10:     for (i = 0; i < 8; i++) {
yading@10:         color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
yading@10:         r = ((color >> 8) & 0x000F) * 17;
yading@10:         g = ((color >> 4) & 0x000F) * 17;
yading@10:         b = ((color     ) & 0x000F) * 17;
yading@10:         palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b;
yading@10:     }
yading@10:     cc->frame->palette_has_changed = 1;
yading@10: }
yading@10: 
yading@10: static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
yading@10: {
yading@10:     unsigned ci, ri;
yading@10:     int color;
yading@10:     int x, y;
yading@10:     int ai;
yading@10:     int stride   = cc->frame->linesize[0];
yading@10:     uint8_t *buf = cc->frame->data[0];
yading@10: 
yading@10:     ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
yading@10:     ci = (data[3] & 0x3F) * CDG_TILE_WIDTH  + cc->hscroll;
yading@10: 
yading@10:     if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
yading@10:         return AVERROR(EINVAL);
yading@10:     if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
yading@10:         return AVERROR(EINVAL);
yading@10: 
yading@10:     for (y = 0; y < CDG_TILE_HEIGHT; y++) {
yading@10:         for (x = 0; x < CDG_TILE_WIDTH; x++) {
yading@10:             if (!((data[4 + y] >> (5 - x)) & 0x01))
yading@10:                 color = data[0] & 0x0F;
yading@10:             else
yading@10:                 color = data[1] & 0x0F;
yading@10: 
yading@10:             ai = ci + x + (stride * (ri + y));
yading@10:             if (b)
yading@10:                 color ^= buf[ai];
yading@10:             buf[ai] = color;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: #define UP    2
yading@10: #define DOWN  1
yading@10: #define LEFT  2
yading@10: #define RIGHT 1
yading@10: 
yading@10: static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
yading@10:                               int in_tl_x, int in_tl_y, uint8_t *in,
yading@10:                               int w, int h, int stride)
yading@10: {
yading@10:     int y;
yading@10: 
yading@10:     in  += in_tl_x  + in_tl_y  * stride;
yading@10:     out += out_tl_x + out_tl_y * stride;
yading@10:     for (y = 0; y < h; y++)
yading@10:         memcpy(out + y * stride, in + y * stride, w);
yading@10: }
yading@10: 
yading@10: static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
yading@10:                                  int color, int w, int h, int stride)
yading@10: {
yading@10:     int y;
yading@10: 
yading@10:     for (y = tl_y; y < tl_y + h; y++)
yading@10:         memset(out + tl_x + y * stride, color, w);
yading@10: }
yading@10: 
yading@10: static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
yading@10:                              int in_tl_x, int in_tl_y, uint8_t *in,
yading@10:                              int color, int w, int h, int stride, int roll)
yading@10: {
yading@10:     if (roll) {
yading@10:         cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
yading@10:                           in, w, h, stride);
yading@10:     } else {
yading@10:         cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
yading@10:                        AVFrame *new_frame, int roll_over)
yading@10: {
yading@10:     int color;
yading@10:     int hscmd, h_off, hinc, vscmd, v_off, vinc;
yading@10:     int y;
yading@10:     int stride   = cc->frame->linesize[0];
yading@10:     uint8_t *in  = cc->frame->data[0];
yading@10:     uint8_t *out = new_frame->data[0];
yading@10: 
yading@10:     color =  data[0] & 0x0F;
yading@10:     hscmd = (data[1] & 0x30) >> 4;
yading@10:     vscmd = (data[2] & 0x30) >> 4;
yading@10: 
yading@10:     h_off =  FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH  - 1);
yading@10:     v_off =  FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
yading@10: 
yading@10:     /// find the difference and save the offset for cdg_tile_block usage
yading@10:     hinc = h_off - cc->hscroll;
yading@10:     vinc = v_off - cc->vscroll;
yading@10:     cc->hscroll = h_off;
yading@10:     cc->vscroll = v_off;
yading@10: 
yading@10:     if (vscmd == UP)
yading@10:         vinc -= 12;
yading@10:     if (vscmd == DOWN)
yading@10:         vinc += 12;
yading@10:     if (hscmd == LEFT)
yading@10:         hinc -= 6;
yading@10:     if (hscmd == RIGHT)
yading@10:         hinc += 6;
yading@10: 
yading@10:     if (!hinc && !vinc)
yading@10:         return;
yading@10: 
yading@10:     memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4);
yading@10: 
yading@10:     for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
yading@10:         memcpy(out + FFMAX(0, hinc) + stride * y,
yading@10:                in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
yading@10:                FFMIN(stride + hinc, stride));
yading@10: 
yading@10:     if (vinc > 0)
yading@10:         cdg_fill_wrapper(0, 0, out,
yading@10:                          0, CDG_FULL_HEIGHT - vinc, in, color,
yading@10:                          stride, vinc, stride, roll_over);
yading@10:     else if (vinc < 0)
yading@10:         cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
yading@10:                          0, 0, in, color,
yading@10:                          stride, -1 * vinc, stride, roll_over);
yading@10: 
yading@10:     if (hinc > 0)
yading@10:         cdg_fill_wrapper(0, 0, out,
yading@10:                          CDG_FULL_WIDTH - hinc, 0, in, color,
yading@10:                          hinc, CDG_FULL_HEIGHT, stride, roll_over);
yading@10:     else if (hinc < 0)
yading@10:         cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
yading@10:                          0, 0, in, color,
yading@10:                          -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
yading@10: 
yading@10: }
yading@10: 
yading@10: static int cdg_decode_frame(AVCodecContext *avctx,
yading@10:                             void *data, int *got_frame, AVPacket *avpkt)
yading@10: {
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size       = avpkt->size;
yading@10:     int ret;
yading@10:     uint8_t command, inst;
yading@10:     uint8_t cdg_data[CDG_DATA_SIZE];
yading@10:     AVFrame *frame = data;
yading@10:     CDGraphicsContext *cc = avctx->priv_data;
yading@10: 
yading@10:     if (buf_size < CDG_MINIMUM_PKT_SIZE) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10:     if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10: 
yading@10:     if ((ret = ff_reget_buffer(avctx, cc->frame)) < 0)
yading@10:         return ret;
yading@10:     if (!avctx->frame_number) {
yading@10:         memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height);
yading@10:         memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
yading@10:     }
yading@10: 
yading@10:     command = bytestream_get_byte(&buf);
yading@10:     inst    = bytestream_get_byte(&buf);
yading@10:     inst    &= CDG_MASK;
yading@10:     buf += 2;  /// skipping 2 unneeded bytes
yading@10:     bytestream_get_buffer(&buf, cdg_data, buf_size - CDG_HEADER_SIZE);
yading@10: 
yading@10:     if ((command & CDG_MASK) == CDG_COMMAND) {
yading@10:         switch (inst) {
yading@10:         case CDG_INST_MEMORY_PRESET:
yading@10:             if (!(cdg_data[1] & 0x0F))
yading@10:                 memset(cc->frame->data[0], cdg_data[0] & 0x0F,
yading@10:                        cc->frame->linesize[0] * CDG_FULL_HEIGHT);
yading@10:             break;
yading@10:         case CDG_INST_LOAD_PAL_LO:
yading@10:         case CDG_INST_LOAD_PAL_HIGH:
yading@10:             if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
yading@10:                 av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
yading@10:                 return AVERROR(EINVAL);
yading@10:             }
yading@10: 
yading@10:             cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
yading@10:             break;
yading@10:         case CDG_INST_BORDER_PRESET:
yading@10:             cdg_border_preset(cc, cdg_data);
yading@10:             break;
yading@10:         case CDG_INST_TILE_BLOCK_XOR:
yading@10:         case CDG_INST_TILE_BLOCK:
yading@10:             if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
yading@10:                 av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
yading@10:                 return AVERROR(EINVAL);
yading@10:             }
yading@10: 
yading@10:             ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
yading@10:             if (ret) {
yading@10:                 av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
yading@10:                 return ret;
yading@10:             }
yading@10:             break;
yading@10:         case CDG_INST_SCROLL_PRESET:
yading@10:         case CDG_INST_SCROLL_COPY:
yading@10:             if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
yading@10:                 av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
yading@10:                 return AVERROR(EINVAL);
yading@10:             }
yading@10: 
yading@10:             if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
yading@10:                 return ret;
yading@10: 
yading@10:             cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY);
yading@10:             av_frame_unref(cc->frame);
yading@10:             ret = av_frame_ref(cc->frame, frame);
yading@10:             if (ret < 0)
yading@10:                 return ret;
yading@10:             break;
yading@10:         default:
yading@10:             break;
yading@10:         }
yading@10: 
yading@10:         if (!frame->data[0]) {
yading@10:             ret = av_frame_ref(frame, cc->frame);
yading@10:             if (ret < 0)
yading@10:                 return ret;
yading@10:         }
yading@10:         *got_frame = 1;
yading@10:     } else {
yading@10:         *got_frame = 0;
yading@10:         buf_size   = 0;
yading@10:     }
yading@10: 
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: static av_cold int cdg_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     CDGraphicsContext *cc = avctx->priv_data;
yading@10: 
yading@10:     av_frame_free(&cc->frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_cdgraphics_decoder = {
yading@10:     .name           = "cdgraphics",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_CDGRAPHICS,
yading@10:     .priv_data_size = sizeof(CDGraphicsContext),
yading@10:     .init           = cdg_decode_init,
yading@10:     .close          = cdg_decode_end,
yading@10:     .decode         = cdg_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("CD Graphics video"),
yading@10: };