/* * CD Graphics Video Decoder * Copyright (c) 2009 Michael Tison * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; 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" /** * @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_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;} CDGraphicsContext; static void cdg_init_frame(AVFrame *frame){    avcodec_get_frame_defaults(frame);    frame->reference = 3;    frame->buffer_hints = FF_BUFFER_HINTS_VALID    |                          FF_BUFFER_HINTS_READABLE |                          FF_BUFFER_HINTS_PRESERVE |                          FF_BUFFER_HINTS_REUSABLE;} static av_cold int cdg_decode_init(AVCodecContext *avctx){    CDGraphicsContext *cc = avctx->priv_data;     cdg_init_frame(&cc->frame);     avctx->width   = CDG_FULL_WIDTH;    avctx->height  = CDG_FULL_HEIGHT;    avctx->pix_fmt = 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] = r << 16 | g << 8 | b;    }    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] & 0x07, 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 *data_size, AVPacket *avpkt){    const uint8_t *buf = avpkt->data;    int buf_size       = avpkt->size;    int ret;    uint8_t command, inst;    uint8_t cdg_data[CDG_DATA_SIZE];    AVFrame new_frame;    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);    }     ret = avctx->reget_buffer(avctx, &cc->frame);    if (ret) {        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");        return ret;    }     command = bytestream_get_byte(&buf);    inst    = bytestream_get_byte(&buf);    inst    &= CDG_MASK;    buf += 2;  /// skipping 2 unneeded bytes    bytestream_get_buffer(&buf, cdg_data, buf_size - CDG_HEADER_SIZE);     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);            }             cdg_init_frame(&new_frame);            ret = avctx->get_buffer(avctx, &new_frame);            if (ret) {                av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");                return ret;            }             cdg_scroll(cc, cdg_data, &new_frame, inst == CDG_INST_SCROLL_COPY);            avctx->release_buffer(avctx, &cc->frame);            cc->frame = new_frame;            break;        default:            break;        }         *data_size = sizeof(AVFrame);    } else {        *data_size = 0;        buf_size   = 0;    }     *(AVFrame *) data = cc->frame;    return buf_size;} static av_cold int cdg_decode_end(AVCodecContext *avctx){    CDGraphicsContext *cc = avctx->priv_data;     if (cc->frame.data[0])        avctx->release_buffer(avctx, &cc->frame);     return 0;} AVCodec ff_cdgraphics_decoder = {    .name           = "cdgraphics",    .type           = AVMEDIA_TYPE_VIDEO,    .id             = CODEC_ID_CDGRAPHICS,    .priv_data_size = sizeof(CDGraphicsContext),    .init           = cdg_decode_init,    .close          = cdg_decode_end,    .decode         = cdg_decode_frame,    .capabilities   = CODEC_CAP_DR1,    .long_name      = NULL_IF_CONFIG_SMALL("CD Graphics video"),};