CD+G demuxer and decoder

Patch by Michael Tison (gmail address: blackspike@....)

Originally committed as revision 20890 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 380 insertions, 0 deletions

diff --git a/libavcodec/cdgraphics.c b/libavcodec/cdgraphics.c
new file mode 100644
index 0000000000..fa835b9897
--- /dev/null
+++ b/libavcodec/cdgraphics.c
@@ -0,0 +1,380 @@
+/*
+ * 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"
+
+/**
+ * @file libavcodec/cdgraphics.c
+ * @brief CD Graphics Video Decoder
+ * @author Michael Tison
+ * @sa http://wiki.multimedia.cx/index.php?title=CD_Graphics
+ * @sa 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 = 1;
+    frame->buffer_hints = FF_BUFFER_HINTS_VALID    |
+                          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 cdgraphics_decoder = {
+    "cdgraphics",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_CDGRAPHICS,
+    sizeof(CDGraphicsContext),
+    cdg_decode_init,
+    NULL,
+    cdg_decode_end,
+    cdg_decode_frame,
+    CODEC_CAP_DR1,
+    .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"),
+};