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-rw-r--r--libavcodec/c93.c253
1 files changed, 253 insertions, 0 deletions
diff --git a/libavcodec/c93.c b/libavcodec/c93.c
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+++ b/libavcodec/c93.c
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+/*
+ * Interplay C93 video decoder
+ * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
+ *
+ * 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"
+
+typedef struct {
+ AVFrame pictures[2];
+ int currentpic;
+} C93DecoderContext;
+
+typedef enum {
+ C93_8X8_FROM_PREV = 0x02,
+ C93_4X4_FROM_PREV = 0x06,
+ C93_4X4_FROM_CURR = 0x07,
+ C93_8X8_2COLOR = 0x08,
+ C93_4X4_2COLOR = 0x0A,
+ C93_4X4_4COLOR_GRP = 0x0B,
+ C93_4X4_4COLOR = 0x0D,
+ C93_NOOP = 0x0E,
+ C93_8X8_INTRA = 0x0F,
+} C93BlockType;
+
+#define WIDTH 320
+#define HEIGHT 192
+
+#define C93_HAS_PALETTE 0x01
+#define C93_FIRST_FRAME 0x02
+
+static int c93_decode_init(AVCodecContext *avctx)
+{
+ avctx->pix_fmt = PIX_FMT_PAL8;
+ return 0;
+}
+
+static int c93_decode_end(AVCodecContext *avctx)
+{
+ C93DecoderContext * const c93 = avctx->priv_data;
+
+ if (c93->pictures[0].data[0])
+ avctx->release_buffer(avctx, &c93->pictures[0]);
+ if (c93->pictures[1].data[0])
+ avctx->release_buffer(avctx, &c93->pictures[1]);
+ return 0;
+}
+
+static inline int c93_copy_block(AVCodecContext *avctx, uint8_t *to,
+ uint8_t *from, int offset, int height, int stride)
+{
+ int i;
+ int width = height;
+ int from_x = offset % WIDTH;
+ int from_y = offset / WIDTH;
+ int overflow = from_x + width - WIDTH;
+
+ if (!from) {
+ /* silently ignoring predictive blocks in first frame */
+ return 0;
+ }
+
+ if (from_y + height > HEIGHT) {
+ av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
+ offset);
+ return -1;
+ }
+
+ if (overflow > 0) {
+ width -= overflow;
+ for (i = 0; i < height; i++) {
+ memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
+ }
+ }
+
+ for (i = 0; i < height; i++) {
+ memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
+ }
+
+ return 0;
+}
+
+static inline void c93_draw_n_color(uint8_t *out, int stride, int width,
+ int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
+{
+ int x, y;
+ for (y = 0; y < height; y++) {
+ if (grps)
+ cols[0] = grps[3 * (y >> 1)];
+ for (x = 0; x < width; x++) {
+ if (grps)
+ cols[1]= grps[(x >> 1) + 1];
+ out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
+ col >>= bpp;
+ }
+ }
+}
+
+static int c93_decode_frame(AVCodecContext *avctx, void *data,
+ int *data_size, uint8_t * buf, int buf_size)
+{
+ C93DecoderContext * const c93 = avctx->priv_data;
+ AVFrame * const newpic = &c93->pictures[c93->currentpic];
+ AVFrame * const oldpic = &c93->pictures[c93->currentpic^1];
+ AVFrame *picture = data;
+ uint8_t *out;
+ int stride, i, x, y;
+ C93BlockType bt = 0;
+
+ c93->currentpic ^= 1;
+
+ newpic->reference = 1;
+ newpic->buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
+ FF_BUFFER_HINTS_REUSABLE | FF_BUFFER_HINTS_READABLE;
+ if (avctx->reget_buffer(avctx, newpic)) {
+ av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
+ return -1;
+ }
+
+ stride = newpic->linesize[0];
+
+ if (buf[0] & C93_FIRST_FRAME) {
+ newpic->pict_type = FF_I_TYPE;
+ newpic->key_frame = 1;
+ } else {
+ newpic->pict_type = FF_P_TYPE;
+ newpic->key_frame = 0;
+ }
+
+ if (*buf++ & C93_HAS_PALETTE) {
+ uint32_t *palette = (uint32_t *) newpic->data[1];
+ uint8_t *palbuf = buf + buf_size - 768 - 1;
+ for (i = 0; i < 256; i++) {
+ palette[i] = bytestream_get_be24(&palbuf);
+ }
+ } else {
+ if (oldpic->data[1])
+ memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
+ }
+
+ for (y = 0; y < HEIGHT; y += 8) {
+ out = newpic->data[0] + y * stride;
+ for (x = 0; x < WIDTH; x += 8) {
+ uint8_t *copy_from = oldpic->data[0];
+ unsigned int offset, j;
+ uint8_t cols[4], grps[4];
+
+ if (!bt)
+ bt = *buf++;
+
+ switch (bt & 0x0F) {
+ case C93_8X8_FROM_PREV:
+ offset = bytestream_get_le16(&buf);
+ if (c93_copy_block(avctx, out, copy_from, offset, 8, stride))
+ return -1;
+ break;
+
+ case C93_4X4_FROM_CURR:
+ copy_from = newpic->data[0];
+ case C93_4X4_FROM_PREV:
+ for (j = 0; j < 8; j += 4) {
+ for (i = 0; i < 8; i += 4) {
+ offset = bytestream_get_le16(&buf);
+ if (c93_copy_block(avctx, &out[j*stride+i],
+ copy_from, offset, 4, stride))
+ return -1;
+ }
+ }
+ break;
+
+ case C93_8X8_2COLOR:
+ bytestream_get_buffer(&buf, cols, 2);
+ for (i = 0; i < 8; i++) {
+ c93_draw_n_color(out + i*stride, stride, 8, 1, 1, cols,
+ NULL, *buf++);
+ }
+
+ break;
+
+ case C93_4X4_2COLOR:
+ case C93_4X4_4COLOR:
+ case C93_4X4_4COLOR_GRP:
+ for (j = 0; j < 8; j += 4) {
+ for (i = 0; i < 8; i += 4) {
+ if ((bt & 0x0F) == C93_4X4_2COLOR) {
+ bytestream_get_buffer(&buf, cols, 2);
+ c93_draw_n_color(out + i + j*stride, stride, 4, 4,
+ 1, cols, NULL, bytestream_get_le16(&buf));
+ } else if ((bt & 0x0F) == C93_4X4_4COLOR) {
+ bytestream_get_buffer(&buf, cols, 4);
+ c93_draw_n_color(out + i + j*stride, stride, 4, 4,
+ 2, cols, NULL, bytestream_get_le32(&buf));
+ } else {
+ bytestream_get_buffer(&buf, grps, 4);
+ c93_draw_n_color(out + i + j*stride, stride, 4, 4,
+ 1, cols, grps, bytestream_get_le16(&buf));
+ }
+ }
+ }
+ break;
+
+ case C93_NOOP:
+ break;
+
+ case C93_8X8_INTRA:
+ for (j = 0; j < 8; j++)
+ bytestream_get_buffer(&buf, out + j*stride, 8);
+ break;
+
+ default:
+ av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",
+ bt & 0x0F, x, y);
+ return -1;
+ }
+ bt >>= 4;
+ out += 8;
+ }
+ }
+
+ *picture = *newpic;
+ *data_size = sizeof(AVFrame);
+
+ return buf_size;
+}
+
+AVCodec c93_decoder = {
+ "c93",
+ CODEC_TYPE_VIDEO,
+ CODEC_ID_C93,
+ sizeof(C93DecoderContext),
+ c93_decode_init,
+ NULL,
+ c93_decode_end,
+ c93_decode_frame,
+ CODEC_CAP_DR1,
+};