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Diffstat (limited to 'libavcodec/c93.c')
| -rw-r--r-- | libavcodec/c93.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/libavcodec/c93.c b/libavcodec/c93.c new file mode 100644 index 0000000000..1e90efbc2a --- /dev/null +++ b/libavcodec/c93.c @@ -0,0 +1,253 @@ +/* + * 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, +}; |