yading@10: /*
yading@10:  * Interplay C93 video decoder
yading@10:  * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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: typedef struct {
yading@10:     AVFrame pictures[2];
yading@10:     int currentpic;
yading@10: } C93DecoderContext;
yading@10: 
yading@10: typedef enum {
yading@10:     C93_8X8_FROM_PREV  = 0x02,
yading@10:     C93_4X4_FROM_PREV  = 0x06,
yading@10:     C93_4X4_FROM_CURR  = 0x07,
yading@10:     C93_8X8_2COLOR     = 0x08,
yading@10:     C93_4X4_2COLOR     = 0x0A,
yading@10:     C93_4X4_4COLOR_GRP = 0x0B,
yading@10:     C93_4X4_4COLOR     = 0x0D,
yading@10:     C93_NOOP           = 0x0E,
yading@10:     C93_8X8_INTRA      = 0x0F,
yading@10: } C93BlockType;
yading@10: 
yading@10: #define WIDTH   320
yading@10: #define HEIGHT  192
yading@10: 
yading@10: #define C93_HAS_PALETTE 0x01
yading@10: #define C93_FIRST_FRAME 0x02
yading@10: 
yading@10: static av_cold int decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     C93DecoderContext *s = avctx->priv_data;
yading@10:     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10:     avcodec_get_frame_defaults(&s->pictures[0]);
yading@10:     avcodec_get_frame_defaults(&s->pictures[1]);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     C93DecoderContext * const c93 = avctx->priv_data;
yading@10: 
yading@10:     av_frame_unref(&c93->pictures[0]);
yading@10:     av_frame_unref(&c93->pictures[1]);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static inline int copy_block(AVCodecContext *avctx, uint8_t *to,
yading@10:         uint8_t *from, int offset, int height, int stride)
yading@10: {
yading@10:     int i;
yading@10:     int width = height;
yading@10:     int from_x = offset % WIDTH;
yading@10:     int from_y = offset / WIDTH;
yading@10:     int overflow = from_x + width - WIDTH;
yading@10: 
yading@10:     if (!from) {
yading@10:         /* silently ignoring predictive blocks in first frame */
yading@10:         return 0;
yading@10:     }
yading@10: 
yading@10:     if (from_y + height > HEIGHT) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
yading@10:                offset);
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     if (overflow > 0) {
yading@10:         width -= overflow;
yading@10:         for (i = 0; i < height; i++) {
yading@10:             memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     for (i = 0; i < height; i++) {
yading@10:         memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static inline void draw_n_color(uint8_t *out, int stride, int width,
yading@10:          int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
yading@10: {
yading@10:     int x, y;
yading@10:     for (y = 0; y < height; y++) {
yading@10:         if (grps)
yading@10:             cols[0] = grps[3 * (y >> 1)];
yading@10:         for (x = 0; x < width; x++) {
yading@10:             if (grps)
yading@10:                 cols[1]= grps[(x >> 1) + 1];
yading@10:             out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
yading@10:             col >>= bpp;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static int decode_frame(AVCodecContext *avctx, void *data,
yading@10:                         int *got_frame, AVPacket *avpkt)
yading@10: {
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size = avpkt->size;
yading@10:     C93DecoderContext * const c93 = avctx->priv_data;
yading@10:     AVFrame * const newpic = &c93->pictures[c93->currentpic];
yading@10:     AVFrame * const oldpic = &c93->pictures[c93->currentpic^1];
yading@10:     GetByteContext gb;
yading@10:     uint8_t *out;
yading@10:     int stride, ret, i, x, y, b, bt = 0;
yading@10: 
yading@10:     c93->currentpic ^= 1;
yading@10: 
yading@10:     if ((ret = ff_reget_buffer(avctx, newpic)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     stride = newpic->linesize[0];
yading@10: 
yading@10:     bytestream2_init(&gb, buf, buf_size);
yading@10:     b = bytestream2_get_byte(&gb);
yading@10:     if (b & C93_FIRST_FRAME) {
yading@10:         newpic->pict_type = AV_PICTURE_TYPE_I;
yading@10:         newpic->key_frame = 1;
yading@10:     } else {
yading@10:         newpic->pict_type = AV_PICTURE_TYPE_P;
yading@10:         newpic->key_frame = 0;
yading@10:     }
yading@10: 
yading@10:     for (y = 0; y < HEIGHT; y += 8) {
yading@10:         out = newpic->data[0] + y * stride;
yading@10:         for (x = 0; x < WIDTH; x += 8) {
yading@10:             uint8_t *copy_from = oldpic->data[0];
yading@10:             unsigned int offset, j;
yading@10:             uint8_t cols[4], grps[4];
yading@10:             C93BlockType block_type;
yading@10: 
yading@10:             if (!bt)
yading@10:                 bt = bytestream2_get_byte(&gb);
yading@10: 
yading@10:             block_type= bt & 0x0F;
yading@10:             switch (block_type) {
yading@10:             case C93_8X8_FROM_PREV:
yading@10:                 offset = bytestream2_get_le16(&gb);
yading@10:                 if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)
yading@10:                     return ret;
yading@10:                 break;
yading@10: 
yading@10:             case C93_4X4_FROM_CURR:
yading@10:                 copy_from = newpic->data[0];
yading@10:             case C93_4X4_FROM_PREV:
yading@10:                 for (j = 0; j < 8; j += 4) {
yading@10:                     for (i = 0; i < 8; i += 4) {
yading@10:                         int offset = bytestream2_get_le16(&gb);
yading@10:                         int from_x = offset % WIDTH;
yading@10:                         int from_y = offset / WIDTH;
yading@10:                         if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&
yading@10:                             (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {
yading@10:                             avpriv_request_sample(avctx, "block overlap %d %d %d %d\n", from_x, x+i, from_y, y+j);
yading@10:                             return AVERROR_INVALIDDATA;
yading@10:                         }
yading@10:                         if ((ret = copy_block(avctx, &out[j*stride+i],
yading@10:                                               copy_from, offset, 4, stride)) < 0)
yading@10:                             return ret;
yading@10:                     }
yading@10:                 }
yading@10:                 break;
yading@10: 
yading@10:             case C93_8X8_2COLOR:
yading@10:                 bytestream2_get_buffer(&gb, cols, 2);
yading@10:                 for (i = 0; i < 8; i++) {
yading@10:                     draw_n_color(out + i*stride, stride, 8, 1, 1, cols,
yading@10:                                      NULL, bytestream2_get_byte(&gb));
yading@10:                 }
yading@10: 
yading@10:                 break;
yading@10: 
yading@10:             case C93_4X4_2COLOR:
yading@10:             case C93_4X4_4COLOR:
yading@10:             case C93_4X4_4COLOR_GRP:
yading@10:                 for (j = 0; j < 8; j += 4) {
yading@10:                     for (i = 0; i < 8; i += 4) {
yading@10:                         if (block_type == C93_4X4_2COLOR) {
yading@10:                             bytestream2_get_buffer(&gb, cols, 2);
yading@10:                             draw_n_color(out + i + j*stride, stride, 4, 4,
yading@10:                                     1, cols, NULL, bytestream2_get_le16(&gb));
yading@10:                         } else if (block_type == C93_4X4_4COLOR) {
yading@10:                             bytestream2_get_buffer(&gb, cols, 4);
yading@10:                             draw_n_color(out + i + j*stride, stride, 4, 4,
yading@10:                                     2, cols, NULL, bytestream2_get_le32(&gb));
yading@10:                         } else {
yading@10:                             bytestream2_get_buffer(&gb, grps, 4);
yading@10:                             draw_n_color(out + i + j*stride, stride, 4, 4,
yading@10:                                     1, cols, grps, bytestream2_get_le16(&gb));
yading@10:                         }
yading@10:                     }
yading@10:                 }
yading@10:                 break;
yading@10: 
yading@10:             case C93_NOOP:
yading@10:                 break;
yading@10: 
yading@10:             case C93_8X8_INTRA:
yading@10:                 for (j = 0; j < 8; j++)
yading@10:                     bytestream2_get_buffer(&gb, out + j*stride, 8);
yading@10:                 break;
yading@10: 
yading@10:             default:
yading@10:                 av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",
yading@10:                        block_type, x, y);
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             }
yading@10:             bt >>= 4;
yading@10:             out += 8;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     if (b & C93_HAS_PALETTE) {
yading@10:         uint32_t *palette = (uint32_t *) newpic->data[1];
yading@10:         for (i = 0; i < 256; i++) {
yading@10:             palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);
yading@10:         }
yading@10:         newpic->palette_has_changed = 1;
yading@10:     } else {
yading@10:         if (oldpic->data[1])
yading@10:             memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
yading@10:     }
yading@10: 
yading@10:     if ((ret = av_frame_ref(data, newpic)) < 0)
yading@10:         return ret;
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: AVCodec ff_c93_decoder = {
yading@10:     .name           = "c93",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_C93,
yading@10:     .priv_data_size = sizeof(C93DecoderContext),
yading@10:     .init           = decode_init,
yading@10:     .close          = decode_end,
yading@10:     .decode         = decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Interplay C93"),
yading@10: };