yading@10: /*
yading@10:  * RL2 Video Decoder
yading@10:  * Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de)
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: /**
yading@10:  * @file
yading@10:  * RL2 Video Decoder
yading@10:  * @author Sascha Sommer (saschasommer@freenet.de)
yading@10:  * @see http://wiki.multimedia.cx/index.php?title=RL2
yading@10:  */
yading@10: 
yading@10: #include <stdio.h>
yading@10: #include <stdlib.h>
yading@10: #include <string.h>
yading@10: 
yading@10: #include "libavutil/internal.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "libavutil/mem.h"
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: 
yading@10: #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette
yading@10: 
yading@10: typedef struct Rl2Context {
yading@10:     AVCodecContext *avctx;
yading@10: 
yading@10:     uint16_t video_base;  ///< initial drawing offset
yading@10:     uint32_t clr_count;   ///< number of used colors (currently unused)
yading@10:     uint8_t *back_frame;  ///< background frame
yading@10:     uint32_t palette[AVPALETTE_COUNT];
yading@10: } Rl2Context;
yading@10: 
yading@10: /**
yading@10:  * Run Length Decode a single 320x200 frame
yading@10:  * @param s rl2 context
yading@10:  * @param in input buffer
yading@10:  * @param size input buffer size
yading@10:  * @param out output buffer
yading@10:  * @param stride stride of the output buffer
yading@10:  * @param video_base offset of the rle data inside the frame
yading@10:  */
yading@10: static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size,
yading@10:                                uint8_t *out, int stride, int video_base)
yading@10: {
yading@10:     int base_x = video_base % s->avctx->width;
yading@10:     int base_y = video_base / s->avctx->width;
yading@10:     int stride_adj = stride - s->avctx->width;
yading@10:     int i;
yading@10:     const uint8_t *back_frame = s->back_frame;
yading@10:     const uint8_t *in_end     = in + size;
yading@10:     const uint8_t *out_end    = out + stride * s->avctx->height;
yading@10:     uint8_t *line_end;
yading@10: 
yading@10:     /** copy start of the background frame */
yading@10:     for (i = 0; i <= base_y; i++) {
yading@10:         if (s->back_frame)
yading@10:             memcpy(out, back_frame, s->avctx->width);
yading@10:         out        += stride;
yading@10:         back_frame += s->avctx->width;
yading@10:     }
yading@10:     back_frame += base_x - s->avctx->width;
yading@10:     line_end    = out - stride_adj;
yading@10:     out        += base_x - stride;
yading@10: 
yading@10:     /** decode the variable part of the frame */
yading@10:     while (in < in_end) {
yading@10:         uint8_t val = *in++;
yading@10:         int len     = 1;
yading@10:         if (val >= 0x80) {
yading@10:             if (in >= in_end)
yading@10:                 break;
yading@10:             len = *in++;
yading@10:             if (!len)
yading@10:                 break;
yading@10:         }
yading@10: 
yading@10:         if (len >= out_end - out)
yading@10:             break;
yading@10: 
yading@10:         if (s->back_frame)
yading@10:             val |= 0x80;
yading@10:         else
yading@10:             val &= ~0x80;
yading@10: 
yading@10:         while (len--) {
yading@10:             *out++ = (val == 0x80) ? *back_frame : val;
yading@10:             back_frame++;
yading@10:             if (out == line_end) {
yading@10:                  out      += stride_adj;
yading@10:                  line_end += stride;
yading@10:                  if (len >= out_end - out)
yading@10:                      break;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     /** copy the rest from the background frame */
yading@10:     if (s->back_frame) {
yading@10:         while (out < out_end) {
yading@10:             memcpy(out, back_frame, line_end - out);
yading@10:             back_frame += line_end - out;
yading@10:             out         = line_end + stride_adj;
yading@10:             line_end   += stride;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: 
yading@10: /**
yading@10:  * Initialize the decoder
yading@10:  * @param avctx decoder context
yading@10:  * @return 0 success, -1 on error
yading@10:  */
yading@10: static av_cold int rl2_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     Rl2Context *s = avctx->priv_data;
yading@10:     int back_size;
yading@10:     int i;
yading@10: 
yading@10:     s->avctx       = avctx;
yading@10:     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10: 
yading@10:     /** parse extra data */
yading@10:     if (!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10: 
yading@10:     /** get frame_offset */
yading@10:     s->video_base = AV_RL16(&avctx->extradata[0]);
yading@10:     s->clr_count  = AV_RL32(&avctx->extradata[2]);
yading@10: 
yading@10:     if (s->video_base >= avctx->width * avctx->height) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     /** initialize palette */
yading@10:     for (i = 0; i < AVPALETTE_COUNT; i++)
yading@10:         s->palette[i] = 0xFFU << 24 | AV_RB24(&avctx->extradata[6 + i * 3]);
yading@10: 
yading@10:     /** decode background frame if present */
yading@10:     back_size = avctx->extradata_size - EXTRADATA1_SIZE;
yading@10: 
yading@10:     if (back_size > 0) {
yading@10:         uint8_t *back_frame = av_mallocz(avctx->width*avctx->height);
yading@10:         if (!back_frame)
yading@10:             return AVERROR(ENOMEM);
yading@10:         rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size,
yading@10:                        back_frame, avctx->width, 0);
yading@10:         s->back_frame = back_frame;
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: static int rl2_decode_frame(AVCodecContext *avctx,
yading@10:                             void *data, int *got_frame,
yading@10:                             AVPacket *avpkt)
yading@10: {
yading@10:     AVFrame *frame     = data;
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int ret, buf_size  = avpkt->size;
yading@10:     Rl2Context *s = avctx->priv_data;
yading@10: 
yading@10:     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     /** run length decode */
yading@10:     rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0],
yading@10:                    s->video_base);
yading@10: 
yading@10:     /** make the palette available on the way out */
yading@10:     memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
yading@10: 
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     /** report that the buffer was completely consumed */
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: 
yading@10: /**
yading@10:  * Uninit decoder
yading@10:  * @param avctx decoder context
yading@10:  * @return 0 success, -1 on error
yading@10:  */
yading@10: static av_cold int rl2_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     Rl2Context *s = avctx->priv_data;
yading@10: 
yading@10:     av_free(s->back_frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: AVCodec ff_rl2_decoder = {
yading@10:     .name           = "rl2",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_RL2,
yading@10:     .priv_data_size = sizeof(Rl2Context),
yading@10:     .init           = rl2_decode_init,
yading@10:     .close          = rl2_decode_end,
yading@10:     .decode         = rl2_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("RL2 video"),
yading@10: };