/* * American Laser Games MM Video Decoder * Copyright (c) 2006,2008 Peter Ross * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * American Laser Games MM Video Decoder * by Peter Ross (pross@xvid.org) * * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games, * including Mad Dog McCree and Crime Patrol. * * Technical details here: * http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM */ #include "libavutil/intreadwrite.h" #include "avcodec.h" #define MM_PREAMBLE_SIZE 6 #define MM_TYPE_INTER 0x5 #define MM_TYPE_INTRA 0x8 #define MM_TYPE_INTRA_HH 0xc #define MM_TYPE_INTER_HH 0xd #define MM_TYPE_INTRA_HHV 0xe #define MM_TYPE_INTER_HHV 0xf #define MM_TYPE_PALETTE 0x31 typedef struct MmContext { AVCodecContext *avctx; AVFrame frame; int palette[AVPALETTE_COUNT]; } MmContext; static av_cold int mm_decode_init(AVCodecContext *avctx) { MmContext *s = avctx->priv_data; s->avctx = avctx; avctx->pix_fmt = PIX_FMT_PAL8; s->frame.reference = 1; return 0; } static void mm_decode_pal(MmContext *s, const uint8_t *buf, const uint8_t *buf_end) { int i; buf += 4; for (i=0; i<128 && buf+2<buf_end; i++) { s->palette[i] = AV_RB24(buf); s->palette[i+128] = s->palette[i]<<2; buf += 3; } } /** * @param half_horiz Half horizontal resolution (0 or 1) * @param half_vert Half vertical resolution (0 or 1) */ static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size) { int i, x, y; i=0; x=0; y=0; while(i<buf_size) { int run_length, color; if (y >= s->avctx->height) return; if (buf[i] & 0x80) { run_length = 1; color = buf[i]; i++; }else{ run_length = (buf[i] & 0x7f) + 2; color = buf[i+1]; i+=2; } if (half_horiz) run_length *=2; if (color) { memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length); if (half_vert) memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length); } x+= run_length; if (x >= s->avctx->width) { x=0; y += 1 + half_vert; } } } /* * @param half_horiz Half horizontal resolution (0 or 1) * @param half_vert Half vertical resolution (0 or 1) */ static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size) { const int data_ptr = 2 + AV_RL16(&buf[0]); int d, r, y; d = data_ptr; r = 2; y = 0; while(r < data_ptr) { int i, j; int length = buf[r] & 0x7f; int x = buf[r+1] + ((buf[r] & 0x80) << 1); r += 2; if (length==0) { y += x; continue; } if (y + half_vert >= s->avctx->height) return; for(i=0; i<length; i++) { for(j=0; j<8; j++) { int replace = (buf[r+i] >> (7-j)) & 1; if (replace) { int color = buf[d]; s->frame.data[0][y*s->frame.linesize[0] + x] = color; if (half_horiz) s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color; if (half_vert) { s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color; if (half_horiz) s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color; } d++; } x += 1 + half_horiz; } } r += length; y += 1 + half_vert; } } static int mm_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; MmContext *s = avctx->priv_data; const uint8_t *buf_end = buf+buf_size; int type; type = AV_RL16(&buf[0]); buf += MM_PREAMBLE_SIZE; buf_size -= MM_PREAMBLE_SIZE; if (avctx->reget_buffer(avctx, &s->frame) < 0) { av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return -1; } switch(type) { case MM_TYPE_PALETTE : mm_decode_pal(s, buf, buf_end); return buf_size; case MM_TYPE_INTRA : mm_decode_intra(s, 0, 0, buf, buf_size); break; case MM_TYPE_INTRA_HH : mm_decode_intra(s, 1, 0, buf, buf_size); break; case MM_TYPE_INTRA_HHV : mm_decode_intra(s, 1, 1, buf, buf_size); break; case MM_TYPE_INTER : mm_decode_inter(s, 0, 0, buf, buf_size); break; case MM_TYPE_INTER_HH : mm_decode_inter(s, 1, 0, buf, buf_size); break; case MM_TYPE_INTER_HHV : mm_decode_inter(s, 1, 1, buf, buf_size); break; default : return -1; } memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE); *data_size = sizeof(AVFrame); *(AVFrame*)data = s->frame; return buf_size; } static av_cold int mm_decode_end(AVCodecContext *avctx) { MmContext *s = avctx->priv_data; if(s->frame.data[0]) avctx->release_buffer(avctx, &s->frame); return 0; } AVCodec ff_mmvideo_decoder = { "mmvideo", AVMEDIA_TYPE_VIDEO, CODEC_ID_MMVIDEO, sizeof(MmContext), mm_decode_init, NULL, mm_decode_end, mm_decode_frame, CODEC_CAP_DR1, .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"), };