/* * 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" #include "bytestream.h" #include "internal.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]; GetByteContext gb; } MmContext; static av_cold int mm_decode_init(AVCodecContext *avctx) { MmContext *s = avctx->priv_data; s->avctx = avctx; avctx->pix_fmt = AV_PIX_FMT_PAL8; if (!avctx->width || !avctx->height || (avctx->width & 1) || (avctx->height & 1)) { av_log(avctx, AV_LOG_ERROR, "Invalid video dimensions: %dx%d\n", avctx->width, avctx->height); return AVERROR(EINVAL); } s->frame = av_frame_alloc(); if (!s->frame) return AVERROR(ENOMEM); return 0; } static int mm_decode_pal(MmContext *s) { int i; bytestream2_skip(&s->gb, 4); for (i = 0; i < 128; i++) { s->palette[i] = bytestream2_get_be24(&s->gb); s->palette[i+128] = s->palette[i]<<2; } return 0; } /** * @param half_horiz Half horizontal resolution (0 or 1) * @param half_vert Half vertical resolution (0 or 1) */ static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert) { int x = 0, y = 0; while (bytestream2_get_bytes_left(&s->gb) > 0) { int run_length, color; // writes one more line when half_vert is true if (y >= s->avctx->height + !!half_vert) return 0; color = bytestream2_get_byte(&s->gb); if (color & 0x80) { run_length = 1; }else{ run_length = (color & 0x7f) + 2; color = bytestream2_get_byte(&s->gb); } if (half_horiz) run_length *=2; if (s->avctx->width - x < run_length) return AVERROR_INVALIDDATA; 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; } } return 0; } /* * @param half_horiz Half horizontal resolution (0 or 1) * @param half_vert Half vertical resolution (0 or 1) */ static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert) { int data_off = bytestream2_get_le16(&s->gb); int y = 0; GetByteContext data_ptr; if (bytestream2_get_bytes_left(&s->gb) < data_off) return AVERROR_INVALIDDATA; bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off); while (s->gb.buffer < data_ptr.buffer_start) { int i, j; int length = bytestream2_get_byte(&s->gb); int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1); length &= 0x7F; if (length==0) { y += x; continue; } if (y + half_vert >= s->avctx->height) return 0; for(i=0; i<length; i++) { int replace_array = bytestream2_get_byte(&s->gb); for(j=0; j<8; j++) { int replace = (replace_array >> (7-j)) & 1; if (x + half_horiz >= s->avctx->width) return AVERROR_INVALIDDATA; if (replace) { int color = bytestream2_get_byte(&data_ptr); 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; } } x += 1 + half_horiz; } } y += 1 + half_vert; } return 0; } static int mm_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; MmContext *s = avctx->priv_data; int type, res; if (buf_size < MM_PREAMBLE_SIZE) return AVERROR_INVALIDDATA; type = AV_RL16(&buf[0]); buf += MM_PREAMBLE_SIZE; buf_size -= MM_PREAMBLE_SIZE; bytestream2_init(&s->gb, buf, buf_size); if ((res = ff_reget_buffer(avctx, s->frame)) < 0) { av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return res; } switch(type) { case MM_TYPE_PALETTE : res = mm_decode_pal(s); return buf_size; case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break; case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break; case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break; case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break; case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break; case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break; default: res = AVERROR_INVALIDDATA; break; } if (res < 0) return res; memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE); if ((res = av_frame_ref(data, s->frame)) < 0) return res; *got_frame = 1; return buf_size; } static av_cold int mm_decode_end(AVCodecContext *avctx) { MmContext *s = avctx->priv_data; av_frame_free(&s->frame); return 0; } AVCodec ff_mmvideo_decoder = { .name = "mmvideo", .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_MMVIDEO, .priv_data_size = sizeof(MmContext), .init = mm_decode_init, .close = mm_decode_end, .decode = mm_decode_frame, .capabilities = AV_CODEC_CAP_DR1, };