yading@10: /*
yading@10:  * American Laser Games MM Video Decoder
yading@10:  * Copyright (c) 2006,2008 Peter Ross
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:  * American Laser Games MM Video Decoder
yading@10:  * by Peter Ross (pross@xvid.org)
yading@10:  *
yading@10:  * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
yading@10:  * including Mad Dog McCree and Crime Patrol.
yading@10:  *
yading@10:  * Technical details here:
yading@10:  *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
yading@10:  */
yading@10: 
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "avcodec.h"
yading@10: #include "bytestream.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: #define MM_PREAMBLE_SIZE    6
yading@10: 
yading@10: #define MM_TYPE_INTER       0x5
yading@10: #define MM_TYPE_INTRA       0x8
yading@10: #define MM_TYPE_INTRA_HH    0xc
yading@10: #define MM_TYPE_INTER_HH    0xd
yading@10: #define MM_TYPE_INTRA_HHV   0xe
yading@10: #define MM_TYPE_INTER_HHV   0xf
yading@10: #define MM_TYPE_PALETTE     0x31
yading@10: 
yading@10: typedef struct MmContext {
yading@10:     AVCodecContext *avctx;
yading@10:     AVFrame frame;
yading@10:     int palette[AVPALETTE_COUNT];
yading@10:     GetByteContext gb;
yading@10: } MmContext;
yading@10: 
yading@10: static av_cold int mm_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     MmContext *s = avctx->priv_data;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10: 
yading@10:     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10: 
yading@10:     avcodec_get_frame_defaults(&s->frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int mm_decode_pal(MmContext *s)
yading@10: {
yading@10:     int i;
yading@10: 
yading@10:     bytestream2_skip(&s->gb, 4);
yading@10:     for (i = 0; i < 128; i++) {
yading@10:         s->palette[i] = 0xFFU << 24 | bytestream2_get_be24(&s->gb);
yading@10:         s->palette[i+128] = s->palette[i]<<2;
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * @param half_horiz Half horizontal resolution (0 or 1)
yading@10:  * @param half_vert Half vertical resolution (0 or 1)
yading@10:  */
yading@10: static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
yading@10: {
yading@10:     int x = 0, y = 0;
yading@10: 
yading@10:     while (bytestream2_get_bytes_left(&s->gb) > 0) {
yading@10:         int run_length, color;
yading@10: 
yading@10:         if (y >= s->avctx->height)
yading@10:             return 0;
yading@10: 
yading@10:         color = bytestream2_get_byte(&s->gb);
yading@10:         if (color & 0x80) {
yading@10:             run_length = 1;
yading@10:         }else{
yading@10:             run_length = (color & 0x7f) + 2;
yading@10:             color = bytestream2_get_byte(&s->gb);
yading@10:         }
yading@10: 
yading@10:         if (half_horiz)
yading@10:             run_length *=2;
yading@10: 
yading@10:         if (color) {
yading@10:             memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
yading@10:             if (half_vert)
yading@10:                 memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
yading@10:         }
yading@10:         x+= run_length;
yading@10: 
yading@10:         if (x >= s->avctx->width) {
yading@10:             x=0;
yading@10:             y += 1 + half_vert;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * @param half_horiz Half horizontal resolution (0 or 1)
yading@10:  * @param half_vert Half vertical resolution (0 or 1)
yading@10:  */
yading@10: static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
yading@10: {
yading@10:     int data_off = bytestream2_get_le16(&s->gb), y = 0;
yading@10:     GetByteContext data_ptr;
yading@10: 
yading@10:     if (bytestream2_get_bytes_left(&s->gb) < data_off)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
yading@10:     while (s->gb.buffer < data_ptr.buffer_start) {
yading@10:         int i, j;
yading@10:         int length = bytestream2_get_byte(&s->gb);
yading@10:         int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
yading@10:         length &= 0x7F;
yading@10: 
yading@10:         if (length==0) {
yading@10:             y += x;
yading@10:             continue;
yading@10:         }
yading@10: 
yading@10:         if (y + half_vert >= s->avctx->height)
yading@10:             return 0;
yading@10: 
yading@10:         for(i=0; i<length; i++) {
yading@10:             int replace_array = bytestream2_get_byte(&s->gb);
yading@10:             for(j=0; j<8; j++) {
yading@10:                 int replace = (replace_array >> (7-j)) & 1;
yading@10:                 if (replace) {
yading@10:                     int color = bytestream2_get_byte(&data_ptr);
yading@10:                     s->frame.data[0][y*s->frame.linesize[0] + x] = color;
yading@10:                     if (half_horiz)
yading@10:                         s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
yading@10:                     if (half_vert) {
yading@10:                         s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
yading@10:                         if (half_horiz)
yading@10:                             s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
yading@10:                     }
yading@10:                 }
yading@10:                 x += 1 + half_horiz;
yading@10:             }
yading@10:         }
yading@10: 
yading@10:         y += 1 + half_vert;
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int mm_decode_frame(AVCodecContext *avctx,
yading@10:                             void *data, int *got_frame,
yading@10:                             AVPacket *avpkt)
yading@10: {
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size = avpkt->size;
yading@10:     MmContext *s = avctx->priv_data;
yading@10:     int type, res;
yading@10: 
yading@10:     if (buf_size < MM_PREAMBLE_SIZE)
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     type = AV_RL16(&buf[0]);
yading@10:     buf += MM_PREAMBLE_SIZE;
yading@10:     buf_size -= MM_PREAMBLE_SIZE;
yading@10:     bytestream2_init(&s->gb, buf, buf_size);
yading@10: 
yading@10:     if ((res = ff_reget_buffer(avctx, &s->frame)) < 0)
yading@10:         return res;
yading@10: 
yading@10:     switch(type) {
yading@10:     case MM_TYPE_PALETTE   : res = mm_decode_pal(s); return avpkt->size;
yading@10:     case MM_TYPE_INTRA     : res = mm_decode_intra(s, 0, 0); break;
yading@10:     case MM_TYPE_INTRA_HH  : res = mm_decode_intra(s, 1, 0); break;
yading@10:     case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
yading@10:     case MM_TYPE_INTER     : res = mm_decode_inter(s, 0, 0); break;
yading@10:     case MM_TYPE_INTER_HH  : res = mm_decode_inter(s, 1, 0); break;
yading@10:     case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
yading@10:     default:
yading@10:         res = AVERROR_INVALIDDATA;
yading@10:         break;
yading@10:     }
yading@10:     if (res < 0)
yading@10:         return res;
yading@10: 
yading@10:     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
yading@10: 
yading@10:     if ((res = av_frame_ref(data, &s->frame)) < 0)
yading@10:         return res;
yading@10: 
yading@10:     *got_frame      = 1;
yading@10: 
yading@10:     return avpkt->size;
yading@10: }
yading@10: 
yading@10: static av_cold int mm_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     MmContext *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_unref(&s->frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_mmvideo_decoder = {
yading@10:     .name           = "mmvideo",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_MMVIDEO,
yading@10:     .priv_data_size = sizeof(MmContext),
yading@10:     .init           = mm_decode_init,
yading@10:     .close          = mm_decode_end,
yading@10:     .decode         = mm_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
yading@10: };