LCOV - code coverage report
Current view: top level - libavcodec - kgv1dec.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 67 81 82.7 %
Date: 2017-12-15 11:05:35 Functions: 4 4 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Kega Game Video (KGV1) decoder
       3             :  * Copyright (c) 2010 Daniel Verkamp
       4             :  *
       5             :  * This file is part of FFmpeg.
       6             :  *
       7             :  * FFmpeg is free software; you can redistribute it and/or
       8             :  * modify it under the terms of the GNU Lesser General Public
       9             :  * License as published by the Free Software Foundation; either
      10             :  * version 2.1 of the License, or (at your option) any later version.
      11             :  *
      12             :  * FFmpeg is distributed in the hope that it will be useful,
      13             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15             :  * Lesser General Public License for more details.
      16             :  *
      17             :  * You should have received a copy of the GNU Lesser General Public
      18             :  * License along with FFmpeg; if not, write to the Free Software
      19             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      20             :  */
      21             : 
      22             : /**
      23             :  * @file
      24             :  * Kega Game Video decoder
      25             :  */
      26             : 
      27             : #include "libavutil/common.h"
      28             : #include "libavutil/intreadwrite.h"
      29             : #include "libavutil/imgutils.h"
      30             : #include "avcodec.h"
      31             : #include "internal.h"
      32             : 
      33             : typedef struct KgvContext {
      34             :     uint16_t *frame_buffer;
      35             :     uint16_t *last_frame_buffer;
      36             : } KgvContext;
      37             : 
      38           2 : static void decode_flush(AVCodecContext *avctx)
      39             : {
      40           2 :     KgvContext * const c = avctx->priv_data;
      41             : 
      42           2 :     av_freep(&c->frame_buffer);
      43           2 :     av_freep(&c->last_frame_buffer);
      44           2 : }
      45             : 
      46         313 : static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
      47             :                         AVPacket *avpkt)
      48             : {
      49         313 :     AVFrame *frame = data;
      50         313 :     const uint8_t *buf = avpkt->data;
      51         313 :     const uint8_t *buf_end = buf + avpkt->size;
      52         313 :     KgvContext * const c = avctx->priv_data;
      53             :     int offsets[8];
      54             :     uint8_t *out, *prev;
      55         313 :     int outcnt = 0, maxcnt;
      56             :     int w, h, i, res;
      57             : 
      58         313 :     if (avpkt->size < 2)
      59           0 :         return AVERROR_INVALIDDATA;
      60             : 
      61         313 :     w = (buf[0] + 1) * 8;
      62         313 :     h = (buf[1] + 1) * 8;
      63         313 :     buf += 2;
      64             : 
      65         313 :     if (avpkt->size < 2 + w*h / 513)
      66           0 :         return AVERROR_INVALIDDATA;
      67             : 
      68         313 :     if (w != avctx->width || h != avctx->height) {
      69           0 :         av_freep(&c->frame_buffer);
      70           0 :         av_freep(&c->last_frame_buffer);
      71           0 :         if ((res = ff_set_dimensions(avctx, w, h)) < 0)
      72           0 :             return res;
      73             :     }
      74             : 
      75         313 :     if (!c->frame_buffer) {
      76           1 :         c->frame_buffer      = av_mallocz(avctx->width * avctx->height * 2);
      77           1 :         c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
      78           1 :         if (!c->frame_buffer || !c->last_frame_buffer) {
      79           0 :             decode_flush(avctx);
      80           0 :             return AVERROR(ENOMEM);
      81             :         }
      82             :     }
      83             : 
      84         313 :     maxcnt = w * h;
      85             : 
      86         313 :     if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
      87           0 :         return res;
      88         313 :     out  = (uint8_t*)c->frame_buffer;
      89         313 :     prev = (uint8_t*)c->last_frame_buffer;
      90             : 
      91        2817 :     for (i = 0; i < 8; i++)
      92        2504 :         offsets[i] = -1;
      93             : 
      94       51417 :     while (outcnt < maxcnt && buf_end - 2 >= buf) {
      95       50791 :         int code = AV_RL16(buf);
      96       50791 :         buf += 2;
      97             : 
      98       50791 :         if (!(code & 0x8000)) {
      99         756 :             AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
     100         756 :             outcnt++;
     101             :         } else {
     102             :             int count;
     103             : 
     104       50035 :             if ((code & 0x6000) == 0x6000) {
     105             :                 // copy from previous frame
     106       22112 :                 int oidx = (code >> 10) & 7;
     107             :                 int start;
     108             : 
     109       22112 :                 count = (code & 0x3FF) + 3;
     110             : 
     111       22112 :                 if (offsets[oidx] < 0) {
     112         304 :                     if (buf_end - 3 < buf)
     113           0 :                         break;
     114         304 :                     offsets[oidx] = AV_RL24(buf);
     115         304 :                     buf += 3;
     116             :                 }
     117             : 
     118       22112 :                 start = (outcnt + offsets[oidx]) % maxcnt;
     119             : 
     120       22112 :                 if (maxcnt - start < count || maxcnt - outcnt < count)
     121             :                     break;
     122             : 
     123       22112 :                 if (!prev) {
     124           0 :                     av_log(avctx, AV_LOG_ERROR,
     125             :                            "Frame reference does not exist\n");
     126           0 :                     break;
     127             :                 }
     128             : 
     129       22112 :                 memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
     130             :             } else {
     131             :                 // copy from earlier in this frame
     132       27923 :                 int offset = (code & 0x1FFF) + 1;
     133             : 
     134       27923 :                 if (!(code & 0x6000)) {
     135        1091 :                     count = 2;
     136       26832 :                 } else if ((code & 0x6000) == 0x2000) {
     137         776 :                     count = 3;
     138             :                 } else {
     139       26056 :                     if (buf_end - 1 < buf)
     140           0 :                         break;
     141       26056 :                     count = 4 + *buf++;
     142             :                 }
     143             : 
     144       27923 :                 if (outcnt < offset || maxcnt - outcnt < count)
     145             :                     break;
     146             : 
     147       27923 :                 av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
     148             :             }
     149       50035 :             outcnt += count;
     150             :         }
     151             :     }
     152             : 
     153         313 :     if (outcnt - maxcnt)
     154           0 :         av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
     155             : 
     156        1252 :     av_image_copy_plane(frame->data[0], frame->linesize[0],
     157         626 :                         (const uint8_t*)c->frame_buffer,  avctx->width * 2,
     158         313 :                         avctx->width * 2, avctx->height);
     159         313 :     FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer);
     160             : 
     161         313 :     *got_frame = 1;
     162             : 
     163         313 :     return avpkt->size;
     164             : }
     165             : 
     166           2 : static av_cold int decode_init(AVCodecContext *avctx)
     167             : {
     168           2 :     avctx->pix_fmt = AV_PIX_FMT_RGB555;
     169             : 
     170           2 :     return 0;
     171             : }
     172             : 
     173           2 : static av_cold int decode_end(AVCodecContext *avctx)
     174             : {
     175           2 :     decode_flush(avctx);
     176           2 :     return 0;
     177             : }
     178             : 
     179             : AVCodec ff_kgv1_decoder = {
     180             :     .name           = "kgv1",
     181             :     .long_name      = NULL_IF_CONFIG_SMALL("Kega Game Video"),
     182             :     .type           = AVMEDIA_TYPE_VIDEO,
     183             :     .id             = AV_CODEC_ID_KGV1,
     184             :     .priv_data_size = sizeof(KgvContext),
     185             :     .init           = decode_init,
     186             :     .close          = decode_end,
     187             :     .decode         = decode_frame,
     188             :     .flush          = decode_flush,
     189             :     .capabilities   = AV_CODEC_CAP_DR1,
     190             : };

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