1/* 2 * MatchWare Screen Capture Codec decoder 3 * 4 * Copyright (c) 2018 Paul B Mahol 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include <stdio.h> 24#include <stdlib.h> 25#include <string.h> 26 27#include "avcodec.h" 28#include "bytestream.h" 29#include "codec_internal.h" 30#include "internal.h" 31#include "zlib_wrapper.h" 32 33#include <zlib.h> 34 35typedef struct MWSCContext { 36 unsigned int decomp_size; 37 uint8_t *decomp_buf; 38 AVFrame *prev_frame; 39 FFZStream zstream; 40} MWSCContext; 41 42static int rle_uncompress(GetByteContext *gb, PutByteContext *pb, GetByteContext *gbp, 43 int width, int height, int stride, int pb_linesize, int gbp_linesize) 44{ 45 int intra = 1, w = 0; 46 47 bytestream2_seek_p(pb, (height - 1) * pb_linesize, SEEK_SET); 48 49 while (bytestream2_get_bytes_left(gb) > 0) { 50 uint32_t fill = bytestream2_get_le24(gb); 51 unsigned run = bytestream2_get_byte(gb); 52 53 if (run == 0) { 54 run = bytestream2_get_le32(gb); 55 for (int j = 0; j < run; j++, w++) { 56 if (w == width) { 57 w = 0; 58 bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR); 59 } 60 bytestream2_put_le24(pb, fill); 61 } 62 } else if (run == 255) { 63 int pos = bytestream2_tell_p(pb); 64 65 bytestream2_seek(gbp, pos, SEEK_SET); 66 for (int j = 0; j < fill; j++, w++) { 67 if (w == width) { 68 w = 0; 69 bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR); 70 bytestream2_seek(gbp, -(gbp_linesize + stride), SEEK_CUR); 71 } 72 bytestream2_put_le24(pb, bytestream2_get_le24(gbp)); 73 } 74 75 intra = 0; 76 } else { 77 for (int j = 0; j < run; j++, w++) { 78 if (w == width) { 79 w = 0; 80 bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR); 81 } 82 bytestream2_put_le24(pb, fill); 83 } 84 } 85 } 86 87 return intra; 88} 89 90static int decode_frame(AVCodecContext *avctx, AVFrame *frame, 91 int *got_frame, AVPacket *avpkt) 92{ 93 MWSCContext *s = avctx->priv_data; 94 z_stream *const zstream = &s->zstream.zstream; 95 const uint8_t *buf = avpkt->data; 96 int buf_size = avpkt->size; 97 GetByteContext gb; 98 GetByteContext gbp; 99 PutByteContext pb; 100 int ret; 101 102 ret = inflateReset(zstream); 103 if (ret != Z_OK) { 104 av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret); 105 return AVERROR_EXTERNAL; 106 } 107 zstream->next_in = buf; 108 zstream->avail_in = buf_size; 109 zstream->next_out = s->decomp_buf; 110 zstream->avail_out = s->decomp_size; 111 ret = inflate(zstream, Z_FINISH); 112 if (ret != Z_STREAM_END) { 113 av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", ret); 114 return AVERROR_EXTERNAL; 115 } 116 117 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) 118 return ret; 119 120 bytestream2_init(&gb, s->decomp_buf, zstream->total_out); 121 bytestream2_init(&gbp, s->prev_frame->data[0], avctx->height * s->prev_frame->linesize[0]); 122 bytestream2_init_writer(&pb, frame->data[0], avctx->height * frame->linesize[0]); 123 124 frame->key_frame = rle_uncompress(&gb, &pb, &gbp, avctx->width, avctx->height, avctx->width * 3, 125 frame->linesize[0], s->prev_frame->linesize[0]); 126 127 frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P; 128 129 av_frame_unref(s->prev_frame); 130 if ((ret = av_frame_ref(s->prev_frame, frame)) < 0) 131 return ret; 132 133 *got_frame = 1; 134 135 return avpkt->size; 136} 137 138static av_cold int decode_init(AVCodecContext *avctx) 139{ 140 MWSCContext *s = avctx->priv_data; 141 int64_t size; 142 143 avctx->pix_fmt = AV_PIX_FMT_BGR24; 144 145 size = 32LL * avctx->height * avctx->width; 146 if (size >= INT32_MAX) 147 return AVERROR_INVALIDDATA; 148 s->decomp_size = size; 149 if (!(s->decomp_buf = av_malloc(s->decomp_size))) 150 return AVERROR(ENOMEM); 151 152 s->prev_frame = av_frame_alloc(); 153 if (!s->prev_frame) 154 return AVERROR(ENOMEM); 155 156 return ff_inflate_init(&s->zstream, avctx); 157} 158 159static av_cold int decode_close(AVCodecContext *avctx) 160{ 161 MWSCContext *s = avctx->priv_data; 162 163 av_frame_free(&s->prev_frame); 164 av_freep(&s->decomp_buf); 165 s->decomp_size = 0; 166 ff_inflate_end(&s->zstream); 167 168 return 0; 169} 170 171const FFCodec ff_mwsc_decoder = { 172 .p.name = "mwsc", 173 .p.long_name = NULL_IF_CONFIG_SMALL("MatchWare Screen Capture Codec"), 174 .p.type = AVMEDIA_TYPE_VIDEO, 175 .p.id = AV_CODEC_ID_MWSC, 176 .priv_data_size = sizeof(MWSCContext), 177 .init = decode_init, 178 .close = decode_close, 179 FF_CODEC_DECODE_CB(decode_frame), 180 .p.capabilities = AV_CODEC_CAP_DR1, 181 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | 182 FF_CODEC_CAP_INIT_CLEANUP, 183}; 184