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tscc.c
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1 /*
2  * TechSmith Camtasia decoder
3  * Copyright (c) 2004 Konstantin Shishkov
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  * TechSmith Camtasia decoder
25  *
26  * Fourcc: TSCC
27  *
28  * Codec is very simple:
29  * it codes picture (picture difference, really)
30  * with algorithm almost identical to Windows RLE8,
31  * only without padding and with greater pixel sizes,
32  * then this coded picture is packed with ZLib
33  *
34  * Supports: BGR8,BGR555,BGR24 - only BGR8 and BGR555 tested
35  *
36  */
37 
38 #include <stdio.h>
39 #include <stdlib.h>
40 
41 #include "avcodec.h"
42 #include "internal.h"
43 #include "msrledec.h"
44 
45 #include <zlib.h>
46 
47 typedef struct TsccContext {
48 
51 
52  // Bits per pixel
53  int bpp;
54  // Decompressed data size
55  unsigned int decomp_size;
56  // Decompression buffer
57  unsigned char* decomp_buf;
59  int height;
60  z_stream zstream;
61 
62  uint32_t pal[256];
64 
65 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
66  AVPacket *avpkt)
67 {
68  const uint8_t *buf = avpkt->data;
69  int buf_size = avpkt->size;
70  CamtasiaContext * const c = avctx->priv_data;
71  const unsigned char *encoded = buf;
72  AVFrame *frame = c->frame;
73  int zret; // Zlib return code
74  int ret, len = buf_size;
75 
76  if ((ret = ff_reget_buffer(avctx, frame)) < 0)
77  return ret;
78 
79  zret = inflateReset(&c->zstream);
80  if (zret != Z_OK) {
81  av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
82  return AVERROR_UNKNOWN;
83  }
84  c->zstream.next_in = (uint8_t*)encoded;
85  c->zstream.avail_in = len;
86  c->zstream.next_out = c->decomp_buf;
87  c->zstream.avail_out = c->decomp_size;
88  zret = inflate(&c->zstream, Z_FINISH);
89  // Z_DATA_ERROR means empty picture
90  if ((zret != Z_OK) && (zret != Z_STREAM_END) && (zret != Z_DATA_ERROR)) {
91  av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", zret);
92  return AVERROR_UNKNOWN;
93  }
94 
95 
96  if (zret != Z_DATA_ERROR) {
98  c->decomp_size - c->zstream.avail_out);
99  ff_msrle_decode(avctx, (AVPicture*)frame, c->bpp, &c->gb);
100  }
101 
102  /* make the palette available on the way out */
103  if (c->avctx->pix_fmt == AV_PIX_FMT_PAL8) {
104  const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
105 
106  if (pal) {
107  frame->palette_has_changed = 1;
108  memcpy(c->pal, pal, AVPALETTE_SIZE);
109  }
110  memcpy(frame->data[1], c->pal, AVPALETTE_SIZE);
111  }
112 
113  if ((ret = av_frame_ref(data, frame)) < 0)
114  return ret;
115  *got_frame = 1;
116 
117  /* always report that the buffer was completely consumed */
118  return buf_size;
119 }
120 
122 {
123  CamtasiaContext * const c = avctx->priv_data;
124  int zret; // Zlib return code
125 
126  c->avctx = avctx;
127 
128  c->height = avctx->height;
129 
130  // Needed if zlib unused or init aborted before inflateInit
131  memset(&c->zstream, 0, sizeof(z_stream));
132  switch(avctx->bits_per_coded_sample){
133  case 8: avctx->pix_fmt = AV_PIX_FMT_PAL8; break;
134  case 16: avctx->pix_fmt = AV_PIX_FMT_RGB555; break;
135  case 24:
136  avctx->pix_fmt = AV_PIX_FMT_BGR24;
137  break;
138  case 32: avctx->pix_fmt = AV_PIX_FMT_RGB32; break;
139  default: av_log(avctx, AV_LOG_ERROR, "Camtasia error: unknown depth %i bpp\n", avctx->bits_per_coded_sample);
140  return AVERROR_PATCHWELCOME;
141  }
142  c->bpp = avctx->bits_per_coded_sample;
143  // buffer size for RLE 'best' case when 2-byte code precedes each pixel and there may be padding after it too
144  c->decomp_size = (((avctx->width * c->bpp + 7) >> 3) + 3 * avctx->width + 2) * avctx->height + 2;
145 
146  /* Allocate decompression buffer */
147  if (c->decomp_size) {
148  if ((c->decomp_buf = av_malloc(c->decomp_size)) == NULL) {
149  av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
150  return AVERROR(ENOMEM);
151  }
152  }
153 
154  c->zstream.zalloc = Z_NULL;
155  c->zstream.zfree = Z_NULL;
156  c->zstream.opaque = Z_NULL;
157  zret = inflateInit(&c->zstream);
158  if (zret != Z_OK) {
159  av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
160  return AVERROR_UNKNOWN;
161  }
162 
163  c->frame = av_frame_alloc();
164 
165  return 0;
166 }
167 
169 {
170  CamtasiaContext * const c = avctx->priv_data;
171 
172  av_freep(&c->decomp_buf);
173  av_frame_free(&c->frame);
174 
175  inflateEnd(&c->zstream);
176 
177  return 0;
178 }
179 
181  .name = "camtasia",
182  .type = AVMEDIA_TYPE_VIDEO,
183  .id = AV_CODEC_ID_TSCC,
184  .priv_data_size = sizeof(CamtasiaContext),
185  .init = decode_init,
186  .close = decode_end,
187  .decode = decode_frame,
188  .capabilities = CODEC_CAP_DR1,
189  .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Capture Codec"),
190 };