FFmpeg
cscd.c
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1 /*
2  * CamStudio decoder
3  * Copyright (c) 2006 Reimar Doeffinger
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 #include "avcodec.h"
23 #include "codec_internal.h"
24 #include "decode.h"
25 #include "libavutil/mem.h"
26 
27 #if CONFIG_ZLIB
28 #include <zlib.h>
29 #endif
30 #include "libavutil/lzo.h"
31 
32 typedef struct CamStudioContext {
35  unsigned int decomp_size;
36  unsigned char* decomp_buf;
38 
39 static void copy_frame_default(AVFrame *f, const uint8_t *src,
40  int linelen, int height)
41 {
42  int i, src_stride = FFALIGN(linelen, 4);
43  uint8_t *dst = f->data[0];
44  dst += (height - 1) * f->linesize[0];
45  for (i = height; i; i--) {
46  memcpy(dst, src, linelen);
47  src += src_stride;
48  dst -= f->linesize[0];
49  }
50 }
51 
52 static void add_frame_default(AVFrame *f, const uint8_t *src,
53  int linelen, int height)
54 {
55  int i, j, src_stride = FFALIGN(linelen, 4);
56  uint8_t *dst = f->data[0];
57  dst += (height - 1) * f->linesize[0];
58  for (i = height; i; i--) {
59  for (j = linelen; j; j--)
60  *dst++ += *src++;
61  src += src_stride - linelen;
62  dst -= f->linesize[0] + linelen;
63  }
64 }
65 
66 static int decode_frame(AVCodecContext *avctx, AVFrame *rframe,
67  int *got_frame, AVPacket *avpkt)
68 {
69  const uint8_t *buf = avpkt->data;
70  int buf_size = avpkt->size;
71  CamStudioContext *c = avctx->priv_data;
72  int ret;
73  int bpp = avctx->bits_per_coded_sample / 8;
74  int bugdelta = FFALIGN(avctx->width * bpp, 4) * avctx->height
75  - (avctx->width & ~3) * bpp * avctx->height;
76 
77  if (buf_size < 2) {
78  av_log(avctx, AV_LOG_ERROR, "coded frame too small\n");
79  return AVERROR_INVALIDDATA;
80  }
81 
82  if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
83  return ret;
84 
85  // decompress data
86  switch ((buf[0] >> 1) & 7) {
87  case 0: { // lzo compression
88  int outlen = c->decomp_size, inlen = buf_size - 2;
89  if (av_lzo1x_decode(c->decomp_buf, &outlen, &buf[2], &inlen) || (outlen && outlen != bugdelta)) {
90  av_log(avctx, AV_LOG_ERROR, "error during lzo decompression\n");
91  return AVERROR_INVALIDDATA;
92  }
93  break;
94  }
95  case 1: { // zlib compression
96 #if CONFIG_ZLIB
97  unsigned long dlen = c->decomp_size;
98  if (uncompress(c->decomp_buf, &dlen, &buf[2], buf_size - 2) != Z_OK || (dlen != c->decomp_size && dlen != c->decomp_size - bugdelta)) {
99  av_log(avctx, AV_LOG_ERROR, "error during zlib decompression\n");
100  return AVERROR_INVALIDDATA;
101  }
102  break;
103 #else
104  av_log(avctx, AV_LOG_ERROR, "compiled without zlib support\n");
105  return AVERROR(ENOSYS);
106 #endif
107  }
108  default:
109  av_log(avctx, AV_LOG_ERROR, "unknown compression\n");
110  return AVERROR_INVALIDDATA;
111  }
112 
113  // flip upside down, add difference frame
114  if (buf[0] & 1) { // keyframe
115  c->pic->pict_type = AV_PICTURE_TYPE_I;
116  c->pic->flags |= AV_FRAME_FLAG_KEY;
117  copy_frame_default(c->pic, c->decomp_buf,
118  c->linelen, c->height);
119  } else {
120  c->pic->pict_type = AV_PICTURE_TYPE_P;
121  c->pic->flags &= ~AV_FRAME_FLAG_KEY;
122  add_frame_default(c->pic, c->decomp_buf,
123  c->linelen, c->height);
124  }
125 
126  *got_frame = 1;
127  if ((ret = av_frame_ref(rframe, c->pic)) < 0)
128  return ret;
129 
130  return buf_size;
131 }
132 
134 {
135  CamStudioContext *c = avctx->priv_data;
136  int stride;
137  switch (avctx->bits_per_coded_sample) {
138  case 16: avctx->pix_fmt = AV_PIX_FMT_RGB555LE; break;
139  case 24: avctx->pix_fmt = AV_PIX_FMT_BGR24; break;
140  case 32: avctx->pix_fmt = AV_PIX_FMT_BGR0; break;
141  default:
142  av_log(avctx, AV_LOG_ERROR,
143  "CamStudio codec error: invalid depth %i bpp\n",
144  avctx->bits_per_coded_sample);
145  return AVERROR_INVALIDDATA;
146  }
147  c->bpp = avctx->bits_per_coded_sample;
148  c->linelen = avctx->width * avctx->bits_per_coded_sample / 8;
149  c->height = avctx->height;
150  stride = FFALIGN(c->linelen, 4);
151  c->decomp_size = c->height * stride;
152  c->decomp_buf = av_malloc(c->decomp_size + AV_LZO_OUTPUT_PADDING);
153  if (!c->decomp_buf) {
154  av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
155  return AVERROR(ENOMEM);
156  }
157  c->pic = av_frame_alloc();
158  if (!c->pic)
159  return AVERROR(ENOMEM);
160  return 0;
161 }
162 
164 {
165  CamStudioContext *c = avctx->priv_data;
166  av_freep(&c->decomp_buf);
167  av_frame_free(&c->pic);
168  return 0;
169 }
170 
172  .p.name = "camstudio",
173  CODEC_LONG_NAME("CamStudio"),
174  .p.type = AVMEDIA_TYPE_VIDEO,
175  .p.id = AV_CODEC_ID_CSCD,
176  .priv_data_size = sizeof(CamStudioContext),
177  .init = decode_init,
178  .close = decode_end,
180  .p.capabilities = AV_CODEC_CAP_DR1,
181  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
182 };
decode_end
static av_cold int decode_end(AVCodecContext *avctx)
Definition: cscd.c:163
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: codec_internal.h:42
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:160
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:375
AVPacket::data
uint8_t * data
Definition: packet.h:524
FFCodec
Definition: codec_internal.h:127
AV_PIX_FMT_BGR24
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:76
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:30
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:131
decode_init
static av_cold int decode_init(AVCodecContext *avctx)
Definition: cscd.c:133
CamStudioContext::height
int height
Definition: cscd.c:34
ff_cscd_decoder
const FFCodec ff_cscd_decoder
Definition: cscd.c:171
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:148
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
AV_FRAME_FLAG_KEY
#define AV_FRAME_FLAG_KEY
A flag to mark frames that are keyframes.
Definition: frame.h:626
copy_frame_default
static void copy_frame_default(AVFrame *f, const uint8_t *src, int linelen, int height)
Definition: cscd.c:39
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:287
CamStudioContext::decomp_buf
unsigned char * decomp_buf
Definition: cscd.c:36
add_frame_default
static void add_frame_default(AVFrame *f, const uint8_t *src, int linelen, int height)
Definition: cscd.c:52
decode.h
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:272
if
if(ret)
Definition: filter_design.txt:179
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:279
AV_PIX_FMT_BGR0
@ AV_PIX_FMT_BGR0
packed BGR 8:8:8, 32bpp, BGRXBGRX... X=unused/undefined
Definition: pixfmt.h:265
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
f
f
Definition: af_crystalizer.c:121
av_lzo1x_decode
int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen)
Decodes LZO 1x compressed data.
Definition: lzo.c:136
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:366
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:525
av_frame_ref
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:384
codec_internal.h
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
CamStudioContext
Definition: cscd.c:32
CamStudioContext::bpp
int bpp
Definition: cscd.c:34
height
#define height
AVCodecContext::bits_per_coded_sample
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:1567
AV_PIX_FMT_RGB555LE
@ AV_PIX_FMT_RGB555LE
packed RGB 5:5:5, 16bpp, (msb)1X 5R 5G 5B(lsb), little-endian, X=unused/undefined
Definition: pixfmt.h:115
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
AV_LZO_OUTPUT_PADDING
#define AV_LZO_OUTPUT_PADDING
Definition: lzo.h:47
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:194
AVCodecContext::height
int height
Definition: avcodec.h:618
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:657
avcodec.h
stride
#define stride
Definition: h264pred_template.c:537
ff_reget_buffer
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Identical in function to ff_get_buffer(), except it reuses the existing buffer if available.
Definition: decode.c:1663
ret
ret
Definition: filter_design.txt:187
AV_CODEC_ID_CSCD
@ AV_CODEC_ID_CSCD
Definition: codec_id.h:131
CamStudioContext::pic
AVFrame * pic
Definition: cscd.c:33
lzo.h
decode_frame
static int decode_frame(AVCodecContext *avctx, AVFrame *rframe, int *got_frame, AVPacket *avpkt)
Definition: cscd.c:66
AVCodecContext
main external API structure.
Definition: avcodec.h:445
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:280
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
mem.h
CamStudioContext::linelen
int linelen
Definition: cscd.c:34
FFALIGN
#define FFALIGN(x, a)
Definition: macros.h:78
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:472
AVPacket
This structure stores compressed data.
Definition: packet.h:501
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:618
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
CamStudioContext::decomp_size
unsigned int decomp_size
Definition: cscd.c:35