FFmpeg
mwsc.c
Go to the documentation of this file.
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 "internal.h"
30 
31 #include <zlib.h>
32 
33 typedef struct MWSCContext {
34  unsigned int decomp_size;
36  z_stream zstream;
38 } MWSCContext;
39 
41  int width, int height, int stride, int pb_linesize, int gbp_linesize)
42 {
43  int intra = 1, w = 0;
44 
45  bytestream2_seek_p(pb, (height - 1) * pb_linesize, SEEK_SET);
46 
47  while (bytestream2_get_bytes_left(gb) > 0) {
48  uint32_t fill = bytestream2_get_le24(gb);
49  unsigned run = bytestream2_get_byte(gb);
50 
51  if (run == 0) {
52  run = bytestream2_get_le32(gb);
53  for (int j = 0; j < run; j++, w++) {
54  if (w == width) {
55  w = 0;
56  bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
57  }
58  bytestream2_put_le24(pb, fill);
59  }
60  } else if (run == 255) {
61  int pos = bytestream2_tell_p(pb);
62 
63  bytestream2_seek(gbp, pos, SEEK_SET);
64  for (int j = 0; j < fill; j++, w++) {
65  if (w == width) {
66  w = 0;
67  bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
68  bytestream2_seek(gbp, -(gbp_linesize + stride), SEEK_CUR);
69  }
70  bytestream2_put_le24(pb, bytestream2_get_le24(gbp));
71  }
72 
73  intra = 0;
74  } else {
75  for (int j = 0; j < run; j++, w++) {
76  if (w == width) {
77  w = 0;
78  bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
79  }
80  bytestream2_put_le24(pb, fill);
81  }
82  }
83  }
84 
85  return intra;
86 }
87 
88 static int decode_frame(AVCodecContext *avctx,
89  void *data, int *got_frame,
90  AVPacket *avpkt)
91 {
92  MWSCContext *s = avctx->priv_data;
93  AVFrame *frame = data;
94  uint8_t *buf = avpkt->data;
95  int buf_size = avpkt->size;
96  GetByteContext gb;
97  GetByteContext gbp;
98  PutByteContext pb;
99  int ret;
100 
101  ret = inflateReset(&s->zstream);
102  if (ret != Z_OK) {
103  av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret);
104  return AVERROR_EXTERNAL;
105  }
106  s->zstream.next_in = buf;
107  s->zstream.avail_in = buf_size;
108  s->zstream.next_out = s->decomp_buf;
109  s->zstream.avail_out = s->decomp_size;
110  ret = inflate(&s->zstream, Z_FINISH);
111  if (ret != Z_STREAM_END) {
112  av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", ret);
113  return AVERROR_EXTERNAL;
114  }
115 
116  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
117  return ret;
118 
119  bytestream2_init(&gb, s->decomp_buf, s->zstream.total_out);
120  bytestream2_init(&gbp, s->prev_frame->data[0], avctx->height * s->prev_frame->linesize[0]);
121  bytestream2_init_writer(&pb, frame->data[0], avctx->height * frame->linesize[0]);
122 
123  frame->key_frame = rle_uncompress(&gb, &pb, &gbp, avctx->width, avctx->height, avctx->width * 3,
124  frame->linesize[0], s->prev_frame->linesize[0]);
125 
127 
129  if ((ret = av_frame_ref(s->prev_frame, frame)) < 0)
130  return ret;
131 
132  *got_frame = 1;
133 
134  return avpkt->size;
135 }
136 
138 {
139  MWSCContext *s = avctx->priv_data;
140  int64_t size;
141  int zret;
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->zstream.zalloc = Z_NULL;
153  s->zstream.zfree = Z_NULL;
154  s->zstream.opaque = Z_NULL;
155  zret = inflateInit(&s->zstream);
156  if (zret != Z_OK) {
157  av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
158  return AVERROR_EXTERNAL;
159  }
160 
161  s->prev_frame = av_frame_alloc();
162  if (!s->prev_frame)
163  return AVERROR(ENOMEM);
164 
165  return 0;
166 }
167 
169 {
170  MWSCContext *s = avctx->priv_data;
171 
173  av_freep(&s->decomp_buf);
174  s->decomp_size = 0;
175  inflateEnd(&s->zstream);
176 
177  return 0;
178 }
179 
181  .name = "mwsc",
182  .long_name = NULL_IF_CONFIG_SMALL("MatchWare Screen Capture Codec"),
183  .type = AVMEDIA_TYPE_VIDEO,
184  .id = AV_CODEC_ID_MWSC,
185  .priv_data_size = sizeof(MWSCContext),
186  .init = decode_init,
187  .close = decode_close,
188  .decode = decode_frame,
189  .capabilities = AV_CODEC_CAP_DR1,
190  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
192 };
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: internal.h:48
static av_cold int decode_close(AVCodecContext *avctx)
Definition: mwsc.c:168
static int rle_uncompress(GetByteContext *gb, PutByteContext *pb, GetByteContext *gbp, int width, int height, int stride, int pb_linesize, int gbp_linesize)
Definition: mwsc.c:40
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1481
static av_always_inline void bytestream2_init_writer(PutByteContext *p, uint8_t *buf, int buf_size)
Definition: bytestream.h:143
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1778
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:133
uint8_t run
Definition: svq3.c:206
AVCodec.
Definition: avcodec.h:3492
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:40
uint8_t
static av_cold int decode_init(AVCodecContext *avctx)
Definition: mwsc.c:137
#define av_cold
Definition: attributes.h:82
#define av_malloc(s)
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:189
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:443
#define height
uint8_t * data
Definition: avcodec.h:1480
ptrdiff_t size
Definition: opengl_enc.c:100
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:202
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
Definition: bytestream.h:154
const char * name
Name of the codec implementation.
Definition: avcodec.h:3499
static av_always_inline int bytestream2_tell_p(PutByteContext *p)
Definition: bytestream.h:193
AVCodec ff_mwsc_decoder
Definition: mwsc.c:180
z_stream zstream
Definition: mwsc.c:36
uint8_t * decomp_buf
Definition: mwsc.c:35
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:378
#define width
int width
picture width / height.
Definition: avcodec.h:1741
uint8_t w
Definition: llviddspenc.c:38
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
#define s(width, name)
Definition: cbs_vp9.c:257
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
static av_always_inline int bytestream2_seek_p(PutByteContext *p, int offset, int whence)
Definition: bytestream.h:232
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
main external API structure.
Definition: avcodec.h:1568
AVFrame * prev_frame
Definition: mwsc.c:37
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1968
void * buf
Definition: avisynth_c.h:766
static void inflate(uint8_t *dst, const uint8_t *p1, int width, int threshold, const uint8_t *coordinates[], int coord, int maxc)
Definition: vf_neighbor.c:197
void av_frame_unref(AVFrame *frame)
Unreference all the buffers referenced by frame and reset the frame fields.
Definition: frame.c:553
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
GLint GLenum GLboolean GLsizei stride
Definition: opengl_enc.c:104
common internal api header.
void * priv_data
Definition: avcodec.h:1595
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:373
static av_always_inline int bytestream2_seek(GetByteContext *g, int offset, int whence)
Definition: bytestream.h:208
unsigned int decomp_size
Definition: mwsc.c:34
#define av_freep(p)
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
#define AVERROR_EXTERNAL
Generic error in an external library.
Definition: error.h:57
This structure stores compressed data.
Definition: avcodec.h:1457
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: mwsc.c:88
#define AV_GET_BUFFER_FLAG_REF
The decoder will keep a reference to the frame and may reuse it later.
Definition: avcodec.h:1179
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:984
Predicted.
Definition: avutil.h:275