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screenpresso.c
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1 /*
2  * Screenpresso decoder
3  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
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  * Screenpresso decoder
25  *
26  * Fourcc: SPV1
27  *
28  * Screenpresso simply horizontally flips and then deflates frames,
29  * alternating full pictures and deltas. Deltas are related to the currently
30  * rebuilt frame (not the reference), and since there is no coordinate system
31  * they contain exactly as many pixel as the keyframe.
32  *
33  * Supports: BGR0, BGR24, RGB555
34  */
35 
36 #include <stdint.h>
37 #include <string.h>
38 #include <zlib.h>
39 
40 #include "libavutil/imgutils.h"
41 #include "libavutil/internal.h"
42 #include "libavutil/mem.h"
43 
44 #include "avcodec.h"
45 #include "internal.h"
46 
47 typedef struct ScreenpressoContext {
49 
50  /* zlib interaction */
52  uLongf inflated_size;
54 
56 {
58 
59  av_frame_free(&ctx->current);
60  av_freep(&ctx->inflated_buf);
61 
62  return 0;
63 }
64 
66 {
68 
69  /* These needs to be set to estimate uncompressed buffer */
70  int ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
71  if (ret < 0) {
72  av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n",
73  avctx->width, avctx->height);
74  return ret;
75  }
76 
77  /* Allocate current frame */
78  ctx->current = av_frame_alloc();
79  if (!ctx->current)
80  return AVERROR(ENOMEM);
81 
82  /* Allocate maximum size possible, a full RGBA frame */
83  ctx->inflated_size = avctx->width * avctx->height * 4;
85  if (!ctx->inflated_buf)
86  return AVERROR(ENOMEM);
87 
88  return 0;
89 }
90 
91 static void sum_delta_flipped(uint8_t *dst, int dst_linesize,
92  const uint8_t *src, int src_linesize,
93  int bytewidth, int height)
94 {
95  int i;
96  for (; height > 0; height--) {
97  for (i = 0; i < bytewidth; i++)
98  dst[i] += src[(height - 1) * src_linesize + i];
99  dst += dst_linesize;
100  }
101 }
102 
104  int *got_frame, AVPacket *avpkt)
105 {
107  AVFrame *frame = data;
108  uLongf length = ctx->inflated_size;
109  int keyframe, component_size, src_linesize;
110  int ret;
111 
112  /* Size check */
113  if (avpkt->size < 3) {
114  av_log(avctx, AV_LOG_ERROR, "Packet too small (%d)\n", avpkt->size);
115  return AVERROR_INVALIDDATA;
116  }
117 
118  /* Compression level (4 bits) and keyframe information (1 bit) */
119  av_log(avctx, AV_LOG_DEBUG, "Compression level %d\n", avpkt->data[0] >> 4);
120  keyframe = avpkt->data[0] & 1;
121 
122  /* Pixel size */
123  component_size = ((avpkt->data[1] >> 2) & 0x03) + 1;
124  switch (component_size) {
125  case 2:
126  avctx->pix_fmt = AV_PIX_FMT_RGB555LE;
127  break;
128  case 3:
129  avctx->pix_fmt = AV_PIX_FMT_BGR24;
130  break;
131  case 4:
132  avctx->pix_fmt = AV_PIX_FMT_BGR0;
133  break;
134  default:
135  av_log(avctx, AV_LOG_ERROR, "Invalid bits per pixel value (%d)\n",
136  component_size);
137  return AVERROR_INVALIDDATA;
138  }
139 
140  /* Inflate the frame after the 2 byte header */
141  ret = uncompress(ctx->inflated_buf, &length,
142  avpkt->data + 2, avpkt->size - 2);
143  if (ret) {
144  av_log(avctx, AV_LOG_ERROR, "Deflate error %d.\n", ret);
145  return AVERROR_UNKNOWN;
146  }
147 
148  ret = ff_reget_buffer(avctx, ctx->current);
149  if (ret < 0)
150  return ret;
151 
152  /* Codec has aligned strides */
153  src_linesize = FFALIGN(avctx->width * component_size, 4);
154 
155  /* When a keyframe is found, copy it (flipped) */
156  if (keyframe)
157  av_image_copy_plane(ctx->current->data[0] +
158  ctx->current->linesize[0] * (avctx->height - 1),
159  -1 * ctx->current->linesize[0],
160  ctx->inflated_buf, src_linesize,
161  avctx->width * component_size, avctx->height);
162  /* Otherwise sum the delta on top of the current frame */
163  else
164  sum_delta_flipped(ctx->current->data[0], ctx->current->linesize[0],
165  ctx->inflated_buf, src_linesize,
166  avctx->width * component_size, avctx->height);
167 
168  /* Frame is ready to be output */
169  ret = av_frame_ref(frame, ctx->current);
170  if (ret < 0)
171  return ret;
172 
173  /* Usual properties */
174  if (keyframe) {
175  frame->pict_type = AV_PICTURE_TYPE_I;
176  frame->key_frame = 1;
177  } else {
178  frame->pict_type = AV_PICTURE_TYPE_P;
179  }
180  *got_frame = 1;
181 
182  return avpkt->size;
183 }
184 
186  .name = "screenpresso",
187  .long_name = NULL_IF_CONFIG_SMALL("Screenpresso"),
188  .type = AVMEDIA_TYPE_VIDEO,
190  .init = screenpresso_init,
191  .decode = screenpresso_decode_frame,
192  .close = screenpresso_close,
193  .priv_data_size = sizeof(ScreenpressoContext),
194  .capabilities = AV_CODEC_CAP_DR1,
195  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
197 };
#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
#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:201
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
misc image utilities
Memory handling functions.
packed RGB 5:5:5, 16bpp, (msb)1X 5R 5G 5B(lsb), little-endian, X=unused/undefined ...
Definition: pixfmt.h:104
int size
Definition: avcodec.h:1401
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1697
AVCodec ff_screenpresso_decoder
Definition: screenpresso.c:185
#define src
Definition: vp8dsp.c:254
AVCodec.
Definition: avcodec.h:3351
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame)
Identical in function to av_frame_make_writable(), except it uses ff_get_buffer() to allocate the buf...
Definition: decode.c:1935
#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
#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:150
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:400
static AVFrame * frame
#define height
static av_cold int screenpresso_close(AVCodecContext *avctx)
Definition: screenpresso.c:55
uint8_t * data
Definition: avcodec.h:1400
#define FFALIGN(x, a)
Definition: macros.h:48
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define AVERROR(e)
Definition: error.h:43
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:163
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
GLsizei GLsizei * length
Definition: opengl_enc.c:115
const char * name
Name of the codec implementation.
Definition: avcodec.h:3358
common internal API header
int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of the image can be address...
Definition: imgutils.c:282
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:284
uint8_t * inflated_buf
Definition: screenpresso.c:51
int width
picture width / height.
Definition: avcodec.h:1660
AVFormatContext * ctx
Definition: movenc.c:48
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:65
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:232
main external API structure.
Definition: avcodec.h:1488
packed BGR 8:8:8, 32bpp, BGRXBGRX... X=unused/undefined
Definition: pixfmt.h:236
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:215
common internal api header.
static av_cold int screenpresso_init(AVCodecContext *avctx)
Definition: screenpresso.c:65
#define AVERROR_UNKNOWN
Unknown error, typically from an external library.
Definition: error.h:71
static void sum_delta_flipped(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize, int bytewidth, int height)
Definition: screenpresso.c:91
void * priv_data
Definition: avcodec.h:1515
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:279
#define av_freep(p)
static int screenpresso_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: screenpresso.c:103
void av_image_copy_plane(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize, int bytewidth, int height)
Copy image plane from src to dst.
Definition: imgutils.c:338
This structure stores compressed data.
Definition: avcodec.h:1377
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:956
Predicted.
Definition: avutil.h:275