FFmpeg
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, 0);
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:295
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
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:108
int size
Definition: avcodec.h:1481
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1778
AVCodec ff_screenpresso_decoder
Definition: screenpresso.c:185
#define src
Definition: vp8dsp.c:254
AVCodec.
Definition: avcodec.h:3492
#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: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
static av_cold int screenpresso_close(AVCodecContext *avctx)
Definition: screenpresso.c:55
uint8_t * data
Definition: avcodec.h:1480
#define FFALIGN(x, a)
Definition: macros.h:48
#define av_log(a,...)
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#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
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:2015
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
GLsizei GLsizei * length
Definition: opengl_enc.c:114
const char * name
Name of the codec implementation.
Definition: avcodec.h:3499
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:378
uint8_t * inflated_buf
Definition: screenpresso.c:51
int width
picture width / height.
Definition: avcodec.h:1741
AVFormatContext * ctx
Definition: movenc.c:48
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
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
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
packed BGR 8:8:8, 32bpp, BGRXBGRX... X=unused/undefined
Definition: pixfmt.h:240
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
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:1595
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:373
#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
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
This structure stores compressed data.
Definition: avcodec.h:1457
#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