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 <zlib.h>
38 
39 #include "libavutil/imgutils.h"
40 #include "libavutil/internal.h"
41 #include "libavutil/mem.h"
42 
43 #include "avcodec.h"
44 #include "codec_internal.h"
45 #include "decode.h"
46 
47 typedef struct ScreenpressoContext {
49 
50  /* zlib interaction */
51  uint8_t *inflated_buf;
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;
84  ctx->inflated_buf = av_malloc(ctx->inflated_size);
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  const uint8_t *src1 = &src[(height - 1) * src_linesize];
98  for (i = 0; i < bytewidth; i++)
99  dst[i] += src1[i];
100  dst += dst_linesize;
101  }
102 }
103 
105  int *got_frame, AVPacket *avpkt)
106 {
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  .p.name = "screenpresso",
187  CODEC_LONG_NAME("Screenpresso"),
188  .p.type = AVMEDIA_TYPE_VIDEO,
189  .p.id = AV_CODEC_ID_SCREENPRESSO,
190  .init = screenpresso_init,
192  .close = screenpresso_close,
193  .priv_data_size = sizeof(ScreenpressoContext),
194  .p.capabilities = AV_CODEC_CAP_DR1,
195  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
196 };
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
ScreenpressoContext::inflated_size
uLongf inflated_size
Definition: screenpresso.c:52
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
src1
const pixel * src1
Definition: h264pred_template.c:421
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:116
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
AVPacket::data
uint8_t * data
Definition: packet.h:374
FFCodec
Definition: codec_internal.h:119
AV_PIX_FMT_BGR24
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
AV_CODEC_ID_SCREENPRESSO
@ AV_CODEC_ID_SCREENPRESSO
Definition: codec_id.h:244
AVERROR_UNKNOWN
#define AVERROR_UNKNOWN
Unknown error, typically from an external library.
Definition: error.h:73
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:30
av_image_copy_plane
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:374
ScreenpressoContext
Definition: screenpresso.c:47
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:123
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:104
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
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:279
ScreenpressoContext::inflated_buf
uint8_t * inflated_buf
Definition: screenpresso.c:51
ff_screenpresso_decoder
const FFCodec ff_screenpresso_decoder
Definition: screenpresso.c:185
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
ctx
AVFormatContext * ctx
Definition: movenc.c:48
decode.h
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:264
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
AV_PIX_FMT_BGR0
@ AV_PIX_FMT_BGR0
packed BGR 8:8:8, 32bpp, BGRXBGRX... X=unused/undefined
Definition: pixfmt.h:230
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:375
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:353
codec_internal.h
height
#define height
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:108
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
internal.h
sum_delta_flipped
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
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
AVCodecContext::height
int height
Definition: avcodec.h:571
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:608
avcodec.h
screenpresso_decode_frame
static int screenpresso_decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *avpkt)
Definition: screenpresso.c:104
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:1568
ret
ret
Definition: filter_design.txt:187
frame
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
Definition: filter_design.txt:264
AVCodecContext
main external API structure.
Definition: avcodec.h:398
screenpresso_init
static av_cold int screenpresso_init(AVCodecContext *avctx)
Definition: screenpresso.c:65
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:275
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
mem.h
FFALIGN
#define FFALIGN(x, a)
Definition: macros.h:78
AVPacket
This structure stores compressed data.
Definition: packet.h:351
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:425
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
ScreenpressoContext::current
AVFrame * current
Definition: screenpresso.c:48
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:571
imgutils.h
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
screenpresso_close
static av_cold int screenpresso_close(AVCodecContext *avctx)
Definition: screenpresso.c:55
av_image_check_size
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:318