FFmpeg
rl2.c
Go to the documentation of this file.
1 /*
2  * RL2 Video Decoder
3  * Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de)
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  * RL2 Video Decoder
25  * @author Sascha Sommer (saschasommer@freenet.de)
26  * @see http://wiki.multimedia.cx/index.php?title=RL2
27  */
28 
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 
33 #include "libavutil/internal.h"
34 #include "libavutil/intreadwrite.h"
35 #include "libavutil/mem.h"
36 #include "avcodec.h"
37 #include "internal.h"
38 
39 
40 #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette
41 
42 typedef struct Rl2Context {
44 
45  uint16_t video_base; ///< initial drawing offset
46  uint32_t clr_count; ///< number of used colors (currently unused)
47  uint8_t *back_frame; ///< background frame
49 } Rl2Context;
50 
51 /**
52  * Run Length Decode a single 320x200 frame
53  * @param s rl2 context
54  * @param in input buffer
55  * @param size input buffer size
56  * @param out output buffer
57  * @param stride stride of the output buffer
58  * @param video_base offset of the rle data inside the frame
59  */
60 static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size,
61  uint8_t *out, int stride, int video_base)
62 {
63  int base_x = video_base % s->avctx->width;
64  int base_y = video_base / s->avctx->width;
65  int stride_adj = stride - s->avctx->width;
66  int i;
67  const uint8_t *back_frame = s->back_frame;
68  const uint8_t *in_end = in + size;
69  const uint8_t *out_end = out + stride * s->avctx->height;
70  uint8_t *line_end;
71 
72  /** copy start of the background frame */
73  for (i = 0; i <= base_y; i++) {
74  if (s->back_frame)
75  memcpy(out, back_frame, s->avctx->width);
76  out += stride;
77  back_frame += s->avctx->width;
78  }
79  back_frame += base_x - s->avctx->width;
80  line_end = out - stride_adj;
81  out += base_x - stride;
82 
83  /** decode the variable part of the frame */
84  while (in < in_end) {
85  uint8_t val = *in++;
86  int len = 1;
87  if (val >= 0x80) {
88  if (in >= in_end)
89  break;
90  len = *in++;
91  if (!len)
92  break;
93  }
94 
95  if (len >= out_end - out)
96  break;
97 
98  if (s->back_frame)
99  val |= 0x80;
100  else
101  val &= ~0x80;
102 
103  while (len--) {
104  *out++ = (val == 0x80) ? *back_frame : val;
105  back_frame++;
106  if (out == line_end) {
107  out += stride_adj;
108  line_end += stride;
109  if (len >= out_end - out)
110  break;
111  }
112  }
113  }
114 
115  /** copy the rest from the background frame */
116  if (s->back_frame) {
117  while (out < out_end) {
118  memcpy(out, back_frame, line_end - out);
119  back_frame += line_end - out;
120  out = line_end + stride_adj;
121  line_end += stride;
122  }
123  }
124 }
125 
126 
127 /**
128  * Initialize the decoder
129  * @param avctx decoder context
130  * @return 0 success, -1 on error
131  */
133 {
134  Rl2Context *s = avctx->priv_data;
135  int back_size;
136  int i;
137  int ret;
138 
139  s->avctx = avctx;
140  avctx->pix_fmt = AV_PIX_FMT_PAL8;
141 
142  ret = ff_set_dimensions(avctx, 320, 200);
143  if (ret < 0)
144  return ret;
145 
146  /** parse extra data */
147  if (!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE) {
148  av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
149  return AVERROR(EINVAL);
150  }
151 
152  /** get frame_offset */
153  s->video_base = AV_RL16(&avctx->extradata[0]);
154  s->clr_count = AV_RL32(&avctx->extradata[2]);
155 
156  if (s->video_base >= avctx->width * avctx->height) {
157  av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
158  return AVERROR_INVALIDDATA;
159  }
160 
161  /** initialize palette */
162  for (i = 0; i < AVPALETTE_COUNT; i++)
163  s->palette[i] = 0xFFU << 24 | AV_RB24(&avctx->extradata[6 + i * 3]);
164 
165  /** decode background frame if present */
166  back_size = avctx->extradata_size - EXTRADATA1_SIZE;
167 
168  if (back_size > 0) {
169  uint8_t *back_frame = av_mallocz(avctx->width*avctx->height);
170  if (!back_frame)
171  return AVERROR(ENOMEM);
172  rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size,
173  back_frame, avctx->width, 0);
174  s->back_frame = back_frame;
175  }
176  return 0;
177 }
178 
179 
181  void *data, int *got_frame,
182  AVPacket *avpkt)
183 {
184  AVFrame *frame = data;
185  const uint8_t *buf = avpkt->data;
186  int ret, buf_size = avpkt->size;
187  Rl2Context *s = avctx->priv_data;
188 
189  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
190  return ret;
191 
192  /** run length decode */
193  rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0],
194  s->video_base);
195 
196  /** make the palette available on the way out */
197  memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
198 
199  *got_frame = 1;
200 
201  /** report that the buffer was completely consumed */
202  return buf_size;
203 }
204 
205 
206 /**
207  * Uninit decoder
208  * @param avctx decoder context
209  * @return 0 success, -1 on error
210  */
212 {
213  Rl2Context *s = avctx->priv_data;
214 
215  av_freep(&s->back_frame);
216 
217  return 0;
218 }
219 
220 
222  .name = "rl2",
223  .long_name = NULL_IF_CONFIG_SMALL("RL2 video"),
224  .type = AVMEDIA_TYPE_VIDEO,
225  .id = AV_CODEC_ID_RL2,
226  .priv_data_size = sizeof(Rl2Context),
228  .close = rl2_decode_end,
230  .capabilities = AV_CODEC_CAP_DR1,
231  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
232 };
AVCodec
AVCodec.
Definition: codec.h:202
stride
int stride
Definition: mace.c:144
FF_CODEC_CAP_INIT_THREADSAFE
#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: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
out
FILE * out
Definition: movenc.c:54
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:317
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:373
data
const char data[16]
Definition: mxf.c:143
Rl2Context::clr_count
uint32_t clr_count
number of used colors (currently unused)
Definition: rl2.c:46
rl2_decode_frame
static int rl2_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: rl2.c:180
ff_rl2_decoder
const AVCodec ff_rl2_decoder
Definition: rl2.c:221
Rl2Context::back_frame
uint8_t * back_frame
background frame
Definition: rl2.c:47
init
static int init
Definition: av_tx.c:47
val
static double val(void *priv, double ch)
Definition: aeval.c:76
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
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
AVCodecContext::extradata_size
int extradata_size
Definition: avcodec.h:485
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
AV_CODEC_ID_RL2
@ AV_CODEC_ID_RL2
Definition: codec_id.h:164
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
Rl2Context::avctx
AVCodecContext * avctx
Definition: rl2.c:43
Rl2Context
Definition: rl2.c:42
AVPALETTE_SIZE
#define AVPALETTE_SIZE
Definition: pixfmt.h:32
AVPALETTE_COUNT
#define AVPALETTE_COUNT
Definition: pixfmt.h:33
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1652
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:374
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
size
int size
Definition: twinvq_data.h:10344
rl2_decode_init
static av_cold int rl2_decode_init(AVCodecContext *avctx)
Initialize the decoder.
Definition: rl2.c:132
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
AVCodecContext::extradata
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:484
internal.h
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:263
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:209
len
int len
Definition: vorbis_enc_data.h:426
AVCodecContext::height
int height
Definition: avcodec.h:556
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:593
avcodec.h
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
ret
ret
Definition: filter_design.txt:187
rl2_decode_end
static av_cold int rl2_decode_end(AVCodecContext *avctx)
Uninit decoder.
Definition: rl2.c:211
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
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
AVCodecContext
main external API structure.
Definition: avcodec.h:383
rl2_rle_decode
static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, uint8_t *out, int stride, int video_base)
Run Length Decode a single 320x200 frame.
Definition: rl2.c:60
Rl2Context::video_base
uint16_t video_base
initial drawing offset
Definition: rl2.c:45
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
mem.h
ff_set_dimensions
int ff_set_dimensions(AVCodecContext *s, int width, int height)
Check that the provided frame dimensions are valid and set them on the codec context.
Definition: utils.c:86
EXTRADATA1_SIZE
#define EXTRADATA1_SIZE
video base, clr count, palette
Definition: rl2.c:40
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:410
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:556
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
AV_RB24
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_RB24
Definition: bytestream.h:97
Rl2Context::palette
uint32_t palette[AVPALETTE_COUNT]
Definition: rl2.c:48