FFmpeg
rl2.c
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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 "codec_internal.h"
38 #include "internal.h"
39 
40 
41 #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette
42 
43 typedef struct Rl2Context {
45 
46  uint16_t video_base; ///< initial drawing offset
47  uint32_t clr_count; ///< number of used colors (currently unused)
48  uint8_t *back_frame; ///< background frame
50 } Rl2Context;
51 
52 /**
53  * Run Length Decode a single 320x200 frame
54  * @param s rl2 context
55  * @param in input buffer
56  * @param size input buffer size
57  * @param out output buffer
58  * @param stride stride of the output buffer
59  * @param video_base offset of the rle data inside the frame
60  */
61 static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size,
62  uint8_t *out, int stride, int video_base)
63 {
64  int base_x = video_base % s->avctx->width;
65  int base_y = video_base / s->avctx->width;
66  int stride_adj = stride - s->avctx->width;
67  int i;
68  const uint8_t *back_frame = s->back_frame;
69  const uint8_t *in_end = in + size;
70  const uint8_t *out_end = out + stride * s->avctx->height;
71  uint8_t *line_end;
72 
73  /** copy start of the background frame */
74  for (i = 0; i <= base_y; i++) {
75  if (s->back_frame)
76  memcpy(out, back_frame, s->avctx->width);
77  out += stride;
78  back_frame += s->avctx->width;
79  }
80  back_frame += base_x - s->avctx->width;
81  line_end = out - stride_adj;
82  out += base_x - stride;
83 
84  /** decode the variable part of the frame */
85  while (in < in_end) {
86  uint8_t val = *in++;
87  int len = 1;
88  if (val >= 0x80) {
89  if (in >= in_end)
90  break;
91  len = *in++;
92  if (!len)
93  break;
94  }
95 
96  if (len >= out_end - out)
97  break;
98 
99  if (s->back_frame)
100  val |= 0x80;
101  else
102  val &= ~0x80;
103 
104  while (len--) {
105  *out++ = (val == 0x80) ? *back_frame : val;
106  back_frame++;
107  if (out == line_end) {
108  out += stride_adj;
109  line_end += stride;
110  if (len >= out_end - out)
111  break;
112  }
113  }
114  }
115 
116  /** copy the rest from the background frame */
117  if (s->back_frame) {
118  while (out < out_end) {
119  memcpy(out, back_frame, line_end - out);
120  back_frame += line_end - out;
121  out = line_end + stride_adj;
122  line_end += stride;
123  }
124  }
125 }
126 
127 
128 /**
129  * Initialize the decoder
130  * @param avctx decoder context
131  * @return 0 success, -1 on error
132  */
134 {
135  Rl2Context *s = avctx->priv_data;
136  int back_size;
137  int i;
138  int ret;
139 
140  s->avctx = avctx;
141  avctx->pix_fmt = AV_PIX_FMT_PAL8;
142 
143  ret = ff_set_dimensions(avctx, 320, 200);
144  if (ret < 0)
145  return ret;
146 
147  /** parse extra data */
148  if (!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE) {
149  av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
150  return AVERROR(EINVAL);
151  }
152 
153  /** get frame_offset */
154  s->video_base = AV_RL16(&avctx->extradata[0]);
155  s->clr_count = AV_RL32(&avctx->extradata[2]);
156 
157  if (s->video_base >= avctx->width * avctx->height) {
158  av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
159  return AVERROR_INVALIDDATA;
160  }
161 
162  /** initialize palette */
163  for (i = 0; i < AVPALETTE_COUNT; i++)
164  s->palette[i] = 0xFFU << 24 | AV_RB24(&avctx->extradata[6 + i * 3]);
165 
166  /** decode background frame if present */
167  back_size = avctx->extradata_size - EXTRADATA1_SIZE;
168 
169  if (back_size > 0) {
170  uint8_t *back_frame = av_mallocz(avctx->width*avctx->height);
171  if (!back_frame)
172  return AVERROR(ENOMEM);
173  rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size,
174  back_frame, avctx->width, 0);
175  s->back_frame = back_frame;
176  }
177  return 0;
178 }
179 
180 
182  int *got_frame, AVPacket *avpkt)
183 {
184  const uint8_t *buf = avpkt->data;
185  int ret, buf_size = avpkt->size;
186  Rl2Context *s = avctx->priv_data;
187 
188  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
189  return ret;
190 
191  /** run length decode */
192  rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0],
193  s->video_base);
194 
195  /** make the palette available on the way out */
196  memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
197 
198  *got_frame = 1;
199 
200  /** report that the buffer was completely consumed */
201  return buf_size;
202 }
203 
204 
205 /**
206  * Uninit decoder
207  * @param avctx decoder context
208  * @return 0 success, -1 on error
209  */
211 {
212  Rl2Context *s = avctx->priv_data;
213 
214  av_freep(&s->back_frame);
215 
216  return 0;
217 }
218 
219 
221  .p.name = "rl2",
222  .p.long_name = NULL_IF_CONFIG_SMALL("RL2 video"),
223  .p.type = AVMEDIA_TYPE_VIDEO,
224  .p.id = AV_CODEC_ID_RL2,
225  .priv_data_size = sizeof(Rl2Context),
227  .close = rl2_decode_end,
229  .p.capabilities = AV_CODEC_CAP_DR1,
230 };
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:325
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:374
FFCodec
Definition: codec_internal.h:118
Rl2Context::clr_count
uint32_t clr_count
number of used colors (currently unused)
Definition: rl2.c:47
Rl2Context::back_frame
uint8_t * back_frame
background frame
Definition: rl2.c:48
init
static int init
Definition: av_tx.c:47
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:122
val
static double val(void *priv, double ch)
Definition: aeval.c:77
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
AVCodecContext::extradata_size
int extradata_size
Definition: avcodec.h:500
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:260
rl2_decode_frame
static int rl2_decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *avpkt)
Definition: rl2.c:181
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:256
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:44
ff_rl2_decoder
const FFCodec ff_rl2_decoder
Definition: rl2.c:220
Rl2Context
Definition: rl2.c:43
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:1462
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
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
codec_internal.h
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:133
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
AVCodecContext::extradata
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:499
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:264
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
len
int len
Definition: vorbis_enc_data.h:426
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
stride
#define stride
Definition: h264pred_template.c:537
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:210
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:398
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:61
Rl2Context::video_base
uint16_t video_base
initial drawing offset
Definition: rl2.c:46
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:90
EXTRADATA1_SIZE
#define EXTRADATA1_SIZE
video base, clr count, palette
Definition: rl2.c:41
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
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:571
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
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:49