FFmpeg
idcinvideo.c
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1 /*
2  * id Quake II CIN Video Decoder
3  * Copyright (C) 2003 The FFmpeg project
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  * id Quake II Cin Video Decoder by Dr. Tim Ferguson
25  * For more information about the id CIN format, visit:
26  * http://www.csse.monash.edu.au/~timf/
27  *
28  * This video decoder outputs PAL8 colorspace data. Interacting with this
29  * decoder is a little involved. During initialization, the demuxer must
30  * transmit the 65536-byte Huffman table(s) to the decoder via extradata.
31  * Then, whenever a palette change is encountered while demuxing the file,
32  * the demuxer must use the same extradata space to transmit an
33  * AVPaletteControl structure.
34  *
35  * id CIN video is purely Huffman-coded, intraframe-only codec. It achieves
36  * a little more compression by exploiting the fact that adjacent pixels
37  * tend to be similar.
38  *
39  * Note that this decoder could use libavcodec's optimized VLC facilities
40  * rather than naive, tree-based Huffman decoding. However, there are 256
41  * Huffman tables. Plus, the VLC bit coding order is right -> left instead
42  * or left -> right, so all of the bits would have to be reversed. Further,
43  * the original Quake II implementation likely used a similar naive
44  * decoding algorithm and it worked fine on much lower spec machines.
45  */
46 
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 
51 #include "avcodec.h"
52 #include "decode.h"
53 #include "internal.h"
54 #include "libavutil/internal.h"
55 
56 #define HUFFMAN_TABLE_SIZE 64 * 1024
57 #define HUF_TOKENS 256
58 #define PALETTE_COUNT 256
59 
60 typedef struct hnode {
61  int count;
62  unsigned char used;
63  int children[2];
64 } hnode;
65 
66 typedef struct IdcinContext {
67 
69 
70  const unsigned char *buf;
71  int size;
72 
74  int num_huff_nodes[256];
75 
76  uint32_t pal[256];
77 } IdcinContext;
78 
79 /**
80  * Find the lowest probability node in a Huffman table, and mark it as
81  * being assigned to a higher probability.
82  * @return the node index of the lowest unused node, or -1 if all nodes
83  * are used.
84  */
85 static int huff_smallest_node(hnode *hnodes, int num_hnodes) {
86  int i;
87  int best, best_node;
88 
89  best = 99999999;
90  best_node = -1;
91  for(i = 0; i < num_hnodes; i++) {
92  if(hnodes[i].used)
93  continue;
94  if(!hnodes[i].count)
95  continue;
96  if(hnodes[i].count < best) {
97  best = hnodes[i].count;
98  best_node = i;
99  }
100  }
101 
102  if(best_node == -1)
103  return -1;
104  hnodes[best_node].used = 1;
105  return best_node;
106 }
107 
108 /*
109  * Build the Huffman tree using the generated/loaded probabilities histogram.
110  *
111  * On completion:
112  * huff_nodes[prev][i < HUF_TOKENS] - are the nodes at the base of the tree.
113  * huff_nodes[prev][i >= HUF_TOKENS] - are used to construct the tree.
114  * num_huff_nodes[prev] - contains the index to the root node of the tree.
115  * That is: huff_nodes[prev][num_huff_nodes[prev]] is the root node.
116  */
117 static av_cold void huff_build_tree(IdcinContext *s, int prev) {
118  hnode *node, *hnodes;
119  int num_hnodes, i;
120 
121  num_hnodes = HUF_TOKENS;
122  hnodes = s->huff_nodes[prev];
123  for(i = 0; i < HUF_TOKENS * 2; i++)
124  hnodes[i].used = 0;
125 
126  while (1) {
127  node = &hnodes[num_hnodes]; /* next free node */
128 
129  /* pick two lowest counts */
130  node->children[0] = huff_smallest_node(hnodes, num_hnodes);
131  if(node->children[0] == -1)
132  break; /* reached the root node */
133 
134  node->children[1] = huff_smallest_node(hnodes, num_hnodes);
135  if(node->children[1] == -1)
136  break; /* reached the root node */
137 
138  /* combine nodes probability for new node */
139  node->count = hnodes[node->children[0]].count +
140  hnodes[node->children[1]].count;
141  num_hnodes++;
142  }
143 
144  s->num_huff_nodes[prev] = num_hnodes - 1;
145 }
146 
148 {
149  IdcinContext *s = avctx->priv_data;
150  int i, j, histogram_index = 0;
151  unsigned char *histograms;
152 
153  s->avctx = avctx;
154  avctx->pix_fmt = AV_PIX_FMT_PAL8;
155 
156  /* make sure the Huffman tables make it */
157  if (s->avctx->extradata_size != HUFFMAN_TABLE_SIZE) {
158  av_log(s->avctx, AV_LOG_ERROR, " id CIN video: expected extradata size of %d\n", HUFFMAN_TABLE_SIZE);
159  return -1;
160  }
161 
162  /* build the 256 Huffman decode trees */
163  histograms = (unsigned char *)s->avctx->extradata;
164  for (i = 0; i < 256; i++) {
165  for(j = 0; j < HUF_TOKENS; j++)
166  s->huff_nodes[i][j].count = histograms[histogram_index++];
167  huff_build_tree(s, i);
168  }
169 
170  return 0;
171 }
172 
174 {
175  hnode *hnodes;
176  long x, y;
177  int prev;
178  unsigned char v = 0;
179  int bit_pos, node_num, dat_pos;
180 
181  prev = bit_pos = dat_pos = 0;
182  for (y = 0; y < (frame->linesize[0] * s->avctx->height);
183  y += frame->linesize[0]) {
184  for (x = y; x < y + s->avctx->width; x++) {
185  node_num = s->num_huff_nodes[prev];
186  hnodes = s->huff_nodes[prev];
187 
188  while(node_num >= HUF_TOKENS) {
189  if(!bit_pos) {
190  if(dat_pos >= s->size) {
191  av_log(s->avctx, AV_LOG_ERROR, "Huffman decode error.\n");
192  return -1;
193  }
194  bit_pos = 8;
195  v = s->buf[dat_pos++];
196  }
197 
198  node_num = hnodes[node_num].children[v & 0x01];
199  v = v >> 1;
200  bit_pos--;
201  }
202 
203  frame->data[0][x] = node_num;
204  prev = node_num;
205  }
206  }
207 
208  return 0;
209 }
210 
212  void *data, int *got_frame,
213  AVPacket *avpkt)
214 {
215  const uint8_t *buf = avpkt->data;
216  int buf_size = avpkt->size;
217  IdcinContext *s = avctx->priv_data;
218  AVFrame *frame = data;
219  int ret;
220 
221  s->buf = buf;
222  s->size = buf_size;
223 
224  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
225  return ret;
226 
227  if (idcin_decode_vlcs(s, frame))
228  return AVERROR_INVALIDDATA;
229 
230  frame->palette_has_changed = ff_copy_palette(s->pal, avpkt, avctx);
231  /* make the palette available on the way out */
232  memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
233 
234  *got_frame = 1;
235 
236  /* report that the buffer was completely consumed */
237  return buf_size;
238 }
239 
240 static const AVCodecDefault idcin_defaults[] = {
241  { "max_pixels", "320*240" },
242  { NULL },
243 };
244 
246  .name = "idcinvideo",
247  .long_name = NULL_IF_CONFIG_SMALL("id Quake II CIN video"),
248  .type = AVMEDIA_TYPE_VIDEO,
249  .id = AV_CODEC_ID_IDCIN,
250  .priv_data_size = sizeof(IdcinContext),
253  .capabilities = AV_CODEC_CAP_DR1,
255  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
256 };
AVCodec
AVCodec.
Definition: codec.h:197
HUF_TOKENS
#define HUF_TOKENS
Definition: idcinvideo.c:57
AV_CODEC_ID_IDCIN
@ AV_CODEC_ID_IDCIN
Definition: codec_id.h:97
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
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
hnode::used
unsigned char used
Definition: idcinvideo.c:62
IdcinContext::pal
uint32_t pal[256]
Definition: idcinvideo.c:76
idcin_defaults
static const AVCodecDefault idcin_defaults[]
Definition: idcinvideo.c:240
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:373
data
const char data[16]
Definition: mxf.c:143
IdcinContext::num_huff_nodes
int num_huff_nodes[256]
Definition: idcinvideo.c:74
defaults
static const AVCodecDefault defaults[]
Definition: amfenc_h264.c:361
IdcinContext::buf
const unsigned char * buf
Definition: idcinvideo.c:70
IdcinContext::huff_nodes
hnode huff_nodes[256][HUF_TOKENS *2]
Definition: idcinvideo.c:73
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
huff_build_tree
static av_cold void huff_build_tree(IdcinContext *s, int prev)
Definition: idcinvideo.c:117
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
s
#define s(width, name)
Definition: cbs_vp9.c:257
decode.h
AVCodecDefault
Definition: internal.h:213
IdcinContext
Definition: idcinvideo.c:66
NULL
#define NULL
Definition: coverity.c:32
huff_smallest_node
static int huff_smallest_node(hnode *hnodes, int num_hnodes)
Find the lowest probability node in a Huffman table, and mark it as being assigned to a higher probab...
Definition: idcinvideo.c:85
AVPALETTE_SIZE
#define AVPALETTE_SIZE
Definition: pixfmt.h:32
IdcinContext::size
int size
Definition: idcinvideo.c:71
HUFFMAN_TABLE_SIZE
#define HUFFMAN_TABLE_SIZE
Definition: idcinvideo.c:56
for
for(j=16;j >0;--j)
Definition: h264pred_template.c:469
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1648
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:116
hnode::children
int children[2]
Definition: idcinvideo.c:63
i
int i
Definition: input.c:406
hnode::count
int count
Definition: idcinvideo.c:61
internal.h
idcin_decode_frame
static int idcin_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: idcinvideo.c:211
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:589
avcodec.h
ff_idcin_decoder
const AVCodec ff_idcin_decoder
Definition: idcinvideo.c:245
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
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:379
idcin_decode_init
static av_cold int idcin_decode_init(AVCodecContext *avctx)
Definition: idcinvideo.c:147
IdcinContext::avctx
AVCodecContext * avctx
Definition: idcinvideo.c:68
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
hnode
Definition: idcinvideo.c:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:406
idcin_decode_vlcs
static int idcin_decode_vlcs(IdcinContext *s, AVFrame *frame)
Definition: idcinvideo.c:173
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
ff_copy_palette
int ff_copy_palette(void *dst, const AVPacket *src, void *logctx)
Check whether the side-data of src contains a palette of size AVPALETTE_SIZE; if so,...
Definition: decode.c:1850