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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 "internal.h"
53 #include "libavutil/internal.h"
54 
55 #define HUFFMAN_TABLE_SIZE 64 * 1024
56 #define HUF_TOKENS 256
57 #define PALETTE_COUNT 256
58 
59 typedef struct hnode {
60  int count;
61  unsigned char used;
62  int children[2];
63 } hnode;
64 
65 typedef struct IdcinContext {
66 
68 
69  const unsigned char *buf;
70  int size;
71 
73  int num_huff_nodes[256];
74 
75  uint32_t pal[256];
76 } IdcinContext;
77 
78 /**
79  * Find the lowest probability node in a Huffman table, and mark it as
80  * being assigned to a higher probability.
81  * @return the node index of the lowest unused node, or -1 if all nodes
82  * are used.
83  */
84 static int huff_smallest_node(hnode *hnodes, int num_hnodes) {
85  int i;
86  int best, best_node;
87 
88  best = 99999999;
89  best_node = -1;
90  for(i = 0; i < num_hnodes; i++) {
91  if(hnodes[i].used)
92  continue;
93  if(!hnodes[i].count)
94  continue;
95  if(hnodes[i].count < best) {
96  best = hnodes[i].count;
97  best_node = i;
98  }
99  }
100 
101  if(best_node == -1)
102  return -1;
103  hnodes[best_node].used = 1;
104  return best_node;
105 }
106 
107 /*
108  * Build the Huffman tree using the generated/loaded probabilities histogram.
109  *
110  * On completion:
111  * huff_nodes[prev][i < HUF_TOKENS] - are the nodes at the base of the tree.
112  * huff_nodes[prev][i >= HUF_TOKENS] - are used to construct the tree.
113  * num_huff_nodes[prev] - contains the index to the root node of the tree.
114  * That is: huff_nodes[prev][num_huff_nodes[prev]] is the root node.
115  */
116 static av_cold void huff_build_tree(IdcinContext *s, int prev) {
117  hnode *node, *hnodes;
118  int num_hnodes, i;
119 
120  num_hnodes = HUF_TOKENS;
121  hnodes = s->huff_nodes[prev];
122  for(i = 0; i < HUF_TOKENS * 2; i++)
123  hnodes[i].used = 0;
124 
125  while (1) {
126  node = &hnodes[num_hnodes]; /* next free node */
127 
128  /* pick two lowest counts */
129  node->children[0] = huff_smallest_node(hnodes, num_hnodes);
130  if(node->children[0] == -1)
131  break; /* reached the root node */
132 
133  node->children[1] = huff_smallest_node(hnodes, num_hnodes);
134  if(node->children[1] == -1)
135  break; /* reached the root node */
136 
137  /* combine nodes probability for new node */
138  node->count = hnodes[node->children[0]].count +
139  hnodes[node->children[1]].count;
140  num_hnodes++;
141  }
142 
143  s->num_huff_nodes[prev] = num_hnodes - 1;
144 }
145 
147 {
148  IdcinContext *s = avctx->priv_data;
149  int i, j, histogram_index = 0;
150  unsigned char *histograms;
151 
152  s->avctx = avctx;
153  avctx->pix_fmt = AV_PIX_FMT_PAL8;
154 
155  /* make sure the Huffman tables make it */
157  av_log(s->avctx, AV_LOG_ERROR, " id CIN video: expected extradata size of %d\n", HUFFMAN_TABLE_SIZE);
158  return -1;
159  }
160 
161  /* build the 256 Huffman decode trees */
162  histograms = (unsigned char *)s->avctx->extradata;
163  for (i = 0; i < 256; i++) {
164  for(j = 0; j < HUF_TOKENS; j++)
165  s->huff_nodes[i][j].count = histograms[histogram_index++];
166  huff_build_tree(s, i);
167  }
168 
169  return 0;
170 }
171 
173 {
174  hnode *hnodes;
175  long x, y;
176  int prev;
177  unsigned char v = 0;
178  int bit_pos, node_num, dat_pos;
179 
180  prev = bit_pos = dat_pos = 0;
181  for (y = 0; y < (frame->linesize[0] * s->avctx->height);
182  y += frame->linesize[0]) {
183  for (x = y; x < y + s->avctx->width; x++) {
184  node_num = s->num_huff_nodes[prev];
185  hnodes = s->huff_nodes[prev];
186 
187  while(node_num >= HUF_TOKENS) {
188  if(!bit_pos) {
189  if(dat_pos >= s->size) {
190  av_log(s->avctx, AV_LOG_ERROR, "Huffman decode error.\n");
191  return -1;
192  }
193  bit_pos = 8;
194  v = s->buf[dat_pos++];
195  }
196 
197  node_num = hnodes[node_num].children[v & 0x01];
198  v = v >> 1;
199  bit_pos--;
200  }
201 
202  frame->data[0][x] = node_num;
203  prev = node_num;
204  }
205  }
206 
207  return 0;
208 }
209 
211  void *data, int *got_frame,
212  AVPacket *avpkt)
213 {
214  const uint8_t *buf = avpkt->data;
215  int buf_size = avpkt->size;
216  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  if (pal) {
231  frame->palette_has_changed = 1;
232  memcpy(s->pal, pal, AVPALETTE_SIZE);
233  }
234  /* make the palette available on the way out */
235  memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
236 
237  *got_frame = 1;
238 
239  /* report that the buffer was completely consumed */
240  return buf_size;
241 }
242 
244  .name = "idcinvideo",
245  .long_name = NULL_IF_CONFIG_SMALL("id Quake II CIN video"),
246  .type = AVMEDIA_TYPE_VIDEO,
247  .id = AV_CODEC_ID_IDCIN,
248  .priv_data_size = sizeof(IdcinContext),
251  .capabilities = AV_CODEC_CAP_DR1,
252 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
#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:184
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1589
static int idcin_decode_vlcs(IdcinContext *s, AVFrame *frame)
Definition: idcinvideo.c:172
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1885
AVCodec.
Definition: avcodec.h:3559
int num_huff_nodes[256]
Definition: idcinvideo.c:73
uint8_t
#define av_cold
Definition: attributes.h:82
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:73
#define AVPALETTE_SIZE
Definition: pixfmt.h:32
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1772
AVCodec ff_idcin_decoder
Definition: idcinvideo.c:243
static AVFrame * frame
uint8_t * data
Definition: avcodec.h:1588
hnode huff_nodes[256][HUF_TOKENS *2]
Definition: idcinvideo.c:72
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
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:84
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
#define HUFFMAN_TABLE_SIZE
Definition: idcinvideo.c:55
const char * name
Name of the codec implementation.
Definition: avcodec.h:3566
GLsizei count
Definition: opengl_enc.c:109
common internal API header
int width
picture width / height.
Definition: avcodec.h:1844
int count
Definition: idcinvideo.c:60
static av_cold void huff_build_tree(IdcinContext *s, int prev)
Definition: idcinvideo.c:116
const unsigned char * buf
Definition: idcinvideo.c:69
AVCodecContext * avctx
Definition: idcinvideo.c:67
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:215
main external API structure.
Definition: avcodec.h:1657
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:928
int children[2]
Definition: idcinvideo.c:62
void * buf
Definition: avisynth_c.h:553
int extradata_size
Definition: avcodec.h:1773
int palette_has_changed
Tell user application that palette has changed from previous frame.
Definition: frame.h:328
#define HUF_TOKENS
Definition: idcinvideo.c:56
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:198
static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt)
Definition: ccaption_dec.c:752
common internal api header.
static av_cold int idcin_decode_init(AVCodecContext *avctx)
Definition: idcinvideo.c:146
void * priv_data
Definition: avcodec.h:1699
static int idcin_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: idcinvideo.c:210
uint32_t pal[256]
Definition: idcinvideo.c:75
unsigned char used
Definition: idcinvideo.c:61
uint8_t * av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type, int *size)
Get side information from packet.
Definition: avpacket.c:334
This structure stores compressed data.
Definition: avcodec.h:1565
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:956
for(j=16;j >0;--j)