FFmpeg coverage

GCC Code Coverage Report

Directory:	../../../ffmpeg/		Exec	Total	Coverage
File:	src/libavcodec/idcinvideo.c	Lines:	80	87	92.0 %
Date:	2020-11-28 20:53:16	Branches:	36	42	85.7 %


/*
 * id Quake II CIN Video Decoder
 * Copyright (C) 2003 The FFmpeg project
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * id Quake II Cin Video Decoder by Dr. Tim Ferguson
 * For more information about the id CIN format, visit:
 *   http://www.csse.monash.edu.au/~timf/
 *
 * This video decoder outputs PAL8 colorspace data. Interacting with this
 * decoder is a little involved. During initialization, the demuxer must
 * transmit the 65536-byte Huffman table(s) to the decoder via extradata.
 * Then, whenever a palette change is encountered while demuxing the file,
 * the demuxer must use the same extradata space to transmit an
 * AVPaletteControl structure.
 *
 * id CIN video is purely Huffman-coded, intraframe-only codec. It achieves
 * a little more compression by exploiting the fact that adjacent pixels
 * tend to be similar.
 *
 * Note that this decoder could use libavcodec's optimized VLC facilities
 * rather than naive, tree-based Huffman decoding. However, there are 256
 * Huffman tables. Plus, the VLC bit coding order is right -> left instead
 * or left -> right, so all of the bits would have to be reversed. Further,
 * the original Quake II implementation likely used a similar naive
 * decoding algorithm and it worked fine on much lower spec machines.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "avcodec.h"
#include "internal.h"
#include "libavutil/internal.h"

#define HUFFMAN_TABLE_SIZE 64 * 1024
#define HUF_TOKENS 256
#define PALETTE_COUNT 256

typedef struct hnode {
  int count;
  unsigned char used;
  int children[2];
} hnode;

typedef struct IdcinContext {

    AVCodecContext *avctx;

    const unsigned char *buf;
    int size;

    hnode huff_nodes[256][HUF_TOKENS*2];
    int num_huff_nodes[256];

    uint32_t pal[256];
} IdcinContext;

/**
 * Find the lowest probability node in a Huffman table, and mark it as
 * being assigned to a higher probability.
 * @return the node index of the lowest unused node, or -1 if all nodes
 * are used.
 */
static int huff_smallest_node(hnode *hnodes, int num_hnodes) {
    int i;
    int best, best_node;

    best = 99999999;
    best_node = -1;
    for(i = 0; i < num_hnodes; i++) {
        if(hnodes[i].used)
            continue;
        if(!hnodes[i].count)
            continue;
        if(hnodes[i].count < best) {
            best = hnodes[i].count;
            best_node = i;
        }
    }

    if(best_node == -1)
        return -1;
    hnodes[best_node].used = 1;
    return best_node;
}

/*
 * Build the Huffman tree using the generated/loaded probabilities histogram.
 *
 * On completion:
 *  huff_nodes[prev][i < HUF_TOKENS] - are the nodes at the base of the tree.
 *  huff_nodes[prev][i >= HUF_TOKENS] - are used to construct the tree.
 *  num_huff_nodes[prev] - contains the index to the root node of the tree.
 *    That is: huff_nodes[prev][num_huff_nodes[prev]] is the root node.
 */
static av_cold void huff_build_tree(IdcinContext *s, int prev) {
    hnode *node, *hnodes;
     int num_hnodes, i;

    num_hnodes = HUF_TOKENS;
    hnodes = s->huff_nodes[prev];
    for(i = 0; i < HUF_TOKENS * 2; i++)
        hnodes[i].used = 0;

    while (1) {
        node = &hnodes[num_hnodes];             /* next free node */

        /* pick two lowest counts */
        node->children[0] = huff_smallest_node(hnodes, num_hnodes);
        if(node->children[0] == -1)
            break;      /* reached the root node */

        node->children[1] = huff_smallest_node(hnodes, num_hnodes);
        if(node->children[1] == -1)
            break;      /* reached the root node */

        /* combine nodes probability for new node */
        node->count = hnodes[node->children[0]].count +
        hnodes[node->children[1]].count;
        num_hnodes++;
    }

    s->num_huff_nodes[prev] = num_hnodes - 1;
}

static av_cold int idcin_decode_init(AVCodecContext *avctx)
{
    IdcinContext *s = avctx->priv_data;
    int i, j, histogram_index = 0;
    unsigned char *histograms;

    s->avctx = avctx;
    avctx->pix_fmt = AV_PIX_FMT_PAL8;

    /* make sure the Huffman tables make it */
    if (s->avctx->extradata_size != HUFFMAN_TABLE_SIZE) {
        av_log(s->avctx, AV_LOG_ERROR, "  id CIN video: expected extradata size of %d\n", HUFFMAN_TABLE_SIZE);
        return -1;
    }

    /* build the 256 Huffman decode trees */
    histograms = (unsigned char *)s->avctx->extradata;
    for (i = 0; i < 256; i++) {
        for(j = 0; j < HUF_TOKENS; j++)
            s->huff_nodes[i][j].count = histograms[histogram_index++];
        huff_build_tree(s, i);
    }

    return 0;
}

static int idcin_decode_vlcs(IdcinContext *s, AVFrame *frame)
{
    hnode *hnodes;
    long x, y;
    int prev;
    unsigned char v = 0;
    int bit_pos, node_num, dat_pos;

    prev = bit_pos = dat_pos = 0;
    for (y = 0; y < (frame->linesize[0] * s->avctx->height);
        y += frame->linesize[0]) {
        for (x = y; x < y + s->avctx->width; x++) {
            node_num = s->num_huff_nodes[prev];
            hnodes = s->huff_nodes[prev];

            while(node_num >= HUF_TOKENS) {
                if(!bit_pos) {
                    if(dat_pos >= s->size) {
                        av_log(s->avctx, AV_LOG_ERROR, "Huffman decode error.\n");
                        return -1;
                    }
                    bit_pos = 8;
                    v = s->buf[dat_pos++];
                }

                node_num = hnodes[node_num].children[v & 0x01];
                v = v >> 1;
                bit_pos--;
            }

            frame->data[0][x] = node_num;
            prev = node_num;
        }
    }

    return 0;
}

static int idcin_decode_frame(AVCodecContext *avctx,
                              void *data, int *got_frame,
                              AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    IdcinContext *s = avctx->priv_data;
    int pal_size;
    const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, &pal_size);
    AVFrame *frame = data;
    int ret;

    s->buf = buf;
    s->size = buf_size;

    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
        return ret;

    if (idcin_decode_vlcs(s, frame))
        return AVERROR_INVALIDDATA;

    if (pal && pal_size == AVPALETTE_SIZE) {
        frame->palette_has_changed = 1;
        memcpy(s->pal, pal, AVPALETTE_SIZE);
    } else if (pal) {
        av_log(avctx, AV_LOG_ERROR, "Palette size %d is wrong\n", pal_size);
    }
    /* make the palette available on the way out */
    memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);

    *got_frame = 1;

    /* report that the buffer was completely consumed */
    return buf_size;
}

static const AVCodecDefault idcin_defaults[] = {
    { "max_pixels", "320*240" },
    { NULL },
};

AVCodec ff_idcin_decoder = {
    .name           = "idcinvideo",
    .long_name      = NULL_IF_CONFIG_SMALL("id Quake II CIN video"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_IDCIN,
    .priv_data_size = sizeof(IdcinContext),
    .init           = idcin_decode_init,
    .decode         = idcin_decode_frame,
    .capabilities   = AV_CODEC_CAP_DR1,
    .defaults       = idcin_defaults,
};


Generated by: GCOVR (Version 4.2)

Line	Branch	Exec	Source
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
67			AVCodecContext *avctx;
68
69			const unsigned char *buf;
70			int size;
71
72			hnode huff_nodes[256][HUF_TOKENS*2];
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		36984	static int huff_smallest_node(hnode *hnodes, int num_hnodes) {
85			int i;
86			int best, best_node;
87
88		36984	best = 99999999;
89		36984	best_node = -1;
90	✓✓	10824952	for(i = 0; i < num_hnodes; i++) {
91	✓✓	10787968	if(hnodes[i].used)
92		2658518	continue;
93	✓✓	8129450	if(!hnodes[i].count)
94		6790996	continue;
95	✓✓	1338454	if(hnodes[i].count < best) {
96		132488	best = hnodes[i].count;
97		132488	best_node = i;
98			}
99			}
100
101	✓✓	36984	if(best_node == -1)
102		512	return -1;
103		36472	hnodes[best_node].used = 1;
104		36472	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		512	static av_cold void huff_build_tree(IdcinContext *s, int prev) {
117			hnode node, hnodes;
118			int num_hnodes, i;
119
120		512	num_hnodes = HUF_TOKENS;
121		512	hnodes = s->huff_nodes[prev];
122	✓✓	262656	for(i = 0; i < HUF_TOKENS * 2; i++)
123		262144	hnodes[i].used = 0;
124
125			while (1) {
126		18594	node = &hnodes[num_hnodes]; /* next free node */
127
128			/* pick two lowest counts */
129		18594	node->children[0] = huff_smallest_node(hnodes, num_hnodes);
130	✓✓	18594	if(node->children[0] == -1)
131		204	break; /* reached the root node */
132
133		18390	node->children[1] = huff_smallest_node(hnodes, num_hnodes);
134	✓✓	18390	if(node->children[1] == -1)
135		308	break; /* reached the root node */
136
137			/* combine nodes probability for new node */
138		18082	node->count = hnodes[node->children[0]].count +
139		18082	hnodes[node->children[1]].count;
140		18082	num_hnodes++;
141			}
142
143		512	s->num_huff_nodes[prev] = num_hnodes - 1;
144		512	}
145
146		2	static av_cold int idcin_decode_init(AVCodecContext *avctx)
147			{
148		2	IdcinContext *s = avctx->priv_data;
149		2	int i, j, histogram_index = 0;
150			unsigned char *histograms;
151
152		2	s->avctx = avctx;
153		2	avctx->pix_fmt = AV_PIX_FMT_PAL8;
154
155			/* make sure the Huffman tables make it */
156	✗✓	2	if (s->avctx->extradata_size != HUFFMAN_TABLE_SIZE) {
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		2	histograms = (unsigned char *)s->avctx->extradata;
163	✓✓	514	for (i = 0; i < 256; i++) {
164	✓✓	131584	for(j = 0; j < HUF_TOKENS; j++)
165		131072	s->huff_nodes[i][j].count = histograms[histogram_index++];
166		512	huff_build_tree(s, i);
167			}
168
169		2	return 0;
170			}
171
172		52	static int idcin_decode_vlcs(IdcinContext s, AVFrame frame)
173			{
174			hnode *hnodes;
175			long x, y;
176			int prev;
177		52	unsigned char v = 0;
178			int bit_pos, node_num, dat_pos;
179
180		52	prev = bit_pos = dat_pos = 0;
181	✓✓	12532	for (y = 0; y < (frame->linesize[0] * s->avctx->height);
182		12480	y += frame->linesize[0]) {
183	✓✓	4006080	for (x = y; x < y + s->avctx->width; x++) {
184		3993600	node_num = s->num_huff_nodes[prev];
185		3993600	hnodes = s->huff_nodes[prev];
186
187	✓✓	17457808	while(node_num >= HUF_TOKENS) {
188	✓✓	13464208	if(!bit_pos) {
189	✗✓	1683045	if(dat_pos >= s->size) {
190			av_log(s->avctx, AV_LOG_ERROR, "Huffman decode error.\n");
191			return -1;
192			}
193		1683045	bit_pos = 8;
194		1683045	v = s->buf[dat_pos++];
195			}
196
197		13464208	node_num = hnodes[node_num].children[v & 0x01];
198		13464208	v = v >> 1;
199		13464208	bit_pos--;
200			}
201
202		3993600	frame->data[0][x] = node_num;
203		3993600	prev = node_num;
204			}
205			}
206
207		52	return 0;
208			}
209
210		52	static int idcin_decode_frame(AVCodecContext *avctx,
211			void data, int got_frame,
212			AVPacket *avpkt)
213			{
214		52	const uint8_t *buf = avpkt->data;
215		52	int buf_size = avpkt->size;
216		52	IdcinContext *s = avctx->priv_data;
217			int pal_size;
218		52	const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, &pal_size);
219		52	AVFrame *frame = data;
220			int ret;
221
222		52	s->buf = buf;
223		52	s->size = buf_size;
224
225	✗✓	52	if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
226			return ret;
227
228	✗✓	52	if (idcin_decode_vlcs(s, frame))
229			return AVERROR_INVALIDDATA;
230
231	✓✓✓✗	52	if (pal && pal_size == AVPALETTE_SIZE) {
232		1	frame->palette_has_changed = 1;
233		1	memcpy(s->pal, pal, AVPALETTE_SIZE);
234	✗✓	51	} else if (pal) {
235			av_log(avctx, AV_LOG_ERROR, "Palette size %d is wrong\n", pal_size);
236			}
237			/* make the palette available on the way out */
238		52	memcpy(frame->data[1], s->pal, AVPALETTE_SIZE);
239
240		52	*got_frame = 1;
241
242			/* report that the buffer was completely consumed */
243		52	return buf_size;
244			}
245
246			static const AVCodecDefault idcin_defaults[] = {
247			{ "max_pixels", "320*240" },
248			{ NULL },
249			};
250
251			AVCodec ff_idcin_decoder = {
252			.name = "idcinvideo",
253			.long_name = NULL_IF_CONFIG_SMALL("id Quake II CIN video"),
254			.type = AVMEDIA_TYPE_VIDEO,
255			.id = AV_CODEC_ID_IDCIN,
256			.priv_data_size = sizeof(IdcinContext),
257			.init = idcin_decode_init,
258			.decode = idcin_decode_frame,
259			.capabilities = AV_CODEC_CAP_DR1,
260			.defaults = idcin_defaults,
261			};