libavcodec/idcinvideo.c - vendor/opensource/ffmpeg - Git at Google

 /*
  * 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 libavcodec/idcinvideo.c
  * 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 ffmpeg'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 <unistd.h>

 #include "avcodec.h"

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

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

 typedef struct IdcinContext {

     AVCodecContext *avctx;
     AVFrame frame;

     const unsigned char *buf;
     int size;

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

 } IdcinContext;

 /*
  * Find the lowest probability node in a Huffman table, and mark it as
  * being assigned to a higher probability.
  * Returns 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 = 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);
     }

     s->frame.data[0] = NULL;

     return 0;
 }

 static void idcin_decode_vlcs(IdcinContext *s)
 {
     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 < (s->frame.linesize[0] * s->avctx->height);
         y += s->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;
                     }
                     bit_pos = 8;
                     v = s->buf[dat_pos++];
                 }

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

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

 static int idcin_decode_frame(AVCodecContext *avctx,
                               void *data, int *data_size,
                               const uint8_t *buf, int buf_size)
 {
     IdcinContext *s = avctx->priv_data;
     AVPaletteControl *palette_control = avctx->palctrl;

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

     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);

     if (avctx->get_buffer(avctx, &s->frame)) {
         av_log(avctx, AV_LOG_ERROR, "  id CIN Video: get_buffer() failed\n");
         return -1;
     }

     idcin_decode_vlcs(s);

     /* make the palette available on the way out */
     memcpy(s->frame.data[1], palette_control->palette, PALETTE_COUNT * 4);
     /* If palette changed inform application*/
     if (palette_control->palette_changed) {
         palette_control->palette_changed = 0;
         s->frame.palette_has_changed = 1;
     }

     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = s->frame;

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

 static av_cold int idcin_decode_end(AVCodecContext *avctx)
 {
     IdcinContext *s = avctx->priv_data;

     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);

     return 0;
 }

 AVCodec idcin_decoder = {
     "idcinvideo",
     CODEC_TYPE_VIDEO,
     CODEC_ID_IDCIN,
     sizeof(IdcinContext),
     idcin_decode_init,
     NULL,
     idcin_decode_end,
     idcin_decode_frame,
     CODEC_CAP_DR1,
     .long_name = NULL_IF_CONFIG_SMALL("id Quake II CIN video"),
 };
	/*
	* 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 libavcodec/idcinvideo.c
	* 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 ffmpeg'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 <unistd.h>

	#include "avcodec.h"

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

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

	typedef struct IdcinContext {

	AVCodecContext *avctx;
	AVFrame frame;

	const unsigned char *buf;
	int size;

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

	} IdcinContext;

	/*
	* Find the lowest probability node in a Huffman table, and mark it as
	* being assigned to a higher probability.
	* Returns 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 = 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);
	}

	s->frame.data[0] = NULL;

	return 0;
	}

	static void idcin_decode_vlcs(IdcinContext *s)
	{
	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 < (s->frame.linesize[0] * s->avctx->height);
	y += s->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;
	}
	bit_pos = 8;
	v = s->buf[dat_pos++];
	}

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

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

	static int idcin_decode_frame(AVCodecContext *avctx,
	void data, int data_size,
	const uint8_t *buf, int buf_size)
	{
	IdcinContext *s = avctx->priv_data;
	AVPaletteControl *palette_control = avctx->palctrl;

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

	if (s->frame.data[0])
	avctx->release_buffer(avctx, &s->frame);

	if (avctx->get_buffer(avctx, &s->frame)) {
	av_log(avctx, AV_LOG_ERROR, " id CIN Video: get_buffer() failed\n");
	return -1;
	}

	idcin_decode_vlcs(s);

	/* make the palette available on the way out */
	memcpy(s->frame.data[1], palette_control->palette, PALETTE_COUNT * 4);
	/* If palette changed inform application*/
	if (palette_control->palette_changed) {
	palette_control->palette_changed = 0;
	s->frame.palette_has_changed = 1;
	}

	*data_size = sizeof(AVFrame);
	(AVFrame)data = s->frame;

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

	static av_cold int idcin_decode_end(AVCodecContext *avctx)
	{
	IdcinContext *s = avctx->priv_data;

	if (s->frame.data[0])
	avctx->release_buffer(avctx, &s->frame);

	return 0;
	}

	AVCodec idcin_decoder = {
	"idcinvideo",
	CODEC_TYPE_VIDEO,
	CODEC_ID_IDCIN,
	sizeof(IdcinContext),
	idcin_decode_init,
	NULL,
	idcin_decode_end,
	idcin_decode_frame,
	CODEC_CAP_DR1,
	.long_name = NULL_IF_CONFIG_SMALL("id Quake II CIN video"),
	};