ffmpeg-2.8.5

git-svn-id: svn://kolibrios.org@6147 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/ffmpeg/ffmpeg-2.8/libavcodec/idcinvideo.c

@@ -0,0 +1,252 @@
+/*
+ * 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;
+    const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
+    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) {
+        frame->palette_has_changed = 1;
+        memcpy(s->pal, pal, AVPALETTE_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;
+}
+
+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,
+};