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moves fraps huffman decoder to its own file, making it more generic

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Originally committed as revision 10736 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Aurelien Jacobs
2007-10-14 21:19:40 +00:00
parent 5d25d2a983
commit 437c2079b7
4 changed files with 149 additions and 80 deletions
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86
libavcodec/fraps.c
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@@ -33,30 +33,18 @@
#include "avcodec.h"
#include "bitstream.h"
#include "huffman.h"
#include "bytestream.h"
#include "dsputil.h"
#define FPS_TAG MKTAG('F', 'P', 'S', 'x')
/* symbol for Huffman tree node */
#define HNODE -1
/**
* Huffman node
* FIXME one day this should belong to one general framework
*/
typedef struct Node{
int16_t sym;
int16_t n0;
int count;
}Node;
/**
* local variable storage
*/
typedef struct FrapsContext{
AVCodecContext *avctx;
AVFrame frame;
Node nodes[512];
uint8_t *tmpbuf;
DSPContext dsp;
} FrapsContext;
@@ -92,36 +80,6 @@ static int huff_cmp(const void *va, const void *vb){
return (a->count - b->count)*256 + a->sym - b->sym;
}
static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat, Node *nodes, int node, uint32_t pfx, int pl, int *pos)
{
int s;
s = nodes[node].sym;
if(s != HNODE || !nodes[node].count){
bits[*pos] = pfx;
lens[*pos] = pl;
xlat[*pos] = s;
(*pos)++;
}else{
pfx <<= 1;
pl++;
get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0, pfx, pl, pos);
pfx |= 1;
get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0+1, pfx, pl, pos);
}
}
static int build_huff_tree(VLC *vlc, Node *nodes, uint8_t *xlat)
{
uint32_t bits[256];
int16_t lens[256];
int pos = 0;
get_tree_codes(bits, lens, xlat, nodes, 510, 0, 0, &pos);
return init_vlc(vlc, 9, pos, lens, 2, 2, bits, 4, 4, 0);
}
/**
* decode Fraps v2 packed plane
*/
@@ -129,45 +87,15 @@ static int fraps2_decode_plane(FrapsContext *s, uint8_t *dst, int stride, int w,
int h, uint8_t *src, int size, int Uoff)
{
int i, j;
int cur_node;
GetBitContext gb;
VLC vlc;
int64_t sum = 0;
uint8_t recode[256];
Node nodes[512];
for(i = 0; i < 256; i++){
s->nodes[i].sym = i;
s->nodes[i].count = AV_RL32(src);
s->nodes[i].n0 = -2;
if(s->nodes[i].count < 0) {
av_log(s->avctx, AV_LOG_ERROR, "Symbol count < 0\n");
return -1;
}
src += 4;
sum += s->nodes[i].count;
}
for(i = 0; i < 256; i++)
nodes[i].count = bytestream_get_le32(&src);
size -= 1024;
if(sum >> 31) {
av_log(s->avctx, AV_LOG_ERROR, "Too high symbol frequencies. Tree construction is not possible\n");
if (ff_huff_build_tree(s->avctx, &vlc, 256, nodes, huff_cmp, 0) < 0)
return -1;
}
qsort(s->nodes, 256, sizeof(Node), huff_cmp);
cur_node = 256;
for(i = 0; i < 511; i += 2){
s->nodes[cur_node].sym = HNODE;
s->nodes[cur_node].count = s->nodes[i].count + s->nodes[i+1].count;
s->nodes[cur_node].n0 = i;
for(j = cur_node; j > 0; j--){
if(s->nodes[j].count >= s->nodes[j - 1].count) break;
FFSWAP(Node, s->nodes[j], s->nodes[j - 1]);
}
cur_node++;
}
if(build_huff_tree(&vlc, s->nodes, recode) < 0){
av_log(s->avctx, AV_LOG_ERROR, "Error building tree\n");
return -1;
}
/* we have built Huffman table and are ready to decode plane */
/* convert bits so they may be used by standard bitreader */
@@ -176,7 +104,7 @@ static int fraps2_decode_plane(FrapsContext *s, uint8_t *dst, int stride, int w,
init_get_bits(&gb, s->tmpbuf, size * 8);
for(j = 0; j < h; j++){
for(i = 0; i < w; i++){
dst[i] = recode[get_vlc2(&gb, vlc.table, 9, 3)];
dst[i] = get_vlc2(&gb, vlc.table, 9, 3);
/* lines are stored as deltas between previous lines
* and we need to add 0x80 to the first lines of chroma planes
*/