#include "thread.h"
#include "utvideo.h"
-static int build_huff(const uint8_t *src, VLC *vlc, int *fsym, unsigned nb_elems)
+typedef struct HuffEntry {
+ uint8_t len;
+ uint16_t sym;
+} HuffEntry;
+
+static int build_huff(UtvideoContext *c, const uint8_t *src, VLC *vlc,
+ int *fsym, unsigned nb_elems)
{
int i;
HuffEntry he[1024];
- int last;
- uint32_t codes[1024];
uint8_t bits[1024];
- uint16_t syms[1024];
- uint32_t code;
+ uint16_t codes_count[33] = { 0 };
*fsym = -1;
for (i = 0; i < nb_elems; i++) {
- he[i].sym = i;
- he[i].len = *src++;
- }
- qsort(he, nb_elems, sizeof(*he), ff_ut10_huff_cmp_len);
+ if (src[i] == 0) {
+ *fsym = i;
+ return 0;
+ } else if (src[i] == 255) {
+ bits[i] = 0;
+ } else if (src[i] <= 32) {
+ bits[i] = src[i];
+ } else
+ return AVERROR_INVALIDDATA;
- if (!he[0].len) {
- *fsym = he[0].sym;
- return 0;
+ codes_count[bits[i]]++;
}
+ if (codes_count[0] == nb_elems)
+ return AVERROR_INVALIDDATA;
- last = nb_elems - 1;
- while (he[last].len == 255 && last)
- last--;
+ /* For Ut Video, longer codes are to the left of the tree and
+ * for codes with the same length the symbol is descending from
+ * left to right. So after the next loop --codes_count[i] will
+ * be the index of the first (lowest) symbol of length i when
+ * indexed by the position in the tree with left nodes being first. */
+ for (int i = 31; i >= 0; i--)
+ codes_count[i] += codes_count[i + 1];
- if (he[last].len > 32) {
- return -1;
- }
+ for (unsigned i = 0; i < nb_elems; i++)
+ he[--codes_count[bits[i]]] = (HuffEntry) { bits[i], i };
- code = 0;
- for (i = last; i >= 0; i--) {
- codes[i] = code >> (32 - he[i].len);
- bits[i] = he[i].len;
- syms[i] = he[i].sym;
- code += 0x80000000u >> (he[i].len - 1);
- }
#define VLC_BITS 11
- return ff_init_vlc_sparse(vlc, VLC_BITS, last + 1,
- bits, sizeof(*bits), sizeof(*bits),
- codes, sizeof(*codes), sizeof(*codes),
- syms, sizeof(*syms), sizeof(*syms), 0);
+ return ff_init_vlc_from_lengths(vlc, VLC_BITS, codes_count[0],
+ &he[0].len, sizeof(*he),
+ &he[0].sym, sizeof(*he), 2, 0, 0, c->avctx);
}
static int decode_plane10(UtvideoContext *c, int plane_no,
GetBitContext gb;
int prev, fsym;
- if ((ret = build_huff(huff, &vlc, &fsym, 1024)) < 0) {
+ if ((ret = build_huff(c, huff, &vlc, &fsym, 1024)) < 0) {
av_log(c->avctx, AV_LOG_ERROR, "Cannot build Huffman codes\n");
return ret;
}
return 0;
}
- if (build_huff(src, &vlc, &fsym, 256)) {
+ if (build_huff(c, src, &vlc, &fsym, 256)) {
av_log(c->avctx, AV_LOG_ERROR, "Cannot build Huffman codes\n");
return AVERROR_INVALIDDATA;
}
return 0;
}
-AVCodec ff_utvideo_decoder = {
+const AVCodec ff_utvideo_decoder = {
.name = "utvideo",
.long_name = NULL_IF_CONFIG_SMALL("Ut Video"),
.type = AVMEDIA_TYPE_VIDEO,