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-rw-r--r--libavcodec/msmpeg4.c931
1 files changed, 931 insertions, 0 deletions
diff --git a/libavcodec/msmpeg4.c b/libavcodec/msmpeg4.c
new file mode 100644
index 0000000000..044d964ee5
--- /dev/null
+++ b/libavcodec/msmpeg4.c
@@ -0,0 +1,931 @@
+/*
+ * MSMPEG4 backend for ffmpeg encoder and decoder
+ * Copyright (c) 2001 Gerard Lantau.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include "common.h"
+#include "dsputil.h"
+#include "mpegvideo.h"
+
+/*
+ * You can also call this codec : MPEG4 with a twist !
+ *
+ * TODO:
+ * - (encoding) select best mv table (two choices)
+ * - (encoding) select best vlc/dc table
+ * - (decoding) handle slice indication
+ */
+//#define DEBUG
+
+/* motion vector table */
+typedef struct MVTable {
+ int n;
+ const UINT16 *table_mv_code;
+ const UINT8 *table_mv_bits;
+ const UINT8 *table_mvx;
+ const UINT8 *table_mvy;
+ UINT16 *table_mv_index; /* encoding: convert mv to index in table_mv */
+ VLC vlc; /* decoding: vlc */
+} MVTable;
+
+static void msmpeg4_encode_block(MpegEncContext * s, DCTELEM * block, int n);
+static int msmpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
+ int n, int coded);
+static int msmpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr);
+static int msmpeg4_decode_motion(MpegEncContext * s,
+ int *mx_ptr, int *my_ptr);
+
+#ifdef DEBUG
+int intra_count = 0;
+int frame_count = 0;
+#endif
+/* XXX: move it to mpegvideo.h */
+
+static int init_done = 0;
+
+#include "msmpeg4data.h"
+
+#ifdef STATS
+
+const char *st_names[ST_NB] = {
+ "unknown",
+ "dc",
+ "intra_ac",
+ "inter_ac",
+ "intra_mb",
+ "inter_mb",
+ "mv",
+};
+
+int st_current_index = 0;
+unsigned int st_bit_counts[ST_NB];
+unsigned int st_out_bit_counts[ST_NB];
+
+#define set_stat(var) st_current_index = var;
+
+void print_stats(void)
+{
+ unsigned int total;
+ int i;
+
+ printf("Input:\n");
+ total = 0;
+ for(i=0;i<ST_NB;i++)
+ total += st_bit_counts[i];
+ if (total == 0)
+ total = 1;
+ for(i=0;i<ST_NB;i++) {
+ printf("%-10s : %10.1f %5.1f%%\n",
+ st_names[i],
+ (double)st_bit_counts[i] / 8.0,
+ (double)st_bit_counts[i] * 100.0 / total);
+ }
+ printf("%-10s : %10.1f %5.1f%%\n",
+ "total",
+ (double)total / 8.0,
+ 100.0);
+
+ printf("Output:\n");
+ total = 0;
+ for(i=0;i<ST_NB;i++)
+ total += st_out_bit_counts[i];
+ if (total == 0)
+ total = 1;
+ for(i=0;i<ST_NB;i++) {
+ printf("%-10s : %10.1f %5.1f%%\n",
+ st_names[i],
+ (double)st_out_bit_counts[i] / 8.0,
+ (double)st_out_bit_counts[i] * 100.0 / total);
+ }
+ printf("%-10s : %10.1f %5.1f%%\n",
+ "total",
+ (double)total / 8.0,
+ 100.0);
+}
+
+#else
+
+#define set_stat(var)
+
+#endif
+
+/* build the table which associate a (x,y) motion vector to a vlc */
+static void init_mv_table(MVTable *tab)
+{
+ int i, x, y;
+
+ tab->table_mv_index = malloc(sizeof(UINT16) * 4096);
+ /* mark all entries as not used */
+ for(i=0;i<4096;i++)
+ tab->table_mv_index[i] = tab->n;
+
+ for(i=0;i<tab->n;i++) {
+ x = tab->table_mvx[i];
+ y = tab->table_mvy[i];
+ tab->table_mv_index[(x << 6) | y] = i;
+ }
+}
+
+static void code012(PutBitContext *pb, int n)
+{
+ if (n == 0) {
+ put_bits(pb, 1, 0);
+ } else {
+ put_bits(pb, 1, 1);
+ put_bits(pb, 1, (n >= 2));
+ }
+}
+
+/* write MSMPEG4 V3 compatible frame header */
+void msmpeg4_encode_picture_header(MpegEncContext * s, int picture_number)
+{
+ int i;
+
+ align_put_bits(&s->pb);
+
+ put_bits(&s->pb, 2, s->pict_type - 1);
+
+ put_bits(&s->pb, 5, s->qscale);
+
+ s->rl_table_index = 2;
+ s->rl_chroma_table_index = 1; /* only for I frame */
+ s->dc_table_index = 1;
+ s->mv_table_index = 1; /* only if P frame */
+ s->use_skip_mb_code = 1; /* only if P frame */
+
+ if (s->pict_type == I_TYPE) {
+ put_bits(&s->pb, 5, 0x17); /* indicate only one "slice" */
+
+ code012(&s->pb, s->rl_chroma_table_index);
+ code012(&s->pb, s->rl_table_index);
+
+ put_bits(&s->pb, 1, s->dc_table_index);
+ s->no_rounding = 1;
+ } else {
+ put_bits(&s->pb, 1, s->use_skip_mb_code);
+
+ s->rl_chroma_table_index = s->rl_table_index;
+ code012(&s->pb, s->rl_table_index);
+
+ put_bits(&s->pb, 1, s->dc_table_index);
+
+ put_bits(&s->pb, 1, s->mv_table_index);
+ s->no_rounding ^= 1;
+ }
+
+ if (!init_done) {
+ /* init various encoding tables */
+ init_done = 1;
+ init_mv_table(&mv_tables[0]);
+ init_mv_table(&mv_tables[1]);
+ for(i=0;i<NB_RL_TABLES;i++)
+ init_rl(&rl_table[i]);
+ }
+
+#ifdef DEBUG
+ intra_count = 0;
+ printf("*****frame %d:\n", frame_count++);
+#endif
+}
+
+/* predict coded block */
+static inline int coded_block_pred(MpegEncContext * s, int n, UINT8 **coded_block_ptr)
+{
+ int x, y, wrap, pred, a, b, c;
+
+ x = 2 * s->mb_x + 1 + (n & 1);
+ y = 2 * s->mb_y + 1 + ((n & 2) >> 1);
+ wrap = s->mb_width * 2 + 2;
+
+ /* B C
+ * A X
+ */
+ a = s->coded_block[(x - 1) + (y) * wrap];
+ b = s->coded_block[(x - 1) + (y - 1) * wrap];
+ c = s->coded_block[(x) + (y - 1) * wrap];
+
+ if (b == c) {
+ pred = a;
+ } else {
+ pred = c;
+ }
+
+ /* store value */
+ *coded_block_ptr = &s->coded_block[(x) + (y) * wrap];
+
+ return pred;
+}
+
+static void msmpeg4_encode_motion(MpegEncContext * s,
+ int mx, int my)
+{
+ int code;
+ MVTable *mv;
+
+ /* modulo encoding */
+ /* WARNING : you cannot reach all the MVs even with the modulo
+ encoding. This is a somewhat strange compromise they took !!! */
+ if (mx <= -64)
+ mx += 64;
+ else if (mx >= 64)
+ mx -= 64;
+ if (my <= -64)
+ my += 64;
+ else if (my >= 64)
+ my -= 64;
+
+ mx += 32;
+ my += 32;
+#if 0
+ if ((unsigned)mx >= 64 ||
+ (unsigned)my >= 64)
+ fprintf(stderr, "error mx=%d my=%d\n", mx, my);
+#endif
+ mv = &mv_tables[s->mv_table_index];
+
+ code = mv->table_mv_index[(mx << 6) | my];
+ set_stat(ST_MV);
+ put_bits(&s->pb,
+ mv->table_mv_bits[code],
+ mv->table_mv_code[code]);
+ if (code == mv->n) {
+ /* escape : code litterally */
+ put_bits(&s->pb, 6, mx);
+ put_bits(&s->pb, 6, my);
+ }
+}
+
+void msmpeg4_encode_mb(MpegEncContext * s,
+ DCTELEM block[6][64],
+ int motion_x, int motion_y)
+{
+ int cbp, coded_cbp, i;
+ int pred_x, pred_y;
+ UINT8 *coded_block;
+
+ if (!s->mb_intra) {
+ /* compute cbp */
+ set_stat(ST_INTER_MB);
+ cbp = 0;
+ for (i = 0; i < 6; i++) {
+ if (s->block_last_index[i] >= 0)
+ cbp |= 1 << (5 - i);
+ }
+ if (s->use_skip_mb_code && (cbp | motion_x | motion_y) == 0) {
+ /* skip macroblock */
+ put_bits(&s->pb, 1, 1);
+ return;
+ }
+ if (s->use_skip_mb_code)
+ put_bits(&s->pb, 1, 0); /* mb coded */
+
+ put_bits(&s->pb,
+ table_mb_non_intra[cbp + 64][1],
+ table_mb_non_intra[cbp + 64][0]);
+
+ /* motion vector */
+ h263_pred_motion(s, 0, &pred_x, &pred_y);
+ msmpeg4_encode_motion(s, motion_x - pred_x,
+ motion_y - pred_y);
+ } else {
+ /* compute cbp */
+ cbp = 0;
+ coded_cbp = 0;
+ for (i = 0; i < 6; i++) {
+ int val, pred;
+ val = (s->block_last_index[i] >= 1);
+ cbp |= val << (5 - i);
+ if (i < 4) {
+ /* predict value for close blocks only for luma */
+ pred = coded_block_pred(s, i, &coded_block);
+ *coded_block = val;
+ val = val ^ pred;
+ }
+ coded_cbp |= val << (5 - i);
+ }
+#if 0
+ if (coded_cbp)
+ printf("cbp=%x %x\n", cbp, coded_cbp);
+#endif
+
+ if (s->pict_type == I_TYPE) {
+ set_stat(ST_INTRA_MB);
+ put_bits(&s->pb,
+ table_mb_intra[coded_cbp][1], table_mb_intra[coded_cbp][0]);
+ } else {
+ if (s->use_skip_mb_code)
+ put_bits(&s->pb, 1, 0); /* mb coded */
+ put_bits(&s->pb,
+ table_mb_non_intra[cbp][1],
+ table_mb_non_intra[cbp][0]);
+ }
+ set_stat(ST_INTRA_MB);
+ put_bits(&s->pb, 1, 0); /* no AC prediction yet */
+ }
+
+ for (i = 0; i < 6; i++) {
+ msmpeg4_encode_block(s, block[i], i);
+ }
+}
+
+
+/* strongly inspirated from MPEG4, but not exactly the same ! */
+void msmpeg4_dc_scale(MpegEncContext * s)
+{
+ int scale;
+
+ if (s->qscale < 5)
+ scale = 8;
+ else if (s->qscale < 9)
+ scale = 2 * s->qscale;
+ else
+ scale = s->qscale + 8;
+ s->y_dc_scale = scale;
+ s->c_dc_scale = (s->qscale + 13) / 2;
+}
+
+/* dir = 0: left, dir = 1: top prediction */
+static int msmpeg4_pred_dc(MpegEncContext * s, int n,
+ UINT16 **dc_val_ptr, int *dir_ptr)
+{
+ int a, b, c, x, y, wrap, pred, scale;
+ UINT16 *dc_val;
+
+ /* find prediction */
+ if (n < 4) {
+ x = 2 * s->mb_x + 1 + (n & 1);
+ y = 2 * s->mb_y + 1 + ((n & 2) >> 1);
+ wrap = s->mb_width * 2 + 2;
+ dc_val = s->dc_val[0];
+ scale = s->y_dc_scale;
+ } else {
+ x = s->mb_x + 1;
+ y = s->mb_y + 1;
+ wrap = s->mb_width + 2;
+ dc_val = s->dc_val[n - 4 + 1];
+ scale = s->c_dc_scale;
+ }
+
+ /* B C
+ * A X
+ */
+ a = dc_val[(x - 1) + (y) * wrap];
+ b = dc_val[(x - 1) + (y - 1) * wrap];
+ c = dc_val[(x) + (y - 1) * wrap];
+
+ /* XXX: the following solution consumes divisions, but it does not
+ necessitate to modify mpegvideo.c. The problem comes from the
+ fact they decided to store the quantized DC (which would lead
+ to problems if Q could vary !) */
+ a = (a + (scale >> 1)) / scale;
+ b = (b + (scale >> 1)) / scale;
+ c = (c + (scale >> 1)) / scale;
+
+ /* XXX: WARNING: they did not choose the same test as MPEG4. This
+ is very important ! */
+ if (abs(a - b) <= abs(b - c)) {
+ pred = c;
+ *dir_ptr = 1;
+ } else {
+ pred = a;
+ *dir_ptr = 0;
+ }
+
+ /* update predictor */
+ *dc_val_ptr = &dc_val[(x) + (y) * wrap];
+ return pred;
+}
+
+#define DC_MAX 119
+
+static void msmpeg4_encode_dc(MpegEncContext * s, int level, int n, int *dir_ptr)
+{
+ int sign, code;
+ int pred;
+ UINT16 *dc_val;
+
+ pred = msmpeg4_pred_dc(s, n, &dc_val, dir_ptr);
+
+ /* update predictor */
+ if (n < 4) {
+ *dc_val = level * s->y_dc_scale;
+ } else {
+ *dc_val = level * s->c_dc_scale;
+ }
+
+ /* do the prediction */
+ level -= pred;
+
+ sign = 0;
+ if (level < 0) {
+ level = -level;
+ sign = 1;
+ }
+
+ code = level;
+ if (code > DC_MAX)
+ code = DC_MAX;
+
+ if (s->dc_table_index == 0) {
+ if (n < 4) {
+ put_bits(&s->pb, table0_dc_lum[code][1], table0_dc_lum[code][0]);
+ } else {
+ put_bits(&s->pb, table0_dc_chroma[code][1], table0_dc_chroma[code][0]);
+ }
+ } else {
+ if (n < 4) {
+ put_bits(&s->pb, table1_dc_lum[code][1], table1_dc_lum[code][0]);
+ } else {
+ put_bits(&s->pb, table1_dc_chroma[code][1], table1_dc_chroma[code][0]);
+ }
+ }
+
+ if (code == DC_MAX)
+ put_bits(&s->pb, 8, level);
+
+ if (level != 0) {
+ put_bits(&s->pb, 1, sign);
+ }
+}
+
+/* Encoding of a block. Very similar to MPEG4 except for a different
+ escape coding (same as H263) and more vlc tables.
+ */
+static void msmpeg4_encode_block(MpegEncContext * s, DCTELEM * block, int n)
+{
+ int level, run, last, i, j, last_index;
+ int last_non_zero, sign, slevel;
+ int code, run_diff, dc_pred_dir;
+ const RLTable *rl;
+
+ if (s->mb_intra) {
+ set_stat(ST_DC);
+ msmpeg4_encode_dc(s, block[0], n, &dc_pred_dir);
+ i = 1;
+ if (n < 4) {
+ rl = &rl_table[s->rl_table_index];
+ } else {
+ rl = &rl_table[3 + s->rl_chroma_table_index];
+ }
+ run_diff = 0;
+ set_stat(ST_INTRA_AC);
+ } else {
+ i = 0;
+ rl = &rl_table[3 + s->rl_table_index];
+ run_diff = 1;
+ set_stat(ST_INTER_AC);
+ }
+
+ /* AC coefs */
+ last_index = s->block_last_index[n];
+ last_non_zero = i - 1;
+ for (; i <= last_index; i++) {
+ j = zigzag_direct[i];
+ level = block[j];
+ if (level) {
+ run = i - last_non_zero - 1;
+ last = (i == last_index);
+ sign = 0;
+ slevel = level;
+ if (level < 0) {
+ sign = 1;
+ level = -level;
+ }
+ code = get_rl_index(rl, last, run, level);
+ put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
+ if (code == rl->n) {
+ int level1, run1;
+
+ level1 = level - rl->max_level[last][run];
+ if (level1 < 1)
+ goto esc2;
+ code = get_rl_index(rl, last, run, level1);
+ if (code == rl->n) {
+ esc2:
+ put_bits(&s->pb, 1, 0);
+ if (level > MAX_LEVEL)
+ goto esc3;
+ run1 = run - rl->max_run[last][level] - run_diff;
+ if (run1 < 0)
+ goto esc3;
+ code = get_rl_index(rl, last, run1, level);
+ if (code == rl->n) {
+ esc3:
+ /* third escape */
+ put_bits(&s->pb, 1, 0);
+ put_bits(&s->pb, 1, last);
+ put_bits(&s->pb, 6, run);
+ put_bits(&s->pb, 8, slevel & 0xff);
+ } else {
+ /* second escape */
+ put_bits(&s->pb, 1, 1);
+ put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
+ put_bits(&s->pb, 1, sign);
+ }
+ } else {
+ /* first escape */
+ put_bits(&s->pb, 1, 1);
+ put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
+ put_bits(&s->pb, 1, sign);
+ }
+ } else {
+ put_bits(&s->pb, 1, sign);
+ }
+ last_non_zero = i;
+ }
+ }
+}
+
+/****************************************/
+/* decoding stuff */
+
+static VLC mb_non_intra_vlc;
+static VLC mb_intra_vlc;
+static VLC dc_lum_vlc[2];
+static VLC dc_chroma_vlc[2];
+
+/* init all vlc decoding tables */
+int msmpeg4_decode_init_vlc(MpegEncContext *s)
+{
+ int i;
+ MVTable *mv;
+
+ for(i=0;i<NB_RL_TABLES;i++) {
+ init_rl(&rl_table[i]);
+ init_vlc_rl(&rl_table[i]);
+ }
+ for(i=0;i<2;i++) {
+ mv = &mv_tables[i];
+ init_vlc(&mv->vlc, 9, mv->n + 1,
+ mv->table_mv_bits, 1, 1,
+ mv->table_mv_code, 2, 2);
+ }
+
+ init_vlc(&dc_lum_vlc[0], 9, 120,
+ &table0_dc_lum[0][1], 8, 4,
+ &table0_dc_lum[0][0], 8, 4);
+ init_vlc(&dc_chroma_vlc[0], 9, 120,
+ &table0_dc_chroma[0][1], 8, 4,
+ &table0_dc_chroma[0][0], 8, 4);
+ init_vlc(&dc_lum_vlc[1], 9, 120,
+ &table1_dc_lum[0][1], 8, 4,
+ &table1_dc_lum[0][0], 8, 4);
+ init_vlc(&dc_chroma_vlc[1], 9, 120,
+ &table1_dc_chroma[0][1], 8, 4,
+ &table1_dc_chroma[0][0], 8, 4);
+
+ init_vlc(&mb_non_intra_vlc, 9, 128,
+ &table_mb_non_intra[0][1], 8, 4,
+ &table_mb_non_intra[0][0], 8, 4);
+ init_vlc(&mb_intra_vlc, 9, 128,
+ &table_mb_intra[0][1], 4, 2,
+ &table_mb_intra[0][0], 4, 2);
+ return 0;
+}
+
+static int decode012(GetBitContext *gb)
+{
+ int n;
+ n = get_bits(gb, 1);
+ if (n == 0)
+ return 0;
+ else
+ return get_bits(gb, 1) + 1;
+}
+
+int msmpeg4_decode_picture_header(MpegEncContext * s)
+{
+ int code;
+
+ s->pict_type = get_bits(&s->gb, 2) + 1;
+ if (s->pict_type != I_TYPE &&
+ s->pict_type != P_TYPE)
+ return -1;
+
+ s->qscale = get_bits(&s->gb, 5);
+
+ if (s->pict_type == I_TYPE) {
+ code = get_bits(&s->gb, 5);
+ /* 0x17: one slice, 0x18: three slices */
+ /* XXX: implement it */
+ if (code < 0x17)
+ return -1;
+ s->slice_height = s->mb_height / (code - 0x16);
+ s->rl_chroma_table_index = decode012(&s->gb);
+ s->rl_table_index = decode012(&s->gb);
+
+ s->dc_table_index = get_bits(&s->gb, 1);
+ s->no_rounding = 1;
+ } else {
+ s->use_skip_mb_code = get_bits(&s->gb, 1);
+
+ s->rl_table_index = decode012(&s->gb);
+ s->rl_chroma_table_index = s->rl_table_index;
+
+ s->dc_table_index = get_bits(&s->gb, 1);
+
+ s->mv_table_index = get_bits(&s->gb, 1);
+ s->no_rounding ^= 1;
+ }
+#ifdef DEBUG
+ printf("*****frame %d:\n", frame_count++);
+#endif
+ return 0;
+}
+
+void memsetw(short *tab, int val, int n)
+{
+ int i;
+ for(i=0;i<n;i++)
+ tab[i] = val;
+}
+
+int msmpeg4_decode_mb(MpegEncContext *s,
+ DCTELEM block[6][64])
+{
+ int cbp, code, i;
+ int pred, val;
+ UINT8 *coded_val;
+
+ /* special slice handling */
+ if (s->mb_x == 0) {
+ if ((s->mb_y % s->slice_height) == 0) {
+ int wrap;
+ /* reset DC pred (set previous line to 1024) */
+ wrap = 2 * s->mb_width + 2;
+ memsetw(&s->dc_val[0][(1) + (2 * s->mb_y) * wrap],
+ 1024, 2 * s->mb_width);
+ wrap = s->mb_width + 2;
+ memsetw(&s->dc_val[1][(1) + (s->mb_y) * wrap],
+ 1024, s->mb_width);
+ memsetw(&s->dc_val[2][(1) + (s->mb_y) * wrap],
+ 1024, s->mb_width);
+
+ s->first_slice_line = 1;
+ } else {
+ s->first_slice_line = 0;
+ }
+ }
+
+ if (s->pict_type == P_TYPE) {
+ set_stat(ST_INTER_MB);
+ if (s->use_skip_mb_code) {
+ if (get_bits(&s->gb, 1)) {
+ /* skip mb */
+ s->mb_intra = 0;
+ for(i=0;i<6;i++)
+ s->block_last_index[i] = -1;
+ s->mv_dir = MV_DIR_FORWARD;
+ s->mv_type = MV_TYPE_16X16;
+ s->mv[0][0][0] = 0;
+ s->mv[0][0][1] = 0;
+ return 0;
+ }
+ }
+
+ code = get_vlc(&s->gb, &mb_non_intra_vlc);
+ if (code < 0)
+ return -1;
+ if (code & 0x40)
+ s->mb_intra = 0;
+ else
+ s->mb_intra = 1;
+
+ cbp = code & 0x3f;
+ } else {
+ set_stat(ST_INTRA_MB);
+ s->mb_intra = 1;
+ code = get_vlc(&s->gb, &mb_intra_vlc);
+ if (code < 0)
+ return -1;
+ /* predict coded block pattern */
+ cbp = 0;
+ for(i=0;i<6;i++) {
+ val = ((code >> (5 - i)) & 1);
+ if (i < 4) {
+ pred = coded_block_pred(s, i, &coded_val);
+ val = val ^ pred;
+ *coded_val = val;
+ }
+ cbp |= val << (5 - i);
+ }
+ }
+
+ if (!s->mb_intra) {
+ int mx, my;
+ set_stat(ST_MV);
+ h263_pred_motion(s, 0, &mx, &my);
+ if (msmpeg4_decode_motion(s, &mx, &my) < 0)
+ return -1;
+ s->mv_dir = MV_DIR_FORWARD;
+ s->mv_type = MV_TYPE_16X16;
+ s->mv[0][0][0] = mx;
+ s->mv[0][0][1] = my;
+ } else {
+ set_stat(ST_INTRA_MB);
+ s->ac_pred = get_bits(&s->gb, 1);
+ }
+
+ for (i = 0; i < 6; i++) {
+ if (msmpeg4_decode_block(s, block[i], i, (cbp >> (5 - i)) & 1) < 0)
+ return -1;
+ }
+ return 0;
+}
+
+static int msmpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
+ int n, int coded)
+{
+ int code, level, i, j, last, run, run_diff;
+ int dc_pred_dir;
+ RLTable *rl;
+ const UINT8 *scan_table;
+
+ if (s->mb_intra) {
+ /* DC coef */
+ set_stat(ST_DC);
+ level = msmpeg4_decode_dc(s, n, &dc_pred_dir);
+ if (level < 0)
+ return -1;
+ block[0] = level;
+ if (n < 4) {
+ rl = &rl_table[s->rl_table_index];
+ } else {
+ rl = &rl_table[3 + s->rl_chroma_table_index];
+ }
+ run_diff = 0;
+ i = 1;
+ if (!coded) {
+ goto not_coded;
+ }
+ if (s->ac_pred) {
+ if (dc_pred_dir == 0)
+ scan_table = ff_alternate_vertical_scan; /* left */
+ else
+ scan_table = ff_alternate_horizontal_scan; /* top */
+ } else {
+ scan_table = zigzag_direct;
+ }
+ set_stat(ST_INTRA_AC);
+ } else {
+ i = 0;
+ rl = &rl_table[3 + s->rl_table_index];
+ run_diff = 1;
+ if (!coded) {
+ s->block_last_index[n] = i - 1;
+ return 0;
+ }
+ scan_table = zigzag_direct;
+ set_stat(ST_INTER_AC);
+ }
+
+ for(;;) {
+ code = get_vlc(&s->gb, &rl->vlc);
+ if (code < 0)
+ return -1;
+ if (code == rl->n) {
+ /* escape */
+ if (get_bits(&s->gb, 1) == 0) {
+ if (get_bits(&s->gb, 1) == 0) {
+ /* third escape */
+ last = get_bits(&s->gb, 1);
+ run = get_bits(&s->gb, 6);
+ level = get_bits(&s->gb, 8);
+ level = (level << 24) >> 24; /* sign extend */
+ } else {
+ /* second escape */
+ code = get_vlc(&s->gb, &rl->vlc);
+ if (code < 0 || code >= rl->n)
+ return -1;
+ run = rl->table_run[code];
+ level = rl->table_level[code];
+ last = code >= rl->last;
+ run += rl->max_run[last][level] + run_diff;
+ if (get_bits(&s->gb, 1))
+ level = -level;
+ }
+ } else {
+ /* first escape */
+ code = get_vlc(&s->gb, &rl->vlc);
+ if (code < 0 || code >= rl->n)
+ return -1;
+ run = rl->table_run[code];
+ level = rl->table_level[code];
+ last = code >= rl->last;
+ level += rl->max_level[last][run];
+ if (get_bits(&s->gb, 1))
+ level = -level;
+ }
+ } else {
+ run = rl->table_run[code];
+ level = rl->table_level[code];
+ last = code >= rl->last;
+ if (get_bits(&s->gb, 1))
+ level = -level;
+ }
+ i += run;
+ if (i >= 64)
+ return -1;
+ j = scan_table[i];
+ block[j] = level;
+ i++;
+ if (last)
+ break;
+ }
+ not_coded:
+ if (s->mb_intra) {
+ mpeg4_pred_ac(s, block, n, dc_pred_dir);
+ if (s->ac_pred) {
+ i = 64; /* XXX: not optimal */
+ }
+ }
+ s->block_last_index[n] = i - 1;
+
+ return 0;
+}
+
+static int msmpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
+{
+ int level, pred;
+ UINT16 *dc_val;
+
+ if (n < 4) {
+ level = get_vlc(&s->gb, &dc_lum_vlc[s->dc_table_index]);
+ } else {
+ level = get_vlc(&s->gb, &dc_chroma_vlc[s->dc_table_index]);
+ }
+ if (level < 0)
+ return -1;
+
+ if (level == DC_MAX) {
+ level = get_bits(&s->gb, 8);
+ if (get_bits(&s->gb, 1))
+ level = -level;
+ } else if (level != 0) {
+ if (get_bits(&s->gb, 1))
+ level = -level;
+ }
+
+ pred = msmpeg4_pred_dc(s, n, &dc_val, dir_ptr);
+ level += pred;
+
+ /* update predictor */
+ if (n < 4) {
+ *dc_val = level * s->y_dc_scale;
+ } else {
+ *dc_val = level * s->c_dc_scale;
+ }
+
+ return level;
+}
+
+static int msmpeg4_decode_motion(MpegEncContext * s,
+ int *mx_ptr, int *my_ptr)
+{
+ MVTable *mv;
+ int code, mx, my;
+
+ mv = &mv_tables[s->mv_table_index];
+
+ code = get_vlc(&s->gb, &mv->vlc);
+ if (code < 0)
+ return -1;
+ if (code == mv->n) {
+ mx = get_bits(&s->gb, 6);
+ my = get_bits(&s->gb, 6);
+ } else {
+ mx = mv->table_mvx[code];
+ my = mv->table_mvy[code];
+ }
+
+ mx += *mx_ptr - 32;
+ my += *my_ptr - 32;
+ /* WARNING : they do not do exactly modulo encoding */
+ if (mx <= -64)
+ mx += 64;
+ else if (mx >= 64)
+ mx -= 64;
+
+ if (my <= -64)
+ my += 64;
+ else if (my >= 64)
+ my -= 64;
+ *mx_ptr = mx;
+ *my_ptr = my;
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 02:06:44 +0000