h264: factor out pred weight table parsing into a separate file

This will allow decoupling the parser from the decoder.

1 files changed, 86 insertions, 0 deletions

diff --git a/libavcodec/h264_parse.c b/libavcodec/h264_parse.c
new file mode 100644
index 0000000000..88caa48f19
--- /dev/null
+++ b/libavcodec/h264_parse.c
@@ -0,0 +1,86 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "get_bits.h"
+#include "golomb.h"
+#include "h264.h"
+#include "h264_parse.h"
+
+int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
+                              const int *ref_count, int slice_type_nos,
+                              H264PredWeightTable *pwt)
+{
+    int list, i;
+    int luma_def, chroma_def;
+
+    pwt->use_weight             = 0;
+    pwt->use_weight_chroma      = 0;
+    pwt->luma_log2_weight_denom = get_ue_golomb(gb);
+    if (sps->chroma_format_idc)
+        pwt->chroma_log2_weight_denom = get_ue_golomb(gb);
+    luma_def   = 1 << pwt->luma_log2_weight_denom;
+    chroma_def = 1 << pwt->chroma_log2_weight_denom;
+
+    for (list = 0; list < 2; list++) {
+        pwt->luma_weight_flag[list]   = 0;
+        pwt->chroma_weight_flag[list] = 0;
+        for (i = 0; i < ref_count[list]; i++) {
+            int luma_weight_flag, chroma_weight_flag;
+
+            luma_weight_flag = get_bits1(gb);
+            if (luma_weight_flag) {
+                pwt->luma_weight[i][list][0] = get_se_golomb(gb);
+                pwt->luma_weight[i][list][1] = get_se_golomb(gb);
+                if (pwt->luma_weight[i][list][0] != luma_def ||
+                    pwt->luma_weight[i][list][1] != 0) {
+                    pwt->use_weight             = 1;
+                    pwt->luma_weight_flag[list] = 1;
+                }
+            } else {
+                pwt->luma_weight[i][list][0] = luma_def;
+                pwt->luma_weight[i][list][1] = 0;
+            }
+
+            if (sps->chroma_format_idc) {
+                chroma_weight_flag = get_bits1(gb);
+                if (chroma_weight_flag) {
+                    int j;
+                    for (j = 0; j < 2; j++) {
+                        pwt->chroma_weight[i][list][j][0] = get_se_golomb(gb);
+                        pwt->chroma_weight[i][list][j][1] = get_se_golomb(gb);
+                        if (pwt->chroma_weight[i][list][j][0] != chroma_def ||
+                            pwt->chroma_weight[i][list][j][1] != 0) {
+                            pwt->use_weight_chroma        = 1;
+                            pwt->chroma_weight_flag[list] = 1;
+                        }
+                    }
+                } else {
+                    int j;
+                    for (j = 0; j < 2; j++) {
+                        pwt->chroma_weight[i][list][j][0] = chroma_def;
+                        pwt->chroma_weight[i][list][j][1] = 0;
+                    }
+                }
+            }
+        }
+        if (slice_type_nos != AV_PICTURE_TYPE_B)
+            break;
+    }
+    pwt->use_weight = pwt->use_weight || pwt->use_weight_chroma;
+    return 0;
+}