avfilter/vf_libvmaf: fix string comparison bug

The libvmaf filter was doing substring checks in place of string equality
comparisons. This led to a bug when the user specified the pooling method
"harmonic_mean", since "mean" was checked first and the substring comparison
returned true. This patch changes all substring comparisons for string equality
comparisons. This is both correct and more efficient than the existing method.

Signed-off-by: nilfm <nilf@netflix.com>

libavfilter/vf_libvmaf.c

@@ -243,7 +243,7 @@ static int parse_features(AVFilterContext *ctx)
         const AVDictionaryEntry *e = NULL;
 
         while (e = av_dict_iterate(dict[i], e)) {
-            if (av_stristr(e->key, "name")) {
+            if (!strcmp(e->key, "name")) {
                 feature_name = e->value;
                 continue;
             }
@@ -304,29 +304,29 @@ static int parse_models(AVFilterContext *ctx)
         char  *path = NULL;
 
         while (e = av_dict_iterate(dict[i], e)) {
-            if (av_stristr(e->key, "disable_clip")) {
-                model_cfg.flags |= av_stristr(e->value, "true") ?
+            if (!strcmp(e->key, "disable_clip")) {
+                model_cfg.flags |= !strcmp(e->value, "true") ?
                     VMAF_MODEL_FLAG_DISABLE_CLIP : 0;
                 continue;
             }
 
-            if (av_stristr(e->key, "enable_transform")) {
-                model_cfg.flags |= av_stristr(e->value, "true") ?
+            if (!strcmp(e->key, "enable_transform")) {
+                model_cfg.flags |= !strcmp(e->value, "true") ?
                     VMAF_MODEL_FLAG_ENABLE_TRANSFORM : 0;
                 continue;
             }
 
-            if (av_stristr(e->key, "name")) {
+            if (!strcmp(e->key, "name")) {
                 model_cfg.name = e->value;
                 continue;
             }
 
-            if (av_stristr(e->key, "version")) {
+            if (!strcmp(e->key, "version")) {
                 version = e->value;
                 continue;
             }
 
-            if (av_stristr(e->key, "path")) {
+            if (!strcmp(e->key, "path")) {
                 path = e->value;
                 continue;
             }
@@ -521,13 +521,13 @@ static int activate(AVFilterContext *ctx)
 static enum VmafOutputFormat log_fmt_map(const char *log_fmt)
 {
     if (log_fmt) {
-        if (av_stristr(log_fmt, "xml"))
+        if (!strcmp(log_fmt, "xml"))
             return VMAF_OUTPUT_FORMAT_XML;
-        if (av_stristr(log_fmt, "json"))
+        if (!strcmp(log_fmt, "json"))
             return VMAF_OUTPUT_FORMAT_JSON;
-        if (av_stristr(log_fmt, "csv"))
+        if (!strcmp(log_fmt, "csv"))
             return VMAF_OUTPUT_FORMAT_CSV;
-        if (av_stristr(log_fmt, "sub"))
+        if (!strcmp(log_fmt, "sub"))
             return VMAF_OUTPUT_FORMAT_SUB;
     }
 
@@ -537,11 +537,11 @@ static enum VmafOutputFormat log_fmt_map(const char *log_fmt)
 static enum VmafPoolingMethod pool_method_map(const char *pool_method)
 {
     if (pool_method) {
-        if (av_stristr(pool_method, "min"))
+        if (!strcmp(pool_method, "min"))
             return VMAF_POOL_METHOD_MIN;
-        if (av_stristr(pool_method, "mean"))
+        if (!strcmp(pool_method, "mean"))
             return VMAF_POOL_METHOD_MEAN;
-        if (av_stristr(pool_method, "harmonic_mean"))
+        if (!strcmp(pool_method, "harmonic_mean"))
             return VMAF_POOL_METHOD_HARMONIC_MEAN;
     }