libavfilter: Remove Async Flag from DNN Filter Side

Remove async flag from filter's perspective after the unification
of async and sync modes in the DNN backend.

Signed-off-by: Shubhanshu Saxena <shubhanshu.e01@gmail.com>

doc/filters.texi

@@ -10291,11 +10291,8 @@ and the second line is the name of label id 1, etc.
 The label id is considered as name if the label file is not provided.
 
 @item backend_configs
-Set the configs to be passed into backend
-
-@item async
-use DNN async execution if set (default: set),
-roll back to sync execution if the backend does not support async.
+Set the configs to be passed into backend. To use async execution, set async (default: set).
+Roll back to sync execution if the backend does not support async.
 
 @end table
 
@@ -10347,15 +10344,12 @@ Set the input name of the dnn network.
 Set the output name of the dnn network.
 
 @item backend_configs
-Set the configs to be passed into backend
+Set the configs to be passed into backend. To use async execution, set async (default: set).
+Roll back to sync execution if the backend does not support async.
 
 For tensorflow backend, you can set its configs with @option{sess_config} options,
 please use tools/python/tf_sess_config.py to get the configs of TensorFlow backend for your system.
 
-@item async
-use DNN async execution if set (default: set),
-roll back to sync execution if the backend does not support async.
-
 @end table
 
 @subsection Examples

libavfilter/dnn/dnn_backend_tf.c

@@ -884,6 +884,13 @@ DNNModel *ff_dnn_load_model_tf(const char *model_filename, DNNFunctionType func_
         ctx->options.nireq = av_cpu_count() / 2 + 1;
     }
 
+#if !HAVE_PTHREAD_CANCEL
+    if (ctx->options.async) {
+        ctx->options.async = 0;
+        av_log(filter_ctx, AV_LOG_WARNING, "pthread is not supported, roll back to sync.\n");
+    }
+#endif
+
     tf_model->request_queue = ff_safe_queue_create();
     if (!tf_model->request_queue) {
         goto err;

libavfilter/dnn_filter_common.c

@@ -84,13 +84,6 @@ int ff_dnn_init(DnnContext *ctx, DNNFunctionType func_type, AVFilterContext *fil
         return AVERROR(EINVAL);
     }
 
-#if !HAVE_PTHREAD_CANCEL
-    if (ctx->async) {
-        ctx->async = 0;
-        av_log(filter_ctx, AV_LOG_WARNING, "pthread is not supported, roll back to sync.\n");
-    }
-#endif
-
     return 0;
 }
 

libavfilter/dnn_filter_common.h

@@ -46,7 +46,7 @@ typedef struct DnnContext {
     { "output",             "output name of the model",   OFFSET(model_outputnames_string), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },\
     { "backend_configs",    "backend configs",            OFFSET(backend_options),  AV_OPT_TYPE_STRING,    { .str = NULL }, 0, 0, FLAGS },\
     { "options", "backend configs (deprecated, use backend_configs)", OFFSET(backend_options),  AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS | AV_OPT_FLAG_DEPRECATED},\
-    { "async",              "use DNN async inference",    OFFSET(async),            AV_OPT_TYPE_BOOL,      { .i64 = 1},     0, 1, FLAGS},
+    { "async",              "use DNN async inference (ignored, use backend_configs='async=1')",    OFFSET(async),            AV_OPT_TYPE_BOOL,      { .i64 = 1},     0, 1, FLAGS},
 
 
 int ff_dnn_init(DnnContext *ctx, DNNFunctionType func_type, AVFilterContext *filter_ctx);