From 32e24b18dd10e2576f9d097445ef9fbee7661037 Mon Sep 17 00:00:00 2001
From: Kim Minjong <make.dirty.code@gmail.com>
Date: Sat, 30 Aug 2025 14:42:45 +0900
Subject: [PATCH 1/2] Add avfilter_process_command

---
 av/filter/context.pyi            |  3 +++
 av/filter/context.pyx            | 40 ++++++++++++++++++++++++++++++++
 include/libavfilter/avfilter.pxd |  9 +++++++
 3 files changed, 52 insertions(+)

diff --git a/av/filter/context.pyi b/av/filter/context.pyi
index 13ee480c2..d37febdb9 100644
--- a/av/filter/context.pyi
+++ b/av/filter/context.pyi
@@ -12,3 +12,6 @@ class FilterContext:
     def graph(self) -> Graph: ...
     def push(self, frame: Frame) -> None: ...
     def pull(self) -> Frame: ...
+    def process_command(
+        self, cmd: str, arg: str | None = None, res_len: int = 1024, flags: int = 0
+    ) -> str | None: ...
diff --git a/av/filter/context.pyx b/av/filter/context.pyx
index ba5981ff1..635a76a43 100644
--- a/av/filter/context.pyx
+++ b/av/filter/context.pyx
@@ -1,3 +1,5 @@
+cimport libav as lib
+
 import weakref
 
 from av.audio.frame cimport alloc_audio_frame
@@ -132,3 +134,41 @@ cdef class FilterContext:
         frame._init_user_attributes()
         frame.time_base = avrational_to_fraction(&self.ptr.inputs[0].time_base)
         return frame
+
+    def process_command(self, cmd, arg=None, int res_len=1024, int flags=0):
+        if cmd is None:
+            raise ValueError("cmd is required")
+
+        cdef char *c_cmd = NULL
+        cdef char *c_arg = NULL
+
+        c_cmd = cmd
+        if arg is not None:
+            c_arg = arg
+
+        cdef char *c_res = NULL
+        cdef int ret
+        cdef bytearray res_buf = None
+        cdef unsigned char[:] view
+        cdef bytes b
+        cdef int nul
+
+        if res_len > 0:
+            res_buf = bytearray(res_len)
+            view = res_buf
+            c_res = <char*>&view[0]
+        else:
+            c_res = NULL
+
+        with nogil:
+            ret = lib.avfilter_process_command(self.ptr, c_cmd, c_arg, c_res, res_len, flags)
+        err_check(ret)
+
+        if res_buf is not None:
+            b = bytes(res_buf)
+            nul = b.find(b'\x00')
+            if nul >= 0:
+                b = b[:nul]
+            if b:
+                return b.decode('utf-8', 'strict')
+        return None
diff --git a/include/libavfilter/avfilter.pxd b/include/libavfilter/avfilter.pxd
index b1ced248b..8d4c05f6f 100644
--- a/include/libavfilter/avfilter.pxd
+++ b/include/libavfilter/avfilter.pxd
@@ -62,6 +62,15 @@ cdef extern from "libavfilter/avfilter.h" nogil:
     # custom
     cdef set pyav_get_available_filters()
 
+    int avfilter_process_command(AVFilterContext *filter,
+                                 const char *cmd,
+                                 const char *arg,
+                                 char *res,
+                                 int res_len,
+                                 int flags)
+
+    cdef int AVFILTER_CMD_FLAG_FAST
+
 
 cdef extern from "libavfilter/buffersink.h" nogil:
     cdef void av_buffersink_set_frame_size(AVFilterContext *ctx, unsigned frame_size)

From 156bc8267dd222170e7ac6e802ed7d930368f20f Mon Sep 17 00:00:00 2001
From: WyattBlue <wyattblue@auto-editor.com>
Date: Sat, 30 Aug 2025 09:43:28 -0400
Subject: [PATCH 2/2] Check truthiness

---
 av/filter/context.pyx | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/av/filter/context.pyx b/av/filter/context.pyx
index 635a76a43..85c23863b 100644
--- a/av/filter/context.pyx
+++ b/av/filter/context.pyx
@@ -136,8 +136,8 @@ cdef class FilterContext:
         return frame
 
     def process_command(self, cmd, arg=None, int res_len=1024, int flags=0):
-        if cmd is None:
-            raise ValueError("cmd is required")
+        if not cmd:
+            raise ValueError("Invalid cmd")
 
         cdef char *c_cmd = NULL
         cdef char *c_arg = NULL
@@ -170,5 +170,5 @@ cdef class FilterContext:
             if nul >= 0:
                 b = b[:nul]
             if b:
-                return b.decode('utf-8', 'strict')
+                return b.decode("utf-8", "strict")
         return None