diff --git a/.github/workflows/pythonapp.yml b/.github/workflows/pythonapp.yml
index 0ea133b..a3a0437 100644
--- a/.github/workflows/pythonapp.yml
+++ b/.github/workflows/pythonapp.yml
@@ -134,7 +134,7 @@ jobs:
         }
 
   linux_test:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
       - name: Set up Python 3.x
@@ -143,7 +143,6 @@ jobs:
           python-version: 3.x
       - name: Install
         run: |
-          sudo add-apt-repository ppa:jonathonf/ffmpeg-4 -y
           sudo apt update
           sudo apt install ffmpeg libavcodec-dev libavdevice-dev libavfilter-dev libavformat-dev
           sudo apt install libavutil-dev libswscale-dev libswresample-dev libpostproc-dev libsdl2-dev libsdl2-2.0-0
@@ -165,7 +164,7 @@ jobs:
           pytest "$name/tests"
 
   linux_wheels:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
       - name: Set up Python 3.x
@@ -213,7 +212,7 @@ jobs:
           pytest "$name/tests"
 
   osx_wheels:
-    runs-on: macos-10.15
+    runs-on: macos-latest
     steps:
       - uses: actions/checkout@v1
       - name: Brew setup
@@ -289,7 +288,7 @@ jobs:
           pytest "$name/tests"
 
   docs:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
       - name: Set up Python 3.x
diff --git a/ffpyplayer/clib/misc.c b/ffpyplayer/clib/misc.c
index 55181d1..3fe0a3d 100644
--- a/ffpyplayer/clib/misc.c
+++ b/ffpyplayer/clib/misc.c
@@ -159,8 +159,7 @@ int get_plane_sizes(int size[4], int required_plane[4], enum AVPixelFormat pix_f
         return AVERROR(EINVAL);
     size[0] = linesizes[0] * height;
 
-    if (desc->flags & AV_PIX_FMT_FLAG_PAL ||
-        desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL) {
+    if (desc->flags & AV_PIX_FMT_FLAG_PAL) {
         size[1] = 256 * 4;
         required_plane[0] = 1;
         return size[0] + size[1];
diff --git a/ffpyplayer/includes/ffmpeg.pxi b/ffpyplayer/includes/ffmpeg.pxi
index 9793f21..562caf0 100644
--- a/ffpyplayer/includes/ffmpeg.pxi
+++ b/ffpyplayer/includes/ffmpeg.pxi
@@ -299,8 +299,8 @@ cdef:
         int av_interleaved_write_frame(AVFormatContext *, AVPacket *)
         void avformat_free_context(AVFormatContext *)
         uint8_t *av_stream_get_side_data (AVStream *, AVPacketSideDataType, int *)
-        AVOutputFormat *av_oformat_next(AVOutputFormat *)
-        AVInputFormat *av_iformat_next(AVInputFormat  *)
+        const AVOutputFormat *av_muxer_iterate(void **)
+        const AVInputFormat *av_demuxer_iterate(void **)
 
     extern from "libavdevice/avdevice.h" nogil:
         void avdevice_register_all()
diff --git a/ffpyplayer/tests/test_write.py b/ffpyplayer/tests/test_write.py
index 2f26330..15e0d87 100644
--- a/ffpyplayer/tests/test_write.py
+++ b/ffpyplayer/tests/test_write.py
@@ -19,8 +19,7 @@ def get_gray_image_with_val(w, h, val):
     # Construct images
     size = w * h
     buf = bytearray([int(val)] * size)
-    buf2 = bytearray([0] * size)
-    img = Image(plane_buffers=[buf, buf2], pix_fmt='gray', size=(w, h))
+    img = Image(plane_buffers=[buf], pix_fmt='gray', size=(w, h))
     return img
 
 
diff --git a/ffpyplayer/tools.pyx b/ffpyplayer/tools.pyx
index 85ab807..5c9f801 100644
--- a/ffpyplayer/tools.pyx
+++ b/ffpyplayer/tools.pyx
@@ -317,10 +317,12 @@ cpdef get_fmts(int input=False, int output=False):
     cdef list fmts = [], full_names = [], exts = []
     cdef AVOutputFormat *ofmt = NULL
     cdef AVInputFormat *ifmt = NULL
+    cdef void *ifmt_opaque = NULL
+    cdef void *ofmt_opaque = NULL
     cdef object names, full_name, ext
 
     if output:
-        ofmt = av_oformat_next(ofmt)
+        ofmt = av_muxer_iterate(&ofmt_opaque)
         while ofmt != NULL:
             if ofmt.name != NULL:
                 names = tcode(ofmt.name).split(',')
@@ -330,10 +332,10 @@ cpdef get_fmts(int input=False, int output=False):
                 fmts.extend(names)
                 full_names.extend([full_name, ] * len(names))
                 exts.extend([ext, ] * len(names))
-            ofmt = av_oformat_next(ofmt)
+            ofmt = av_muxer_iterate(&ofmt_opaque)
 
     if input:
-        ifmt = av_iformat_next(ifmt)
+        ifmt = av_demuxer_iterate(&ifmt_opaque)
         while ifmt != NULL:
             if ifmt.name != NULL:
                 names = tcode(ifmt.name).split(',')
@@ -343,7 +345,7 @@ cpdef get_fmts(int input=False, int output=False):
                 fmts.extend(names)
                 full_names.extend([full_name, ] * len(names))
                 exts.extend([ext, ] * len(names))
-            ifmt = av_iformat_next(ifmt)
+            ifmt = av_demuxer_iterate(&ifmt_opaque)
 
     exts = [x for (y, x) in sorted(zip(fmts, exts), key=_get_item0)]
     full_names = [x for (y, x) in sorted(zip(fmts, full_names), key=_get_item0)]