diff --git a/AAXtoMP3 b/AAXtoMP3
index 9b16c09..2a10ccb 100755
--- a/AAXtoMP3
+++ b/AAXtoMP3
@@ -968,23 +968,29 @@ do
 
   if [ -f "${cover_file}" ]; then
     log "Adding cover art"
-    # Create temporary output file name - ensure extention matches previous appropriate output file to keep ffmpeg happy
-    cover_output_file="${output_file%.*}.cover.${output_file##*.}"
-    # Copy audio stream from current output, and video stream from cover file, setting appropriate metadata
-    </dev/null "$FFMPEG" -loglevel quiet \
-      -nostats \
-      -i "${output_file}" \
-      -i "${cover_file}" \
-      -map 0:a:0 \
-      -map 1:v:0 \
-      -acodec copy \
-      -vcodec copy \
-      -id3v2_version 3 \
-      -metadata:s:v title="Album cover" \
-      -metadata:s:v comment="Cover (front)" \
-      "${cover_output_file}"
-      # Replace original output file with version including cover
-      mv "${cover_output_file}" "${output_file}"
+    # FFMGEP does not support MPEG-4 containers fully #
+    if [ "${container}" == "mp4" ] ; then
+      mp4art --add "${cover_file}" "${output_file}"
+    # FFMPEG for everything else #
+    else
+      # Create temporary output file name - ensure extention matches previous appropriate output file to keep ffmpeg happy
+      cover_output_file="${output_file%.*}.cover.${output_file##*.}"
+      # Copy audio stream from current output, and video stream from cover file, setting appropriate metadata
+      </dev/null "$FFMPEG" -loglevel quiet \
+        -nostats \
+        -i "${output_file}" \
+        -i "${cover_file}" \
+        -map 0:a:0 \
+        -map 1:v:0 \
+        -acodec copy \
+        -vcodec copy \
+        -id3v2_version 3 \
+        -metadata:s:v title="Album cover" \
+        -metadata:s:v comment="Cover (front)" \
+        "${cover_output_file}"
+        # Replace original output file with version including cover
+        mv "${cover_output_file}" "${output_file}"
+    fi
   fi
 
   # -----
diff --git a/README.md b/README.md
index f11fbfe..2df29d0 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,7 @@ Audible fails for some reason.
 * GNU sed - see above
 * GNU find - see above
 * jq - only if `--use-audible-cli-data` is set or if converting an .aaxc file
+* mp4art used to add cover art to m4a and m4b files. Optional
 * mediainfo used to add additional media tags like narrator. Optional
 
 ## Usage(s)
@@ -218,6 +219,28 @@ brew install grep
 brew install findutils
 ```
 
+#### mp4art/mp4chaps
+_Note: This is an optional dependency, required for adding cover art to m4a and b4b files only._
+
+__Ubuntu, Linux Mint, Debian__
+```
+sudo apt-get update
+sudo apt-get install mp4v2-utils
+```
+
+On Debian and Ubuntu the mp4v2-utils package has been deprecated and removed, as the upsteam project is no longer maintained.
+The package was removed in Debian Buster, and Ubuntu Focal [ 20.04 ].
+
+__CentOS, RHEL & Fedora__
+```
+# CentOS/RHEL and Fedora users make sure that you have enabled atrpms repository in system. Let’s begin installing FFmpeg as per your operating system.
+yum install mp4v2-utils
+```
+__MacOS__
+```
+brew install mp4v2
+```
+
 #### mediainfo
 _Note: This is an optional dependency._