diff --git a/README.md b/README.md
index abb76a2..cef6f28 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ binary2video [-f fps] [-w width] [-h height] [-v] infile outfile
 
 -h height   Set height, default 240.
 
--c codec    Set video codec: h.264, vp9, ffv1, or ffv1.3. Default is vp9.
+-c codec    Set video codec: h264, vp9, ffv1, or ffv1l3. Default is vp9.
 
 -v          Be verbose.
 
@@ -43,6 +43,18 @@ infile      The name and path of the video file from which the original binary f
 outfile     The name and path of the binary file to which the original data should be
             restored to.
 ```
+
+## Compatibility matrix
+
+| Container vs. Codec | **h264** | **vp9** | **ffv1** | **ffv1l3** |
+|--------------------:|:--------:|:-------:|:--------:|:----------:|
+| **.mp4**            | ✓        | ✓       |          |            |
+| **.webm**           |          | ✓       |          |            |
+| **.avi**            | ✓        | ✓       | ✓        | ✓          |
+| **.mkv**            | ✓        | ✓       | ✓        | ✓          |
+
+Other containers have not been tested and may also work.
+
 ## Internal process
 
 ### Conversion from binary file to video file
@@ -70,5 +82,6 @@ Run the unit tests with
 
 ## References
 * FFmpeg Formats Documentation: [Demuxers - rawvideo](https://ffmpeg.org/ffmpeg-formats.html#rawvideo)
+* FFmpeg FFV1: [FFV1 encoding cheatsheet](https://trac.ffmpeg.org/wiki/Encode/FFV1)
 * AntumDeluge: [List of Lossless FFmpeg Video Encoders](https://antumdeluge.wordpress.com/lossless-ffmpeg-video-encoders/)
 * Fufu Fang: [Converting-Arbitrary-Data-To-Video](https://github.com/fangfufu/Converting-Arbitrary-Data-To-Video)
diff --git a/binary2video b/binary2video
index d44c8f5..25505bc 100755
--- a/binary2video
+++ b/binary2video
@@ -1,34 +1,67 @@
 #!/usr/bin/env bash
 
 usage_and_exit () {
-    echo "Usage: binary2video [-f fps] [-w width] [-h height] [-c codec] [-v] infile outfile"
+    echo "Usage: binary2video [-f fps] [-w width] [-h height] [-c (vp9 | h264 | ffv1 | ffv1l3)] [-v] infile outfile"
+    echo "  Defaults: fps=1 width=320 height=240 codec=vp9"
     exit $1
 }
+check_executable_or_exit() {
+    if [ ! -x $1 ]; then
+        echo "error: no $(basename $1) at $gzip"
+        exit 2
+    fi
+}
 
-if [ $# = 1 -a x$1 = 'x--help' ]; then
+if [ \( $# -eq 1 \) -a \( "$1" = '--help' \) ]; then
     usage_and_exit 0
 fi
 
+# check needed binaries
 gzip=/usr/bin/gzip
+check_executable_or_exit $gzip
 ffmpeg=/usr/bin/ffmpeg
+check_executable_or_exit $ffmpeg
+
+# check parameters
 width=320
 height=240
 framerate=1
-while getopts 'f:w:h:' option; do
-    case $option in
+codec=vp9
+verbose=0
+while getopts 'f:w:h:c:v' option; do
+    case "$option" in
     f) framerate="$OPTARG";;
     w) width="$OPTARG";;
     h) height="$OPTARG";;
+    c) codec="$OPTARG";;
+    v) verbose=1;;
     ?) usage_and_exit 1;;
     esac
 done
 shift $(($OPTIND - 1))
-# echo $framerate $width $height $1 $2
-# exit 0
+
+# verify codec
+case "$codec" in
+    h264) ;;
+    vp9) ;;
+    ffv1) ;;
+    ffv1l3) ;;
+    *)
+        echo "error: unknown codec '$codec'"
+        usage_and_exit 3
+        ;;
+esac
 
 if [ $# != 2 ]; then
     usage_and_exit 1
 fi
+if [ ! -r "$1" ]; then
+    echo "error: file '$1' does not exist or is not readable"
+    exit 4
+fi
+if [ $verbose = 1 ]; then
+    echo "parameters: fps=$framerate width=$width height=$height codec=$codec"
+fi
 
 tmpfile_gzipped=$(mktemp --tmpdir binary2video.gz.XXXXXXXXXX)
 tmpfile_padded=$(mktemp --tmpdir binary2video.padded.XXXXXXXXXX)
@@ -37,43 +70,57 @@ infile="$1"
 outfile="$2"
 pixel_format=rgb24
 blocksize=$(($width * $height * 3))
-echo "blocksize is $blocksize bytes"
-
-md5sum "${infile}"
+if [ $verbose = 1 ]; then
+    echo "blocksize is $blocksize bytes"
+    echo -n "input file MD5: "
+    md5sum "${infile}" | cut -d\  -f1
+fi
 
 $gzip --fast --to-stdout "${infile}" > ${tmpfile_gzipped}
 size_gzipped=$(stat --format=%s ${tmpfile_gzipped})
-echo "gzipped file has $size_gzipped bytes"
+if [ $verbose = 1 ]; then
+    echo "gzipped file has $size_gzipped bytes"
+fi
 
 padding_needed=$(($blocksize - ($size_gzipped % $blocksize)))
-echo "padding needed: $padding_needed bytes"
+if [ $verbose = 1 ]; then
+    echo "padding needed: $padding_needed bytes"
+fi
 
 (cat ${tmpfile_gzipped}; dd if=/dev/zero bs=$padding_needed count=1 status=none) >> ${tmpfile_padded}
 size_padded=$(stat --format=%s ${tmpfile_padded})
-echo "padded file has $size_padded bytes"
+if [ $verbose = 1 ]; then
+    echo "padded file has $size_padded bytes"
+fi
 
-# vp9 works in mp4/webm/avi/mkv
-$ffmpeg -y -hide_banner -loglevel error \
-    -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
-    -c:v libvpx-vp9 -lossless 1 \
-    "${outfile}"
-# ffv1 version 1 works only in mkv/avi
-# $ffmpeg -y -hide_banner -loglevel error \
-#     -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
-#     -c:v ffv1 -level 1 -coder 1 -context 1 -g 1 \
-#     "${outfile}"
-# ffv1 version 3 works only in mkv/avi
-# $ffmpeg -y -hide_banner -loglevel error \
-#     -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
-#     -c:v ffv1 -level 3 -threads 8 -coder 1 -context 1 -g 1 -slices 24 -slicecrc 1 \
-#     "${outfile}"
-# h.264 works in mp4/avi/mkv
-# $ffmpeg -y -hide_banner -loglevel error \
-#     -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
-#     -c:v libx264rgb -preset ultrafast -qp 0 \
-#     "${outfile}"
+if [ $codec = "vp9" ]; then
+    $ffmpeg -y -hide_banner -loglevel error \
+        -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
+        -c:v libvpx-vp9 -lossless 1 \
+        "${outfile}"
+elif [ $codec = "h264" ]; then
+    $ffmpeg -y -hide_banner -loglevel error \
+        -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
+        -c:v libx264rgb -preset ultrafast -qp 0 \
+        "${outfile}"
+elif [ $codec = "ffv1" ]; then
+    $ffmpeg -y -hide_banner -loglevel error \
+        -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
+        -c:v ffv1 -level 1 -coder 1 -context 1 -g 1 \
+        "${outfile}"
+elif [ $codec = "ffv1l3" ]; then
+    $ffmpeg -y -hide_banner -loglevel error \
+        -f rawvideo -pixel_format $pixel_format -video_size "${width}x${height}" -framerate ${framerate} -i "${tmpfile_padded}" \
+        -c:v ffv1 -level 3 -threads 8 -coder 1 -context 1 -g 1 -slices 24 -slicecrc 1 \
+        "${outfile}"
+else
+    echo "error: unknown codec '$codec'"
+    usage_and_exit 5
+fi
 
-echo "output file has $(stat --format=%s "${outfile}") bytes"
+if [ $verbose = 1 ]; then
+    echo "output file has $(stat --format=%s "${outfile}") bytes"
+fi
 
 rm ${tmpfile_gzipped}
 rm ${tmpfile_padded}
diff --git a/test/test.bats b/test/test.bats
index 1c3251e..a2a3e37 100644
--- a/test/test.bats
+++ b/test/test.bats
@@ -1,10 +1,10 @@
 teardown() {
-    rm -f test/LICENSE.{mp4,webm,avi} test/LICENSE_restored
-    rm -f test/9.{mp4,webm,avi} test/9.txt_restored
-    rm -f test/42.{mp4,webm,avi} test/42.txt_restored
-    rm -f test/16777216.{mp4,webm,avi} test/16777216.txt_restored
-    rm -f test/'filename with spaces'.{mp4,webm,avi} test/'filename with spaces'.txt_restored
-    rm -f test/'filename with (brackets)'.{mp4,webm,avi} test/'filename with (brackets)'.txt_restored
+    rm -f test/LICENSE.{mp4,webm,avi,mkv} test/LICENSE_restored
+    rm -f test/9.{mp4,webm,avi,mkv} test/9.txt_restored
+    rm -f test/42.{mp4,webm,avi,mkv} test/42.txt_restored
+    rm -f test/16777216.{mp4,webm,avi,mkv} test/16777216.txt_restored
+    rm -f test/'filename with spaces'.{mp4,webm,avi,mkv} test/'filename with spaces'.txt_restored
+    rm -f test/'filename with (brackets)'.{mp4,webm,avi,mkv} test/'filename with (brackets)'.txt_restored
 }
 
 @test "can run binary2video" {
@@ -31,7 +31,7 @@ teardown() {
     [[ "${lines[0]}" == "Usage:"* ]]
 }
 
-@test "convert to MP4 and restore file LICENSE" {
+@test "convert to MP4/default and restore file LICENSE" {
     echo "********** convert **********"
     ./binary2video LICENSE test/LICENSE.mp4
     echo "********** restore **********"
@@ -40,7 +40,7 @@ teardown() {
     cmp --silent LICENSE test/LICENSE_restored
 }
 
-@test "convert To WebM and restore file test/9.txt" {
+@test "convert To WebM/default and restore file test/9.txt" {
     echo "********** convert **********"
     ./binary2video test/9.txt test/9.webm
     echo "********** restore **********"
@@ -49,7 +49,7 @@ teardown() {
     cmp --silent test/9.txt test/9.txt_restored
 }
 
-@test "convert to AVI and restore file test/42.txt" {
+@test "convert to AVI/default and restore file test/42.txt" {
     echo "********** convert **********"
     ./binary2video test/42.txt test/42.avi
     echo "********** restore **********"
@@ -58,7 +58,7 @@ teardown() {
     cmp --silent test/42.txt test/42.txt_restored
 }
 
-@test "convert to MP4 and restore file test/16777216.txt" {
+@test "convert to MP4/default and restore file test/16777216.txt" {
     echo "********** convert **********"
     ./binary2video test/16777216.txt test/16777216.mp4
     echo "********** restore **********"
@@ -67,7 +67,7 @@ teardown() {
     cmp --silent test/16777216.txt test/16777216.txt_restored
 }
 
-@test "convert to MP4 and restore file 'test/filename with spaces.txt'" {
+@test "convert to MP4/default and restore file 'test/filename with spaces.txt'" {
     echo "********** convert **********"
     ./binary2video 'test/filename with spaces.txt' 'test/filename with spaces.mp4'
     echo "********** restore **********"
@@ -76,7 +76,7 @@ teardown() {
     cmp --silent 'test/filename with spaces.txt' 'test/filename with spaces.txt_restored'
 }
 
-@test "convert to MP4 and restore file 'test/filename with (brackets).txt'" {
+@test "convert to MP4/default and restore file 'test/filename with (brackets).txt'" {
     echo "********** convert **********"
     ./binary2video 'test/filename with (brackets).txt' 'test/filename with (brackets).mp4'
     echo "********** restore **********"
@@ -84,3 +84,39 @@ teardown() {
     echo "********** compare **********"
     cmp --silent 'test/filename with (brackets).txt' 'test/filename with (brackets).txt_restored'
 }
+
+@test "convert to MKV/vp9 and restore file LICENSE" {
+    echo "********** convert **********"
+    ./binary2video -c vp9 LICENSE test/LICENSE.mkv
+    echo "********** restore **********"
+    ./video2binary test/LICENSE.mkv test/LICENSE_restored
+    echo "********** compare **********"
+    cmp --silent LICENSE test/LICENSE_restored
+}
+
+@test "convert to MKV/h264 and restore file LICENSE" {
+    echo "********** convert **********"
+    ./binary2video -c h264 LICENSE test/LICENSE.mkv
+    echo "********** restore **********"
+    ./video2binary test/LICENSE.mkv test/LICENSE_restored
+    echo "********** compare **********"
+    cmp --silent LICENSE test/LICENSE_restored
+}
+
+@test "convert to MKV/ffv1 and restore file LICENSE" {
+    echo "********** convert **********"
+    ./binary2video -c ffv1 LICENSE test/LICENSE.mkv
+    echo "********** restore **********"
+    ./video2binary test/LICENSE.mkv test/LICENSE_restored
+    echo "********** compare **********"
+    cmp --silent LICENSE test/LICENSE_restored
+}
+
+@test "convert to MKV/ffv1l3 and restore file LICENSE" {
+    echo "********** convert **********"
+    ./binary2video -c ffv1l3 LICENSE test/LICENSE.mkv
+    echo "********** restore **********"
+    ./video2binary test/LICENSE.mkv test/LICENSE_restored
+    echo "********** compare **********"
+    cmp --silent LICENSE test/LICENSE_restored
+}
diff --git a/video2binary b/video2binary
index 5899173..014e858 100755
--- a/video2binary
+++ b/video2binary
@@ -4,30 +4,59 @@ usage_and_exit () {
     echo "Usage: video2binary [-v] infile outfile"
     exit $1
 }
+check_executable_or_exit() {
+    if [ ! -x $1 ]; then
+        echo "error: no $(basename $1) at $gzip"
+        exit 2
+    fi
+}
 
-if [ $# = 1 -a x$1 = 'x--help' ]; then
+if [ \( $# -eq 1 \) -a \( "$1" = '--help' \) ]; then
    usage_and_exit 0
 fi
 
+# check needed binaries
+gzip=/usr/bin/gzip
+check_executable_or_exit $gzip
+ffmpeg=/usr/bin/ffmpeg
+check_executable_or_exit $ffmpeg
+
+# check parameters
+verbose=0
+while getopts 'v' option; do
+    case "$option" in
+    v) verbose=1;;
+    ?) usage_and_exit 1;;
+    esac
+done
+shift $(($OPTIND - 1))
+
 if [ $# != 2 ]; then
     usage_and_exit 1
 fi
+if [ ! -r "$1" ]; then
+    echo "error: file '$1' does not exist or is not readable"
+    exit 4
+fi
 
 tmpfile_gzipped=$(mktemp --tmpdir video2binary.gz.XXXXXXXXXX)
 
 infile="$1"
 outfile="$2"
-gzip=/usr/bin/gzip
-ffmpeg=/usr/bin/ffmpeg
 pixel_format=rgb24
 
 $ffmpeg -y -hide_banner -loglevel error \
     -i "${infile}" -f rawvideo -pix_fmt rgb24 "${tmpfile_gzipped}"
 size_gzipped=$(stat --format=%s ${tmpfile_gzipped})
-echo "gzipped file has $size_gzipped bytes"
+if [ $verbose = 1 ]; then
+    echo "gzipped file has $size_gzipped bytes"
+fi
 
 $gzip -d -c "${tmpfile_gzipped}" > "${outfile}"
-echo "output file has $(stat --format=%s "${outfile}") bytes"
-md5sum "${outfile}"
+if [ $verbose = 1 ]; then
+    echo "output file has $(stat --format=%s "${outfile}") bytes"
+    echo -n "output file MD5: "
+    md5sum "${outfile}" | cut -d\  -f1
+fi
 
 rm ${tmpfile_gzipped}