diff --git a/pkg/codecs/mpeg1audio/frame_header.go b/pkg/codecs/mpeg1audio/frame_header.go
index e13ef32..987065a 100644
--- a/pkg/codecs/mpeg1audio/frame_header.go
+++ b/pkg/codecs/mpeg1audio/frame_header.go
@@ -119,15 +119,15 @@ func (h FrameHeader) FrameLen() int {
 // SampleCount returns the number of samples contained into the frame.
 func (h FrameHeader) SampleCount() int {
 	/*
-			 MPEG-1:
-			 * layer 1: 384
-			 * layer 2: 1152
-			 * layer 3: 1152
-
-		     MPEG-2:
-			 * layer 1: 384
-			 * layer 2: 1152
-			 * layer 3: 576
+		MPEG-1:
+		* layer 1: 384
+		* layer 2: 1152
+		* layer 3: 1152
+
+		MPEG-2:
+		* layer 1: 384
+		* layer 2: 1152
+		* layer 3: 576
 	*/
 	return 1152
 }
diff --git a/pkg/formats/fmp4/init.go b/pkg/formats/fmp4/init.go
index a93772c..eba30cc 100644
--- a/pkg/formats/fmp4/init.go
+++ b/pkg/formats/fmp4/init.go
@@ -555,16 +555,16 @@ func (i *Init) Unmarshal(r io.ReadSeeker) error {
 // Marshal encodes a fMP4 initialization file.
 func (i *Init) Marshal(w io.WriteSeeker) error {
 	/*
-		- ftyp
-		- moov
-		  - mvhd
-		  - trak
-		  - trak
-		  - ...
-		- mvex
-		  - trex
-		  - trex
-		  - ...
+		|ftyp|
+		|moov|
+		|    |mvhd|
+		|    |    |trak|
+		|    |    |trak|
+		|    |    |....|
+		|    |mvex|
+		|    |    |trex|
+		|    |    |trex|
+		|    |    |....|
 	*/
 
 	mw := newMP4Writer(w)
diff --git a/pkg/formats/fmp4/init_track.go b/pkg/formats/fmp4/init_track.go
index c0afd43..697a827 100644
--- a/pkg/formats/fmp4/init_track.go
+++ b/pkg/formats/fmp4/init_track.go
@@ -26,50 +26,50 @@ type InitTrack struct {
 
 func (track *InitTrack) marshal(w *mp4Writer) error {
 	/*
-		   trak
-		   - tkhd
-		   - mdia
-			 - mdhd
-			 - hdlr
-			 - minf
-			   - vmhd (video)
-			   - smhd (audio)
-			   - dinf
-				 - dref
-				   - url
-			   - stbl
-				 - stsd
-				   - av01 (AV1)
-					 - av1C
-					 - btrt
-				   - vp09 (VP9)
-					 - vpcC
-					 - btrt
-				   - hev1 (H265)
-					 - hvcC
-					 - btrt
-				   - avc1 (H264)
-					 - avcC
-					 - btrt
-				   - mp4v (MPEG-4/2/1 video, MJPEG)
-					 - esds
-					 - btrt
-				   - Opus (Opus)
-					 - dOps
-					 - btrt
-				   - mp4a (MPEG-4 audio)
-					 - esds
-					 - btrt
-				   - mp4a (MPEG-1 audio)
-					 - esds
-					 - btrt
-				   - ac-3 (AC-3)
-					 - dac3
-					 - btrt
-				 - stts
-				 - stsc
-				 - stsz
-				 - stco
+		|trak|
+		|    |tkhd|
+		|    |mdia|
+		|    |    |mdhd|
+		|    |    |hdlr|
+		|    |    |minf|
+		|    |    |    |vmhd| (video)
+		|    |    |    |smhd| (audio)
+		|    |    |    |dinf|
+		|    |    |    |    |dref|
+		|    |    |    |    |    |url|
+		|    |    |    |stbl|
+		|    |    |    |    |stsd|
+		|    |    |    |    |    |av01| (AV1)
+		|    |    |    |    |    |    |av1C|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |vp09| (VP9)
+		|    |    |    |    |    |    |vpcC|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |hev1| (H265)
+		|    |    |    |    |    |    |hvcC|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |avc1| (H264)
+		|    |    |    |    |    |    |avcC|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |mp4v| (MPEG-4/2/1 video, MJPEG)
+		|    |    |    |    |    |    |esds|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |Opus| (Opus)
+		|    |    |    |    |    |    |dOps|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |mp4a| (MPEG-4/1 audio)
+		|    |    |    |    |    |    |esds|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |ac-3| (AC-3)
+		|    |    |    |    |    |    |dac3|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |    |ipcm| (LPCM)
+		|    |    |    |    |    |    |pcmC|
+		|    |    |    |    |    |    |btrt|
+		|    |    |    |    |stts|
+		|    |    |    |    |stsc|
+		|    |    |    |    |stsz|
+		|    |    |    |    |stco|
 	*/
 
 	_, err := w.writeBoxStart(&mp4.Trak{}) // <trak>
diff --git a/pkg/formats/fmp4/part.go b/pkg/formats/fmp4/part.go
index 8098e28..1b73eab 100644
--- a/pkg/formats/fmp4/part.go
+++ b/pkg/formats/fmp4/part.go
@@ -25,11 +25,12 @@ type Part struct {
 // Marshal encodes a fMP4 part.
 func (p *Part) Marshal(w io.WriteSeeker) error {
 	/*
-		moof
-		- mfhd
-		- traf (video)
-		- traf (audio)
-		mdat
+		|moof|
+		|    |mfhd|
+		|    |    |traf|
+		|    |    |traf|
+		|    |    |....|
+		|    |mdat|
 	*/
 
 	mw := newMP4Writer(w)
diff --git a/pkg/formats/fmp4/part_track.go b/pkg/formats/fmp4/part_track.go
index 74c8de0..f915bad 100644
--- a/pkg/formats/fmp4/part_track.go
+++ b/pkg/formats/fmp4/part_track.go
@@ -13,10 +13,10 @@ type PartTrack struct {
 
 func (pt *PartTrack) marshal(w *mp4Writer) (*mp4.Trun, int, error) {
 	/*
-		traf
-		- tfhd
-		- tfdt
-		- trun
+		|traf|
+		|    |tfhd|
+		|    |tfdt|
+		|    |trun|
 	*/
 
 	_, err := w.writeBoxStart(&mp4.Traf{}) // <traf>