mpegts: prevent wrong results in codec comparisons (#167)

pkg/formats/mpegts/codec_h264.go

@@ -5,7 +5,12 @@ import (
 )
 
 // CodecH264 is a H264 codec.
-type CodecH264 struct{}
+type CodecH264 struct {
+	// in Go, empty structs share the same pointer,
+	// therefore they cannot be used as map keys
+	// or in equality operations. Prevent this.
+	unused int //nolint:unused
+}
 
 // IsVideo implements Codec.
 func (CodecH264) IsVideo() bool {

pkg/formats/mpegts/codec_h265.go

@@ -5,7 +5,12 @@ import (
 )
 
 // CodecH265 is a H265 codec.
-type CodecH265 struct{}
+type CodecH265 struct {
+	// in Go, empty structs share the same pointer,
+	// therefore they cannot be used as map keys
+	// or in equality operations. Prevent this.
+	unused int //nolint:unused
+}
 
 // IsVideo implements Codec.
 func (CodecH265) IsVideo() bool {

pkg/formats/mpegts/codec_mpeg1_audio.go

@@ -5,7 +5,12 @@ import (
 )
 
 // CodecMPEG1Audio is a MPEG-1 Audio codec.
-type CodecMPEG1Audio struct{}
+type CodecMPEG1Audio struct {
+	// in Go, empty structs share the same pointer,
+	// therefore they cannot be used as map keys
+	// or in equality operations. Prevent this.
+	unused int //nolint:unused
+}
 
 // IsVideo implements Codec.
 func (CodecMPEG1Audio) IsVideo() bool {

pkg/formats/mpegts/codec_mpeg1_video.go

@@ -5,7 +5,12 @@ import (
 )
 
 // CodecMPEG1Video is a MPEG-1/2 Video codec.
-type CodecMPEG1Video struct{}
+type CodecMPEG1Video struct {
+	// in Go, empty structs share the same pointer,
+	// therefore they cannot be used as map keys
+	// or in equality operations. Prevent this.
+	unused int //nolint:unused
+}
 
 // IsVideo implements Codec.
 func (CodecMPEG1Video) IsVideo() bool {

pkg/formats/mpegts/codec_mpeg4_video.go

@@ -5,7 +5,12 @@ import (
 )
 
 // CodecMPEG4Video is a MPEG-4 Video codec.
-type CodecMPEG4Video struct{}
+type CodecMPEG4Video struct {
+	// in Go, empty structs share the same pointer,
+	// therefore they cannot be used as map keys
+	// or in equality operations. Prevent this.
+	unused int //nolint:unused
+}
 
 // IsVideo implements Codec.
 func (CodecMPEG4Video) IsVideo() bool {

pkg/formats/mpegts/codec_unsupported.go

@@ -5,7 +5,12 @@ import (
 )
 
 // CodecUnsupported is an unsupported codec.
-type CodecUnsupported struct{}
+type CodecUnsupported struct {
+	// in Go, empty structs share the same pointer,
+	// therefore they cannot be used as map keys
+	// or in equality operations. Prevent this.
+	unused int //nolint:unused
+}
 
 // IsVideo implements Codec.
 func (CodecUnsupported) IsVideo() bool {