[feature] Enable basic video support (mp4 only) (#1274)

* [feature] basic video support

* fix missing semicolon

* replace text shadow with stacked icons

Co-authored-by: f0x <f0x@cthu.lu>

vendor/github.com/abema/go-mp4/box.go

@@ -0,0 +1,188 @@
+package mp4
+
+import (
+	"errors"
+	"io"
+	"math"
+
+	"github.com/abema/go-mp4/bitio"
+)
+
+const LengthUnlimited = math.MaxUint32
+
+type ICustomFieldObject interface {
+	// GetFieldSize returns size of dynamic field
+	GetFieldSize(name string, ctx Context) uint
+
+	// GetFieldLength returns length of dynamic field
+	GetFieldLength(name string, ctx Context) uint
+
+	// IsOptFieldEnabled check whether if the optional field is enabled
+	IsOptFieldEnabled(name string, ctx Context) bool
+
+	// StringifyField returns field value as string
+	StringifyField(name string, indent string, depth int, ctx Context) (string, bool)
+
+	IsPString(name string, bytes []byte, remainingSize uint64, ctx Context) bool
+
+	BeforeUnmarshal(r io.ReadSeeker, size uint64, ctx Context) (n uint64, override bool, err error)
+
+	OnReadField(name string, r bitio.ReadSeeker, leftBits uint64, ctx Context) (rbits uint64, override bool, err error)
+
+	OnWriteField(name string, w bitio.Writer, ctx Context) (wbits uint64, override bool, err error)
+}
+
+type BaseCustomFieldObject struct {
+}
+
+// GetFieldSize returns size of dynamic field
+func (box *BaseCustomFieldObject) GetFieldSize(string, Context) uint {
+	panic(errors.New("GetFieldSize not implemented"))
+}
+
+// GetFieldLength returns length of dynamic field
+func (box *BaseCustomFieldObject) GetFieldLength(string, Context) uint {
+	panic(errors.New("GetFieldLength not implemented"))
+}
+
+// IsOptFieldEnabled check whether if the optional field is enabled
+func (box *BaseCustomFieldObject) IsOptFieldEnabled(string, Context) bool {
+	return false
+}
+
+// StringifyField returns field value as string
+func (box *BaseCustomFieldObject) StringifyField(string, string, int, Context) (string, bool) {
+	return "", false
+}
+
+func (*BaseCustomFieldObject) IsPString(name string, bytes []byte, remainingSize uint64, ctx Context) bool {
+	return true
+}
+
+func (*BaseCustomFieldObject) BeforeUnmarshal(io.ReadSeeker, uint64, Context) (uint64, bool, error) {
+	return 0, false, nil
+}
+
+func (*BaseCustomFieldObject) OnReadField(string, bitio.ReadSeeker, uint64, Context) (uint64, bool, error) {
+	return 0, false, nil
+}
+
+func (*BaseCustomFieldObject) OnWriteField(string, bitio.Writer, Context) (uint64, bool, error) {
+	return 0, false, nil
+}
+
+// IImmutableBox is common interface of box
+type IImmutableBox interface {
+	ICustomFieldObject
+
+	// GetVersion returns the box version
+	GetVersion() uint8
+
+	// GetFlags returns the flags
+	GetFlags() uint32
+
+	// CheckFlag checks the flag status
+	CheckFlag(uint32) bool
+
+	// GetType returns the BoxType
+	GetType() BoxType
+}
+
+// IBox is common interface of box
+type IBox interface {
+	IImmutableBox
+
+	// SetVersion sets the box version
+	SetVersion(uint8)
+
+	// SetFlags sets the flags
+	SetFlags(uint32)
+
+	// AddFlag adds the flag
+	AddFlag(uint32)
+
+	// RemoveFlag removes the flag
+	RemoveFlag(uint32)
+}
+
+type Box struct {
+	BaseCustomFieldObject
+}
+
+// GetVersion returns the box version
+func (box *Box) GetVersion() uint8 {
+	return 0
+}
+
+// SetVersion sets the box version
+func (box *Box) SetVersion(uint8) {
+}
+
+// GetFlags returns the flags
+func (box *Box) GetFlags() uint32 {
+	return 0x000000
+}
+
+// CheckFlag checks the flag status
+func (box *Box) CheckFlag(flag uint32) bool {
+	return true
+}
+
+// SetFlags sets the flags
+func (box *Box) SetFlags(uint32) {
+}
+
+// AddFlag adds the flag
+func (box *Box) AddFlag(flag uint32) {
+}
+
+// RemoveFlag removes the flag
+func (box *Box) RemoveFlag(flag uint32) {
+}
+
+// FullBox is ISOBMFF FullBox
+type FullBox struct {
+	BaseCustomFieldObject
+	Version uint8   `mp4:"0,size=8"`
+	Flags   [3]byte `mp4:"1,size=8"`
+}
+
+// GetVersion returns the box version
+func (box *FullBox) GetVersion() uint8 {
+	return box.Version
+}
+
+// SetVersion sets the box version
+func (box *FullBox) SetVersion(version uint8) {
+	box.Version = version
+}
+
+// GetFlags returns the flags
+func (box *FullBox) GetFlags() uint32 {
+	flag := uint32(box.Flags[0]) << 16
+	flag ^= uint32(box.Flags[1]) << 8
+	flag ^= uint32(box.Flags[2])
+	return flag
+}
+
+// CheckFlag checks the flag status
+func (box *FullBox) CheckFlag(flag uint32) bool {
+	return box.GetFlags()&flag != 0
+}
+
+// SetFlags sets the flags
+func (box *FullBox) SetFlags(flags uint32) {
+	box.Flags[0] = byte(flags >> 16)
+	box.Flags[1] = byte(flags >> 8)
+	box.Flags[2] = byte(flags)
+}
+
+// AddFlag adds the flag
+func (box *FullBox) AddFlag(flag uint32) {
+	box.SetFlags(box.GetFlags() | flag)
+}
+
+// RemoveFlag removes the flag
+func (box *FullBox) RemoveFlag(flag uint32) {
+	box.SetFlags(box.GetFlags() & (^flag))
+}