Transcode stream refactor (#609)

* Remove forceMkv and forceHEVC
* Add HLS support and refactor
* Add new streaming endpoints

pkg/utils/byterange.go

@@ -0,0 +1,59 @@
+package utils
+
+import (
+	"strconv"
+	"strings"
+)
+
+type ByteRange struct {
+	Start     int64
+	End       *int64
+	RawString string
+}
+
+func CreateByteRange(s string) ByteRange {
+	// strip bytes=
+	r := strings.TrimPrefix(s, "bytes=")
+	e := strings.Split(r, "-")
+
+	ret := ByteRange{
+		RawString: s,
+	}
+	if len(e) > 0 {
+		ret.Start, _ = strconv.ParseInt(e[0], 10, 64)
+	}
+	if len(e) > 1 && e[1] != "" {
+		end, _ := strconv.ParseInt(e[1], 10, 64)
+		ret.End = &end
+	}
+
+	return ret
+}
+
+func (r ByteRange) getBytesToRead() int64 {
+	if r.End == nil {
+		return 0
+	}
+
+	return *r.End - r.Start + 1
+}
+
+func (r ByteRange) ToHeaderValue(fileLength int64) string {
+	if r.End == nil {
+		return ""
+	}
+	end := *r.End
+	return "bytes " + strconv.FormatInt(r.Start, 10) + "-" + strconv.FormatInt(end, 10) + "/" + strconv.FormatInt(fileLength, 10)
+}
+
+func (r ByteRange) Apply(bytes []byte) []byte {
+	if r.End == nil {
+		return bytes[r.Start:]
+	}
+
+	end := *r.End + 1
+	if int(end) > len(bytes) {
+		end = int64(len(bytes))
+	}
+	return bytes[r.Start:end]
+}