ts信息

mformat/ts.go

@@ -0,0 +1,149 @@
+package mformat
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// TsInfo 用于保存 ts 文件的下载地址和文件名
+type TsInfo struct {
+	Name                    string
+	Url                     string // 后续填充
+	URI                     string
+	Seq                     uint64  // 如果是aes加密并且没有iv, 这个seq需要充当iv
+	TimeSec                 float64 // 此ts片段占用多少秒
+	Idx_EXT_X_DISCONTINUITY int     // 分段编号
+	Key                     TsKeyInfo
+}
+
+type TsKeyInfo struct {
+	Method string
+	Key    []byte
+	KeyURI string // 后续填充
+	Iv     []byte
+}
+
+// IsNestedPlaylists 返回是否为 嵌套播放列表
+func (this *M3U8File) IsNestedPlaylists() bool {
+	for _, one := range this.PartList {
+		if one.Playlist != nil {
+			return true
+		}
+	}
+	return false
+}
+
+func (this *M3U8File) ContainsMediaSegment() bool {
+	for _, one := range this.PartList {
+		if one.Segment != nil {
+			return true
+		}
+	}
+	return false
+}
+
+// LookupHDPlaylist 找个最高清的播放列表
+func (this *M3U8File) LookupHDPlaylist() (playlist *M3U8Playlist) {
+	for _, one := range this.PartList {
+		if one.Playlist != nil {
+			if playlist == nil {
+				playlist = one.Playlist
+			} else if one.Playlist.Bandwidth != playlist.Bandwidth {
+				if one.Playlist.Bandwidth > playlist.Bandwidth {
+					playlist = one.Playlist
+				}
+			} else if one.Playlist.Resolution.Width != playlist.Resolution.Width {
+				if one.Playlist.Resolution.Width > playlist.Resolution.Width {
+					playlist = one.Playlist
+				}
+			}
+		}
+	}
+	return playlist
+}
+
+// GetTsList 获取ts文件列表, 此处不组装url, 不下载key内容
+func (this *M3U8File) GetTsList() (list []TsInfo) {
+	var beginSeq = uint64(this.MediaSequence)
+	var index = 0
+	var discontinutyIdx = 0
+	var curKey *M3U8Key
+
+	for _, part := range this.PartList {
+		if part.Is_EXT_X_DISCONTINUITY && len(list) > 0 {
+			discontinutyIdx++
+		}
+		if part.Key != nil {
+			if part.Key.Method == EncryptMethod_NONE {
+				curKey = nil
+			} else {
+				curKey = part.Key
+			}
+		}
+		if part.Segment != nil {
+			var seg = part.Segment
+			index++
+			var info = TsInfo{
+				Name:                    fmt.Sprintf("%05d.ts", index), // ts视频片段命名规则
+				URI:                     seg.URI,
+				Url:                     "", // 之后填充
+				Seq:                     beginSeq + uint64(index-1),
+				TimeSec:                 seg.Duration,
+				Idx_EXT_X_DISCONTINUITY: discontinutyIdx,
+			}
+			if curKey != nil {
+				iv := []byte(strings.TrimPrefix(strings.ToLower(curKey.IV), "0x"))
+				if len(iv) == 0 {
+					if curKey.Method == EncryptMethod_AES128 {
+						iv = make([]byte, 16)
+						binary.BigEndian.PutUint64(iv[8:], info.Seq)
+					}
+				} else {
+					var err error
+					iv, err = hex.DecodeString(string(iv))
+					if err != nil {
+						iv = nil
+					}
+				}
+				info.Key = TsKeyInfo{
+					Method: curKey.Method,
+					Key:    nil, // 之后填充
+					KeyURI: curKey.URI,
+					Iv:     iv,
+				}
+			}
+			list = append(list, info)
+		}
+	}
+	return list
+}
+
+// AesDecrypt 解密加密后的ts文件
+func AesDecrypt(encrypted []byte, key TsKeyInfo) ([]byte, error) {
+	block, err := aes.NewCipher(key.Key)
+	if err != nil {
+		return nil, err
+	}
+	iv := key.Iv
+	if len(iv) == 0 {
+		return nil, errors.New("key URI " + key.KeyURI + ", invalid iv len(iv) == 0")
+	}
+	blockMode := cipher.NewCBCDecrypter(block, iv)
+	if len(iv) == 0 || len(encrypted)%len(iv) != 0 {
+		return nil, errors.New("invalid encrypted data len " + strconv.Itoa(len(encrypted)))
+	}
+	origData := make([]byte, len(encrypted))
+	blockMode.CryptBlocks(origData, encrypted)
+	length := len(origData)
+	unpadding := int(origData[length-1])
+	if length-unpadding < 0 {
+		return nil, fmt.Errorf(`invalid length of unpadding %v - %v`, length, unpadding)
+	}
+	return origData[:(length - unpadding)], nil
+}

mformat/ts_test.go

@@ -0,0 +1,99 @@
+package mformat
+
+import (
+	"bytes"
+	"encoding/binary"
+	"testing"
+)
+
+func TestAesDecrypt(t *testing.T) {
+	encInfo := TsKeyInfo{
+		Method: EncryptMethod_AES128,
+		Key:    []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6},
+		Iv:     make([]byte, 16),
+	}
+	binary.BigEndian.PutUint64(encInfo.Iv[8:], 1)
+	before := []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 4}
+	after, err := AesDecrypt(before, encInfo)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if bytes.Equal(after, []byte{69, 46, 52, 180, 68, 205, 99, 220, 193, 44, 116, 174, 96, 196, 199, 87, 214, 77, 67, 5, 37, 8, 139, 146, 229, 120, 164, 76, 107, 0, 204, 0}) == false {
+		t.Fatal(after)
+	}
+}
+
+func TestM3U8File_GetTsList(t *testing.T) {
+	info, ok := M3U8Parse([]byte(`#EXTM3U
+#EXT-X-VERSION:3
+#EXT-X-PLAYLIST-TYPE:VOD
+#EXT-X-MEDIA-SEQUENCE:0
+#EXT-X-TARGETDURATION:8
+#EXT-X-KEY:METHOD=AES-128,URI="/20230502/xthms/2000kb/hls/key.key",IV=0x10c27a9e3fa363dfe4c44b59b67304b3
+#EXT-X-DISCONTINUITY
+#EXTINF:4,
+0000000.ts
+#EXTINF:4.24,
+0000001.ts
+#EXTINF:4.08,
+0000002.ts
+#EXT-X-ENDLIST
+`))
+	if !ok || len(info.PartList) != 6 {
+		t.Fatal()
+	}
+
+	list := info.GetTsList()
+	if len(list) != 3 {
+		t.Fatal()
+	}
+	if info.ContainsMediaSegment() == false {
+		t.Fatal()
+	}
+	for _, one := range list {
+		if one.Idx_EXT_X_DISCONTINUITY != 0 {
+			t.Fatal(one.Idx_EXT_X_DISCONTINUITY, one.Seq)
+		}
+		switch one.Seq {
+		case 0:
+			if one.URI != `0000000.ts` || one.Name != "00001.ts" {
+				t.Fatal(one.URI, one.Name)
+			}
+		case 1:
+			if one.URI != `0000001.ts` || one.Name != "00002.ts" {
+				t.Fatal(one.URI, one.Name)
+			}
+		case 2:
+			if one.URI != `0000002.ts` || one.Name != "00003.ts" {
+				t.Fatal(one.URI, one.Name)
+			}
+		}
+	}
+}
+
+func TestM3U8File_LookupHDPlaylist(t *testing.T) {
+	info, ok := M3U8Parse([]byte(`#EXTM3U
+#EXT-X-VERSION:3
+#EXT-X-STREAM-INF:BANDWIDTH=1280000,RESOLUTION=640x480
+master_640x480.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=2560000,RESOLUTION=1280x720
+master_1280x720.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=5120000,RESOLUTION=1920x1080
+master_1920x1080.m3u8
+#EXT-X-STREAM-INF:BANDWIDTH=5120000,RESOLUTION=2560x1440
+master_2560X1440.m3u8
+`))
+	if ok == false || len(info.PartList) != 4 {
+		t.Fatal()
+	}
+
+	is := info.IsNestedPlaylists()
+	if is == false {
+		t.Fatal()
+	}
+
+	playlist := info.LookupHDPlaylist()
+	if playlist == nil || playlist.URI != "master_2560X1440.m3u8" {
+		t.Fatal(playlist.URI)
+	}
+}