add more options for audio

Author: Philip Ye

Diff for: ffmpeg/metadata.go

@@ -53,6 +53,8 @@ type Streams struct {
 	Duration           string      `json:"duration"`
 	Disposition        Disposition `json:"disposition"`
 	BitRate            string      `json:"bit_rate"`
+	SampleRate         string      `json:"sample_rate"`
+	BitsPerSample      string      `json:"bits_per_sample"`
 }
 
 // Tags ...
@@ -287,6 +289,14 @@ func (s Streams) GetBitRate() string {
 	return s.BitRate
 }
 
+func (s Streams) GetSampleRate() string {
+	return s.SampleRate
+}
+
+func (s Streams) GetBitsPerSample() string {
+	return s.BitsPerSample
+}
+
 //GetDefault ...
 func (d Disposition) GetDefault() int {
 	return d.Default

Diff for: metadata.go

@@ -51,6 +51,8 @@ type Streams interface {
 	GetDuration() string
 	GetDisposition() Disposition
 	GetBitRate() string
+	GetSampleRate() string
+	GetBitsPerSample() string
 }
 
 // Tags ...