Documentation
¶
Overview ¶
Package aac - parse and generate AAC meta data including ADTS headers.
Index ¶
Constants ¶
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const ( // AAClc - AAC-LC Low Complexity AAClc = 2 // HEAACv1 - HE-AAC version 1 with SBR HEAACv1 = 5 // HEAACv2 - HE-AAC version 2 with SBR and PS HEAACv2 = 29 )
Variables ¶
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var FrequencyTable = map[byte]int{
0: 96000,
1: 88200,
2: 64000,
3: 48000,
4: 44100,
5: 32000,
6: 24000,
7: 22050,
8: 16000,
9: 12000,
10: 11025,
11: 8000,
12: 7350,
}
FrequencyTable maps frequency index to sample rate in Hz
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var ReverseFrequencies = map[int]byte{
96000: 0,
88200: 1,
64000: 2,
48000: 3,
44100: 4,
32000: 5,
24000: 6,
22050: 7,
16000: 8,
12000: 9,
11025: 10,
8000: 11,
7350: 12,
}
ReverseFrequencies converts sample frequency to index
Functions ¶
This section is empty.
Types ¶
type ADTSHeader ¶
type ADTSHeader struct {
ID byte // 0 is MPEG-4, 1 is MPEG-2
ObjectType byte
SamplingFrequencyIndex byte
ChannelConfig byte
HeaderLength byte // Should be 7 or 9
PayloadLength uint16
BufferFullness uint16
}
ADTSHeader - data for an unencrypted ADTS Header with one AAC frame. Not used in mp4 files, but in MPEG-2 TS. Defined in ISO/IEC 13818-7
func DecodeADTSHeader ¶
func DecodeADTSHeader(r io.Reader) (header *ADTSHeader, offset int, err error)
DecodeADTSHeader by first looking for sync word
func NewADTSHeader ¶
func NewADTSHeader(samplingFrequency int, channelConfig byte, objectType byte, plLen uint16) (*ADTSHeader, error)
NewADTSHeader - create a new ADTS header
func (ADTSHeader) Encode ¶
func (a ADTSHeader) Encode() []byte
Encode - encode ADTSHeader into byte slice
func (ADTSHeader) Frequency ¶
func (a ADTSHeader) Frequency() uint16
Frequency looks up the sampling frequency for index in ADTSHeader
type AudioSpecificConfig ¶
type AudioSpecificConfig struct {
ObjectType byte
ChannelConfiguration byte // Defined in Table 1.19
SamplingFrequency int
ExtensionFrequency int
SBRPresentFlag bool
PSPresentFlag bool
}
AudioSpecificConfig according to ISO/IEC 14496-3 Syntax specified in Table 1.15
func DecodeAudioSpecificConfig ¶
func DecodeAudioSpecificConfig(r io.Reader) (*AudioSpecificConfig, error)
DecodeAudioSpecificConfig -
Source Files
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