mirror of
https://github.com/wader/fq.git
synced 2024-12-18 02:41:44 +03:00
73 lines
1.9 KiB
Go
73 lines
1.9 KiB
Go
package mpeg
|
|
|
|
// https://wiki.multimedia.cx/index.php/MPEG-4_Audio
|
|
|
|
import (
|
|
"github.com/wader/fq/format"
|
|
"github.com/wader/fq/format/registry"
|
|
"github.com/wader/fq/pkg/decode"
|
|
)
|
|
|
|
func init() {
|
|
registry.MustRegister(&decode.Format{
|
|
Name: format.MPEG_ASC,
|
|
Description: "MPEG-4 Audio Specific Config",
|
|
DecodeFn: ascDecoder,
|
|
})
|
|
}
|
|
|
|
var frequencyIndexHz = map[uint64]int{
|
|
0x0: 96000,
|
|
0x1: 88200,
|
|
0x2: 64000,
|
|
0x3: 48000,
|
|
0x4: 44100,
|
|
0x5: 32000,
|
|
0x6: 24000,
|
|
0x7: 22050,
|
|
0x8: 16000,
|
|
0x9: 12000,
|
|
0xa: 11025,
|
|
0xb: 8000,
|
|
0xc: 7350,
|
|
0xd: -1,
|
|
0xe: -1,
|
|
0xf: -1,
|
|
}
|
|
|
|
var channelConfigurationNames = map[uint64]string{
|
|
0: "Defined in AOT Specifc Config",
|
|
1: "channel: front-center",
|
|
2: "channels: front-left, front-right",
|
|
3: "channels: front-center, front-left, front-right",
|
|
4: "channels: front-center, front-left, front-right, back-center",
|
|
5: "channels: front-center, front-left, front-right, back-left, back-right",
|
|
6: "channels: front-center, front-left, front-right, back-left, back-right, LFE-channel",
|
|
7: "channels: front-center, front-left, front-right, side-left, side-right, back-left, back-right, LFE-channel",
|
|
}
|
|
|
|
func ascDecoder(d *decode.D, in interface{}) interface{} {
|
|
objectType, _ := d.FieldStringMapFn("object_type", format.MPEGAudioObjectTypeNames, "Unknown", func() uint64 {
|
|
n := d.U5()
|
|
if n == 31 {
|
|
n = 32 + d.U6()
|
|
}
|
|
return n
|
|
}, decode.NumberDecimal)
|
|
d.FieldUFn("frequency_index", func() (uint64, decode.DisplayFormat, string) {
|
|
v := d.U4()
|
|
if v == 15 {
|
|
return d.U24(), decode.NumberDecimal, ""
|
|
}
|
|
if f, ok := frequencyIndexHz[v]; ok {
|
|
return uint64(f), decode.NumberDecimal, ""
|
|
}
|
|
return 0, decode.NumberDecimal, "Invalid"
|
|
})
|
|
d.FieldStringMapFn("channel_configuration", channelConfigurationNames, "Reserved", d.U4, decode.NumberDecimal)
|
|
// TODO: GASpecificConfig etc
|
|
d.FieldBitBufLen("var_aot_or_byte_align", d.BitsLeft())
|
|
|
|
return format.MPEGASCOut{ObjectType: int(objectType)}
|
|
}
|