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fq/format/flac/flac_streaminfo.go
Mattias Wadman 2fc0a71a47 decode: Refactor scalar usage
Move scalar into own package.
Split scalar code into decode related scalar code (that reads etc) and
scalar code that just transform the scalar value.
Use a scalar.Mapper interface instead of just a function.
Make mappers, assert and validat impement the interface.
2021-12-02 17:39:26 +01:00

44 lines
1.3 KiB
Go

package flac
import (
"github.com/wader/fq/format"
"github.com/wader/fq/format/registry"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/scalar"
)
func init() {
registry.MustRegister(decode.Format{
Name: format.FLAC_STREAMINFO,
Description: "FLAC streaminfo",
DecodeFn: streaminfoDecode,
})
}
func streaminfoDecode(d *decode.D, in interface{}) interface{} {
d.FieldU16("minimum_block_size")
d.FieldU16("maximum_block_size")
d.FieldU24("minimum_frame_size")
d.FieldU24("maximum_frame_size")
sampleRate := d.FieldU("sample_rate", 20)
// <3> (number of channels)-1. FLAC supports from 1 to 8 channels
d.FieldU3("channels", scalar.UAdd(1))
// <5> (bits per sample)-1. FLAC supports from 4 to 32 bits per sample. Currently the reference encoder and decoders only support up to 24 bits per sample.
bitPerSample := d.FieldU5("bits_per_sample", scalar.UAdd(1))
totalSamplesInStream := d.FieldU("total_samples_in_stream", 36)
md5BB := d.FieldRawLen("md5", 16*8, scalar.RawHex)
md5b, err := md5BB.Bytes()
if err != nil {
d.IOPanic(err, "md5BB.Bytes")
}
return format.FlacStreaminfoOut{
StreamInfo: format.FlacStreamInfo{
SampleRate: sampleRate,
BitPerSample: bitPerSample,
TotalSamplesInStream: totalSamplesInStream,
MD5: md5b,
},
}
}