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fq/format/flac/flac_metadatablock.go
2022-07-19 18:33:50 +02:00

98 lines
2.7 KiB
Go

package flac
// TODO: 24 bit picture length truncate warning
// TODO: Cuesheet
import (
"fmt"
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
)
var flacStreaminfoFormat decode.Group
var flacPicture decode.Group
var vorbisCommentFormat decode.Group
func init() {
interp.RegisterFormat(decode.Format{
Name: format.FLAC_METADATABLOCK,
Description: "FLAC metadatablock",
DecodeFn: metadatablockDecode,
Dependencies: []decode.Dependency{
{Names: []string{format.FLAC_STREAMINFO}, Group: &flacStreaminfoFormat},
{Names: []string{format.FLAC_PICTURE}, Group: &flacPicture},
{Names: []string{format.VORBIS_COMMENT}, Group: &vorbisCommentFormat},
},
})
}
const (
MetadataBlockStreaminfo = 0
MetadataBlockPadding = 1
MetadataBlockApplication = 2
MetadataBlockSeektable = 3
MetadataBlockVorbisComment = 4
MetadataBlockCuesheet = 5
MetadataBlockPicture = 6
)
var metadataBlockNames = scalar.UToSymStr{
MetadataBlockStreaminfo: "streaminfo",
MetadataBlockPadding: "padding",
MetadataBlockApplication: "application",
MetadataBlockSeektable: "seektable",
MetadataBlockVorbisComment: "vorbis_comment",
MetadataBlockCuesheet: "cuesheet",
MetadataBlockPicture: "picture",
}
func metadatablockDecode(d *decode.D, _ any) any {
var hasStreamInfo bool
var streamInfo format.FlacStreamInfo
isLastBlock := d.FieldBool("last_block")
typ := d.FieldU7("type", metadataBlockNames)
length := d.FieldU24("length")
switch typ {
case MetadataBlockStreaminfo:
flacStreaminfoOut, ok := d.Format(flacStreaminfoFormat, nil).(format.FlacStreaminfoOut)
if !ok {
panic(fmt.Sprintf("expected FlacStreaminfoOut, got %#+v", flacStreaminfoOut))
}
hasStreamInfo = true
streamInfo = flacStreaminfoOut.StreamInfo
case MetadataBlockVorbisComment:
d.FieldFormatLen("comment", int64(length*8), vorbisCommentFormat, nil)
case MetadataBlockPicture:
d.FieldFormatLen("picture", int64(length*8), flacPicture, nil)
case MetadataBlockSeektable:
seektableCount := length / 18
d.FieldArray("seekpoints", func(d *decode.D) {
for i := uint64(0); i < seektableCount; i++ {
d.FieldStruct("seekpoint", func(d *decode.D) {
d.FieldU64("sample_number", scalar.UToScalar{
0xffff_ffff_ffff_ffff: {Description: "Placeholder"},
})
d.FieldU64("offset")
d.FieldU16("number_of_samples")
})
}
})
case MetadataBlockApplication:
d.FieldUTF8("id", 4)
d.FieldRawLen("data", int64((length-4)*8))
default:
d.FieldRawLen("data", int64(length*8))
}
return format.FlacMetadatablockOut{
IsLastBlock: isLastBlock,
HasStreamInfo: hasStreamInfo,
StreamInfo: streamInfo,
}
}