mirror of
https://github.com/wader/fq.git
synced 2024-11-23 18:56:52 +03:00
95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
package av1
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import (
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"github.com/wader/fq/format"
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"github.com/wader/fq/format/registry"
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"github.com/wader/fq/pkg/decode"
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)
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func init() {
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registry.MustRegister(&decode.Format{
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Name: format.AV1_OBU,
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Description: "AV1 Open Bitstream Unit",
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DecodeFn: obuDecode,
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})
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}
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const (
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OBU_SEQUENCE_HEADER = 1
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OBU_TEMPORAL_DELIMITER = 2
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OBU_FRAME_HEADER = 3
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OBU_TILE_GROUP = 4
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OBU_METADATA = 5
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OBU_FRAME = 6
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OBU_REDUNDANT_FRAME_HEADER = 7
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OBU_TILE_LIST = 8
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OBU_PADDING = 15
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)
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var obuTypeNames = map[uint64]string{
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OBU_SEQUENCE_HEADER: "OBU_SEQUENCE_HEADER",
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OBU_TEMPORAL_DELIMITER: "OBU_TEMPORAL_DELIMITER",
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OBU_FRAME_HEADER: "OBU_FRAME_HEADER",
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OBU_TILE_GROUP: "OBU_TILE_GROUP",
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OBU_METADATA: "OBU_METADATA",
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OBU_FRAME: "OBU_FRAME",
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OBU_REDUNDANT_FRAME_HEADER: "OBU_REDUNDANT_FRAME_HEADER",
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OBU_TILE_LIST: "OBU_TILE_LIST",
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OBU_PADDING: "OBU_PADDING",
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}
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func leb128(d *decode.D) uint64 {
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var v uint64
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for i := 0; i < 8; i++ {
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b := d.U8()
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v = v | (b&0x7f)<<(i*7)
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if b&0x80 == 0 {
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break
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}
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}
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return v
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}
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func fieldLeb128(d *decode.D, name string) uint64 {
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return d.FieldUFn(name, func() (uint64, decode.DisplayFormat, string) {
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return leb128(d), decode.NumberDecimal, ""
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})
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}
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func obuDecode(d *decode.D, in interface{}) interface{} {
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var obuType uint64
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var obuSize int64
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hasExtension := false
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hasSizeField := false
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d.FieldStructFn("header", func(d *decode.D) {
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d.FieldU1("forbidden_bit")
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obuType, _ = d.FieldStringMapFn("type", obuTypeNames, "Reserved", d.U4, decode.NumberDecimal)
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hasExtension = d.FieldBool("extension_flag")
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hasSizeField = d.FieldBool("has_size_field")
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d.FieldU1("reserved_1bit")
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if hasExtension {
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d.FieldU3("temporal_id")
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d.FieldU2("spatial_id")
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d.FieldU3("extension_header_reserved_3bits")
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}
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})
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if hasSizeField {
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obuSize = int64(fieldLeb128(d, "size"))
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} else {
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obuSize = d.BitsLeft() / 8
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if hasExtension {
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obuSize--
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}
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}
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_ = obuType
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if d.BitsLeft() > 0 {
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d.FieldBitBufLen("data", obuSize*8)
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}
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return nil
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}
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