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a6a97136b7
Decode API design is that Try* returns error non-Try panics. Also rename Must* as they should panic and introduce some new Try* functions that were missing.
206 lines
6.6 KiB
Go
206 lines
6.6 KiB
Go
package mpeg
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// http://dvdnav.mplayerhq.hu/dvdinfo/mpeghdrs.html
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// http://stnsoft.com/DVD/sys_hdr.html))
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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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"github.com/wader/fq/pkg/scalar"
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)
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func init() {
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registry.MustRegister(decode.Format{
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Name: format.MPEG_PES_PACKET,
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Description: "MPEG Packetized elementary stream packet",
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DecodeFn: pesPacketDecode,
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})
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}
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const (
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sequenceHeader = 0xb3
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packHeader = 0xba
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systemHeader = 0xbb
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privateStream1 = 0xbd
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)
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type subStreamPacket struct {
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number int
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buf []byte
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}
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var startAndStreamNames = scalar.URangeToScalar{
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{Range: [2]uint64{0x00, 0x00}, S: scalar.S{Sym: "picture"}},
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{Range: [2]uint64{0x01, 0xaf}, S: scalar.S{Sym: "slice"}},
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{Range: [2]uint64{0xb0, 0xb1}, S: scalar.S{Sym: "reserved"}},
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{Range: [2]uint64{0xb2, 0xb2}, S: scalar.S{Sym: "user_data"}},
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{Range: [2]uint64{0xb3, 0xb3}, S: scalar.S{Sym: "sequence_header"}},
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{Range: [2]uint64{0xb4, 0xb4}, S: scalar.S{Sym: "sequence_error"}},
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{Range: [2]uint64{0xb5, 0xb5}, S: scalar.S{Sym: "extension"}},
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{Range: [2]uint64{0xb6, 0xb6}, S: scalar.S{Sym: "reserved"}},
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{Range: [2]uint64{0xb7, 0xb7}, S: scalar.S{Sym: "sequence_end"}},
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{Range: [2]uint64{0xb8, 0xb8}, S: scalar.S{Sym: "group_of_pictures"}},
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{Range: [2]uint64{0xb9, 0xb9}, S: scalar.S{Sym: "program_end"}},
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{Range: [2]uint64{0xba, 0xba}, S: scalar.S{Sym: "pack_header"}},
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{Range: [2]uint64{0xbb, 0xbb}, S: scalar.S{Sym: "system_header"}},
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{Range: [2]uint64{0xbc, 0xbc}, S: scalar.S{Sym: "program_stream_map"}},
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{Range: [2]uint64{0xbd, 0xbd}, S: scalar.S{Sym: "private_stream1"}},
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{Range: [2]uint64{0xbe, 0xbe}, S: scalar.S{Sym: "padding_stream"}},
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{Range: [2]uint64{0xbf, 0xbf}, S: scalar.S{Sym: "private_stream2"}},
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{Range: [2]uint64{0xc0, 0xdf}, S: scalar.S{Sym: "audio_stream"}},
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{Range: [2]uint64{0xe0, 0xef}, S: scalar.S{Sym: "video_stream"}},
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{Range: [2]uint64{0xf0, 0xf0}, S: scalar.S{Sym: "ecm_stream"}},
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{Range: [2]uint64{0xf1, 0xf1}, S: scalar.S{Sym: "emm_stream"}},
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{Range: [2]uint64{0xf2, 0xf2}, S: scalar.S{Sym: "itu_t_rec_h_222_0"}},
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{Range: [2]uint64{0xf3, 0xf3}, S: scalar.S{Sym: "iso_iec_13522_stream"}},
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{Range: [2]uint64{0xf4, 0xf4}, S: scalar.S{Sym: "itu_t_rec_h_222_1_type_a"}},
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{Range: [2]uint64{0xf5, 0xf5}, S: scalar.S{Sym: "itu_t_rec_h_222_1_type_b"}},
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{Range: [2]uint64{0xf6, 0xf6}, S: scalar.S{Sym: "itu_t_rec_h_222_1_type_c"}},
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{Range: [2]uint64{0xf7, 0xf7}, S: scalar.S{Sym: "itu_t_rec_h_222_1_type_d"}},
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{Range: [2]uint64{0xf8, 0xf8}, S: scalar.S{Sym: "itu_t_rec_h_222_1_type_e"}},
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{Range: [2]uint64{0xf9, 0xf9}, S: scalar.S{Sym: "ancillary_stream"}},
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{Range: [2]uint64{0xfa, 0xfe}, S: scalar.S{Sym: "reserved"}},
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{Range: [2]uint64{0xff, 0xff}, S: scalar.S{Sym: "program_stream_directory"}},
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}
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var mpegVersion = scalar.UToDescription{
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0b01: "MPEG2",
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0b10: "MPEG1",
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}
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func pesPacketDecode(d *decode.D, in any) any {
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var v any
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d.FieldU24("prefix", d.AssertU(0b0000_0000_0000_0000_0000_0001), scalar.ActualBin)
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startCode := d.FieldU8("start_code", startAndStreamNames, scalar.ActualHex)
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switch {
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case startCode == sequenceHeader:
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d.FieldU12("horizontal_size")
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d.FieldU12("vertical_size")
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d.FieldU4("aspect_ratio")
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d.FieldU4("frame_rate_code")
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// TODO: bit rate * 400, rounded upwards. Use 0x3FFFF for variable bit rate
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d.FieldU18("bit_rate")
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d.FieldU1("marker_bit")
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d.FieldU10("vbv_buf_size")
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d.FieldU1("constrained_parameters_flag")
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loadIntraQuantizerMatrix := d.FieldBool("load_intra_quantizer_matrix")
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if loadIntraQuantizerMatrix {
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d.FieldRawLen("intra_quantizer_matrix", 8*64)
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}
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loadNonIntraQuantizerMatrix := d.FieldBool("load_non_intra_quantizer_matrix")
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if loadNonIntraQuantizerMatrix {
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d.FieldRawLen("non_intra_quantizer_matrix", 8*64)
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}
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case startCode == packHeader:
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isMPEG2 := d.PeekBits(2) == 0b01
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if isMPEG2 {
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d.FieldU2("marker_bits0", mpegVersion)
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} else {
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d.FieldU4("marker_bits0", mpegVersion)
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}
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scr0 := d.FieldU3("system_clock0")
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d.FieldU1("marker_bits1")
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scr1 := d.FieldU15("system_clock1")
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d.FieldU1("marker_bits2")
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scr2 := d.FieldU15("system_clock2")
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d.FieldU1("marker_bits3")
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if isMPEG2 {
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d.FieldU9("scr_ext")
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}
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d.FieldU1("marker_bits4")
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scr := scr0<<30 | scr1<<15 | scr2
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d.FieldValueU("scr", scr)
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d.FieldU22("mux_rate")
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d.FieldU1("marker_bits5")
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if isMPEG2 {
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d.FieldU1("marker_bits6")
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d.FieldU5("reserved")
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packStuffingLength := d.FieldU3("pack_stuffing_length")
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if packStuffingLength > 0 {
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d.FieldRawLen("stuffing", int64(packStuffingLength*8))
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}
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}
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case startCode == systemHeader:
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d.FieldU16("length")
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d.FieldU1("skip0")
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d.FieldU22("rate_bound")
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d.FieldU1("skip1")
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d.FieldU6("audio_bound")
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d.FieldU1("fixed_flag")
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d.FieldU1("csps_flag")
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d.FieldU1("system_audio_lock_flag")
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d.FieldU1("system_video_lock_flag")
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d.FieldU1("skip2")
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d.FieldU5("video_bound")
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d.FieldU1("packet_rate_restriction_flag")
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d.FieldU7("reserved")
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d.FieldArray("stream_bound_entries", func(d *decode.D) {
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for d.PeekBits(1) == 1 {
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d.FieldStruct("stream_bound_entry", func(d *decode.D) {
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d.FieldU8("stream_id")
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d.FieldU2("skip0")
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d.FieldU1("pstd_buffer_bound_scale")
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d.FieldU13("pstd_buffer_size_bound")
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})
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}
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})
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case startCode >= 0xbd:
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length := d.FieldU16("length")
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// 0xbd-0xbd // Privatestream1
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// 0xc0-0xdf // MPEG1OrMPEG2AudioStream
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// 0xe0-0xef // MPEG1OrMPEG2VideoStream
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hasExtension := startCode == 0xbd || (startCode >= 0xc0 && startCode <= 0xef)
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var headerDataLength uint64
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var extensionLength uint64
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if hasExtension {
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extensionLength = 3
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d.FieldStruct("extension", func(d *decode.D) {
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d.FieldU2("skip0")
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d.FieldU2("scramble_control")
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d.FieldU1("priority")
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d.FieldU1("data_alignment_indicator")
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d.FieldU1("copyright")
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d.FieldU1("original")
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d.FieldU2("pts_dts_flags")
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d.FieldU1("escr_flag")
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d.FieldU1("es_rate_flag")
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d.FieldU1("dsm_trick_mode_flag")
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d.FieldU1("additional_copy_info_flag")
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d.FieldU1("pes_crc_flag")
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d.FieldU1("pes_ext_flag")
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headerDataLength = d.FieldU8("header_data_length")
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})
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// TODO:
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d.FieldRawLen("header_data", int64(headerDataLength)*8)
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}
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dataLen := int64(length-headerDataLength-extensionLength) * 8
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switch startCode {
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case privateStream1:
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d.FieldStruct("data", func(d *decode.D) {
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d.FramedFn(dataLen, func(d *decode.D) {
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substreamNumber := d.FieldU8("substream")
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substreamBR := d.FieldRawLen("data", dataLen-8)
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v = subStreamPacket{
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number: int(substreamNumber),
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buf: d.ReadAllBits(substreamBR),
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}
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})
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})
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default:
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d.FieldRawLen("data", dataLen)
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}
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default:
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d.FieldRawLen("data", d.BitsLeft())
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}
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return v
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}
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